From patchwork Fri Oct 27 18:21:43 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 13438862 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7C58B3C084 for ; Fri, 27 Oct 2023 18:22:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="s0jU3Rgp" Received: from mail-pl1-x649.google.com (mail-pl1-x649.google.com [IPv6:2607:f8b0:4864:20::649]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2BAF3196 for ; Fri, 27 Oct 2023 11:22:28 -0700 (PDT) Received: by mail-pl1-x649.google.com with SMTP id d9443c01a7336-1cc23f2226bso7015925ad.2 for ; Fri, 27 Oct 2023 11:22:28 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1698430947; x=1699035747; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:from:to:cc:subject:date:message-id:reply-to; bh=ySJgJVuGTMb9d8TKULAih8JyrrSd4YVeUb9Jc+6kES0=; b=s0jU3Rgpw7Sefpwq7Aoxxr4+RVgqsmAczpwZnarGUs2RS98QnByA3C5i80GMz3YEhY qS12VS7IWyeVBLqP9Zdvj6K1vZ+UU4LHH/sxr+jOHxQfwMj0OSmYJSwNa1BH601Rtpj1 riFTpK8dqTlZY0liKk4y7VyhLvbhwrePGU8EclNb93exDl//evBoAzVdKQetLr8+j7BZ uSlfO+A9jXtDULNLK/XgmIT5zz+u7iSzKIzKEwi73cdyE9FsQj2SbIll4EPvpvGFMq3q kHOrLt/1QQAzqW6fwLU4b6nHJnpPaACtmwLFqbRQ4nc3Il3U4UYbke0V5OCgZgqxrnUU r/rA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1698430947; x=1699035747; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=ySJgJVuGTMb9d8TKULAih8JyrrSd4YVeUb9Jc+6kES0=; b=r7XRuuWFAZ6q+P/Or5oQDNfu+Hz0EE2lDHSa+OZJ4DX2dezonoBQcpqEbtB5iTjJZk 501FJoLwMC3ZhxmPLctE53k1LTBvN0DEqDg2fAKM+fqqHnx+6rTf494L44xCBXqHC7YX oxvC8By5XRXa7BoBoMBRIvxA6Xdr+yEe5JP8DjEy0VOEMCCIRToSjKYqyj9oj2TdjEC7 KRrm2vFEvfASjKjw1cb/UGjJsPFTIiUW9S5ApucQRZXn2x9eeLCVRTl6T2iLnEViuEtX /O9FEhzJmwYHrROAWPc3VR/cKtPyDi2/uBDMUImzfj3yrqXlMudjpa57tFuxhMxdRKCG ch1A== X-Gm-Message-State: AOJu0YxovfTd9dz5ENZbNho1glL0v5aiDOmfcoaJs7SCGmxVaduThCO3 QPl/Lx820BqhqKtKirngpeJnS6D5+RY= X-Google-Smtp-Source: AGHT+IEjsuFrlNkUUm601K8PUP+r8R6hCJNbQUJrGpc/pHCXTUzh4iBnaMaTICwCQxjFnojaM1raJDMMRNs= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a17:902:ac8e:b0:1cc:30cf:eae6 with SMTP id h14-20020a170902ac8e00b001cc30cfeae6mr955plr.10.1698430947671; Fri, 27 Oct 2023 11:22:27 -0700 (PDT) Reply-To: Sean Christopherson Date: Fri, 27 Oct 2023 11:21:43 -0700 In-Reply-To: <20231027182217.3615211-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20231027182217.3615211-1-seanjc@google.com> X-Mailer: git-send-email 2.42.0.820.g83a721a137-goog Message-ID: <20231027182217.3615211-2-seanjc@google.com> Subject: [PATCH v13 01/35] KVM: Tweak kvm_hva_range and hva_handler_t to allow reusing for gfn ranges From: Sean Christopherson To: Paolo Bonzini , Marc Zyngier , Oliver Upton , Huacai Chen , Michael Ellerman , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Sean Christopherson , Alexander Viro , Christian Brauner , "Matthew Wilcox (Oracle)" , Andrew Morton Cc: kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Xiaoyao Li , Xu Yilun , Chao Peng , Fuad Tabba , Jarkko Sakkinen , Anish Moorthy , David Matlack , Yu Zhang , Isaku Yamahata , " =?utf-8?q?Micka=C3=ABl_Sala?= =?utf-8?q?=C3=BCn?= " , Vlastimil Babka , Vishal Annapurve , Ackerley Tng , Maciej Szmigiero , David Hildenbrand , Quentin Perret , Michael Roth , Wang , Liam Merwick , Isaku Yamahata , "Kirill A . Shutemov" Rework and rename "struct kvm_hva_range" into "kvm_mmu_notifier_range" so that the structure can be used to handle notifications that operate on gfn context, i.e. that aren't tied to a host virtual address. Rename the handler typedef too (arguably it should always have been gfn_handler_t). Practically speaking, this is a nop for 64-bit kernels as the only meaningful change is to store start+end as u64s instead of unsigned longs. Reviewed-by: Paolo Bonzini Reviewed-by: Xiaoyao Li Signed-off-by: Sean Christopherson Reviewed-by: Fuad Tabba Tested-by: Fuad Tabba --- virt/kvm/kvm_main.c | 34 +++++++++++++++++++--------------- 1 file changed, 19 insertions(+), 15 deletions(-) diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 486800a7024b..0524933856d4 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -541,18 +541,22 @@ static inline struct kvm *mmu_notifier_to_kvm(struct mmu_notifier *mn) return container_of(mn, struct kvm, mmu_notifier); } -typedef bool (*hva_handler_t)(struct kvm *kvm, struct kvm_gfn_range *range); +typedef bool (*gfn_handler_t)(struct kvm *kvm, struct kvm_gfn_range *range); typedef void (*on_lock_fn_t)(struct kvm *kvm, unsigned long start, unsigned long end); typedef void (*on_unlock_fn_t)(struct kvm *kvm); -struct kvm_hva_range { - unsigned long start; - unsigned long end; +struct kvm_mmu_notifier_range { + /* + * 64-bit addresses, as KVM notifiers can operate on host virtual + * addresses (unsigned long) and guest physical addresses (64-bit). + */ + u64 start; + u64 end; union kvm_mmu_notifier_arg arg; - hva_handler_t handler; + gfn_handler_t handler; on_lock_fn_t on_lock; on_unlock_fn_t on_unlock; bool flush_on_ret; @@ -581,7 +585,7 @@ static const union kvm_mmu_notifier_arg KVM_MMU_NOTIFIER_NO_ARG; node = interval_tree_iter_next(node, start, last)) \ static __always_inline int __kvm_handle_hva_range(struct kvm *kvm, - const struct kvm_hva_range *range) + const struct kvm_mmu_notifier_range *range) { bool ret = false, locked = false; struct kvm_gfn_range gfn_range; @@ -608,9 +612,9 @@ static __always_inline int __kvm_handle_hva_range(struct kvm *kvm, unsigned long hva_start, hva_end; slot = container_of(node, struct kvm_memory_slot, hva_node[slots->node_idx]); - hva_start = max(range->start, slot->userspace_addr); - hva_end = min(range->end, slot->userspace_addr + - (slot->npages << PAGE_SHIFT)); + hva_start = max_t(unsigned long, range->start, slot->userspace_addr); + hva_end = min_t(unsigned long, range->end, + slot->userspace_addr + (slot->npages << PAGE_SHIFT)); /* * To optimize for the likely case where the address @@ -660,10 +664,10 @@ static __always_inline int kvm_handle_hva_range(struct mmu_notifier *mn, unsigned long start, unsigned long end, union kvm_mmu_notifier_arg arg, - hva_handler_t handler) + gfn_handler_t handler) { struct kvm *kvm = mmu_notifier_to_kvm(mn); - const struct kvm_hva_range range = { + const struct kvm_mmu_notifier_range range = { .start = start, .end = end, .arg = arg, @@ -680,10 +684,10 @@ static __always_inline int kvm_handle_hva_range(struct mmu_notifier *mn, static __always_inline int kvm_handle_hva_range_no_flush(struct mmu_notifier *mn, unsigned long start, unsigned long end, - hva_handler_t handler) + gfn_handler_t handler) { struct kvm *kvm = mmu_notifier_to_kvm(mn); - const struct kvm_hva_range range = { + const struct kvm_mmu_notifier_range range = { .start = start, .end = end, .handler = handler, @@ -771,7 +775,7 @@ static int kvm_mmu_notifier_invalidate_range_start(struct mmu_notifier *mn, const struct mmu_notifier_range *range) { struct kvm *kvm = mmu_notifier_to_kvm(mn); - const struct kvm_hva_range hva_range = { + const struct kvm_mmu_notifier_range hva_range = { .start = range->start, .end = range->end, .handler = kvm_unmap_gfn_range, @@ -835,7 +839,7 @@ static void kvm_mmu_notifier_invalidate_range_end(struct mmu_notifier *mn, const struct mmu_notifier_range *range) { struct kvm *kvm = mmu_notifier_to_kvm(mn); - const struct kvm_hva_range hva_range = { + const struct kvm_mmu_notifier_range hva_range = { .start = range->start, .end = range->end, .handler = (void *)kvm_null_fn, From patchwork Fri Oct 27 18:21:44 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 13438864 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EC1293C698 for ; Fri, 27 Oct 2023 18:22:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; 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Fri, 27 Oct 2023 11:22:29 -0700 (PDT) Reply-To: Sean Christopherson Date: Fri, 27 Oct 2023 11:21:44 -0700 In-Reply-To: <20231027182217.3615211-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20231027182217.3615211-1-seanjc@google.com> X-Mailer: git-send-email 2.42.0.820.g83a721a137-goog Message-ID: <20231027182217.3615211-3-seanjc@google.com> Subject: [PATCH v13 02/35] KVM: Assert that mmu_invalidate_in_progress *never* goes negative From: Sean Christopherson To: Paolo Bonzini , Marc Zyngier , Oliver Upton , Huacai Chen , Michael Ellerman , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Sean Christopherson , Alexander Viro , Christian Brauner , "Matthew Wilcox (Oracle)" , Andrew Morton Cc: kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Xiaoyao Li , Xu Yilun , Chao Peng , Fuad Tabba , Jarkko Sakkinen , Anish Moorthy , David Matlack , Yu Zhang , Isaku Yamahata , " =?utf-8?q?Micka=C3=ABl_Sala?= =?utf-8?q?=C3=BCn?= " , Vlastimil Babka , Vishal Annapurve , Ackerley Tng , Maciej Szmigiero , David Hildenbrand , Quentin Perret , Michael Roth , Wang , Liam Merwick , Isaku Yamahata , "Kirill A . Shutemov" Move the assertion on the in-progress invalidation count from the primary MMU's notifier path to KVM's common notification path, i.e. assert that the count doesn't go negative even when the invalidation is coming from KVM itself. Opportunistically convert the assertion to a KVM_BUG_ON(), i.e. kill only the affected VM, not the entire kernel. A corrupted count is fatal to the VM, e.g. the non-zero (negative) count will cause mmu_invalidate_retry() to block any and all attempts to install new mappings. But it's far from guaranteed that an end() without a start() is fatal or even problematic to anything other than the target VM, e.g. the underlying bug could simply be a duplicate call to end(). And it's much more likely that a missed invalidation, i.e. a potential use-after-free, would manifest as no notification whatsoever, not an end() without a start(). Signed-off-by: Sean Christopherson Reviewed-by: Paolo Bonzini Reviewed-by: Fuad Tabba Tested-by: Fuad Tabba --- virt/kvm/kvm_main.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 0524933856d4..5a97e6c7d9c2 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -833,6 +833,7 @@ void kvm_mmu_invalidate_end(struct kvm *kvm, unsigned long start, * in conjunction with the smp_rmb in mmu_invalidate_retry(). */ kvm->mmu_invalidate_in_progress--; + KVM_BUG_ON(kvm->mmu_invalidate_in_progress < 0, kvm); } static void kvm_mmu_notifier_invalidate_range_end(struct mmu_notifier *mn, @@ -863,8 +864,6 @@ static void kvm_mmu_notifier_invalidate_range_end(struct mmu_notifier *mn, */ if (wake) rcuwait_wake_up(&kvm->mn_memslots_update_rcuwait); - - BUG_ON(kvm->mmu_invalidate_in_progress < 0); } static int kvm_mmu_notifier_clear_flush_young(struct mmu_notifier *mn, From patchwork Fri Oct 27 18:21:45 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 13438866 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6BEED3C09E for ; 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Fri, 27 Oct 2023 11:22:31 -0700 (PDT) Reply-To: Sean Christopherson Date: Fri, 27 Oct 2023 11:21:45 -0700 In-Reply-To: <20231027182217.3615211-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20231027182217.3615211-1-seanjc@google.com> X-Mailer: git-send-email 2.42.0.820.g83a721a137-goog Message-ID: <20231027182217.3615211-4-seanjc@google.com> Subject: [PATCH v13 03/35] KVM: Use gfn instead of hva for mmu_notifier_retry From: Sean Christopherson To: Paolo Bonzini , Marc Zyngier , Oliver Upton , Huacai Chen , Michael Ellerman , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Sean Christopherson , Alexander Viro , Christian Brauner , "Matthew Wilcox (Oracle)" , Andrew Morton Cc: kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Xiaoyao Li , Xu Yilun , Chao Peng , Fuad Tabba , Jarkko Sakkinen , Anish Moorthy , David Matlack , Yu Zhang , Isaku Yamahata , " =?utf-8?q?Micka=C3=ABl_Sala?= =?utf-8?q?=C3=BCn?= " , Vlastimil Babka , Vishal Annapurve , Ackerley Tng , Maciej Szmigiero , David Hildenbrand , Quentin Perret , Michael Roth , Wang , Liam Merwick , Isaku Yamahata , "Kirill A . Shutemov" From: Chao Peng Currently in mmu_notifier invalidate path, hva range is recorded and then checked against by mmu_notifier_retry_hva() in the page fault handling path. However, for the to be introduced private memory, a page fault may not have a hva associated, checking gfn(gpa) makes more sense. For existing hva based shared memory, gfn is expected to also work. The only downside is when aliasing multiple gfns to a single hva, the current algorithm of checking multiple ranges could result in a much larger range being rejected. Such aliasing should be uncommon, so the impact is expected small. Suggested-by: Sean Christopherson Cc: Xu Yilun Signed-off-by: Chao Peng Reviewed-by: Fuad Tabba Tested-by: Fuad Tabba [sean: convert vmx_set_apic_access_page_addr() to gfn-based API] Signed-off-by: Sean Christopherson Reviewed-by: Paolo Bonzini --- arch/x86/kvm/mmu/mmu.c | 10 ++++++---- arch/x86/kvm/vmx/vmx.c | 11 +++++------ include/linux/kvm_host.h | 33 ++++++++++++++++++++------------ virt/kvm/kvm_main.c | 41 +++++++++++++++++++++++++++++++--------- 4 files changed, 64 insertions(+), 31 deletions(-) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index f7901cb4d2fa..d33657d61d80 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -3056,7 +3056,7 @@ static void direct_pte_prefetch(struct kvm_vcpu *vcpu, u64 *sptep) * * There are several ways to safely use this helper: * - * - Check mmu_invalidate_retry_hva() after grabbing the mapping level, before + * - Check mmu_invalidate_retry_gfn() after grabbing the mapping level, before * consuming it. In this case, mmu_lock doesn't need to be held during the * lookup, but it does need to be held while checking the MMU notifier. * @@ -4358,7 +4358,7 @@ static bool is_page_fault_stale(struct kvm_vcpu *vcpu, return true; return fault->slot && - mmu_invalidate_retry_hva(vcpu->kvm, fault->mmu_seq, fault->hva); + mmu_invalidate_retry_gfn(vcpu->kvm, fault->mmu_seq, fault->gfn); } static int direct_page_fault(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault) @@ -6245,7 +6245,9 @@ void kvm_zap_gfn_range(struct kvm *kvm, gfn_t gfn_start, gfn_t gfn_end) write_lock(&kvm->mmu_lock); - kvm_mmu_invalidate_begin(kvm, 0, -1ul); + kvm_mmu_invalidate_begin(kvm); + + kvm_mmu_invalidate_range_add(kvm, gfn_start, gfn_end); flush = kvm_rmap_zap_gfn_range(kvm, gfn_start, gfn_end); @@ -6255,7 +6257,7 @@ void kvm_zap_gfn_range(struct kvm *kvm, gfn_t gfn_start, gfn_t gfn_end) if (flush) kvm_flush_remote_tlbs_range(kvm, gfn_start, gfn_end - gfn_start); - kvm_mmu_invalidate_end(kvm, 0, -1ul); + kvm_mmu_invalidate_end(kvm); write_unlock(&kvm->mmu_lock); } diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 72e3943f3693..6e502ba93141 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -6757,10 +6757,10 @@ static void vmx_set_apic_access_page_addr(struct kvm_vcpu *vcpu) return; /* - * Grab the memslot so that the hva lookup for the mmu_notifier retry - * is guaranteed to use the same memslot as the pfn lookup, i.e. rely - * on the pfn lookup's validation of the memslot to ensure a valid hva - * is used for the retry check. + * Explicitly grab the memslot using KVM's internal slot ID to ensure + * KVM doesn't unintentionally grab a userspace memslot. It _should_ + * be impossible for userspace to create a memslot for the APIC when + * APICv is enabled, but paranoia won't hurt in this case. */ slot = id_to_memslot(slots, APIC_ACCESS_PAGE_PRIVATE_MEMSLOT); if (!slot || slot->flags & KVM_MEMSLOT_INVALID) @@ -6785,8 +6785,7 @@ static void vmx_set_apic_access_page_addr(struct kvm_vcpu *vcpu) return; read_lock(&vcpu->kvm->mmu_lock); - if (mmu_invalidate_retry_hva(kvm, mmu_seq, - gfn_to_hva_memslot(slot, gfn))) { + if (mmu_invalidate_retry_gfn(kvm, mmu_seq, gfn)) { kvm_make_request(KVM_REQ_APIC_PAGE_RELOAD, vcpu); read_unlock(&vcpu->kvm->mmu_lock); goto out; diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index fb6c6109fdca..11d091688346 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -787,8 +787,8 @@ struct kvm { struct mmu_notifier mmu_notifier; unsigned long mmu_invalidate_seq; long mmu_invalidate_in_progress; - unsigned long mmu_invalidate_range_start; - unsigned long mmu_invalidate_range_end; + gfn_t mmu_invalidate_range_start; + gfn_t mmu_invalidate_range_end; #endif struct list_head devices; u64 manual_dirty_log_protect; @@ -1392,10 +1392,9 @@ void kvm_mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc); void *kvm_mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc); #endif -void kvm_mmu_invalidate_begin(struct kvm *kvm, unsigned long start, - unsigned long end); -void kvm_mmu_invalidate_end(struct kvm *kvm, unsigned long start, - unsigned long end); +void kvm_mmu_invalidate_begin(struct kvm *kvm); +void kvm_mmu_invalidate_range_add(struct kvm *kvm, gfn_t start, gfn_t end); +void kvm_mmu_invalidate_end(struct kvm *kvm); long kvm_arch_dev_ioctl(struct file *filp, unsigned int ioctl, unsigned long arg); @@ -1970,9 +1969,9 @@ static inline int mmu_invalidate_retry(struct kvm *kvm, unsigned long mmu_seq) return 0; } -static inline int mmu_invalidate_retry_hva(struct kvm *kvm, +static inline int mmu_invalidate_retry_gfn(struct kvm *kvm, unsigned long mmu_seq, - unsigned long hva) + gfn_t gfn) { lockdep_assert_held(&kvm->mmu_lock); /* @@ -1981,10 +1980,20 @@ static inline int mmu_invalidate_retry_hva(struct kvm *kvm, * that might be being invalidated. Note that it may include some false * positives, due to shortcuts when handing concurrent invalidations. */ - if (unlikely(kvm->mmu_invalidate_in_progress) && - hva >= kvm->mmu_invalidate_range_start && - hva < kvm->mmu_invalidate_range_end) - return 1; + if (unlikely(kvm->mmu_invalidate_in_progress)) { + /* + * Dropping mmu_lock after bumping mmu_invalidate_in_progress + * but before updating the range is a KVM bug. + */ + if (WARN_ON_ONCE(kvm->mmu_invalidate_range_start == INVALID_GPA || + kvm->mmu_invalidate_range_end == INVALID_GPA)) + return 1; + + if (gfn >= kvm->mmu_invalidate_range_start && + gfn < kvm->mmu_invalidate_range_end) + return 1; + } + if (kvm->mmu_invalidate_seq != mmu_seq) return 1; return 0; diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 5a97e6c7d9c2..1a577a25de47 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -543,9 +543,7 @@ static inline struct kvm *mmu_notifier_to_kvm(struct mmu_notifier *mn) typedef bool (*gfn_handler_t)(struct kvm *kvm, struct kvm_gfn_range *range); -typedef void (*on_lock_fn_t)(struct kvm *kvm, unsigned long start, - unsigned long end); - +typedef void (*on_lock_fn_t)(struct kvm *kvm); typedef void (*on_unlock_fn_t)(struct kvm *kvm); struct kvm_mmu_notifier_range { @@ -637,7 +635,8 @@ static __always_inline int __kvm_handle_hva_range(struct kvm *kvm, locked = true; KVM_MMU_LOCK(kvm); if (!IS_KVM_NULL_FN(range->on_lock)) - range->on_lock(kvm, range->start, range->end); + range->on_lock(kvm); + if (IS_KVM_NULL_FN(range->handler)) break; } @@ -742,16 +741,29 @@ static void kvm_mmu_notifier_change_pte(struct mmu_notifier *mn, kvm_handle_hva_range(mn, address, address + 1, arg, kvm_change_spte_gfn); } -void kvm_mmu_invalidate_begin(struct kvm *kvm, unsigned long start, - unsigned long end) +void kvm_mmu_invalidate_begin(struct kvm *kvm) { + lockdep_assert_held_write(&kvm->mmu_lock); /* * The count increase must become visible at unlock time as no * spte can be established without taking the mmu_lock and * count is also read inside the mmu_lock critical section. */ kvm->mmu_invalidate_in_progress++; + if (likely(kvm->mmu_invalidate_in_progress == 1)) { + kvm->mmu_invalidate_range_start = INVALID_GPA; + kvm->mmu_invalidate_range_end = INVALID_GPA; + } +} + +void kvm_mmu_invalidate_range_add(struct kvm *kvm, gfn_t start, gfn_t end) +{ + lockdep_assert_held_write(&kvm->mmu_lock); + + WARN_ON_ONCE(!kvm->mmu_invalidate_in_progress); + + if (likely(kvm->mmu_invalidate_range_start == INVALID_GPA)) { kvm->mmu_invalidate_range_start = start; kvm->mmu_invalidate_range_end = end; } else { @@ -771,6 +783,12 @@ void kvm_mmu_invalidate_begin(struct kvm *kvm, unsigned long start, } } +static bool kvm_mmu_unmap_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range) +{ + kvm_mmu_invalidate_range_add(kvm, range->start, range->end); + return kvm_unmap_gfn_range(kvm, range); +} + static int kvm_mmu_notifier_invalidate_range_start(struct mmu_notifier *mn, const struct mmu_notifier_range *range) { @@ -778,7 +796,7 @@ static int kvm_mmu_notifier_invalidate_range_start(struct mmu_notifier *mn, const struct kvm_mmu_notifier_range hva_range = { .start = range->start, .end = range->end, - .handler = kvm_unmap_gfn_range, + .handler = kvm_mmu_unmap_gfn_range, .on_lock = kvm_mmu_invalidate_begin, .on_unlock = kvm_arch_guest_memory_reclaimed, .flush_on_ret = true, @@ -817,8 +835,7 @@ static int kvm_mmu_notifier_invalidate_range_start(struct mmu_notifier *mn, return 0; } -void kvm_mmu_invalidate_end(struct kvm *kvm, unsigned long start, - unsigned long end) +void kvm_mmu_invalidate_end(struct kvm *kvm) { /* * This sequence increase will notify the kvm page fault that @@ -834,6 +851,12 @@ void kvm_mmu_invalidate_end(struct kvm *kvm, unsigned long start, */ kvm->mmu_invalidate_in_progress--; KVM_BUG_ON(kvm->mmu_invalidate_in_progress < 0, kvm); + + /* + * Assert that at least one range was added between start() and end(). + * Not adding a range isn't fatal, but it is a KVM bug. + */ + WARN_ON_ONCE(kvm->mmu_invalidate_range_start == INVALID_GPA); } static void kvm_mmu_notifier_invalidate_range_end(struct mmu_notifier *mn, From patchwork Fri Oct 27 18:21:46 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 13438865 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 366A83C08B for ; 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Fri, 27 Oct 2023 11:22:33 -0700 (PDT) Reply-To: Sean Christopherson Date: Fri, 27 Oct 2023 11:21:46 -0700 In-Reply-To: <20231027182217.3615211-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20231027182217.3615211-1-seanjc@google.com> X-Mailer: git-send-email 2.42.0.820.g83a721a137-goog Message-ID: <20231027182217.3615211-5-seanjc@google.com> Subject: [PATCH v13 04/35] KVM: WARN if there are dangling MMU invalidations at VM destruction From: Sean Christopherson To: Paolo Bonzini , Marc Zyngier , Oliver Upton , Huacai Chen , Michael Ellerman , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Sean Christopherson , Alexander Viro , Christian Brauner , "Matthew Wilcox (Oracle)" , Andrew Morton Cc: kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Xiaoyao Li , Xu Yilun , Chao Peng , Fuad Tabba , Jarkko Sakkinen , Anish Moorthy , David Matlack , Yu Zhang , Isaku Yamahata , " =?utf-8?q?Micka=C3=ABl_Sala?= =?utf-8?q?=C3=BCn?= " , Vlastimil Babka , Vishal Annapurve , Ackerley Tng , Maciej Szmigiero , David Hildenbrand , Quentin Perret , Michael Roth , Wang , Liam Merwick , Isaku Yamahata , "Kirill A . Shutemov" Add an assertion that there are no in-progress MMU invalidations when a VM is being destroyed, with the exception of the scenario where KVM unregisters its MMU notifier between an .invalidate_range_start() call and the corresponding .invalidate_range_end(). KVM can't detect unpaired calls from the mmu_notifier due to the above exception waiver, but the assertion can detect KVM bugs, e.g. such as the bug that *almost* escaped initial guest_memfd development. Link: https://lore.kernel.org/all/e397d30c-c6af-e68f-d18e-b4e3739c5389@linux.intel.com Signed-off-by: Sean Christopherson Reviewed-by: Paolo Bonzini Reviewed-by: Fuad Tabba Tested-by: Fuad Tabba --- virt/kvm/kvm_main.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 1a577a25de47..4dba682586ee 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -1356,9 +1356,16 @@ static void kvm_destroy_vm(struct kvm *kvm) * No threads can be waiting in kvm_swap_active_memslots() as the * last reference on KVM has been dropped, but freeing * memslots would deadlock without this manual intervention. + * + * If the count isn't unbalanced, i.e. KVM did NOT unregister its MMU + * notifier between a start() and end(), then there shouldn't be any + * in-progress invalidations. */ WARN_ON(rcuwait_active(&kvm->mn_memslots_update_rcuwait)); - kvm->mn_active_invalidate_count = 0; + if (kvm->mn_active_invalidate_count) + kvm->mn_active_invalidate_count = 0; + else + WARN_ON(kvm->mmu_invalidate_in_progress); #else kvm_flush_shadow_all(kvm); #endif From patchwork Fri Oct 27 18:21:47 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 13438867 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 631243C086 for ; Fri, 27 Oct 2023 18:22:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="siqQ9m0B" Received: from mail-pl1-x64a.google.com (mail-pl1-x64a.google.com [IPv6:2607:f8b0:4864:20::64a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 306EE1B6 for ; Fri, 27 Oct 2023 11:22:36 -0700 (PDT) Received: by mail-pl1-x64a.google.com with SMTP id d9443c01a7336-1cc20955634so8186915ad.3 for ; Fri, 27 Oct 2023 11:22:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1698430955; x=1699035755; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:from:to:cc:subject:date:message-id:reply-to; bh=JgU06SXMv6nm3bYLetCIh2Atkw0AeiFtLr3TWBcGDvg=; b=siqQ9m0B9m40Qs7PaCCnI/qS3fb1gku1RkXCkFjHYwI695lydFEzhsJcEwBrjmwFpF IWagKZp3oqCf1sQ0d00aRsezW1on4j+vUKS0GoMckHY5laTg/4r4A8lD67Ox9ovxMl51 oyDooZIHskjXtEE71IOIYGISQluIafOLvjb2Y3mWT5b7ufKS7Z0VSXpgiiLGchattunq SC41iGTcZC/QXcObDgLcvbswqbZYHQAeO9Mb8Oxi2Dk+c0R0u3Q/7dpu8D1Elz9/QUVJ s5oUXolbLZekpH2blov4AhJvHwV/6uKGdHfDAnFita7fVdl6IrUW5oZBVn2dVerunUdV wLdw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1698430955; x=1699035755; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=JgU06SXMv6nm3bYLetCIh2Atkw0AeiFtLr3TWBcGDvg=; b=ki5iBhVInYEM+RKk/rXvYwF3VJt4Umu2x7CDubf7gRNsvblw3DDf2cOxMbIYVnKyHG eCuE5Rkm1vnIhS1EHCAMNiIXJuWdMecZYvkuIYMXJH1lA7Hbb5SZDHKdFWSRDSvnH8eq blj6KsGXrOuewNA1wl5J0SDPcrmSUkDrm3iR1EtN9kGRSrg85l1emdlBvj6rhnewLyhO IurS/sr35BaduL3K6nTAS3lbK/2J6Nl/gPZ+pPfwjJexwtelmCMUTsVgSBwCKyM9VHdx upKaOOQYiAQx1ejs0iuVAmHnFCyDsZeRcauhrC+wddVRGwneYetxazpW+eaG2RT8QARE vMCg== X-Gm-Message-State: AOJu0YxLVqfBos/9Sda/2WoxB+BaT8w5WPGTomn77rlfC5md2JMpQIWh XAlfLu3njDu6ADYpnmmUO8Pw6TnuSyg= X-Google-Smtp-Source: AGHT+IGtvUvxtvF0vLnhcz0wuwQy/3Gylfgr5sP9pToido+ZyPcnNi9qskOerQDKma1HuMTn89KXKiciq2s= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a17:902:c144:b0:1cc:281a:8463 with SMTP id 4-20020a170902c14400b001cc281a8463mr32525plj.7.1698430955693; Fri, 27 Oct 2023 11:22:35 -0700 (PDT) Reply-To: Sean Christopherson Date: Fri, 27 Oct 2023 11:21:47 -0700 In-Reply-To: <20231027182217.3615211-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20231027182217.3615211-1-seanjc@google.com> X-Mailer: git-send-email 2.42.0.820.g83a721a137-goog Message-ID: <20231027182217.3615211-6-seanjc@google.com> Subject: [PATCH v13 05/35] KVM: PPC: Drop dead code related to KVM_ARCH_WANT_MMU_NOTIFIER From: Sean Christopherson To: Paolo Bonzini , Marc Zyngier , Oliver Upton , Huacai Chen , Michael Ellerman , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Sean Christopherson , Alexander Viro , Christian Brauner , "Matthew Wilcox (Oracle)" , Andrew Morton Cc: kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Xiaoyao Li , Xu Yilun , Chao Peng , Fuad Tabba , Jarkko Sakkinen , Anish Moorthy , David Matlack , Yu Zhang , Isaku Yamahata , " =?utf-8?q?Micka=C3=ABl_Sala?= =?utf-8?q?=C3=BCn?= " , Vlastimil Babka , Vishal Annapurve , Ackerley Tng , Maciej Szmigiero , David Hildenbrand , Quentin Perret , Michael Roth , Wang , Liam Merwick , Isaku Yamahata , "Kirill A . Shutemov" Assert that both KVM_ARCH_WANT_MMU_NOTIFIER and CONFIG_MMU_NOTIFIER are defined when KVM is enabled, and return '1' unconditionally for the CONFIG_KVM_BOOK3S_HV_POSSIBLE=n path. All flavors of PPC support for KVM select MMU_NOTIFIER, and KVM_ARCH_WANT_MMU_NOTIFIER is unconditionally defined by arch/powerpc/include/asm/kvm_host.h. Effectively dropping use of KVM_ARCH_WANT_MMU_NOTIFIER will simplify a future cleanup to turn KVM_ARCH_WANT_MMU_NOTIFIER into a Kconfig, i.e. will allow combining all of the #if defined(CONFIG_MMU_NOTIFIER) && defined(KVM_ARCH_WANT_MMU_NOTIFIER) checks into a single #ifdef CONFIG_KVM_GENERIC_MMU_NOTIFIER without having to worry about PPC's "bare" usage of KVM_ARCH_WANT_MMU_NOTIFIER. Signed-off-by: Sean Christopherson Reviewed-by: Paolo Bonzini Reviewed-by: Fuad Tabba --- arch/powerpc/kvm/powerpc.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c index 7197c8256668..b0a512ede764 100644 --- a/arch/powerpc/kvm/powerpc.c +++ b/arch/powerpc/kvm/powerpc.c @@ -632,12 +632,13 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) break; #endif case KVM_CAP_SYNC_MMU: +#if !defined(CONFIG_MMU_NOTIFIER) || !defined(KVM_ARCH_WANT_MMU_NOTIFIER) + BUILD_BUG(); +#endif #ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE r = hv_enabled; -#elif defined(KVM_ARCH_WANT_MMU_NOTIFIER) - r = 1; #else - r = 0; + r = 1; #endif break; #ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE From patchwork Fri Oct 27 18:21:48 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 13438868 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B33313D968 for ; Fri, 27 Oct 2023 18:22:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="0U1zSTSj" Received: from mail-pl1-x649.google.com (mail-pl1-x649.google.com [IPv6:2607:f8b0:4864:20::649]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F2112D45 for ; Fri, 27 Oct 2023 11:22:37 -0700 (PDT) Received: by mail-pl1-x649.google.com with SMTP id d9443c01a7336-1c9d140fcddso23365175ad.1 for ; Fri, 27 Oct 2023 11:22:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1698430957; x=1699035757; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:from:to:cc:subject:date:message-id:reply-to; bh=srqr8yeDZlFrvxNrVECKE5xxuDvV2cb3J0BOKhehVs4=; b=0U1zSTSjnA3BRqEUsHqQ22gj/v+L0Zoy521THY4PBak+iDWT10zt5AKWMazO6galHQ U9MgstUWrVea2OJPPklBLMEOedu4md8jhyAnAb3fkx1Btm2UvqMz52WOKhIKjerUzFH/ EbIHiAeDlUejd0qX5hJpeOX0Sw//UZLki0+o9owPDvyejNmO+buU3e4WZ2ej2RyolcMb DTKC2FItAczUC+gTOifCKo0+jD2aE4Y5PHzHksb94Vzyayf0HrecBtPy0ALIdRGvtkyk oxZMV2LjEMy3Rvvp4lOLmpdIX0UFyfnD5X6RUhN4zE8mS0mnSVSh24TQ2v8r5fbkipSs 1+OA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1698430957; x=1699035757; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=srqr8yeDZlFrvxNrVECKE5xxuDvV2cb3J0BOKhehVs4=; b=R07P4OoEk0u8xfiGRcfbnojanB4aUJ3pnkTgrim6krktC042FdV8G9dMhyQ1dDoKrp j4cikXYB73eCTWR+OD7FYjVyPpRnCFKTU9Ol2otSo+QvpizZMUawutwHkMIeWWNjFaV7 3NXkB32vPY4SSBUNph/aBveHUXPp9+/NPTKZWGttc9S21aQbEDGUJ35042afQvIRMHeS q+NNAaW55HJxO+RgQNAk0Ck9P7kMXl+RrzZNb5keA5pO/8QNFI0oBwzh7BEwkTvTSr5e nDDFeOwxWvy7rco9YvCI3tokTlTRG3Y1cPqxKe0lxClIlDkGGBraNbyhINoCSX0jzNoy W7uw== X-Gm-Message-State: AOJu0YxCiql8mpcmdpqI2BwrF19aWZCSnH0DOdocJIWluhIGhJah0eql im8xC2aqls5fCP5/EyCnAMUO1eOjIkM= X-Google-Smtp-Source: AGHT+IEgJpE7SXSukSyCmrL3MrLSyvY8980C5XITIQh/pYBdmOorR/VvmfyRxJnTS7i/xC9oBoneiM7iOr4= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a17:903:446:b0:1ca:2620:78ad with SMTP id iw6-20020a170903044600b001ca262078admr60815plb.8.1698430957451; Fri, 27 Oct 2023 11:22:37 -0700 (PDT) Reply-To: Sean Christopherson Date: Fri, 27 Oct 2023 11:21:48 -0700 In-Reply-To: <20231027182217.3615211-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20231027182217.3615211-1-seanjc@google.com> X-Mailer: git-send-email 2.42.0.820.g83a721a137-goog Message-ID: <20231027182217.3615211-7-seanjc@google.com> Subject: [PATCH v13 06/35] KVM: PPC: Return '1' unconditionally for KVM_CAP_SYNC_MMU From: Sean Christopherson To: Paolo Bonzini , Marc Zyngier , Oliver Upton , Huacai Chen , Michael Ellerman , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Sean Christopherson , Alexander Viro , Christian Brauner , "Matthew Wilcox (Oracle)" , Andrew Morton Cc: kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Xiaoyao Li , Xu Yilun , Chao Peng , Fuad Tabba , Jarkko Sakkinen , Anish Moorthy , David Matlack , Yu Zhang , Isaku Yamahata , " =?utf-8?q?Micka=C3=ABl_Sala?= =?utf-8?q?=C3=BCn?= " , Vlastimil Babka , Vishal Annapurve , Ackerley Tng , Maciej Szmigiero , David Hildenbrand , Quentin Perret , Michael Roth , Wang , Liam Merwick , Isaku Yamahata , "Kirill A . Shutemov" Advertise that KVM's MMU is synchronized with the primary MMU for all flavors of PPC KVM support, i.e. advertise that the MMU is synchronized when CONFIG_KVM_BOOK3S_HV_POSSIBLE=y but the VM is not using hypervisor mode (a.k.a. PR VMs). PR VMs, via kvm_unmap_gfn_range_pr(), do the right thing for mmu_notifier invalidation events, and more tellingly, KVM returns '1' for KVM_CAP_SYNC_MMU when CONFIG_KVM_BOOK3S_HV_POSSIBLE=n and CONFIG_KVM_BOOK3S_PR_POSSIBLE=y, i.e. KVM already advertises a synchronized MMU for PR VMs, just not when CONFIG_KVM_BOOK3S_HV_POSSIBLE=y. Suggested-by: Paolo Bonzini Signed-off-by: Sean Christopherson --- arch/powerpc/kvm/powerpc.c | 4 ---- 1 file changed, 4 deletions(-) diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c index b0a512ede764..8d3ec483bc2b 100644 --- a/arch/powerpc/kvm/powerpc.c +++ b/arch/powerpc/kvm/powerpc.c @@ -635,11 +635,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) #if !defined(CONFIG_MMU_NOTIFIER) || !defined(KVM_ARCH_WANT_MMU_NOTIFIER) BUILD_BUG(); #endif -#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE - r = hv_enabled; -#else r = 1; -#endif break; #ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE case KVM_CAP_PPC_HTAB_FD: From patchwork Fri Oct 27 18:21:49 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 13438869 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6EC413DFE1 for ; Fri, 27 Oct 2023 18:22:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="p0HIV6Cy" Received: from mail-pl1-x64a.google.com (mail-pl1-x64a.google.com [IPv6:2607:f8b0:4864:20::64a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8139DD5F for ; Fri, 27 Oct 2023 11:22:40 -0700 (PDT) Received: by mail-pl1-x64a.google.com with SMTP id d9443c01a7336-1cc1682607eso13649215ad.1 for ; Fri, 27 Oct 2023 11:22:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1698430959; x=1699035759; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:from:to:cc:subject:date:message-id:reply-to; bh=+AXFJbz5WZr/NYjDBv52nUkuFXaO3S1StF6qZQtTbwQ=; b=p0HIV6Cy9yzhL0TnlO6gL6MVTSd0DcelrvEAuO1pZjP74jjDxfjjEzuptTaP7gDaFZ b87gBdt1YgS08Dfx/aTRwwOIXoVQx//7UMQNCgaXR6XS3hN7B702jzqLMFxWuq1Bntzg thBnhA0W7gN2hygj8ZtBepNk603ATYKKmoJu+8N15GV+I7ejq/kBwsse2lWm9vH3y+R1 /lfxVBbsSJZZheZ20rlXE26HDaAz928IxvKnAzrJ4hAxfoeTQ6vLOxUW4A3lEdi8P8o2 hMjTktouJ8IzTRBMLNY5OXa7l/wdqY/EBM79WxPkdmk9FXhCAd0CgiomGFPMy4dTmJ4e xRgw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1698430959; x=1699035759; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=+AXFJbz5WZr/NYjDBv52nUkuFXaO3S1StF6qZQtTbwQ=; b=UE4rRB18pP457aGPHgfncxhv1DrjS4JjX9RT3oRX2YnGxCAuwwcUIknvlamdpWnICS 5ZpwUED3ayTH+CDR487JUjoa7KbUXjrPIPOqi00Ml408YPIW6fbvlih/c83jjxFUb9BK eIbf2ovLW1WffKlVqXXhaeN/D/GYgKK80NxFX55+Fourq+pKAsOjA+Pnjn2Q58PwhaKK fzFhlxahzfwLBrAhK04wbLZBOyJbaaDHGv5dw6DNWu/NvOoVb3dhyAfW4ZBm+p3BG7ir QHxHYQhrnsFp9xhoziGouBM5GsnUWNWybwK36eW6gz6pO9HzhfyPJIHIzN0RxT0zUW1g LLNA== X-Gm-Message-State: AOJu0YwrPI2So4WoJvsunY5hcZFRKR3cNN9iE7kcI974XPHzVjM+gqmL rfLx1R6nzMnDjAToVY0x2evMej9y2XY= X-Google-Smtp-Source: AGHT+IEo9repSBGZOxXVda3T/byTyJ1q5UTkkyqwmlpHdlfrn0lBxj3W/oLyvthWFNznN6u5r+uymjEP5Uc= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a17:902:c255:b0:1c3:29c4:c4e8 with SMTP id 21-20020a170902c25500b001c329c4c4e8mr57345plg.4.1698430959411; Fri, 27 Oct 2023 11:22:39 -0700 (PDT) Reply-To: Sean Christopherson Date: Fri, 27 Oct 2023 11:21:49 -0700 In-Reply-To: <20231027182217.3615211-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20231027182217.3615211-1-seanjc@google.com> X-Mailer: git-send-email 2.42.0.820.g83a721a137-goog Message-ID: <20231027182217.3615211-8-seanjc@google.com> Subject: [PATCH v13 07/35] KVM: Convert KVM_ARCH_WANT_MMU_NOTIFIER to CONFIG_KVM_GENERIC_MMU_NOTIFIER From: Sean Christopherson To: Paolo Bonzini , Marc Zyngier , Oliver Upton , Huacai Chen , Michael Ellerman , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Sean Christopherson , Alexander Viro , Christian Brauner , "Matthew Wilcox (Oracle)" , Andrew Morton Cc: kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Xiaoyao Li , Xu Yilun , Chao Peng , Fuad Tabba , Jarkko Sakkinen , Anish Moorthy , David Matlack , Yu Zhang , Isaku Yamahata , " =?utf-8?q?Micka=C3=ABl_Sala?= =?utf-8?q?=C3=BCn?= " , Vlastimil Babka , Vishal Annapurve , Ackerley Tng , Maciej Szmigiero , David Hildenbrand , Quentin Perret , Michael Roth , Wang , Liam Merwick , Isaku Yamahata , "Kirill A . Shutemov" Convert KVM_ARCH_WANT_MMU_NOTIFIER into a Kconfig and select it where appropriate to effectively maintain existing behavior. Using a proper Kconfig will simplify building more functionality on top of KVM's mmu_notifier infrastructure. Add a forward declaration of kvm_gfn_range to kvm_types.h so that including arch/powerpc/include/asm/kvm_ppc.h's with CONFIG_KVM=n doesn't generate warnings due to kvm_gfn_range being undeclared. PPC defines hooks for PR vs. HV without guarding them via #ifdeffery, e.g. bool (*unmap_gfn_range)(struct kvm *kvm, struct kvm_gfn_range *range); bool (*age_gfn)(struct kvm *kvm, struct kvm_gfn_range *range); bool (*test_age_gfn)(struct kvm *kvm, struct kvm_gfn_range *range); bool (*set_spte_gfn)(struct kvm *kvm, struct kvm_gfn_range *range); Alternatively, PPC could forward declare kvm_gfn_range, but there's no good reason not to define it in common KVM. Acked-by: Anup Patel Signed-off-by: Sean Christopherson Reviewed-by: Paolo Bonzini Reviewed-by: Fuad Tabba Tested-by: Fuad Tabba --- arch/arm64/include/asm/kvm_host.h | 2 -- arch/arm64/kvm/Kconfig | 2 +- arch/mips/include/asm/kvm_host.h | 2 -- arch/mips/kvm/Kconfig | 2 +- arch/powerpc/include/asm/kvm_host.h | 2 -- arch/powerpc/kvm/Kconfig | 8 ++++---- arch/powerpc/kvm/powerpc.c | 4 +--- arch/riscv/include/asm/kvm_host.h | 2 -- arch/riscv/kvm/Kconfig | 2 +- arch/x86/include/asm/kvm_host.h | 2 -- arch/x86/kvm/Kconfig | 2 +- include/linux/kvm_host.h | 6 +++--- include/linux/kvm_types.h | 1 + virt/kvm/Kconfig | 4 ++++ virt/kvm/kvm_main.c | 10 +++++----- 15 files changed, 22 insertions(+), 29 deletions(-) diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index af06ccb7ee34..9e046b64847a 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -921,8 +921,6 @@ int __kvm_arm_vcpu_get_events(struct kvm_vcpu *vcpu, int __kvm_arm_vcpu_set_events(struct kvm_vcpu *vcpu, struct kvm_vcpu_events *events); -#define KVM_ARCH_WANT_MMU_NOTIFIER - void kvm_arm_halt_guest(struct kvm *kvm); void kvm_arm_resume_guest(struct kvm *kvm); diff --git a/arch/arm64/kvm/Kconfig b/arch/arm64/kvm/Kconfig index 83c1e09be42e..1a777715199f 100644 --- a/arch/arm64/kvm/Kconfig +++ b/arch/arm64/kvm/Kconfig @@ -22,7 +22,7 @@ menuconfig KVM bool "Kernel-based Virtual Machine (KVM) support" depends on HAVE_KVM select KVM_GENERIC_HARDWARE_ENABLING - select MMU_NOTIFIER + select KVM_GENERIC_MMU_NOTIFIER select PREEMPT_NOTIFIERS select HAVE_KVM_CPU_RELAX_INTERCEPT select KVM_MMIO diff --git a/arch/mips/include/asm/kvm_host.h b/arch/mips/include/asm/kvm_host.h index 54a85f1d4f2c..179f320cc231 100644 --- a/arch/mips/include/asm/kvm_host.h +++ b/arch/mips/include/asm/kvm_host.h @@ -810,8 +810,6 @@ int kvm_mips_mkclean_gpa_pt(struct kvm *kvm, gfn_t start_gfn, gfn_t end_gfn); pgd_t *kvm_pgd_alloc(void); void kvm_mmu_free_memory_caches(struct kvm_vcpu *vcpu); -#define KVM_ARCH_WANT_MMU_NOTIFIER - /* Emulation */ enum emulation_result update_pc(struct kvm_vcpu *vcpu, u32 cause); int kvm_get_badinstr(u32 *opc, struct kvm_vcpu *vcpu, u32 *out); diff --git a/arch/mips/kvm/Kconfig b/arch/mips/kvm/Kconfig index a8cdba75f98d..c04987d2ed2e 100644 --- a/arch/mips/kvm/Kconfig +++ b/arch/mips/kvm/Kconfig @@ -25,7 +25,7 @@ config KVM select HAVE_KVM_EVENTFD select HAVE_KVM_VCPU_ASYNC_IOCTL select KVM_MMIO - select MMU_NOTIFIER + select KVM_GENERIC_MMU_NOTIFIER select INTERVAL_TREE select KVM_GENERIC_HARDWARE_ENABLING help diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h index 14ee0dece853..4b5c3f2acf78 100644 --- a/arch/powerpc/include/asm/kvm_host.h +++ b/arch/powerpc/include/asm/kvm_host.h @@ -62,8 +62,6 @@ #include -#define KVM_ARCH_WANT_MMU_NOTIFIER - #define HPTEG_CACHE_NUM (1 << 15) #define HPTEG_HASH_BITS_PTE 13 #define HPTEG_HASH_BITS_PTE_LONG 12 diff --git a/arch/powerpc/kvm/Kconfig b/arch/powerpc/kvm/Kconfig index 902611954200..b33358ee6424 100644 --- a/arch/powerpc/kvm/Kconfig +++ b/arch/powerpc/kvm/Kconfig @@ -42,7 +42,7 @@ config KVM_BOOK3S_64_HANDLER config KVM_BOOK3S_PR_POSSIBLE bool select KVM_MMIO - select MMU_NOTIFIER + select KVM_GENERIC_MMU_NOTIFIER config KVM_BOOK3S_HV_POSSIBLE bool @@ -85,7 +85,7 @@ config KVM_BOOK3S_64_HV tristate "KVM for POWER7 and later using hypervisor mode in host" depends on KVM_BOOK3S_64 && PPC_POWERNV select KVM_BOOK3S_HV_POSSIBLE - select MMU_NOTIFIER + select KVM_GENERIC_MMU_NOTIFIER select CMA help Support running unmodified book3s_64 guest kernels in @@ -194,7 +194,7 @@ config KVM_E500V2 depends on !CONTEXT_TRACKING_USER select KVM select KVM_MMIO - select MMU_NOTIFIER + select KVM_GENERIC_MMU_NOTIFIER help Support running unmodified E500 guest kernels in virtual machines on E500v2 host processors. @@ -211,7 +211,7 @@ config KVM_E500MC select KVM select KVM_MMIO select KVM_BOOKE_HV - select MMU_NOTIFIER + select KVM_GENERIC_MMU_NOTIFIER help Support running unmodified E500MC/E5500/E6500 guest kernels in virtual machines on E500MC/E5500/E6500 host processors. diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c index 8d3ec483bc2b..aac75c98a956 100644 --- a/arch/powerpc/kvm/powerpc.c +++ b/arch/powerpc/kvm/powerpc.c @@ -632,9 +632,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) break; #endif case KVM_CAP_SYNC_MMU: -#if !defined(CONFIG_MMU_NOTIFIER) || !defined(KVM_ARCH_WANT_MMU_NOTIFIER) - BUILD_BUG(); -#endif + BUILD_BUG_ON(!IS_ENABLED(CONFIG_KVM_GENERIC_MMU_NOTIFIER)); r = 1; break; #ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE diff --git a/arch/riscv/include/asm/kvm_host.h b/arch/riscv/include/asm/kvm_host.h index 1ebf20dfbaa6..66ee9ff483e9 100644 --- a/arch/riscv/include/asm/kvm_host.h +++ b/arch/riscv/include/asm/kvm_host.h @@ -249,8 +249,6 @@ struct kvm_vcpu_arch { static inline void kvm_arch_sync_events(struct kvm *kvm) {} static inline void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) {} -#define KVM_ARCH_WANT_MMU_NOTIFIER - #define KVM_RISCV_GSTAGE_TLB_MIN_ORDER 12 void kvm_riscv_local_hfence_gvma_vmid_gpa(unsigned long vmid, diff --git a/arch/riscv/kvm/Kconfig b/arch/riscv/kvm/Kconfig index dfc237d7875b..ae2e05f050ec 100644 --- a/arch/riscv/kvm/Kconfig +++ b/arch/riscv/kvm/Kconfig @@ -30,7 +30,7 @@ config KVM select KVM_GENERIC_HARDWARE_ENABLING select KVM_MMIO select KVM_XFER_TO_GUEST_WORK - select MMU_NOTIFIER + select KVM_GENERIC_MMU_NOTIFIER select PREEMPT_NOTIFIERS help Support hosting virtualized guest machines. diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 70d139406bc8..31e84668014e 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -2129,8 +2129,6 @@ enum { # define kvm_memslots_for_spte_role(kvm, role) __kvm_memslots(kvm, 0) #endif -#define KVM_ARCH_WANT_MMU_NOTIFIER - int kvm_cpu_has_injectable_intr(struct kvm_vcpu *v); int kvm_cpu_has_interrupt(struct kvm_vcpu *vcpu); int kvm_cpu_has_extint(struct kvm_vcpu *v); diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig index ed90f148140d..091b74599c22 100644 --- a/arch/x86/kvm/Kconfig +++ b/arch/x86/kvm/Kconfig @@ -24,7 +24,7 @@ config KVM depends on HIGH_RES_TIMERS depends on X86_LOCAL_APIC select PREEMPT_NOTIFIERS - select MMU_NOTIFIER + select KVM_GENERIC_MMU_NOTIFIER select HAVE_KVM_IRQCHIP select HAVE_KVM_PFNCACHE select HAVE_KVM_IRQFD diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 11d091688346..5faba69403ac 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -253,7 +253,7 @@ bool kvm_setup_async_pf(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, int kvm_async_pf_wakeup_all(struct kvm_vcpu *vcpu); #endif -#ifdef KVM_ARCH_WANT_MMU_NOTIFIER +#ifdef CONFIG_KVM_GENERIC_MMU_NOTIFIER union kvm_mmu_notifier_arg { pte_t pte; }; @@ -783,7 +783,7 @@ struct kvm { struct hlist_head irq_ack_notifier_list; #endif -#if defined(CONFIG_MMU_NOTIFIER) && defined(KVM_ARCH_WANT_MMU_NOTIFIER) +#ifdef CONFIG_KVM_GENERIC_MMU_NOTIFIER struct mmu_notifier mmu_notifier; unsigned long mmu_invalidate_seq; long mmu_invalidate_in_progress; @@ -1946,7 +1946,7 @@ extern const struct _kvm_stats_desc kvm_vm_stats_desc[]; extern const struct kvm_stats_header kvm_vcpu_stats_header; extern const struct _kvm_stats_desc kvm_vcpu_stats_desc[]; -#if defined(CONFIG_MMU_NOTIFIER) && defined(KVM_ARCH_WANT_MMU_NOTIFIER) +#ifdef CONFIG_KVM_GENERIC_MMU_NOTIFIER static inline int mmu_invalidate_retry(struct kvm *kvm, unsigned long mmu_seq) { if (unlikely(kvm->mmu_invalidate_in_progress)) diff --git a/include/linux/kvm_types.h b/include/linux/kvm_types.h index 6f4737d5046a..9d1f7835d8c1 100644 --- a/include/linux/kvm_types.h +++ b/include/linux/kvm_types.h @@ -6,6 +6,7 @@ struct kvm; struct kvm_async_pf; struct kvm_device_ops; +struct kvm_gfn_range; struct kvm_interrupt; struct kvm_irq_routing_table; struct kvm_memory_slot; diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig index 484d0873061c..ecae2914c97e 100644 --- a/virt/kvm/Kconfig +++ b/virt/kvm/Kconfig @@ -92,3 +92,7 @@ config HAVE_KVM_PM_NOTIFIER config KVM_GENERIC_HARDWARE_ENABLING bool + +config KVM_GENERIC_MMU_NOTIFIER + select MMU_NOTIFIER + bool diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 4dba682586ee..6e708017064d 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -535,7 +535,7 @@ void kvm_destroy_vcpus(struct kvm *kvm) } EXPORT_SYMBOL_GPL(kvm_destroy_vcpus); -#if defined(CONFIG_MMU_NOTIFIER) && defined(KVM_ARCH_WANT_MMU_NOTIFIER) +#ifdef CONFIG_KVM_GENERIC_MMU_NOTIFIER static inline struct kvm *mmu_notifier_to_kvm(struct mmu_notifier *mn) { return container_of(mn, struct kvm, mmu_notifier); @@ -960,14 +960,14 @@ static int kvm_init_mmu_notifier(struct kvm *kvm) return mmu_notifier_register(&kvm->mmu_notifier, current->mm); } -#else /* !(CONFIG_MMU_NOTIFIER && KVM_ARCH_WANT_MMU_NOTIFIER) */ +#else /* !CONFIG_KVM_GENERIC_MMU_NOTIFIER */ static int kvm_init_mmu_notifier(struct kvm *kvm) { return 0; } -#endif /* CONFIG_MMU_NOTIFIER && KVM_ARCH_WANT_MMU_NOTIFIER */ +#endif /* CONFIG_KVM_GENERIC_MMU_NOTIFIER */ #ifdef CONFIG_HAVE_KVM_PM_NOTIFIER static int kvm_pm_notifier_call(struct notifier_block *bl, @@ -1287,7 +1287,7 @@ static struct kvm *kvm_create_vm(unsigned long type, const char *fdname) out_err_no_debugfs: kvm_coalesced_mmio_free(kvm); out_no_coalesced_mmio: -#if defined(CONFIG_MMU_NOTIFIER) && defined(KVM_ARCH_WANT_MMU_NOTIFIER) +#ifdef CONFIG_KVM_GENERIC_MMU_NOTIFIER if (kvm->mmu_notifier.ops) mmu_notifier_unregister(&kvm->mmu_notifier, current->mm); #endif @@ -1347,7 +1347,7 @@ static void kvm_destroy_vm(struct kvm *kvm) kvm->buses[i] = NULL; } kvm_coalesced_mmio_free(kvm); -#if defined(CONFIG_MMU_NOTIFIER) && defined(KVM_ARCH_WANT_MMU_NOTIFIER) +#ifdef CONFIG_KVM_GENERIC_MMU_NOTIFIER mmu_notifier_unregister(&kvm->mmu_notifier, kvm->mm); /* * At this point, pending calls to invalidate_range_start() From patchwork Fri Oct 27 18:21:50 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 13438870 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C9FF03DFEE for ; Fri, 27 Oct 2023 18:22:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="jyjoB6LW" Received: from mail-yb1-xb4a.google.com (mail-yb1-xb4a.google.com [IPv6:2607:f8b0:4864:20::b4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A224110D1 for ; 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bh=7QvlKvGCf16Xr+uDo8e13B+5xMJ1JYvNFtX+dCaVrEc=; b=uksSsUYLNpzc1O/shFah46AI/gPYaXWkbu0d1ZtaeS0JOnyHEW8njUZvmSzhbgESYh MYjTBDipuFqCV45H/mxI5oxO+vdX1XC3TsS3bMRRxqLGepYAzkFPJMXNBGg3qkgXqduF dmCI6rXAi8cQovezW2/OwARxRejm5JDpx/iRqjEjwFEn2nzNuV+Yluj9udoMPt1QeyuC UhgBR+p6iT5NMg9PCYNcb9CCPsAX3w+Qp/x/f/HTZmPP6qEelaKptN4D4UGabaAg9Im2 XGMan6/weCwLg/nCfDs+JadJ27YFC/Ld/ubprnoh6uPdqWGlQAHWYT4wm2ZoYMoT0xxX u0Vg== X-Gm-Message-State: AOJu0YxyV7qvA3I+BKAIneMaOv72CtoJcCGXehypmpSQaww0oCHkZ7Sz O5P11M2zxBOpbWzNRyG+m3gH2JGqMH8= X-Google-Smtp-Source: AGHT+IEGteVk64WoocowFgc++46Ydn1QrcnOyupSkq+rT/SBtiB9CXAW8K00cqUCj/t8cf8Aji8XyxJUQTQ= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a25:abe2:0:b0:da0:48e1:5f46 with SMTP id v89-20020a25abe2000000b00da048e15f46mr66725ybi.9.1698430961446; Fri, 27 Oct 2023 11:22:41 -0700 (PDT) Reply-To: Sean Christopherson Date: Fri, 27 Oct 2023 11:21:50 -0700 In-Reply-To: <20231027182217.3615211-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20231027182217.3615211-1-seanjc@google.com> X-Mailer: git-send-email 2.42.0.820.g83a721a137-goog Message-ID: <20231027182217.3615211-9-seanjc@google.com> Subject: [PATCH v13 08/35] KVM: Introduce KVM_SET_USER_MEMORY_REGION2 From: Sean Christopherson To: Paolo Bonzini , Marc Zyngier , Oliver Upton , Huacai Chen , Michael Ellerman , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Sean Christopherson , Alexander Viro , Christian Brauner , "Matthew Wilcox (Oracle)" , Andrew Morton Cc: kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Xiaoyao Li , Xu Yilun , Chao Peng , Fuad Tabba , Jarkko Sakkinen , Anish Moorthy , David Matlack , Yu Zhang , Isaku Yamahata , " =?utf-8?q?Micka=C3=ABl_Sala?= =?utf-8?q?=C3=BCn?= " , Vlastimil Babka , Vishal Annapurve , Ackerley Tng , Maciej Szmigiero , David Hildenbrand , Quentin Perret , Michael Roth , Wang , Liam Merwick , Isaku Yamahata , "Kirill A . Shutemov" Introduce a "version 2" of KVM_SET_USER_MEMORY_REGION so that additional information can be supplied without setting userspace up to fail. The padding in the new kvm_userspace_memory_region2 structure will be used to pass a file descriptor in addition to the userspace_addr, i.e. allow userspace to point at a file descriptor and map memory into a guest that is NOT mapped into host userspace. Alternatively, KVM could simply add "struct kvm_userspace_memory_region2" without a new ioctl(), but as Paolo pointed out, adding a new ioctl() makes detection of bad flags a bit more robust, e.g. if the new fd field is guarded only by a flag and not a new ioctl(), then a userspace bug (setting a "bad" flag) would generate out-of-bounds access instead of an -EINVAL error. Cc: Jarkko Sakkinen Reviewed-by: Paolo Bonzini Reviewed-by: Xiaoyao Li Signed-off-by: Sean Christopherson Reviewed-by: Fuad Tabba Tested-by: Fuad Tabba --- Documentation/virt/kvm/api.rst | 21 +++++++++++++++++++ arch/x86/kvm/x86.c | 2 +- include/linux/kvm_host.h | 4 ++-- include/uapi/linux/kvm.h | 13 ++++++++++++ virt/kvm/kvm_main.c | 38 +++++++++++++++++++++++++++------- 5 files changed, 67 insertions(+), 11 deletions(-) diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index 21a7578142a1..ace984acc125 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -6070,6 +6070,27 @@ writes to the CNTVCT_EL0 and CNTPCT_EL0 registers using the SET_ONE_REG interface. No error will be returned, but the resulting offset will not be applied. +4.139 KVM_SET_USER_MEMORY_REGION2 +--------------------------------- + +:Capability: KVM_CAP_USER_MEMORY2 +:Architectures: all +:Type: vm ioctl +:Parameters: struct kvm_userspace_memory_region2 (in) +:Returns: 0 on success, -1 on error + +:: + + struct kvm_userspace_memory_region2 { + __u32 slot; + __u32 flags; + __u64 guest_phys_addr; + __u64 memory_size; /* bytes */ + __u64 userspace_addr; /* start of the userspace allocated memory */ + }; + +See KVM_SET_USER_MEMORY_REGION. + 5. The kvm_run structure ======================== diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 41cce5031126..6409914428ca 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -12455,7 +12455,7 @@ void __user * __x86_set_memory_region(struct kvm *kvm, int id, gpa_t gpa, } for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) { - struct kvm_userspace_memory_region m; + struct kvm_userspace_memory_region2 m; m.slot = id | (i << 16); m.flags = 0; diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 5faba69403ac..4e741ff27af3 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -1146,9 +1146,9 @@ enum kvm_mr_change { }; int kvm_set_memory_region(struct kvm *kvm, - const struct kvm_userspace_memory_region *mem); + const struct kvm_userspace_memory_region2 *mem); int __kvm_set_memory_region(struct kvm *kvm, - const struct kvm_userspace_memory_region *mem); + const struct kvm_userspace_memory_region2 *mem); void kvm_arch_free_memslot(struct kvm *kvm, struct kvm_memory_slot *slot); void kvm_arch_memslots_updated(struct kvm *kvm, u64 gen); int kvm_arch_prepare_memory_region(struct kvm *kvm, diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index 13065dd96132..bd1abe067f28 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -95,6 +95,16 @@ struct kvm_userspace_memory_region { __u64 userspace_addr; /* start of the userspace allocated memory */ }; +/* for KVM_SET_USER_MEMORY_REGION2 */ +struct kvm_userspace_memory_region2 { + __u32 slot; + __u32 flags; + __u64 guest_phys_addr; + __u64 memory_size; + __u64 userspace_addr; + __u64 pad[16]; +}; + /* * The bit 0 ~ bit 15 of kvm_userspace_memory_region::flags are visible for * userspace, other bits are reserved for kvm internal use which are defined @@ -1192,6 +1202,7 @@ struct kvm_ppc_resize_hpt { #define KVM_CAP_COUNTER_OFFSET 227 #define KVM_CAP_ARM_EAGER_SPLIT_CHUNK_SIZE 228 #define KVM_CAP_ARM_SUPPORTED_BLOCK_SIZES 229 +#define KVM_CAP_USER_MEMORY2 230 #ifdef KVM_CAP_IRQ_ROUTING @@ -1473,6 +1484,8 @@ struct kvm_vfio_spapr_tce { struct kvm_userspace_memory_region) #define KVM_SET_TSS_ADDR _IO(KVMIO, 0x47) #define KVM_SET_IDENTITY_MAP_ADDR _IOW(KVMIO, 0x48, __u64) +#define KVM_SET_USER_MEMORY_REGION2 _IOW(KVMIO, 0x49, \ + struct kvm_userspace_memory_region2) /* enable ucontrol for s390 */ struct kvm_s390_ucas_mapping { diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 6e708017064d..3f5b7c2c5327 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -1578,7 +1578,7 @@ static void kvm_replace_memslot(struct kvm *kvm, } } -static int check_memory_region_flags(const struct kvm_userspace_memory_region *mem) +static int check_memory_region_flags(const struct kvm_userspace_memory_region2 *mem) { u32 valid_flags = KVM_MEM_LOG_DIRTY_PAGES; @@ -1980,7 +1980,7 @@ static bool kvm_check_memslot_overlap(struct kvm_memslots *slots, int id, * Must be called holding kvm->slots_lock for write. */ int __kvm_set_memory_region(struct kvm *kvm, - const struct kvm_userspace_memory_region *mem) + const struct kvm_userspace_memory_region2 *mem) { struct kvm_memory_slot *old, *new; struct kvm_memslots *slots; @@ -2084,7 +2084,7 @@ int __kvm_set_memory_region(struct kvm *kvm, EXPORT_SYMBOL_GPL(__kvm_set_memory_region); int kvm_set_memory_region(struct kvm *kvm, - const struct kvm_userspace_memory_region *mem) + const struct kvm_userspace_memory_region2 *mem) { int r; @@ -2096,7 +2096,7 @@ int kvm_set_memory_region(struct kvm *kvm, EXPORT_SYMBOL_GPL(kvm_set_memory_region); static int kvm_vm_ioctl_set_memory_region(struct kvm *kvm, - struct kvm_userspace_memory_region *mem) + struct kvm_userspace_memory_region2 *mem) { if ((u16)mem->slot >= KVM_USER_MEM_SLOTS) return -EINVAL; @@ -4566,6 +4566,7 @@ static int kvm_vm_ioctl_check_extension_generic(struct kvm *kvm, long arg) { switch (arg) { case KVM_CAP_USER_MEMORY: + case KVM_CAP_USER_MEMORY2: case KVM_CAP_DESTROY_MEMORY_REGION_WORKS: case KVM_CAP_JOIN_MEMORY_REGIONS_WORKS: case KVM_CAP_INTERNAL_ERROR_DATA: @@ -4821,6 +4822,14 @@ static int kvm_vm_ioctl_get_stats_fd(struct kvm *kvm) return fd; } +#define SANITY_CHECK_MEM_REGION_FIELD(field) \ +do { \ + BUILD_BUG_ON(offsetof(struct kvm_userspace_memory_region, field) != \ + offsetof(struct kvm_userspace_memory_region2, field)); \ + BUILD_BUG_ON(sizeof_field(struct kvm_userspace_memory_region, field) != \ + sizeof_field(struct kvm_userspace_memory_region2, field)); \ +} while (0) + static long kvm_vm_ioctl(struct file *filp, unsigned int ioctl, unsigned long arg) { @@ -4843,15 +4852,28 @@ static long kvm_vm_ioctl(struct file *filp, r = kvm_vm_ioctl_enable_cap_generic(kvm, &cap); break; } + case KVM_SET_USER_MEMORY_REGION2: case KVM_SET_USER_MEMORY_REGION: { - struct kvm_userspace_memory_region kvm_userspace_mem; + struct kvm_userspace_memory_region2 mem; + unsigned long size; + + if (ioctl == KVM_SET_USER_MEMORY_REGION) + size = sizeof(struct kvm_userspace_memory_region); + else + size = sizeof(struct kvm_userspace_memory_region2); + + /* Ensure the common parts of the two structs are identical. */ + SANITY_CHECK_MEM_REGION_FIELD(slot); 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Fri, 27 Oct 2023 11:22:43 -0700 (PDT) Reply-To: Sean Christopherson Date: Fri, 27 Oct 2023 11:21:51 -0700 In-Reply-To: <20231027182217.3615211-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20231027182217.3615211-1-seanjc@google.com> X-Mailer: git-send-email 2.42.0.820.g83a721a137-goog Message-ID: <20231027182217.3615211-10-seanjc@google.com> Subject: [PATCH v13 09/35] KVM: Add KVM_EXIT_MEMORY_FAULT exit to report faults to userspace From: Sean Christopherson To: Paolo Bonzini , Marc Zyngier , Oliver Upton , Huacai Chen , Michael Ellerman , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Sean Christopherson , Alexander Viro , Christian Brauner , "Matthew Wilcox (Oracle)" , Andrew Morton Cc: kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Xiaoyao Li , Xu Yilun , Chao Peng , Fuad Tabba , Jarkko Sakkinen , Anish Moorthy , David Matlack , Yu Zhang , Isaku Yamahata , " =?utf-8?q?Micka=C3=ABl_Sala?= =?utf-8?q?=C3=BCn?= " , Vlastimil Babka , Vishal Annapurve , Ackerley Tng , Maciej Szmigiero , David Hildenbrand , Quentin Perret , Michael Roth , Wang , Liam Merwick , Isaku Yamahata , "Kirill A . Shutemov" From: Chao Peng Add a new KVM exit type to allow userspace to handle memory faults that KVM cannot resolve, but that userspace *may* be able to handle (without terminating the guest). KVM will initially use KVM_EXIT_MEMORY_FAULT to report implicit conversions between private and shared memory. With guest private memory, there will be two kind of memory conversions: - explicit conversion: happens when the guest explicitly calls into KVM to map a range (as private or shared) - implicit conversion: happens when the guest attempts to access a gfn that is configured in the "wrong" state (private vs. shared) On x86 (first architecture to support guest private memory), explicit conversions will be reported via KVM_EXIT_HYPERCALL+KVM_HC_MAP_GPA_RANGE, but reporting KVM_EXIT_HYPERCALL for implicit conversions is undesriable as there is (obviously) no hypercall, and there is no guarantee that the guest actually intends to convert between private and shared, i.e. what KVM thinks is an implicit conversion "request" could actually be the result of a guest code bug. KVM_EXIT_MEMORY_FAULT will be used to report memory faults that appear to be implicit conversions. Note! To allow for future possibilities where KVM reports KVM_EXIT_MEMORY_FAULT and fills run->memory_fault on _any_ unresolved fault, KVM returns "-EFAULT" (-1 with errno == EFAULT from userspace's perspective), not '0'! Due to historical baggage within KVM, exiting to userspace with '0' from deep callstacks, e.g. in emulation paths, is infeasible as doing so would require a near-complete overhaul of KVM, whereas KVM already propagates -errno return codes to userspace even when the -errno originated in a low level helper. Report the gpa+size instead of a single gfn even though the initial usage is expected to always report single pages. It's entirely possible, likely even, that KVM will someday support sub-page granularity faults, e.g. Intel's sub-page protection feature allows for additional protections at 128-byte granularity. Link: https://lore.kernel.org/all/20230908222905.1321305-5-amoorthy@google.com Link: https://lore.kernel.org/all/ZQ3AmLO2SYv3DszH@google.com Cc: Anish Moorthy Cc: David Matlack Suggested-by: Sean Christopherson Co-developed-by: Yu Zhang Signed-off-by: Yu Zhang Signed-off-by: Chao Peng Co-developed-by: Sean Christopherson Signed-off-by: Sean Christopherson Reviewed-by: Paolo Bonzini --- Documentation/virt/kvm/api.rst | 41 ++++++++++++++++++++++++++++++++++ arch/x86/kvm/x86.c | 1 + include/linux/kvm_host.h | 11 +++++++++ include/uapi/linux/kvm.h | 8 +++++++ 4 files changed, 61 insertions(+) diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index ace984acc125..860216536810 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -6723,6 +6723,26 @@ array field represents return values. The userspace should update the return values of SBI call before resuming the VCPU. For more details on RISC-V SBI spec refer, https://github.com/riscv/riscv-sbi-doc. +:: + + /* KVM_EXIT_MEMORY_FAULT */ + struct { + __u64 flags; + __u64 gpa; + __u64 size; + } memory; + +KVM_EXIT_MEMORY_FAULT indicates the vCPU has encountered a memory fault that +could not be resolved by KVM. The 'gpa' and 'size' (in bytes) describe the +guest physical address range [gpa, gpa + size) of the fault. The 'flags' field +describes properties of the faulting access that are likely pertinent. +Currently, no flags are defined. + +Note! KVM_EXIT_MEMORY_FAULT is unique among all KVM exit reasons in that it +accompanies a return code of '-1', not '0'! errno will always be set to EFAULT +or EHWPOISON when KVM exits with KVM_EXIT_MEMORY_FAULT, userspace should assume +kvm_run.exit_reason is stale/undefined for all other error numbers. + :: /* KVM_EXIT_NOTIFY */ @@ -7757,6 +7777,27 @@ This capability is aimed to mitigate the threat that malicious VMs can cause CPU stuck (due to event windows don't open up) and make the CPU unavailable to host or other VMs. +7.34 KVM_CAP_MEMORY_FAULT_INFO +------------------------------ + +:Architectures: x86 +:Returns: Informational only, -EINVAL on direct KVM_ENABLE_CAP. + +The presence of this capability indicates that KVM_RUN will fill +kvm_run.memory_fault if KVM cannot resolve a guest page fault VM-Exit, e.g. if +there is a valid memslot but no backing VMA for the corresponding host virtual +address. + +The information in kvm_run.memory_fault is valid if and only if KVM_RUN returns +an error with errno=EFAULT or errno=EHWPOISON *and* kvm_run.exit_reason is set +to KVM_EXIT_MEMORY_FAULT. + +Note: Userspaces which attempt to resolve memory faults so that they can retry +KVM_RUN are encouraged to guard against repeatedly receiving the same +error/annotated fault. + +See KVM_EXIT_MEMORY_FAULT for more information. + 8. Other capabilities. ====================== diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 6409914428ca..ee3cd8c3c0ef 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -4518,6 +4518,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) case KVM_CAP_ENABLE_CAP: case KVM_CAP_VM_DISABLE_NX_HUGE_PAGES: case KVM_CAP_IRQFD_RESAMPLE: + case KVM_CAP_MEMORY_FAULT_INFO: r = 1; break; case KVM_CAP_EXIT_HYPERCALL: diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 4e741ff27af3..96aa930536b1 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -2327,4 +2327,15 @@ static inline void kvm_account_pgtable_pages(void *virt, int nr) /* Max number of entries allowed for each kvm dirty ring */ #define KVM_DIRTY_RING_MAX_ENTRIES 65536 +static inline void kvm_prepare_memory_fault_exit(struct kvm_vcpu *vcpu, + gpa_t gpa, gpa_t size) +{ + vcpu->run->exit_reason = KVM_EXIT_MEMORY_FAULT; + vcpu->run->memory_fault.gpa = gpa; + vcpu->run->memory_fault.size = size; + + /* Flags are not (yet) defined or communicated to userspace. */ + vcpu->run->memory_fault.flags = 0; +} + #endif diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index bd1abe067f28..7ae9987b48dd 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -274,6 +274,7 @@ struct kvm_xen_exit { #define KVM_EXIT_RISCV_SBI 35 #define KVM_EXIT_RISCV_CSR 36 #define KVM_EXIT_NOTIFY 37 +#define KVM_EXIT_MEMORY_FAULT 38 /* For KVM_EXIT_INTERNAL_ERROR */ /* Emulate instruction failed. */ @@ -520,6 +521,12 @@ struct kvm_run { #define KVM_NOTIFY_CONTEXT_INVALID (1 << 0) __u32 flags; } notify; + /* KVM_EXIT_MEMORY_FAULT */ + struct { + __u64 flags; + __u64 gpa; + __u64 size; + } memory_fault; /* Fix the size of the union. */ char padding[256]; }; @@ -1203,6 +1210,7 @@ struct kvm_ppc_resize_hpt { #define KVM_CAP_ARM_EAGER_SPLIT_CHUNK_SIZE 228 #define KVM_CAP_ARM_SUPPORTED_BLOCK_SIZES 229 #define KVM_CAP_USER_MEMORY2 230 +#define KVM_CAP_MEMORY_FAULT_INFO 231 #ifdef KVM_CAP_IRQ_ROUTING From patchwork Fri Oct 27 18:21:52 2023 Content-Type: text/plain; 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Fri, 27 Oct 2023 11:22:45 -0700 (PDT) Reply-To: Sean Christopherson Date: Fri, 27 Oct 2023 11:21:52 -0700 In-Reply-To: <20231027182217.3615211-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20231027182217.3615211-1-seanjc@google.com> X-Mailer: git-send-email 2.42.0.820.g83a721a137-goog Message-ID: <20231027182217.3615211-11-seanjc@google.com> Subject: [PATCH v13 10/35] KVM: Add a dedicated mmu_notifier flag for reclaiming freed memory From: Sean Christopherson To: Paolo Bonzini , Marc Zyngier , Oliver Upton , Huacai Chen , Michael Ellerman , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Sean Christopherson , Alexander Viro , Christian Brauner , "Matthew Wilcox (Oracle)" , Andrew Morton Cc: kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Xiaoyao Li , Xu Yilun , Chao Peng , Fuad Tabba , Jarkko Sakkinen , Anish Moorthy , David Matlack , Yu Zhang , Isaku Yamahata , " =?utf-8?q?Micka=C3=ABl_Sala?= =?utf-8?q?=C3=BCn?= " , Vlastimil Babka , Vishal Annapurve , Ackerley Tng , Maciej Szmigiero , David Hildenbrand , Quentin Perret , Michael Roth , Wang , Liam Merwick , Isaku Yamahata , "Kirill A . Shutemov" Handle AMD SEV's kvm_arch_guest_memory_reclaimed() hook by having __kvm_handle_hva_range() return whether or not an overlapping memslot was found, i.e. mmu_lock was acquired. Using the .on_unlock() hook works, but kvm_arch_guest_memory_reclaimed() needs to run after dropping mmu_lock, which makes .on_lock() and .on_unlock() asymmetrical. Use a small struct to return the tuple of the notifier-specific return, plus whether or not overlap was found. Because the iteration helpers are __always_inlined, practically speaking, the struct will never actually be returned from a function call (not to mention the size of the struct will be two bytes in practice). Signed-off-by: Sean Christopherson Reviewed-by: Paolo Bonzini Reviewed-by: Fuad Tabba Tested-by: Fuad Tabba --- virt/kvm/kvm_main.c | 53 +++++++++++++++++++++++++++++++-------------- 1 file changed, 37 insertions(+), 16 deletions(-) diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 3f5b7c2c5327..2bc04c8ae1f4 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -561,6 +561,19 @@ struct kvm_mmu_notifier_range { bool may_block; }; +/* + * The inner-most helper returns a tuple containing the return value from the + * arch- and action-specific handler, plus a flag indicating whether or not at + * least one memslot was found, i.e. if the handler found guest memory. + * + * Note, most notifiers are averse to booleans, so even though KVM tracks the + * return from arch code as a bool, outer helpers will cast it to an int. :-( + */ +typedef struct kvm_mmu_notifier_return { + bool ret; + bool found_memslot; +} kvm_mn_ret_t; + /* * Use a dedicated stub instead of NULL to indicate that there is no callback * function/handler. The compiler technically can't guarantee that a real @@ -582,22 +595,25 @@ static const union kvm_mmu_notifier_arg KVM_MMU_NOTIFIER_NO_ARG; node; \ node = interval_tree_iter_next(node, start, last)) \ -static __always_inline int __kvm_handle_hva_range(struct kvm *kvm, - const struct kvm_mmu_notifier_range *range) +static __always_inline kvm_mn_ret_t __kvm_handle_hva_range(struct kvm *kvm, + const struct kvm_mmu_notifier_range *range) { - bool ret = false, locked = false; + struct kvm_mmu_notifier_return r = { + .ret = false, + .found_memslot = false, + }; struct kvm_gfn_range gfn_range; struct kvm_memory_slot *slot; struct kvm_memslots *slots; int i, idx; if (WARN_ON_ONCE(range->end <= range->start)) - return 0; + return r; /* A null handler is allowed if and only if on_lock() is provided. */ if (WARN_ON_ONCE(IS_KVM_NULL_FN(range->on_lock) && IS_KVM_NULL_FN(range->handler))) - return 0; + return r; idx = srcu_read_lock(&kvm->srcu); @@ -631,8 +647,8 @@ static __always_inline int __kvm_handle_hva_range(struct kvm *kvm, gfn_range.end = hva_to_gfn_memslot(hva_end + PAGE_SIZE - 1, slot); gfn_range.slot = slot; - if (!locked) { - locked = true; + if (!r.found_memslot) { + r.found_memslot = true; KVM_MMU_LOCK(kvm); if (!IS_KVM_NULL_FN(range->on_lock)) range->on_lock(kvm); @@ -640,14 +656,14 @@ static __always_inline int __kvm_handle_hva_range(struct kvm *kvm, if (IS_KVM_NULL_FN(range->handler)) break; } - ret |= range->handler(kvm, &gfn_range); + r.ret |= range->handler(kvm, &gfn_range); } } - if (range->flush_on_ret && ret) + if (range->flush_on_ret && r.ret) kvm_flush_remote_tlbs(kvm); - if (locked) { + if (r.found_memslot) { KVM_MMU_UNLOCK(kvm); if (!IS_KVM_NULL_FN(range->on_unlock)) range->on_unlock(kvm); @@ -655,8 +671,7 @@ static __always_inline int __kvm_handle_hva_range(struct kvm *kvm, srcu_read_unlock(&kvm->srcu, idx); - /* The notifiers are averse to booleans. :-( */ - return (int)ret; + return r; } static __always_inline int kvm_handle_hva_range(struct mmu_notifier *mn, @@ -677,7 +692,7 @@ static __always_inline int kvm_handle_hva_range(struct mmu_notifier *mn, .may_block = false, }; - return __kvm_handle_hva_range(kvm, &range); + return __kvm_handle_hva_range(kvm, &range).ret; } static __always_inline int kvm_handle_hva_range_no_flush(struct mmu_notifier *mn, @@ -696,7 +711,7 @@ static __always_inline int kvm_handle_hva_range_no_flush(struct mmu_notifier *mn .may_block = false, }; - return __kvm_handle_hva_range(kvm, &range); + return __kvm_handle_hva_range(kvm, &range).ret; } static bool kvm_change_spte_gfn(struct kvm *kvm, struct kvm_gfn_range *range) @@ -798,7 +813,7 @@ static int kvm_mmu_notifier_invalidate_range_start(struct mmu_notifier *mn, .end = range->end, .handler = kvm_mmu_unmap_gfn_range, .on_lock = kvm_mmu_invalidate_begin, - .on_unlock = kvm_arch_guest_memory_reclaimed, + .on_unlock = (void *)kvm_null_fn, .flush_on_ret = true, .may_block = mmu_notifier_range_blockable(range), }; @@ -830,7 +845,13 @@ static int kvm_mmu_notifier_invalidate_range_start(struct mmu_notifier *mn, gfn_to_pfn_cache_invalidate_start(kvm, range->start, range->end, hva_range.may_block); - __kvm_handle_hva_range(kvm, &hva_range); + /* + * If one or more memslots were found and thus zapped, notify arch code + * that guest memory has been reclaimed. This needs to be done *after* + * dropping mmu_lock, as x86's reclaim path is slooooow. + */ + if (__kvm_handle_hva_range(kvm, &hva_range).found_memslot) + kvm_arch_guest_memory_reclaimed(kvm); return 0; } From patchwork Fri Oct 27 18:21:53 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 13438873 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 155BB3D38B for ; Fri, 27 Oct 2023 18:22:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="3xT/ci44" Received: from mail-pl1-x64a.google.com (mail-pl1-x64a.google.com [IPv6:2607:f8b0:4864:20::64a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 550FA18F for ; Fri, 27 Oct 2023 11:22:48 -0700 (PDT) Received: by mail-pl1-x64a.google.com with SMTP id d9443c01a7336-1cc29f3afe0so4664925ad.2 for ; Fri, 27 Oct 2023 11:22:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1698430967; x=1699035767; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:from:to:cc:subject:date:message-id:reply-to; bh=fLrd3AGy66HdihfPmI58EyyG3FCGELBv0TZMEZAIG4Y=; b=3xT/ci44KKzjmmrpAao7ngJthUkPCvXpRnXckArfxBa8Zr2fJkiV/GGCTxm0vyYgnh vv6yfcs4BneSBQUXt/mB0YsqyBZ5wbzwqFoo9Bod2Vk1MyjcsTDxUyOaqvrVCPcPa38Q 32ttnMXcYZbWGrhfz3tqW/C/cXNeWarTxG3N24uN5SnPll/wesBAT3TLmemoDU1LtMo5 WiucU7uTpzEHtyi7rLFqaOet9e3z0o/w1AOA4cn6qjtbOCIhZzZy910UQftKJeSXkd57 vmfr68Fie5ywyab18IL2u0ebB08b0G3NaN81dOAHYtcfnhwyH5rgn4AzwmqQ41JLdjya AovQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1698430967; x=1699035767; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=fLrd3AGy66HdihfPmI58EyyG3FCGELBv0TZMEZAIG4Y=; b=Qra7TmxV1r877iB4Pkvnolhhpd6ZZea3P2f+wrUKy6f5mTl+QCP6rEuVbnXBGZV3qX sPGq0pohcjiOlblWyHgLM3SqRCtqizO1tSSj5+FQpUFYa0KRwckTRpTPr5qGYP4n76ux d+CFra2lwi/2sTbtDCvE11WIb1qOdv/nBRe27zjApShVQKbmRJd9j650XtYl53rHWGY0 jumYRHXIMiOtu/g3BWSMQeLvUnWklo9T+dysnuJUzqKhsB7+3Q9jzBWfms35nyBGbPsL Q5EeF45HNosfwASzIR42m0R+ONhHWPs8m2h6XDsDLSGeQQOiXyzoIUH0wiMmKrOZRutM 8daA== X-Gm-Message-State: AOJu0YzV1rabRQ3x1TzsqOQwmlnqK0iEIyq94Ju2C6sxjpr41dSnus0b Td4DPLMDvxgF7FaFTg3g3t1PfyOqOH8= X-Google-Smtp-Source: AGHT+IFw7CMiVxkdfLmPKgztX5f1RnQlL4BTlZlVKLxMz6aRVtHUrQY578kvMdkjnRTl6BBw2VS25sQYIRo= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a17:902:ee14:b0:1ca:b952:f5fa with SMTP id z20-20020a170902ee1400b001cab952f5famr63161plb.5.1698430967325; Fri, 27 Oct 2023 11:22:47 -0700 (PDT) Reply-To: Sean Christopherson Date: Fri, 27 Oct 2023 11:21:53 -0700 In-Reply-To: <20231027182217.3615211-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20231027182217.3615211-1-seanjc@google.com> X-Mailer: git-send-email 2.42.0.820.g83a721a137-goog Message-ID: <20231027182217.3615211-12-seanjc@google.com> Subject: [PATCH v13 11/35] KVM: Drop .on_unlock() mmu_notifier hook From: Sean Christopherson To: Paolo Bonzini , Marc Zyngier , Oliver Upton , Huacai Chen , Michael Ellerman , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Sean Christopherson , Alexander Viro , Christian Brauner , "Matthew Wilcox (Oracle)" , Andrew Morton Cc: kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Xiaoyao Li , Xu Yilun , Chao Peng , Fuad Tabba , Jarkko Sakkinen , Anish Moorthy , David Matlack , Yu Zhang , Isaku Yamahata , " =?utf-8?q?Micka=C3=ABl_Sala?= =?utf-8?q?=C3=BCn?= " , Vlastimil Babka , Vishal Annapurve , Ackerley Tng , Maciej Szmigiero , David Hildenbrand , Quentin Perret , Michael Roth , Wang , Liam Merwick , Isaku Yamahata , "Kirill A . Shutemov" Drop the .on_unlock() mmu_notifer hook now that it's no longer used for notifying arch code that memory has been reclaimed. Adding .on_unlock() and invoking it *after* dropping mmu_lock was a terrible idea, as doing so resulted in .on_lock() and .on_unlock() having divergent and asymmetric behavior, and set future developers up for failure, i.e. all but asked for bugs where KVM relied on using .on_unlock() to try to run a callback while holding mmu_lock. Opportunistically add a lockdep assertion in kvm_mmu_invalidate_end() to guard against future bugs of this nature. Reported-by: Isaku Yamahata Link: https://lore.kernel.org/all/20230802203119.GB2021422@ls.amr.corp.intel.com Signed-off-by: Sean Christopherson Reviewed-by: Paolo Bonzini Reviewed-by: Fuad Tabba Tested-by: Fuad Tabba --- virt/kvm/kvm_main.c | 13 +++---------- 1 file changed, 3 insertions(+), 10 deletions(-) diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 2bc04c8ae1f4..cb9376833c18 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -544,7 +544,6 @@ static inline struct kvm *mmu_notifier_to_kvm(struct mmu_notifier *mn) typedef bool (*gfn_handler_t)(struct kvm *kvm, struct kvm_gfn_range *range); typedef void (*on_lock_fn_t)(struct kvm *kvm); -typedef void (*on_unlock_fn_t)(struct kvm *kvm); struct kvm_mmu_notifier_range { /* @@ -556,7 +555,6 @@ struct kvm_mmu_notifier_range { union kvm_mmu_notifier_arg arg; gfn_handler_t handler; on_lock_fn_t on_lock; - on_unlock_fn_t on_unlock; bool flush_on_ret; bool may_block; }; @@ -663,11 +661,8 @@ static __always_inline kvm_mn_ret_t __kvm_handle_hva_range(struct kvm *kvm, if (range->flush_on_ret && r.ret) kvm_flush_remote_tlbs(kvm); - if (r.found_memslot) { + if (r.found_memslot) KVM_MMU_UNLOCK(kvm); - if (!IS_KVM_NULL_FN(range->on_unlock)) - range->on_unlock(kvm); - } srcu_read_unlock(&kvm->srcu, idx); @@ -687,7 +682,6 @@ static __always_inline int kvm_handle_hva_range(struct mmu_notifier *mn, .arg = arg, .handler = handler, .on_lock = (void *)kvm_null_fn, - .on_unlock = (void *)kvm_null_fn, .flush_on_ret = true, .may_block = false, }; @@ -706,7 +700,6 @@ static __always_inline int kvm_handle_hva_range_no_flush(struct mmu_notifier *mn .end = end, .handler = handler, .on_lock = (void *)kvm_null_fn, - .on_unlock = (void *)kvm_null_fn, .flush_on_ret = false, .may_block = false, }; @@ -813,7 +806,6 @@ static int kvm_mmu_notifier_invalidate_range_start(struct mmu_notifier *mn, .end = range->end, .handler = kvm_mmu_unmap_gfn_range, .on_lock = kvm_mmu_invalidate_begin, - .on_unlock = (void *)kvm_null_fn, .flush_on_ret = true, .may_block = mmu_notifier_range_blockable(range), }; @@ -858,6 +850,8 @@ static int kvm_mmu_notifier_invalidate_range_start(struct mmu_notifier *mn, void kvm_mmu_invalidate_end(struct kvm *kvm) { + lockdep_assert_held_write(&kvm->mmu_lock); + /* * This sequence increase will notify the kvm page fault that * the page that is going to be mapped in the spte could have @@ -889,7 +883,6 @@ static void kvm_mmu_notifier_invalidate_range_end(struct mmu_notifier *mn, .end = range->end, .handler = (void *)kvm_null_fn, .on_lock = kvm_mmu_invalidate_end, - .on_unlock = (void *)kvm_null_fn, .flush_on_ret = false, .may_block = mmu_notifier_range_blockable(range), }; From patchwork Fri Oct 27 18:21:54 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 13438874 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 088193D986 for ; Fri, 27 Oct 2023 18:23:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="08fNJEpx" Received: from mail-yw1-x1149.google.com (mail-yw1-x1149.google.com [IPv6:2607:f8b0:4864:20::1149]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CA4361A5 for ; 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Shutemov" Add flags to "struct kvm_gfn_range" to let notifier events target only shared and only private mappings, and write up the existing mmu_notifier events to be shared-only (private memory is never associated with a userspace virtual address, i.e. can't be reached via mmu_notifiers). Add two flags so that KVM can handle the three possibilities (shared, private, and shared+private) without needing something like a tri-state enum. Link: https://lore.kernel.org/all/ZJX0hk+KpQP0KUyB@google.com Signed-off-by: Sean Christopherson --- include/linux/kvm_host.h | 2 ++ virt/kvm/kvm_main.c | 7 +++++++ 2 files changed, 9 insertions(+) diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 96aa930536b1..89c1a991a3b8 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -263,6 +263,8 @@ struct kvm_gfn_range { gfn_t start; gfn_t end; union kvm_mmu_notifier_arg arg; + bool only_private; + bool only_shared; bool may_block; }; bool kvm_unmap_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range); diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index cb9376833c18..302ccb87b4c1 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -635,6 +635,13 @@ static __always_inline kvm_mn_ret_t __kvm_handle_hva_range(struct kvm *kvm, * the second or later invocation of the handler). */ gfn_range.arg = range->arg; + + /* + * HVA-based notifications aren't relevant to private + * mappings as they don't have a userspace mapping. + */ + gfn_range.only_private = false; + gfn_range.only_shared = true; gfn_range.may_block = range->may_block; /* From patchwork Fri Oct 27 18:21:55 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 13438875 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E50793DFE0 for ; Fri, 27 Oct 2023 18:23:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="b0E0PO3V" Received: from mail-yw1-x1149.google.com (mail-yw1-x1149.google.com [IPv6:2607:f8b0:4864:20::1149]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F0892D4E for ; Fri, 27 Oct 2023 11:22:53 -0700 (PDT) Received: by mail-yw1-x1149.google.com with SMTP id 00721157ae682-5a7cc433782so21063467b3.3 for ; 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bh=PHuKmbJK++WVHRTr2ixGhZnz3PjglwNcwDhJuJ6xsm0=; b=EoXF3tEMFVI6KfDEOXvrGJEVuX7TLZJRXlYLgcmh51U0VQvrlBXLhl9uLA8yxTgZ2Z 3gQsacmmKFMv83eD2vVLrdc7YIkLaUeNkPGORS0I6RrLCs06qLHtLkPplg4Ng3x/pyDM SSNaxM0owGt28/NHj06q0MiI0NnjlYYW6ftzMR7nm1/zajXOPEinM09VPcKIX9T5AdLQ yxTPDqHNQ47sjvdrxBbcDrXMk2MtiquezS8Xiacoo6W1tPvOSAnilXRMNq2UCmEIuirt 2AinQOvUwhtuLFbrhIOi3sVb93AqNCv0Awg74HBLU6Zol6aDbOdcO1Ai3dqTidm1KLQo GVcw== X-Gm-Message-State: AOJu0YwHVVgJkCNCQreoK5zWvqH5xYGnDGluMaQ77eVYevnsRUzD3pS0 vbgRzuOakZ3332uBMDmDHon9M6R5Et8= X-Google-Smtp-Source: AGHT+IHeAi8c5J1JHmkq3P4PpsdNdjX6Wq3XK5NOfAhf9NwJS3eapFdTXpLG2igv2I31VgMM7Gn14gWqO18= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a0d:ca97:0:b0:5a1:d4a5:7dff with SMTP id m145-20020a0dca97000000b005a1d4a57dffmr73743ywd.6.1698430971510; Fri, 27 Oct 2023 11:22:51 -0700 (PDT) Reply-To: Sean Christopherson Date: Fri, 27 Oct 2023 11:21:55 -0700 In-Reply-To: <20231027182217.3615211-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20231027182217.3615211-1-seanjc@google.com> X-Mailer: git-send-email 2.42.0.820.g83a721a137-goog Message-ID: <20231027182217.3615211-14-seanjc@google.com> Subject: [PATCH v13 13/35] KVM: Introduce per-page memory attributes From: Sean Christopherson To: Paolo Bonzini , Marc Zyngier , Oliver Upton , Huacai Chen , Michael Ellerman , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Sean Christopherson , Alexander Viro , Christian Brauner , "Matthew Wilcox (Oracle)" , Andrew Morton Cc: kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Xiaoyao Li , Xu Yilun , Chao Peng , Fuad Tabba , Jarkko Sakkinen , Anish Moorthy , David Matlack , Yu Zhang , Isaku Yamahata , " =?utf-8?q?Micka=C3=ABl_Sala?= =?utf-8?q?=C3=BCn?= " , Vlastimil Babka , Vishal Annapurve , Ackerley Tng , Maciej Szmigiero , David Hildenbrand , Quentin Perret , Michael Roth , Wang , Liam Merwick , Isaku Yamahata , "Kirill A . Shutemov" From: Chao Peng In confidential computing usages, whether a page is private or shared is necessary information for KVM to perform operations like page fault handling, page zapping etc. There are other potential use cases for per-page memory attributes, e.g. to make memory read-only (or no-exec, or exec-only, etc.) without having to modify memslots. Introduce two ioctls (advertised by KVM_CAP_MEMORY_ATTRIBUTES) to allow userspace to operate on the per-page memory attributes. - KVM_SET_MEMORY_ATTRIBUTES to set the per-page memory attributes to a guest memory range. - KVM_GET_SUPPORTED_MEMORY_ATTRIBUTES to return the KVM supported memory attributes. Use an xarray to store the per-page attributes internally, with a naive, not fully optimized implementation, i.e. prioritize correctness over performance for the initial implementation. Use bit 3 for the PRIVATE attribute so that KVM can use bits 0-2 for RWX attributes/protections in the future, e.g. to give userspace fine-grained control over read, write, and execute protections for guest memory. Provide arch hooks for handling attribute changes before and after common code sets the new attributes, e.g. x86 will use the "pre" hook to zap all relevant mappings, and the "post" hook to track whether or not hugepages can be used to map the range. To simplify the implementation wrap the entire sequence with kvm_mmu_invalidate_{begin,end}() even though the operation isn't strictly guaranteed to be an invalidation. For the initial use case, x86 *will* always invalidate memory, and preventing arch code from creating new mappings while the attributes are in flux makes it much easier to reason about the correctness of consuming attributes. It's possible that future usages may not require an invalidation, e.g. if KVM ends up supporting RWX protections and userspace grants _more_ protections, but again opt for simplicity and punt optimizations to if/when they are needed. Suggested-by: Sean Christopherson Link: https://lore.kernel.org/all/Y2WB48kD0J4VGynX@google.com Cc: Fuad Tabba Cc: Xu Yilun Cc: Mickaël Salaün Signed-off-by: Chao Peng Co-developed-by: Sean Christopherson Signed-off-by: Sean Christopherson --- Documentation/virt/kvm/api.rst | 36 +++++ include/linux/kvm_host.h | 18 +++ include/uapi/linux/kvm.h | 13 ++ virt/kvm/Kconfig | 4 + virt/kvm/kvm_main.c | 233 +++++++++++++++++++++++++++++++++ 5 files changed, 304 insertions(+) diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index 860216536810..e2252c748fd6 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -6091,6 +6091,42 @@ applied. See KVM_SET_USER_MEMORY_REGION. +4.140 KVM_SET_MEMORY_ATTRIBUTES +------------------------------- + +:Capability: KVM_CAP_MEMORY_ATTRIBUTES +:Architectures: x86 +:Type: vm ioctl +:Parameters: struct kvm_memory_attributes(in) +:Returns: 0 on success, <0 on error + +KVM_SET_MEMORY_ATTRIBUTES allows userspace to set memory attributes for a range +of guest physical memory. + +:: + + struct kvm_memory_attributes { + __u64 address; + __u64 size; + __u64 attributes; + __u64 flags; + }; + + #define KVM_MEMORY_ATTRIBUTE_PRIVATE (1ULL << 3) + +The address and size must be page aligned. The supported attributes can be +retrieved via ioctl(KVM_CHECK_EXTENSION) on KVM_CAP_MEMORY_ATTRIBUTES. If +executed on a VM, KVM_CAP_MEMORY_ATTRIBUTES precisely returns the attributes +supported by that VM. If executed at system scope, KVM_CAP_MEMORY_ATTRIBUTES +returns all attributes supported by KVM. The only attribute defined at this +time is KVM_MEMORY_ATTRIBUTE_PRIVATE, which marks the associated gfn as being +guest private memory. + +Note, there is no "get" API. Userspace is responsible for explicitly tracking +the state of a gfn/page as needed. + +The "flags" field is reserved for future extensions and must be '0'. + 5. The kvm_run structure ======================== diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 89c1a991a3b8..df573229651b 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -256,6 +256,7 @@ int kvm_async_pf_wakeup_all(struct kvm_vcpu *vcpu); #ifdef CONFIG_KVM_GENERIC_MMU_NOTIFIER union kvm_mmu_notifier_arg { pte_t pte; + unsigned long attributes; }; struct kvm_gfn_range { @@ -808,6 +809,9 @@ struct kvm { #ifdef CONFIG_HAVE_KVM_PM_NOTIFIER struct notifier_block pm_notifier; +#endif +#ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES + struct xarray mem_attr_array; #endif char stats_id[KVM_STATS_NAME_SIZE]; }; @@ -2340,4 +2344,18 @@ static inline void kvm_prepare_memory_fault_exit(struct kvm_vcpu *vcpu, vcpu->run->memory_fault.flags = 0; } +#ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES +static inline unsigned long kvm_get_memory_attributes(struct kvm *kvm, gfn_t gfn) +{ + return xa_to_value(xa_load(&kvm->mem_attr_array, gfn)); +} + +bool kvm_range_has_memory_attributes(struct kvm *kvm, gfn_t start, gfn_t end, + unsigned long attrs); +bool kvm_arch_pre_set_memory_attributes(struct kvm *kvm, + struct kvm_gfn_range *range); +bool kvm_arch_post_set_memory_attributes(struct kvm *kvm, + struct kvm_gfn_range *range); +#endif /* CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES */ + #endif diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index 7ae9987b48dd..547837feaa28 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -1211,6 +1211,7 @@ struct kvm_ppc_resize_hpt { #define KVM_CAP_ARM_SUPPORTED_BLOCK_SIZES 229 #define KVM_CAP_USER_MEMORY2 230 #define KVM_CAP_MEMORY_FAULT_INFO 231 +#define KVM_CAP_MEMORY_ATTRIBUTES 232 #ifdef KVM_CAP_IRQ_ROUTING @@ -2277,4 +2278,16 @@ struct kvm_s390_zpci_op { /* flags for kvm_s390_zpci_op->u.reg_aen.flags */ #define KVM_S390_ZPCIOP_REGAEN_HOST (1 << 0) +/* Available with KVM_CAP_MEMORY_ATTRIBUTES */ +#define KVM_SET_MEMORY_ATTRIBUTES _IOW(KVMIO, 0xd2, struct kvm_memory_attributes) + +struct kvm_memory_attributes { + __u64 address; + __u64 size; + __u64 attributes; + __u64 flags; +}; + +#define KVM_MEMORY_ATTRIBUTE_PRIVATE (1ULL << 3) + #endif /* __LINUX_KVM_H */ diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig index ecae2914c97e..5bd7fcaf9089 100644 --- a/virt/kvm/Kconfig +++ b/virt/kvm/Kconfig @@ -96,3 +96,7 @@ config KVM_GENERIC_HARDWARE_ENABLING config KVM_GENERIC_MMU_NOTIFIER select MMU_NOTIFIER bool + +config KVM_GENERIC_MEMORY_ATTRIBUTES + select KVM_GENERIC_MMU_NOTIFIER + bool diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 302ccb87b4c1..78a0b09ef2a5 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -1218,6 +1218,9 @@ static struct kvm *kvm_create_vm(unsigned long type, const char *fdname) spin_lock_init(&kvm->mn_invalidate_lock); rcuwait_init(&kvm->mn_memslots_update_rcuwait); xa_init(&kvm->vcpu_array); +#ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES + xa_init(&kvm->mem_attr_array); +#endif INIT_LIST_HEAD(&kvm->gpc_list); spin_lock_init(&kvm->gpc_lock); @@ -1398,6 +1401,9 @@ static void kvm_destroy_vm(struct kvm *kvm) } cleanup_srcu_struct(&kvm->irq_srcu); cleanup_srcu_struct(&kvm->srcu); +#ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES + xa_destroy(&kvm->mem_attr_array); +#endif kvm_arch_free_vm(kvm); preempt_notifier_dec(); hardware_disable_all(); @@ -2396,6 +2402,210 @@ static int kvm_vm_ioctl_clear_dirty_log(struct kvm *kvm, } #endif /* CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT */ +#ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES +/* + * Returns true if _all_ gfns in the range [@start, @end) have attributes + * matching @attrs. + */ +bool kvm_range_has_memory_attributes(struct kvm *kvm, gfn_t start, gfn_t end, + unsigned long attrs) +{ + XA_STATE(xas, &kvm->mem_attr_array, start); + unsigned long index; + bool has_attrs; + void *entry; + + rcu_read_lock(); + + if (!attrs) { + has_attrs = !xas_find(&xas, end - 1); + goto out; + } + + has_attrs = true; + for (index = start; index < end; index++) { + do { + entry = xas_next(&xas); + } while (xas_retry(&xas, entry)); + + if (xas.xa_index != index || xa_to_value(entry) != attrs) { + has_attrs = false; + break; + } + } + +out: + rcu_read_unlock(); + return has_attrs; +} + +static u64 kvm_supported_mem_attributes(struct kvm *kvm) +{ + if (!kvm) + return KVM_MEMORY_ATTRIBUTE_PRIVATE; + + return 0; +} + +static __always_inline void kvm_handle_gfn_range(struct kvm *kvm, + struct kvm_mmu_notifier_range *range) +{ + struct kvm_gfn_range gfn_range; + struct kvm_memory_slot *slot; + struct kvm_memslots *slots; + struct kvm_memslot_iter iter; + bool found_memslot = false; + bool ret = false; + int i; + + gfn_range.arg = range->arg; + gfn_range.may_block = range->may_block; + + /* + * If/when KVM supports more attributes beyond private .vs shared, this + * _could_ set only_{private,shared} appropriately if the entire target + * range already has the desired private vs. shared state (it's unclear + * if that is a net win). For now, KVM reaches this point if and only + * if the private flag is being toggled, i.e. all mappings are in play. + */ + gfn_range.only_private = false; + gfn_range.only_shared = false; + + for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) { + slots = __kvm_memslots(kvm, i); + + kvm_for_each_memslot_in_gfn_range(&iter, slots, range->start, range->end) { + slot = iter.slot; + gfn_range.slot = slot; + + gfn_range.start = max(range->start, slot->base_gfn); + gfn_range.end = min(range->end, slot->base_gfn + slot->npages); + if (gfn_range.start >= gfn_range.end) + continue; + + if (!found_memslot) { + found_memslot = true; + KVM_MMU_LOCK(kvm); + if (!IS_KVM_NULL_FN(range->on_lock)) + range->on_lock(kvm); + } + + ret |= range->handler(kvm, &gfn_range); + } + } + + if (range->flush_on_ret && ret) + kvm_flush_remote_tlbs(kvm); + + if (found_memslot) + KVM_MMU_UNLOCK(kvm); +} + +static bool kvm_pre_set_memory_attributes(struct kvm *kvm, + struct kvm_gfn_range *range) +{ + /* + * Unconditionally add the range to the invalidation set, regardless of + * whether or not the arch callback actually needs to zap SPTEs. E.g. + * if KVM supports RWX attributes in the future and the attributes are + * going from R=>RW, zapping isn't strictly necessary. Unconditionally + * adding the range allows KVM to require that MMU invalidations add at + * least one range between begin() and end(), e.g. allows KVM to detect + * bugs where the add() is missed. Rexlaing the rule *might* be safe, + * but it's not obvious that allowing new mappings while the attributes + * are in flux is desirable or worth the complexity. + */ + kvm_mmu_invalidate_range_add(kvm, range->start, range->end); + + return kvm_arch_pre_set_memory_attributes(kvm, range); +} + +/* Set @attributes for the gfn range [@start, @end). */ +static int kvm_vm_set_mem_attributes(struct kvm *kvm, gfn_t start, gfn_t end, + unsigned long attributes) +{ + struct kvm_mmu_notifier_range pre_set_range = { + .start = start, + .end = end, + .handler = kvm_pre_set_memory_attributes, + .on_lock = kvm_mmu_invalidate_begin, + .flush_on_ret = true, + .may_block = true, + }; + struct kvm_mmu_notifier_range post_set_range = { + .start = start, + .end = end, + .arg.attributes = attributes, + .handler = kvm_arch_post_set_memory_attributes, + .on_lock = kvm_mmu_invalidate_end, + .may_block = true, + }; + unsigned long i; + void *entry; + int r = 0; + + entry = attributes ? xa_mk_value(attributes) : NULL; + + mutex_lock(&kvm->slots_lock); + + /* Nothing to do if the entire range as the desired attributes. */ + if (kvm_range_has_memory_attributes(kvm, start, end, attributes)) + goto out_unlock; + + /* + * Reserve memory ahead of time to avoid having to deal with failures + * partway through setting the new attributes. + */ + for (i = start; i < end; i++) { + r = xa_reserve(&kvm->mem_attr_array, i, GFP_KERNEL_ACCOUNT); + if (r) + goto out_unlock; + } + + kvm_handle_gfn_range(kvm, &pre_set_range); + + for (i = start; i < end; i++) { + r = xa_err(xa_store(&kvm->mem_attr_array, i, entry, + GFP_KERNEL_ACCOUNT)); + KVM_BUG_ON(r, kvm); + } + + kvm_handle_gfn_range(kvm, &post_set_range); + +out_unlock: + mutex_unlock(&kvm->slots_lock); + + return r; +} +static int kvm_vm_ioctl_set_mem_attributes(struct kvm *kvm, + struct kvm_memory_attributes *attrs) +{ + gfn_t start, end; + + /* flags is currently not used. */ + if (attrs->flags) + return -EINVAL; + if (attrs->attributes & ~kvm_supported_mem_attributes(kvm)) + return -EINVAL; + if (attrs->size == 0 || attrs->address + attrs->size < attrs->address) + return -EINVAL; + if (!PAGE_ALIGNED(attrs->address) || !PAGE_ALIGNED(attrs->size)) + return -EINVAL; + + start = attrs->address >> PAGE_SHIFT; + end = (attrs->address + attrs->size) >> PAGE_SHIFT; + + /* + * xarray tracks data using "unsigned long", and as a result so does + * KVM. For simplicity, supports generic attributes only on 64-bit + * architectures. + */ + BUILD_BUG_ON(sizeof(attrs->attributes) != sizeof(unsigned long)); + + return kvm_vm_set_mem_attributes(kvm, start, end, attrs->attributes); +} +#endif /* CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES */ + struct kvm_memory_slot *gfn_to_memslot(struct kvm *kvm, gfn_t gfn) { return __gfn_to_memslot(kvm_memslots(kvm), gfn); @@ -4640,6 +4850,17 @@ static int kvm_vm_ioctl_check_extension_generic(struct kvm *kvm, long arg) case KVM_CAP_BINARY_STATS_FD: case KVM_CAP_SYSTEM_EVENT_DATA: return 1; +#ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES + case KVM_CAP_MEMORY_ATTRIBUTES: + u64 attrs = kvm_supported_mem_attributes(kvm); + + r = -EFAULT; + if (copy_to_user(argp, &attrs, sizeof(attrs))) + goto out; + r = 0; + break; + } +#endif default: break; } @@ -5022,6 +5243,18 @@ static long kvm_vm_ioctl(struct file *filp, break; } #endif /* CONFIG_HAVE_KVM_IRQ_ROUTING */ +#ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES + case KVM_SET_MEMORY_ATTRIBUTES: { + struct kvm_memory_attributes attrs; + + r = -EFAULT; + if (copy_from_user(&attrs, argp, sizeof(attrs))) + goto out; + + r = kvm_vm_ioctl_set_mem_attributes(kvm, &attrs); + break; + } +#endif /* CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES */ case KVM_CREATE_DEVICE: { struct kvm_create_device cd; From patchwork Fri Oct 27 18:21:56 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 13438876 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 08D353C09F for ; Fri, 27 Oct 2023 18:23:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="RX6XtlZy" Received: from mail-yb1-xb49.google.com (mail-yb1-xb49.google.com [IPv6:2607:f8b0:4864:20::b49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 385A21737 for ; 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Shutemov" Add an "unmovable" flag for mappings that cannot be migrated under any circumstance. KVM will use the flag for its upcoming GUEST_MEMFD support, which will not support compaction/migration, at least not in the foreseeable future. Test AS_UNMOVABLE under folio lock as already done for the async compaction/dirty folio case, as the mapping can be removed by truncation while compaction is running. To avoid having to lock every folio with a mapping, assume/require that unmovable mappings are also unevictable, and have mapping_set_unmovable() also set AS_UNEVICTABLE. Cc: Matthew Wilcox Co-developed-by: Vlastimil Babka Signed-off-by: Vlastimil Babka Signed-off-by: Sean Christopherson --- include/linux/pagemap.h | 19 +++++++++++++++++- mm/compaction.c | 43 +++++++++++++++++++++++++++++------------ mm/migrate.c | 2 ++ 3 files changed, 51 insertions(+), 13 deletions(-) diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h index 351c3b7f93a1..82c9bf506b79 100644 --- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h @@ -203,7 +203,8 @@ enum mapping_flags { /* writeback related tags are not used */ AS_NO_WRITEBACK_TAGS = 5, AS_LARGE_FOLIO_SUPPORT = 6, - AS_RELEASE_ALWAYS, /* Call ->release_folio(), even if no private data */ + AS_RELEASE_ALWAYS = 7, /* Call ->release_folio(), even if no private data */ + AS_UNMOVABLE = 8, /* The mapping cannot be moved, ever */ }; /** @@ -289,6 +290,22 @@ static inline void mapping_clear_release_always(struct address_space *mapping) clear_bit(AS_RELEASE_ALWAYS, &mapping->flags); } +static inline void mapping_set_unmovable(struct address_space *mapping) +{ + /* + * It's expected unmovable mappings are also unevictable. Compaction + * migrate scanner (isolate_migratepages_block()) relies on this to + * reduce page locking. + */ + set_bit(AS_UNEVICTABLE, &mapping->flags); + set_bit(AS_UNMOVABLE, &mapping->flags); +} + +static inline bool mapping_unmovable(struct address_space *mapping) +{ + return test_bit(AS_UNMOVABLE, &mapping->flags); +} + static inline gfp_t mapping_gfp_mask(struct address_space * mapping) { return mapping->gfp_mask; diff --git a/mm/compaction.c b/mm/compaction.c index 38c8d216c6a3..12b828aed7c8 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -883,6 +883,7 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn, /* Time to isolate some pages for migration */ for (; low_pfn < end_pfn; low_pfn++) { + bool is_dirty, is_unevictable; if (skip_on_failure && low_pfn >= next_skip_pfn) { /* @@ -1080,8 +1081,10 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn, if (!folio_test_lru(folio)) goto isolate_fail_put; + is_unevictable = folio_test_unevictable(folio); + /* Compaction might skip unevictable pages but CMA takes them */ - if (!(mode & ISOLATE_UNEVICTABLE) && folio_test_unevictable(folio)) + if (!(mode & ISOLATE_UNEVICTABLE) && is_unevictable) goto isolate_fail_put; /* @@ -1093,26 +1096,42 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn, if ((mode & ISOLATE_ASYNC_MIGRATE) && folio_test_writeback(folio)) goto isolate_fail_put; - if ((mode & ISOLATE_ASYNC_MIGRATE) && folio_test_dirty(folio)) { - bool migrate_dirty; + is_dirty = folio_test_dirty(folio); + + if (((mode & ISOLATE_ASYNC_MIGRATE) && is_dirty) || + (mapping && is_unevictable)) { + bool migrate_dirty = true; + bool is_unmovable; /* * Only folios without mappings or that have - * a ->migrate_folio callback are possible to - * migrate without blocking. However, we may - * be racing with truncation, which can free - * the mapping. Truncation holds the folio lock - * until after the folio is removed from the page - * cache so holding it ourselves is sufficient. + * a ->migrate_folio callback are possible to migrate + * without blocking. + * + * Folios from unmovable mappings are not migratable. + * + * However, we can be racing with truncation, which can + * free the mapping that we need to check. Truncation + * holds the folio lock until after the folio is removed + * from the page so holding it ourselves is sufficient. + * + * To avoid locking the folio just to check unmovable, + * assume every unmovable folio is also unevictable, + * which is a cheaper test. If our assumption goes + * wrong, it's not a correctness bug, just potentially + * wasted cycles. */ if (!folio_trylock(folio)) goto isolate_fail_put; mapping = folio_mapping(folio); - migrate_dirty = !mapping || - mapping->a_ops->migrate_folio; + if ((mode & ISOLATE_ASYNC_MIGRATE) && is_dirty) { + migrate_dirty = !mapping || + mapping->a_ops->migrate_folio; + } + is_unmovable = mapping && mapping_unmovable(mapping); folio_unlock(folio); - if (!migrate_dirty) + if (!migrate_dirty || is_unmovable) goto isolate_fail_put; } diff --git a/mm/migrate.c b/mm/migrate.c index 2053b54556ca..ed874e43ecd7 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -956,6 +956,8 @@ static int move_to_new_folio(struct folio *dst, struct folio *src, if (!mapping) rc = migrate_folio(mapping, dst, src, mode); + else if (mapping_unmovable(mapping)) + rc = -EOPNOTSUPP; else if (mapping->a_ops->migrate_folio) /* * Most folios have a mapping and most filesystems From patchwork Fri Oct 27 18:21:57 2023 Content-Type: text/plain; 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Fri, 27 Oct 2023 11:22:55 -0700 (PDT) Reply-To: Sean Christopherson Date: Fri, 27 Oct 2023 11:21:57 -0700 In-Reply-To: <20231027182217.3615211-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20231027182217.3615211-1-seanjc@google.com> X-Mailer: git-send-email 2.42.0.820.g83a721a137-goog Message-ID: <20231027182217.3615211-16-seanjc@google.com> Subject: [PATCH v13 15/35] fs: Export anon_inode_getfile_secure() for use by KVM From: Sean Christopherson To: Paolo Bonzini , Marc Zyngier , Oliver Upton , Huacai Chen , Michael Ellerman , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Sean Christopherson , Alexander Viro , Christian Brauner , "Matthew Wilcox (Oracle)" , Andrew Morton Cc: kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Xiaoyao Li , Xu Yilun , Chao Peng , Fuad Tabba , Jarkko Sakkinen , Anish Moorthy , David Matlack , Yu Zhang , Isaku Yamahata , " =?utf-8?q?Micka=C3=ABl_Sala?= =?utf-8?q?=C3=BCn?= " , Vlastimil Babka , Vishal Annapurve , Ackerley Tng , Maciej Szmigiero , David Hildenbrand , Quentin Perret , Michael Roth , Wang , Liam Merwick , Isaku Yamahata , "Kirill A . Shutemov" Export anon_inode_getfile_secure() so that it can be used by KVM to create and manage file-based guest memory without need a fullblow filesystem. The "standard" anon_inode_getfd() doesn't work for KVM's use case as KVM needs a unique inode for each file, e.g. to be able to independently manage the size and lifecycle of a given file. Note, KVM doesn't need a "secure" version, just unique inodes, i.e. ignore the name. Signed-off-by: Sean Christopherson Reviewed-by: Paolo Bonzini --- fs/anon_inodes.c | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/anon_inodes.c b/fs/anon_inodes.c index 24192a7667ed..4190336180ee 100644 --- a/fs/anon_inodes.c +++ b/fs/anon_inodes.c @@ -176,6 +176,7 @@ struct file *anon_inode_getfile_secure(const char *name, return __anon_inode_getfile(name, fops, priv, flags, context_inode, true); } +EXPORT_SYMBOL_GPL(anon_inode_getfile_secure); static int __anon_inode_getfd(const char *name, const struct file_operations *fops, From patchwork Fri Oct 27 18:21:58 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 13438878 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CB0523D398 for ; Fri, 27 Oct 2023 18:23:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="rYkud3yJ" Received: from mail-pl1-x64a.google.com (mail-pl1-x64a.google.com [IPv6:2607:f8b0:4864:20::64a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6045F198E for ; Fri, 27 Oct 2023 11:22:59 -0700 (PDT) Received: by mail-pl1-x64a.google.com with SMTP id d9443c01a7336-1caaaa873efso23352445ad.3 for ; Fri, 27 Oct 2023 11:22:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1698430977; x=1699035777; darn=vger.kernel.org; h=content-transfer-encoding:cc:to:from:subject:message-id:references :mime-version:in-reply-to:date:reply-to:from:to:cc:subject:date :message-id:reply-to; bh=UYJQgiZVR4iLUgC6P0Z91HbpOn98YamOrMc7NG6h1kc=; b=rYkud3yJHLNKx6U68IxOxPa2JjvRFqlbxlcKWb83G6vxrKxV6hL7AOQNdTMRtoosbq c2b5e9d4lxQqiV3Iot1tNeoRVjzLOOd4ruNGN0Lw/Qm5amLS51TCchKeBpe2uNG+rm2k hJB+MN91aCW7gHC36GdKa1/iF1cEY4mRhvFcESra0LLudGcqcmFomhGn94yI+oHotTbG ZnOL8ALlx/1NSUnw2LroMm1OasrShI3K0LsMD/klphugQIC4Ezxdf/8O8tqEsZ576RNM GaVLAf7wESW7A6yo09lVuTvnIewIbeJNGhMh0X/0BZ/uqykbzt6a0SnerR/JBrAg+5vN oExA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1698430977; x=1699035777; h=content-transfer-encoding:cc:to:from:subject:message-id:references :mime-version:in-reply-to:date:reply-to:x-gm-message-state:from:to :cc:subject:date:message-id:reply-to; bh=UYJQgiZVR4iLUgC6P0Z91HbpOn98YamOrMc7NG6h1kc=; b=T5ANdsxBp178HPAONBv+qRP4G02zVWfLI9mAmE/o8Ui7VXCC8Lwy55SLpJWINLd+ut ZFL9FK/SFIdpPb0ikfiVABQSwpG/kWE7bYUx17CfBtLsWjlZTDOuGwzrU8zef2gIAOPs ubJTgJhfJOsvXlGPNlVR/f+POG/HGCLXRuHQAZ/C7TXw1eKYLsN/cmxPTw29WqpxjTZI BlAHv018onTvb6m5qkVUULSGXcQM2a5nJ8uT8A/vflES3PvvoZxvViGQpnB4v9+Ll5lE LfEePkjz2uI71rHHvVhjTHx7f8LIyUlIYblvsRRxfKI6dcLURyGqE8DbZtR4Ks6SgSQ6 wZow== X-Gm-Message-State: AOJu0YwcLZTEh8MYfd4Fvm5MGV5oY5maoJB/3sUKUabenM98YvmMSIkl 8xFwdgqmhKcONjkzmGmObAs/g0MiF1Y= X-Google-Smtp-Source: AGHT+IFQTLCtveekXD1rlOFkw+wx7na7JcLPvjDu5+U2W4dimd59+gDznHjkZmFjwgKKy1fzp+yLv/HHt2A= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a17:902:7b8f:b0:1c9:f356:b7d5 with SMTP id w15-20020a1709027b8f00b001c9f356b7d5mr60393pll.7.1698430977569; Fri, 27 Oct 2023 11:22:57 -0700 (PDT) Reply-To: Sean Christopherson Date: Fri, 27 Oct 2023 11:21:58 -0700 In-Reply-To: <20231027182217.3615211-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20231027182217.3615211-1-seanjc@google.com> X-Mailer: git-send-email 2.42.0.820.g83a721a137-goog Message-ID: <20231027182217.3615211-17-seanjc@google.com> Subject: [PATCH v13 16/35] KVM: Add KVM_CREATE_GUEST_MEMFD ioctl() for guest-specific backing memory From: Sean Christopherson To: Paolo Bonzini , Marc Zyngier , Oliver Upton , Huacai Chen , Michael Ellerman , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Sean Christopherson , Alexander Viro , Christian Brauner , "Matthew Wilcox (Oracle)" , Andrew Morton Cc: kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Xiaoyao Li , Xu Yilun , Chao Peng , Fuad Tabba , Jarkko Sakkinen , Anish Moorthy , David Matlack , Yu Zhang , Isaku Yamahata , " =?utf-8?q?Micka=C3=ABl_Sala?= =?utf-8?q?=C3=BCn?= " , Vlastimil Babka , Vishal Annapurve , Ackerley Tng , Maciej Szmigiero , David Hildenbrand , Quentin Perret , Michael Roth , Wang , Liam Merwick , Isaku Yamahata , "Kirill A . Shutemov" Introduce an ioctl(), KVM_CREATE_GUEST_MEMFD, to allow creating file-based memory that is tied to a specific KVM virtual machine and whose primary purpose is to serve guest memory. A guest-first memory subsystem allows for optimizations and enhancements that are kludgy or outright infeasible to implement/support in a generic memory subsystem. With guest_memfd, guest protections and mapping sizes are fully decoupled from host userspace mappings. E.g. KVM currently doesn't support mapping memory as writable in the guest without it also being writable in host userspace, as KVM's ABI uses VMA protections to define the allow guest protection. Userspace can fudge this by establishing two mappings, a writable mapping for the guest and readable one for itself, but that’s suboptimal on multiple fronts. Similarly, KVM currently requires the guest mapping size to be a strict subset of the host userspace mapping size, e.g. KVM doesn’t support creating a 1GiB guest mapping unless userspace also has a 1GiB guest mapping. Decoupling the mappings sizes would allow userspace to precisely map only what is needed without impacting guest performance, e.g. to harden against unintentional accesses to guest memory. Decoupling guest and userspace mappings may also allow for a cleaner alternative to high-granularity mappings for HugeTLB, which has reached a bit of an impasse and is unlikely to ever be merged. A guest-first memory subsystem also provides clearer line of sight to things like a dedicated memory pool (for slice-of-hardware VMs) and elimination of "struct page" (for offload setups where userspace _never_ needs to mmap() guest memory). More immediately, being able to map memory into KVM guests without mapping said memory into the host is critical for Confidential VMs (CoCo VMs), the initial use case for guest_memfd. While AMD's SEV and Intel's TDX prevent untrusted software from reading guest private data by encrypting guest memory with a key that isn't usable by the untrusted host, projects such as Protected KVM (pKVM) provide confidentiality and integrity *without* relying on memory encryption. And with SEV-SNP and TDX, accessing guest private memory can be fatal to the host, i.e. KVM must be prevent host userspace from accessing guest memory irrespective of hardware behavior. Attempt #1 to support CoCo VMs was to add a VMA flag to mark memory as being mappable only by KVM (or a similarly enlightened kernel subsystem). That approach was abandoned largely due to it needing to play games with PROT_NONE to prevent userspace from accessing guest memory. Attempt #2 to was to usurp PG_hwpoison to prevent the host from mapping guest private memory into userspace, but that approach failed to meet several requirements for software-based CoCo VMs, e.g. pKVM, as the kernel wouldn't easily be able to enforce a 1:1 page:guest association, let alone a 1:1 pfn:gfn mapping. And using PG_hwpoison does not work for memory that isn't backed by 'struct page', e.g. if devices gain support for exposing encrypted memory regions to guests. Attempt #3 was to extend the memfd() syscall and wrap shmem to provide dedicated file-based guest memory. That approach made it as far as v10 before feedback from Hugh Dickins and Christian Brauner (and others) led to it demise. Hugh's objection was that piggybacking shmem made no sense for KVM's use case as KVM didn't actually *want* the features provided by shmem. I.e. KVM was using memfd() and shmem to avoid having to manage memory directly, not because memfd() and shmem were the optimal solution, e.g. things like read/write/mmap in shmem were dead weight. Christian pointed out flaws with implementing a partial overlay (wrapping only _some_ of shmem), e.g. poking at inode_operations or super_operations would show shmem stuff, but address_space_operations and file_operations would show KVM's overlay. Paraphrashing heavily, Christian suggested KVM stop being lazy and create a proper API. Link: https://lore.kernel.org/all/20201020061859.18385-1-kirill.shutemov@linux.intel.com Link: https://lore.kernel.org/all/20210416154106.23721-1-kirill.shutemov@linux.intel.com Link: https://lore.kernel.org/all/20210824005248.200037-1-seanjc@google.com Link: https://lore.kernel.org/all/20211111141352.26311-1-chao.p.peng@linux.intel.com Link: https://lore.kernel.org/all/20221202061347.1070246-1-chao.p.peng@linux.intel.com Link: https://lore.kernel.org/all/ff5c5b97-acdf-9745-ebe5-c6609dd6322e@google.com Link: https://lore.kernel.org/all/20230418-anfallen-irdisch-6993a61be10b@brauner Link: https://lore.kernel.org/all/ZEM5Zq8oo+xnApW9@google.com Link: https://lore.kernel.org/linux-mm/20230306191944.GA15773@monkey Link: https://lore.kernel.org/linux-mm/ZII1p8ZHlHaQ3dDl@casper.infradead.org Cc: Fuad Tabba Cc: Vishal Annapurve Cc: Ackerley Tng Cc: Jarkko Sakkinen Cc: Maciej Szmigiero Cc: Vlastimil Babka Cc: David Hildenbrand Cc: Quentin Perret Cc: Michael Roth Cc: Wang Cc: Liam Merwick Cc: Isaku Yamahata Co-developed-by: Kirill A. Shutemov Signed-off-by: Kirill A. Shutemov Co-developed-by: Yu Zhang Signed-off-by: Yu Zhang Co-developed-by: Chao Peng Signed-off-by: Chao Peng Co-developed-by: Ackerley Tng Signed-off-by: Ackerley Tng Co-developed-by: Isaku Yamahata Signed-off-by: Isaku Yamahata Co-developed-by: Paolo Bonzini Signed-off-by: Paolo Bonzini Co-developed-by: Michael Roth Signed-off-by: Michael Roth Signed-off-by: Sean Christopherson --- Documentation/virt/kvm/api.rst | 69 ++++- include/linux/kvm_host.h | 48 +++ include/uapi/linux/kvm.h | 15 +- virt/kvm/Kconfig | 4 + virt/kvm/Makefile.kvm | 1 + virt/kvm/guest_memfd.c | 548 +++++++++++++++++++++++++++++++++ virt/kvm/kvm_main.c | 68 +++- virt/kvm/kvm_mm.h | 26 ++ 8 files changed, 764 insertions(+), 15 deletions(-) create mode 100644 virt/kvm/guest_memfd.c diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index e2252c748fd6..e82c69d5e755 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -6079,6 +6079,15 @@ applied. :Parameters: struct kvm_userspace_memory_region2 (in) :Returns: 0 on success, -1 on error +KVM_SET_USER_MEMORY_REGION2 is an extension to KVM_SET_USER_MEMORY_REGION that +allows mapping guest_memfd memory into a guest. All fields shared with +KVM_SET_USER_MEMORY_REGION identically. Userspace can set KVM_MEM_PRIVATE in +flags to have KVM bind the memory region to a given guest_memfd range of +[guest_memfd_offset, guest_memfd_offset + memory_size]. The target guest_memfd +must point at a file created via KVM_CREATE_GUEST_MEMFD on the current VM, and +the target range must not be bound to any other memory region. All standard +bounds checks apply (use common sense). + :: struct kvm_userspace_memory_region2 { @@ -6087,9 +6096,24 @@ applied. __u64 guest_phys_addr; __u64 memory_size; /* bytes */ __u64 userspace_addr; /* start of the userspace allocated memory */ + __u64 guest_memfd_offset; + __u32 guest_memfd; + __u32 pad1; + __u64 pad2[14]; }; -See KVM_SET_USER_MEMORY_REGION. +A KVM_MEM_PRIVATE region _must_ have a valid guest_memfd (private memory) and +userspace_addr (shared memory). However, "valid" for userspace_addr simply +means that the address itself must be a legal userspace address. The backing +mapping for userspace_addr is not required to be valid/populated at the time of +KVM_SET_USER_MEMORY_REGION2, e.g. shared memory can be lazily mapped/allocated +on-demand. + +When mapping a gfn into the guest, KVM selects shared vs. private, i.e consumes +userspace_addr vs. guest_memfd, based on the gfn's KVM_MEMORY_ATTRIBUTE_PRIVATE +state. At VM creation time, all memory is shared, i.e. the PRIVATE attribute +is '0' for all gfns. Userspace can control whether memory is shared/private by +toggling KVM_MEMORY_ATTRIBUTE_PRIVATE via KVM_SET_MEMORY_ATTRIBUTES as needed. 4.140 KVM_SET_MEMORY_ATTRIBUTES ------------------------------- @@ -6127,6 +6151,49 @@ the state of a gfn/page as needed. The "flags" field is reserved for future extensions and must be '0'. +4.141 KVM_CREATE_GUEST_MEMFD +---------------------------- + +:Capability: KVM_CAP_GUEST_MEMFD +:Architectures: none +:Type: vm ioctl +:Parameters: struct struct kvm_create_guest_memfd(in) +:Returns: 0 on success, <0 on error + +KVM_CREATE_GUEST_MEMFD creates an anonymous file and returns a file descriptor +that refers to it. guest_memfd files are roughly analogous to files created +via memfd_create(), e.g. guest_memfd files live in RAM, have volatile storage, +and are automatically released when the last reference is dropped. Unlike +"regular" memfd_create() files, guest_memfd files are bound to their owning +virtual machine (see below), cannot be mapped, read, or written by userspace, +and cannot be resized (guest_memfd files do however support PUNCH_HOLE). + +:: + + struct kvm_create_guest_memfd { + __u64 size; + __u64 flags; + __u64 reserved[6]; + }; + +Conceptually, the inode backing a guest_memfd file represents physical memory, +i.e. is coupled to the virtual machine as a thing, not to a "struct kvm". The +file itself, which is bound to a "struct kvm", is that instance's view of the +underlying memory, e.g. effectively provides the translation of guest addresses +to host memory. This allows for use cases where multiple KVM structures are +used to manage a single virtual machine, e.g. when performing intrahost +migration of a virtual machine. + +KVM currently only supports mapping guest_memfd via KVM_SET_USER_MEMORY_REGION2, +and more specifically via the guest_memfd and guest_memfd_offset fields in +"struct kvm_userspace_memory_region2", where guest_memfd_offset is the offset +into the guest_memfd instance. For a given guest_memfd file, there can be at +most one mapping per page, i.e. binding multiple memory regions to a single +guest_memfd range is not allowed (any number of memory regions can be bound to +a single guest_memfd file, but the bound ranges must not overlap). + +See KVM_SET_USER_MEMORY_REGION2 for additional details. + 5. The kvm_run structure ======================== diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index df573229651b..7de93858054d 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -591,8 +591,20 @@ struct kvm_memory_slot { u32 flags; short id; u16 as_id; + +#ifdef CONFIG_KVM_PRIVATE_MEM + struct { + struct file __rcu *file; + pgoff_t pgoff; + } gmem; +#endif }; +static inline bool kvm_slot_can_be_private(const struct kvm_memory_slot *slot) +{ + return slot && (slot->flags & KVM_MEM_PRIVATE); +} + static inline bool kvm_slot_dirty_track_enabled(const struct kvm_memory_slot *slot) { return slot->flags & KVM_MEM_LOG_DIRTY_PAGES; @@ -687,6 +699,17 @@ static inline int kvm_arch_vcpu_memslots_id(struct kvm_vcpu *vcpu) } #endif +/* + * Arch code must define kvm_arch_has_private_mem if support for private memory + * is enabled. + */ +#if !defined(kvm_arch_has_private_mem) && !IS_ENABLED(CONFIG_KVM_PRIVATE_MEM) +static inline bool kvm_arch_has_private_mem(struct kvm *kvm) +{ + return false; +} +#endif + struct kvm_memslots { u64 generation; atomic_long_t last_used_slot; @@ -1401,6 +1424,7 @@ void *kvm_mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc); void kvm_mmu_invalidate_begin(struct kvm *kvm); void kvm_mmu_invalidate_range_add(struct kvm *kvm, gfn_t start, gfn_t end); void kvm_mmu_invalidate_end(struct kvm *kvm); +bool kvm_mmu_unmap_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range); long kvm_arch_dev_ioctl(struct file *filp, unsigned int ioctl, unsigned long arg); @@ -2356,6 +2380,30 @@ bool kvm_arch_pre_set_memory_attributes(struct kvm *kvm, struct kvm_gfn_range *range); bool kvm_arch_post_set_memory_attributes(struct kvm *kvm, struct kvm_gfn_range *range); + +static inline bool kvm_mem_is_private(struct kvm *kvm, gfn_t gfn) +{ + return IS_ENABLED(CONFIG_KVM_PRIVATE_MEM) && + kvm_get_memory_attributes(kvm, gfn) & KVM_MEMORY_ATTRIBUTE_PRIVATE; +} +#else +static inline bool kvm_mem_is_private(struct kvm *kvm, gfn_t gfn) +{ + return false; +} #endif /* CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES */ +#ifdef CONFIG_KVM_PRIVATE_MEM +int kvm_gmem_get_pfn(struct kvm *kvm, struct kvm_memory_slot *slot, + gfn_t gfn, kvm_pfn_t *pfn, int *max_order); +#else +static inline int kvm_gmem_get_pfn(struct kvm *kvm, + struct kvm_memory_slot *slot, gfn_t gfn, + kvm_pfn_t *pfn, int *max_order) +{ + KVM_BUG_ON(1, kvm); + return -EIO; +} +#endif /* CONFIG_KVM_PRIVATE_MEM */ + #endif diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index 547837feaa28..25caee8d1a80 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -102,7 +102,10 @@ struct kvm_userspace_memory_region2 { __u64 guest_phys_addr; __u64 memory_size; __u64 userspace_addr; - __u64 pad[16]; + __u64 guest_memfd_offset; + __u32 guest_memfd; + __u32 pad1; + __u64 pad2[14]; }; /* @@ -112,6 +115,7 @@ struct kvm_userspace_memory_region2 { */ #define KVM_MEM_LOG_DIRTY_PAGES (1UL << 0) #define KVM_MEM_READONLY (1UL << 1) +#define KVM_MEM_PRIVATE (1UL << 2) /* for KVM_IRQ_LINE */ struct kvm_irq_level { @@ -1212,6 +1216,7 @@ struct kvm_ppc_resize_hpt { #define KVM_CAP_USER_MEMORY2 230 #define KVM_CAP_MEMORY_FAULT_INFO 231 #define KVM_CAP_MEMORY_ATTRIBUTES 232 +#define KVM_CAP_GUEST_MEMFD 233 #ifdef KVM_CAP_IRQ_ROUTING @@ -2290,4 +2295,12 @@ struct kvm_memory_attributes { #define KVM_MEMORY_ATTRIBUTE_PRIVATE (1ULL << 3) +#define KVM_CREATE_GUEST_MEMFD _IOWR(KVMIO, 0xd4, struct kvm_create_guest_memfd) + +struct kvm_create_guest_memfd { + __u64 size; + __u64 flags; + __u64 reserved[6]; +}; + #endif /* __LINUX_KVM_H */ diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig index 5bd7fcaf9089..08afef022db9 100644 --- a/virt/kvm/Kconfig +++ b/virt/kvm/Kconfig @@ -100,3 +100,7 @@ config KVM_GENERIC_MMU_NOTIFIER config KVM_GENERIC_MEMORY_ATTRIBUTES select KVM_GENERIC_MMU_NOTIFIER bool + +config KVM_PRIVATE_MEM + select XARRAY_MULTI + bool diff --git a/virt/kvm/Makefile.kvm b/virt/kvm/Makefile.kvm index 2c27d5d0c367..724c89af78af 100644 --- a/virt/kvm/Makefile.kvm +++ b/virt/kvm/Makefile.kvm @@ -12,3 +12,4 @@ kvm-$(CONFIG_KVM_ASYNC_PF) += $(KVM)/async_pf.o kvm-$(CONFIG_HAVE_KVM_IRQ_ROUTING) += $(KVM)/irqchip.o kvm-$(CONFIG_HAVE_KVM_DIRTY_RING) += $(KVM)/dirty_ring.o kvm-$(CONFIG_HAVE_KVM_PFNCACHE) += $(KVM)/pfncache.o +kvm-$(CONFIG_KVM_PRIVATE_MEM) += $(KVM)/guest_memfd.o diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c new file mode 100644 index 000000000000..98a12da80214 --- /dev/null +++ b/virt/kvm/guest_memfd.c @@ -0,0 +1,548 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include +#include +#include +#include + +#include "kvm_mm.h" + +struct kvm_gmem { + struct kvm *kvm; + struct xarray bindings; + struct list_head entry; +}; + +static struct folio *kvm_gmem_get_folio(struct inode *inode, pgoff_t index) +{ + struct folio *folio; + + /* TODO: Support huge pages. */ + folio = filemap_grab_folio(inode->i_mapping, index); + if (IS_ERR_OR_NULL(folio)) + return NULL; + + /* + * Use the up-to-date flag to track whether or not the memory has been + * zeroed before being handed off to the guest. There is no backing + * storage for the memory, so the folio will remain up-to-date until + * it's removed. + * + * TODO: Skip clearing pages when trusted firmware will do it when + * assigning memory to the guest. + */ + if (!folio_test_uptodate(folio)) { + unsigned long nr_pages = folio_nr_pages(folio); + unsigned long i; + + for (i = 0; i < nr_pages; i++) + clear_highpage(folio_page(folio, i)); + + folio_mark_uptodate(folio); + } + + /* + * Ignore accessed, referenced, and dirty flags. The memory is + * unevictable and there is no storage to write back to. + */ + return folio; +} + +static void kvm_gmem_invalidate_begin(struct kvm_gmem *gmem, pgoff_t start, + pgoff_t end) +{ + bool flush = false, found_memslot = false; + struct kvm_memory_slot *slot; + struct kvm *kvm = gmem->kvm; + unsigned long index; + + xa_for_each_range(&gmem->bindings, index, slot, start, end - 1) { + pgoff_t pgoff = slot->gmem.pgoff; + + struct kvm_gfn_range gfn_range = { + .start = slot->base_gfn + max(pgoff, start) - pgoff, + .end = slot->base_gfn + min(pgoff + slot->npages, end) - pgoff, + .slot = slot, + .may_block = true, + }; + + if (!found_memslot) { + found_memslot = true; + + KVM_MMU_LOCK(kvm); + kvm_mmu_invalidate_begin(kvm); + } + + flush |= kvm_mmu_unmap_gfn_range(kvm, &gfn_range); + } + + if (flush) + kvm_flush_remote_tlbs(kvm); + + if (found_memslot) + KVM_MMU_UNLOCK(kvm); +} + +static void kvm_gmem_invalidate_end(struct kvm_gmem *gmem, pgoff_t start, + pgoff_t end) +{ + struct kvm *kvm = gmem->kvm; + + if (xa_find(&gmem->bindings, &start, end - 1, XA_PRESENT)) { + KVM_MMU_LOCK(kvm); + kvm_mmu_invalidate_end(kvm); + KVM_MMU_UNLOCK(kvm); + } +} + +static long kvm_gmem_punch_hole(struct inode *inode, loff_t offset, loff_t len) +{ + struct list_head *gmem_list = &inode->i_mapping->private_list; + pgoff_t start = offset >> PAGE_SHIFT; + pgoff_t end = (offset + len) >> PAGE_SHIFT; + struct kvm_gmem *gmem; + + /* + * Bindings must stable across invalidation to ensure the start+end + * are balanced. + */ + filemap_invalidate_lock(inode->i_mapping); + + list_for_each_entry(gmem, gmem_list, entry) + kvm_gmem_invalidate_begin(gmem, start, end); + + truncate_inode_pages_range(inode->i_mapping, offset, offset + len - 1); + + list_for_each_entry(gmem, gmem_list, entry) + kvm_gmem_invalidate_end(gmem, start, end); + + filemap_invalidate_unlock(inode->i_mapping); + + return 0; +} + +static long kvm_gmem_allocate(struct inode *inode, loff_t offset, loff_t len) +{ + struct address_space *mapping = inode->i_mapping; + pgoff_t start, index, end; + int r; + + /* Dedicated guest is immutable by default. */ + if (offset + len > i_size_read(inode)) + return -EINVAL; + + filemap_invalidate_lock_shared(mapping); + + start = offset >> PAGE_SHIFT; + end = (offset + len) >> PAGE_SHIFT; + + r = 0; + for (index = start; index < end; ) { + struct folio *folio; + + if (signal_pending(current)) { + r = -EINTR; + break; + } + + folio = kvm_gmem_get_folio(inode, index); + if (!folio) { + r = -ENOMEM; + break; + } + + index = folio_next_index(folio); + + folio_unlock(folio); + folio_put(folio); + + /* 64-bit only, wrapping the index should be impossible. */ + if (WARN_ON_ONCE(!index)) + break; + + cond_resched(); + } + + filemap_invalidate_unlock_shared(mapping); + + return r; +} + +static long kvm_gmem_fallocate(struct file *file, int mode, loff_t offset, + loff_t len) +{ + int ret; + + if (!(mode & FALLOC_FL_KEEP_SIZE)) + return -EOPNOTSUPP; + + if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE)) + return -EOPNOTSUPP; + + if (!PAGE_ALIGNED(offset) || !PAGE_ALIGNED(len)) + return -EINVAL; + + if (mode & FALLOC_FL_PUNCH_HOLE) + ret = kvm_gmem_punch_hole(file_inode(file), offset, len); + else + ret = kvm_gmem_allocate(file_inode(file), offset, len); + + if (!ret) + file_modified(file); + return ret; +} + +static int kvm_gmem_release(struct inode *inode, struct file *file) +{ + struct kvm_gmem *gmem = file->private_data; + struct kvm_memory_slot *slot; + struct kvm *kvm = gmem->kvm; + unsigned long index; + + /* + * Prevent concurrent attempts to *unbind* a memslot. This is the last + * reference to the file and thus no new bindings can be created, but + * dereferencing the slot for existing bindings needs to be protected + * against memslot updates, specifically so that unbind doesn't race + * and free the memslot (kvm_gmem_get_file() will return NULL). + */ + mutex_lock(&kvm->slots_lock); + + filemap_invalidate_lock(inode->i_mapping); + + xa_for_each(&gmem->bindings, index, slot) + rcu_assign_pointer(slot->gmem.file, NULL); + + synchronize_rcu(); + + /* + * All in-flight operations are gone and new bindings can be created. + * Zap all SPTEs pointed at by this file. Do not free the backing + * memory, as its lifetime is associated with the inode, not the file. + */ + kvm_gmem_invalidate_begin(gmem, 0, -1ul); + kvm_gmem_invalidate_end(gmem, 0, -1ul); + + list_del(&gmem->entry); + + filemap_invalidate_unlock(inode->i_mapping); + + mutex_unlock(&kvm->slots_lock); + + xa_destroy(&gmem->bindings); + kfree(gmem); + + kvm_put_kvm(kvm); + + return 0; +} + +static struct file *kvm_gmem_get_file(struct kvm_memory_slot *slot) +{ + struct file *file; + + rcu_read_lock(); + + file = rcu_dereference(slot->gmem.file); + if (file && !get_file_rcu(file)) + file = NULL; + + rcu_read_unlock(); + + return file; +} + +static struct file_operations kvm_gmem_fops = { + .open = generic_file_open, + .release = kvm_gmem_release, + .fallocate = kvm_gmem_fallocate, +}; + +void kvm_gmem_init(struct module *module) +{ + kvm_gmem_fops.owner = module; +} + +static int kvm_gmem_migrate_folio(struct address_space *mapping, + struct folio *dst, struct folio *src, + enum migrate_mode mode) +{ + WARN_ON_ONCE(1); + return -EINVAL; +} + +static int kvm_gmem_error_page(struct address_space *mapping, struct page *page) +{ + struct list_head *gmem_list = &mapping->private_list; + struct kvm_gmem *gmem; + pgoff_t start, end; + + filemap_invalidate_lock_shared(mapping); + + start = page->index; + end = start + thp_nr_pages(page); + + list_for_each_entry(gmem, gmem_list, entry) + kvm_gmem_invalidate_begin(gmem, start, end); + + /* + * Do not truncate the range, what action is taken in response to the + * error is userspace's decision (assuming the architecture supports + * gracefully handling memory errors). If/when the guest attempts to + * access a poisoned page, kvm_gmem_get_pfn() will return -EHWPOISON, + * at which point KVM can either terminate the VM or propagate the + * error to userspace. + */ + + list_for_each_entry(gmem, gmem_list, entry) + kvm_gmem_invalidate_end(gmem, start, end); + + filemap_invalidate_unlock_shared(mapping); + + return MF_DELAYED; +} + +static const struct address_space_operations kvm_gmem_aops = { + .dirty_folio = noop_dirty_folio, +#ifdef CONFIG_MIGRATION + .migrate_folio = kvm_gmem_migrate_folio, +#endif + .error_remove_page = kvm_gmem_error_page, +}; + +static int kvm_gmem_getattr(struct mnt_idmap *idmap, const struct path *path, + struct kstat *stat, u32 request_mask, + unsigned int query_flags) +{ + struct inode *inode = path->dentry->d_inode; + + /* TODO */ + generic_fillattr(idmap, request_mask, inode, stat); + return 0; +} + +static int kvm_gmem_setattr(struct mnt_idmap *idmap, struct dentry *dentry, + struct iattr *attr) +{ + /* TODO */ + return -EINVAL; +} +static const struct inode_operations kvm_gmem_iops = { + .getattr = kvm_gmem_getattr, + .setattr = kvm_gmem_setattr, +}; + +static int __kvm_gmem_create(struct kvm *kvm, loff_t size, u64 flags) +{ + const char *anon_name = "[kvm-gmem]"; + struct kvm_gmem *gmem; + struct inode *inode; + struct file *file; + int fd, err; + + fd = get_unused_fd_flags(0); + if (fd < 0) + return fd; + + gmem = kzalloc(sizeof(*gmem), GFP_KERNEL); + if (!gmem) { + err = -ENOMEM; + goto err_fd; + } + + /* + * Use the so called "secure" variant, which creates a unique inode + * instead of reusing a single inode. Each guest_memfd instance needs + * its own inode to track the size, flags, etc. + */ + file = anon_inode_getfile_secure(anon_name, &kvm_gmem_fops, gmem, + O_RDWR, NULL); + if (IS_ERR(file)) { + err = PTR_ERR(file); + goto err_gmem; + } + + file->f_flags |= O_LARGEFILE; + + inode = file->f_inode; + WARN_ON(file->f_mapping != inode->i_mapping); + + inode->i_private = (void *)(unsigned long)flags; + inode->i_op = &kvm_gmem_iops; + inode->i_mapping->a_ops = &kvm_gmem_aops; + inode->i_mode |= S_IFREG; + inode->i_size = size; + mapping_set_gfp_mask(inode->i_mapping, GFP_HIGHUSER); + mapping_set_unmovable(inode->i_mapping); + /* Unmovable mappings are supposed to be marked unevictable as well. */ + WARN_ON_ONCE(!mapping_unevictable(inode->i_mapping)); + + kvm_get_kvm(kvm); + gmem->kvm = kvm; + xa_init(&gmem->bindings); + list_add(&gmem->entry, &inode->i_mapping->private_list); + + fd_install(fd, file); + return fd; + +err_gmem: + kfree(gmem); +err_fd: + put_unused_fd(fd); + return err; +} + +int kvm_gmem_create(struct kvm *kvm, struct kvm_create_guest_memfd *args) +{ + loff_t size = args->size; + u64 flags = args->flags; + u64 valid_flags = 0; + + if (flags & ~valid_flags) + return -EINVAL; + + if (size < 0 || !PAGE_ALIGNED(size)) + return -EINVAL; + + return __kvm_gmem_create(kvm, size, flags); +} + +int kvm_gmem_bind(struct kvm *kvm, struct kvm_memory_slot *slot, + unsigned int fd, loff_t offset) +{ + loff_t size = slot->npages << PAGE_SHIFT; + unsigned long start, end; + struct kvm_gmem *gmem; + struct inode *inode; + struct file *file; + + BUILD_BUG_ON(sizeof(gfn_t) != sizeof(slot->gmem.pgoff)); + + file = fget(fd); + if (!file) + return -EBADF; + + if (file->f_op != &kvm_gmem_fops) + goto err; + + gmem = file->private_data; + if (gmem->kvm != kvm) + goto err; + + inode = file_inode(file); + + if (offset < 0 || !PAGE_ALIGNED(offset)) + return -EINVAL; + + if (offset + size > i_size_read(inode)) + goto err; + + filemap_invalidate_lock(inode->i_mapping); + + start = offset >> PAGE_SHIFT; + end = start + slot->npages; + + if (!xa_empty(&gmem->bindings) && + xa_find(&gmem->bindings, &start, end - 1, XA_PRESENT)) { + filemap_invalidate_unlock(inode->i_mapping); + goto err; + } + + /* + * No synchronize_rcu() needed, any in-flight readers are guaranteed to + * be see either a NULL file or this new file, no need for them to go + * away. + */ + rcu_assign_pointer(slot->gmem.file, file); + slot->gmem.pgoff = start; + + xa_store_range(&gmem->bindings, start, end - 1, slot, GFP_KERNEL); + filemap_invalidate_unlock(inode->i_mapping); + + /* + * Drop the reference to the file, even on success. The file pins KVM, + * not the other way 'round. Active bindings are invalidated if the + * file is closed before memslots are destroyed. + */ + fput(file); + return 0; + +err: + fput(file); + return -EINVAL; +} + +void kvm_gmem_unbind(struct kvm_memory_slot *slot) +{ + unsigned long start = slot->gmem.pgoff; + unsigned long end = start + slot->npages; + struct kvm_gmem *gmem; + struct file *file; + + /* + * Nothing to do if the underlying file was already closed (or is being + * closed right now), kvm_gmem_release() invalidates all bindings. + */ + file = kvm_gmem_get_file(slot); + if (!file) + return; + + gmem = file->private_data; + + filemap_invalidate_lock(file->f_mapping); + xa_store_range(&gmem->bindings, start, end - 1, NULL, GFP_KERNEL); + rcu_assign_pointer(slot->gmem.file, NULL); + synchronize_rcu(); + filemap_invalidate_unlock(file->f_mapping); + + fput(file); +} + +int kvm_gmem_get_pfn(struct kvm *kvm, struct kvm_memory_slot *slot, + gfn_t gfn, kvm_pfn_t *pfn, int *max_order) +{ + pgoff_t index = gfn - slot->base_gfn + slot->gmem.pgoff; + struct kvm_gmem *gmem; + struct folio *folio; + struct page *page; + struct file *file; + int r; + + file = kvm_gmem_get_file(slot); + if (!file) + return -EFAULT; + + gmem = file->private_data; + + if (WARN_ON_ONCE(xa_load(&gmem->bindings, index) != slot)) { + r = -EIO; + goto out_fput; + } + + folio = kvm_gmem_get_folio(file_inode(file), index); + if (!folio) { + r = -ENOMEM; + goto out_fput; + } + + if (folio_test_hwpoison(folio)) { + r = -EHWPOISON; + goto out_unlock; + } + + page = folio_file_page(folio, index); + + *pfn = page_to_pfn(page); + if (max_order) + *max_order = 0; + + r = 0; + +out_unlock: + folio_unlock(folio); +out_fput: + fput(file); + + return r; +} +EXPORT_SYMBOL_GPL(kvm_gmem_get_pfn); diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 78a0b09ef2a5..5d1a2f1b4e94 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -798,7 +798,7 @@ void kvm_mmu_invalidate_range_add(struct kvm *kvm, gfn_t start, gfn_t end) } } -static bool kvm_mmu_unmap_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range) +bool kvm_mmu_unmap_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range) { kvm_mmu_invalidate_range_add(kvm, range->start, range->end); return kvm_unmap_gfn_range(kvm, range); @@ -1034,6 +1034,9 @@ static void kvm_destroy_dirty_bitmap(struct kvm_memory_slot *memslot) /* This does not remove the slot from struct kvm_memslots data structures */ static void kvm_free_memslot(struct kvm *kvm, struct kvm_memory_slot *slot) { + if (slot->flags & KVM_MEM_PRIVATE) + kvm_gmem_unbind(slot); + kvm_destroy_dirty_bitmap(slot); kvm_arch_free_memslot(kvm, slot); @@ -1605,10 +1608,18 @@ static void kvm_replace_memslot(struct kvm *kvm, } } -static int check_memory_region_flags(const struct kvm_userspace_memory_region2 *mem) +static int check_memory_region_flags(struct kvm *kvm, + const struct kvm_userspace_memory_region2 *mem) { u32 valid_flags = KVM_MEM_LOG_DIRTY_PAGES; + if (kvm_arch_has_private_mem(kvm)) + valid_flags |= KVM_MEM_PRIVATE; + + /* Dirty logging private memory is not currently supported. */ + if (mem->flags & KVM_MEM_PRIVATE) + valid_flags &= ~KVM_MEM_LOG_DIRTY_PAGES; + #ifdef __KVM_HAVE_READONLY_MEM valid_flags |= KVM_MEM_READONLY; #endif @@ -2017,7 +2028,7 @@ int __kvm_set_memory_region(struct kvm *kvm, int as_id, id; int r; - r = check_memory_region_flags(mem); + r = check_memory_region_flags(kvm, mem); if (r) return r; @@ -2036,6 +2047,10 @@ int __kvm_set_memory_region(struct kvm *kvm, !access_ok((void __user *)(unsigned long)mem->userspace_addr, mem->memory_size)) return -EINVAL; + if (mem->flags & KVM_MEM_PRIVATE && + (mem->guest_memfd_offset & (PAGE_SIZE - 1) || + mem->guest_memfd_offset + mem->memory_size < mem->guest_memfd_offset)) + return -EINVAL; if (as_id >= KVM_ADDRESS_SPACE_NUM || id >= KVM_MEM_SLOTS_NUM) return -EINVAL; if (mem->guest_phys_addr + mem->memory_size < mem->guest_phys_addr) @@ -2074,6 +2089,9 @@ int __kvm_set_memory_region(struct kvm *kvm, if ((kvm->nr_memslot_pages + npages) < kvm->nr_memslot_pages) return -EINVAL; } else { /* Modify an existing slot. */ + /* Private memslots are immutable, they can only be deleted. */ + if (mem->flags & KVM_MEM_PRIVATE) + return -EINVAL; if ((mem->userspace_addr != old->userspace_addr) || (npages != old->npages) || ((mem->flags ^ old->flags) & KVM_MEM_READONLY)) @@ -2102,10 +2120,23 @@ int __kvm_set_memory_region(struct kvm *kvm, new->npages = npages; new->flags = mem->flags; new->userspace_addr = mem->userspace_addr; + if (mem->flags & KVM_MEM_PRIVATE) { + r = kvm_gmem_bind(kvm, new, mem->guest_memfd, mem->guest_memfd_offset); + if (r) + goto out; + } r = kvm_set_memslot(kvm, old, new, change); if (r) - kfree(new); + goto out_unbind; + + return 0; + +out_unbind: + if (mem->flags & KVM_MEM_PRIVATE) + kvm_gmem_unbind(new); +out: + kfree(new); return r; } EXPORT_SYMBOL_GPL(__kvm_set_memory_region); @@ -2441,7 +2472,7 @@ bool kvm_range_has_memory_attributes(struct kvm *kvm, gfn_t start, gfn_t end, static u64 kvm_supported_mem_attributes(struct kvm *kvm) { - if (!kvm) + if (!kvm || kvm_arch_has_private_mem(kvm)) return KVM_MEMORY_ATTRIBUTE_PRIVATE; return 0; @@ -4852,14 +4883,11 @@ static int kvm_vm_ioctl_check_extension_generic(struct kvm *kvm, long arg) return 1; #ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES case KVM_CAP_MEMORY_ATTRIBUTES: - u64 attrs = kvm_supported_mem_attributes(kvm); - - r = -EFAULT; - if (copy_to_user(argp, &attrs, sizeof(attrs))) - goto out; - r = 0; - break; - } + return kvm_supported_mem_attributes(kvm); +#endif +#ifdef CONFIG_KVM_PRIVATE_MEM + case KVM_CAP_GUEST_MEMFD: + return !kvm || kvm_arch_has_private_mem(kvm); #endif default: break; @@ -5282,6 +5310,18 @@ static long kvm_vm_ioctl(struct file *filp, case KVM_GET_STATS_FD: r = kvm_vm_ioctl_get_stats_fd(kvm); break; +#ifdef CONFIG_KVM_PRIVATE_MEM + case KVM_CREATE_GUEST_MEMFD: { + struct kvm_create_guest_memfd guest_memfd; + + r = -EFAULT; + if (copy_from_user(&guest_memfd, argp, sizeof(guest_memfd))) + goto out; + + r = kvm_gmem_create(kvm, &guest_memfd); + break; + } +#endif default: r = kvm_arch_vm_ioctl(filp, ioctl, arg); } @@ -6414,6 +6454,8 @@ int kvm_init(unsigned vcpu_size, unsigned vcpu_align, struct module *module) if (WARN_ON_ONCE(r)) goto err_vfio; + kvm_gmem_init(module); + /* * Registration _must_ be the very last thing done, as this exposes * /dev/kvm to userspace, i.e. all infrastructure must be setup! diff --git a/virt/kvm/kvm_mm.h b/virt/kvm/kvm_mm.h index 180f1a09e6ba..ecefc7ec51af 100644 --- a/virt/kvm/kvm_mm.h +++ b/virt/kvm/kvm_mm.h @@ -37,4 +37,30 @@ static inline void gfn_to_pfn_cache_invalidate_start(struct kvm *kvm, } #endif /* HAVE_KVM_PFNCACHE */ +#ifdef CONFIG_KVM_PRIVATE_MEM +void kvm_gmem_init(struct module *module); +int kvm_gmem_create(struct kvm *kvm, struct kvm_create_guest_memfd *args); +int kvm_gmem_bind(struct kvm *kvm, struct kvm_memory_slot *slot, + unsigned int fd, loff_t offset); +void kvm_gmem_unbind(struct kvm_memory_slot *slot); +#else +static inline void kvm_gmem_init(struct module *module) +{ + +} + +static inline int kvm_gmem_bind(struct kvm *kvm, + struct kvm_memory_slot *slot, + unsigned int fd, loff_t offset) +{ + WARN_ON_ONCE(1); + return -EIO; +} + +static inline void kvm_gmem_unbind(struct kvm_memory_slot *slot) +{ + WARN_ON_ONCE(1); +} +#endif /* CONFIG_KVM_PRIVATE_MEM */ + #endif /* __KVM_MM_H__ */ From patchwork Fri Oct 27 18:21:59 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 13438879 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1F9753D3AD for ; 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Fri, 27 Oct 2023 11:22:59 -0700 (PDT) Reply-To: Sean Christopherson Date: Fri, 27 Oct 2023 11:21:59 -0700 In-Reply-To: <20231027182217.3615211-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20231027182217.3615211-1-seanjc@google.com> X-Mailer: git-send-email 2.42.0.820.g83a721a137-goog Message-ID: <20231027182217.3615211-18-seanjc@google.com> Subject: [PATCH v13 17/35] KVM: Add transparent hugepage support for dedicated guest memory From: Sean Christopherson To: Paolo Bonzini , Marc Zyngier , Oliver Upton , Huacai Chen , Michael Ellerman , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Sean Christopherson , Alexander Viro , Christian Brauner , "Matthew Wilcox (Oracle)" , Andrew Morton Cc: kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Xiaoyao Li , Xu Yilun , Chao Peng , Fuad Tabba , Jarkko Sakkinen , Anish Moorthy , David Matlack , Yu Zhang , Isaku Yamahata , " =?utf-8?q?Micka=C3=ABl_Sala?= =?utf-8?q?=C3=BCn?= " , Vlastimil Babka , Vishal Annapurve , Ackerley Tng , Maciej Szmigiero , David Hildenbrand , Quentin Perret , Michael Roth , Wang , Liam Merwick , Isaku Yamahata , "Kirill A . Shutemov" Extended guest_memfd to allow backing guest memory with transparent hugepages. Require userspace to opt-in via a flag even though there's no known/anticipated use case for forcing small pages as THP is optional, i.e. to avoid ending up in a situation where userspace is unaware that KVM can't provide hugepages. For simplicity, require the guest_memfd size to be a multiple of the hugepage size, e.g. so that KVM doesn't need to do bounds checking when deciding whether or not to allocate a huge folio. When reporting the max order when KVM gets a pfn from guest_memfd, force order-0 pages if the hugepage is not fully contained by the memslot binding, e.g. if userspace requested hugepages but punches a hole in the memslot bindings in order to emulate x86's VGA hole. Signed-off-by: Sean Christopherson Signed-off-by: Sean Christopherson --- Documentation/virt/kvm/api.rst | 7 ++++ include/uapi/linux/kvm.h | 2 + virt/kvm/guest_memfd.c | 73 ++++++++++++++++++++++++++++++---- 3 files changed, 75 insertions(+), 7 deletions(-) diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index e82c69d5e755..7f00c310c24a 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -6176,6 +6176,8 @@ and cannot be resized (guest_memfd files do however support PUNCH_HOLE). __u64 reserved[6]; }; + #define KVM_GUEST_MEMFD_ALLOW_HUGEPAGE (1ULL << 0) + Conceptually, the inode backing a guest_memfd file represents physical memory, i.e. is coupled to the virtual machine as a thing, not to a "struct kvm". The file itself, which is bound to a "struct kvm", is that instance's view of the @@ -6192,6 +6194,11 @@ most one mapping per page, i.e. binding multiple memory regions to a single guest_memfd range is not allowed (any number of memory regions can be bound to a single guest_memfd file, but the bound ranges must not overlap). +If KVM_GUEST_MEMFD_ALLOW_HUGEPAGE is set in flags, KVM will attempt to allocate +and map hugepages for the guest_memfd file. This is currently best effort. If +KVM_GUEST_MEMFD_ALLOW_HUGEPAGE is set, the size must be aligned to the maximum +transparent hugepage size supported by the kernel + See KVM_SET_USER_MEMORY_REGION2 for additional details. 5. The kvm_run structure diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index 25caee8d1a80..33d542de0a61 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -2303,4 +2303,6 @@ struct kvm_create_guest_memfd { __u64 reserved[6]; }; +#define KVM_GUEST_MEMFD_ALLOW_HUGEPAGE (1ULL << 0) + #endif /* __LINUX_KVM_H */ diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c index 98a12da80214..94bc478c26f3 100644 --- a/virt/kvm/guest_memfd.c +++ b/virt/kvm/guest_memfd.c @@ -13,14 +13,47 @@ struct kvm_gmem { struct list_head entry; }; +static struct folio *kvm_gmem_get_huge_folio(struct inode *inode, pgoff_t index) +{ +#ifdef CONFIG_TRANSPARENT_HUGEPAGE + unsigned long huge_index = round_down(index, HPAGE_PMD_NR); + unsigned long flags = (unsigned long)inode->i_private; + struct address_space *mapping = inode->i_mapping; + gfp_t gfp = mapping_gfp_mask(mapping); + struct folio *folio; + + if (!(flags & KVM_GUEST_MEMFD_ALLOW_HUGEPAGE)) + return NULL; + + if (filemap_range_has_page(mapping, huge_index << PAGE_SHIFT, + (huge_index + HPAGE_PMD_NR - 1) << PAGE_SHIFT)) + return NULL; + + folio = filemap_alloc_folio(gfp, HPAGE_PMD_ORDER); + if (!folio) + return NULL; + + if (filemap_add_folio(mapping, folio, huge_index, gfp)) { + folio_put(folio); + return NULL; + } + + return folio; +#else + return NULL; +#endif +} + static struct folio *kvm_gmem_get_folio(struct inode *inode, pgoff_t index) { struct folio *folio; - /* TODO: Support huge pages. */ - folio = filemap_grab_folio(inode->i_mapping, index); - if (IS_ERR_OR_NULL(folio)) - return NULL; + folio = kvm_gmem_get_huge_folio(inode, index); + if (!folio) { + folio = filemap_grab_folio(inode->i_mapping, index); + if (IS_ERR_OR_NULL(folio)) + return NULL; + } /* * Use the up-to-date flag to track whether or not the memory has been @@ -373,6 +406,7 @@ static int __kvm_gmem_create(struct kvm *kvm, loff_t size, u64 flags) inode->i_mode |= S_IFREG; inode->i_size = size; mapping_set_gfp_mask(inode->i_mapping, GFP_HIGHUSER); + mapping_set_large_folios(inode->i_mapping); mapping_set_unmovable(inode->i_mapping); /* Unmovable mappings are supposed to be marked unevictable as well. */ WARN_ON_ONCE(!mapping_unevictable(inode->i_mapping)); @@ -398,12 +432,21 @@ int kvm_gmem_create(struct kvm *kvm, struct kvm_create_guest_memfd *args) u64 flags = args->flags; u64 valid_flags = 0; + if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)) + valid_flags |= KVM_GUEST_MEMFD_ALLOW_HUGEPAGE; + if (flags & ~valid_flags) return -EINVAL; if (size < 0 || !PAGE_ALIGNED(size)) return -EINVAL; +#ifdef CONFIG_TRANSPARENT_HUGEPAGE + if ((flags & KVM_GUEST_MEMFD_ALLOW_HUGEPAGE) && + !IS_ALIGNED(size, HPAGE_PMD_SIZE)) + return -EINVAL; +#endif + return __kvm_gmem_create(kvm, size, flags); } @@ -501,7 +544,7 @@ void kvm_gmem_unbind(struct kvm_memory_slot *slot) int kvm_gmem_get_pfn(struct kvm *kvm, struct kvm_memory_slot *slot, gfn_t gfn, kvm_pfn_t *pfn, int *max_order) { - pgoff_t index = gfn - slot->base_gfn + slot->gmem.pgoff; + pgoff_t index, huge_index; struct kvm_gmem *gmem; struct folio *folio; struct page *page; @@ -514,6 +557,7 @@ int kvm_gmem_get_pfn(struct kvm *kvm, struct kvm_memory_slot *slot, gmem = file->private_data; + index = gfn - slot->base_gfn + slot->gmem.pgoff; if (WARN_ON_ONCE(xa_load(&gmem->bindings, index) != slot)) { r = -EIO; goto out_fput; @@ -533,9 +577,24 @@ int kvm_gmem_get_pfn(struct kvm *kvm, struct kvm_memory_slot *slot, page = folio_file_page(folio, index); *pfn = page_to_pfn(page); - if (max_order) + if (!max_order) + goto success; + + *max_order = compound_order(compound_head(page)); + if (!*max_order) + goto success; + + /* + * The folio can be mapped with a hugepage if and only if the folio is + * fully contained by the range the memslot is bound to. 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Shutemov" Initialize run->exit_reason to KVM_EXIT_UNKNOWN early in KVM_RUN to reduce the probability of exiting to userspace with a stale run->exit_reason that *appears* to be valid. To support fd-based guest memory (guest memory without a corresponding userspace virtual address), KVM will exit to userspace for various memory related errors, which userspace *may* be able to resolve, instead of using e.g. BUS_MCEERR_AR. And in the more distant future, KVM will also likely utilize the same functionality to let userspace "intercept" and handle memory faults when the userspace mapping is missing, i.e. when fast gup() fails. Because many of KVM's internal APIs related to guest memory use '0' to indicate "success, continue on" and not "exit to userspace", reporting memory faults/errors to userspace will set run->exit_reason and corresponding fields in the run structure fields in conjunction with a a non-zero, negative return code, e.g. -EFAULT or -EHWPOISON. And because KVM already returns -EFAULT in many paths, there's a relatively high probability that KVM could return -EFAULT without setting run->exit_reason, in which case reporting KVM_EXIT_UNKNOWN is much better than reporting whatever exit reason happened to be in the run structure. Note, KVM must wait until after run->immediate_exit is serviced to sanitize run->exit_reason as KVM's ABI is that run->exit_reason is preserved across KVM_RUN when run->immediate_exit is true. Link: https://lore.kernel.org/all/20230908222905.1321305-1-amoorthy@google.com Link: https://lore.kernel.org/all/ZFFbwOXZ5uI%2Fgdaf@google.com Signed-off-by: Sean Christopherson Reviewed-by: Paolo Bonzini Reviewed-by: Fuad Tabba Tested-by: Fuad Tabba --- arch/x86/kvm/x86.c | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index ee3cd8c3c0ef..f41dbb1465a0 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -10963,6 +10963,7 @@ static int vcpu_run(struct kvm_vcpu *vcpu) { int r; + vcpu->run->exit_reason = KVM_EXIT_UNKNOWN; vcpu->arch.l1tf_flush_l1d = true; for (;;) { From patchwork Fri Oct 27 18:22:01 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 13438881 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 893C03D99E for ; Fri, 27 Oct 2023 18:23:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="TAsoyKwQ" Received: from mail-pl1-x649.google.com (mail-pl1-x649.google.com [IPv6:2607:f8b0:4864:20::649]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 429481BC1 for ; Fri, 27 Oct 2023 11:23:06 -0700 (PDT) Received: by mail-pl1-x649.google.com with SMTP id d9443c01a7336-1c9b774f193so19399585ad.0 for ; Fri, 27 Oct 2023 11:23:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1698430983; x=1699035783; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:from:to:cc:subject:date:message-id:reply-to; bh=X28f2VSZ9uWGkcVQfgyyaL29edWIecAA+BgvPUM1/nQ=; b=TAsoyKwQrRhBkC2T0BV9UzlM42kysMX9+ACqmd/QXr1ijh4RLJ1VlJ4hQPZ4OoCnoP nbCZYhY6pekvlLoUCyZzAwSa+yMc1r43rJfCUAkFISwOFZGHtBAGnEcZa02h/8wBwJdx jSrpIw1Kf0BksuhGm6AkW1SBhu460Fukx/mJT79P4oAo+yp88qo3Bx+q6fn13Zixczmv bT3sGPjIm5mhwuwIz88+7+mCTJmQ/nnl5aiv/qhMojHS9SHHhTZ2DnajDqD5h8uBX8V8 l6DnOXn656nXWd1FKXoRCbrVr+m2oqTQ9B+oMX0yOUdPnYAe4dCLtk6BYZW/7PjKBCdh yrJA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1698430983; x=1699035783; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=X28f2VSZ9uWGkcVQfgyyaL29edWIecAA+BgvPUM1/nQ=; b=DekcAQFinSy4a1XpwN8AhTWWPtMp9FdVT/fR/Qbc3Io/D9qk2smYS6rA/Wb7+yl6bC oA6s7PtPKo4tYiZknUPk6UXQ9ZgR83XS81VmxIV0I4Q/+BMcyjz60fvQp7Nof+8cQfp3 aLE+oWDLxu7h5r7xbdDg1TckRLgeyXrbF5KQetgJdqzfbobtoz0downbudUeW8Cr0THO Phez+vgI3p2sZUNoqkd3LHmndAAL9hEY+w5GFdul+g0P7TXUU+7pNZIZeYBVN/i2pOzu M0ddDUnNqmTCfP94Fp6uCyeeRXQxSpB3iwqmSzM2ZWEgYpvq9qGCG9d1SUAQELsQClec F6EQ== X-Gm-Message-State: AOJu0Yx5WOI+rPxuekYGpEMgTa+YxkKzZoQt1zNIasxUgLJr75NvzJiv MpyNwzIgYInVdamT1Ka5ZnXIXi3Rddk= X-Google-Smtp-Source: AGHT+IERP39eT1EKIW0o0w4FIDOku618XMvV1N7KQCMi55hnYoVKlxflcru5UfA66foRhtHASvLd2ndsc5U= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a17:902:d4cc:b0:1cc:1900:28d7 with SMTP id o12-20020a170902d4cc00b001cc190028d7mr82404plg.12.1698430983359; Fri, 27 Oct 2023 11:23:03 -0700 (PDT) Reply-To: Sean Christopherson Date: Fri, 27 Oct 2023 11:22:01 -0700 In-Reply-To: <20231027182217.3615211-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20231027182217.3615211-1-seanjc@google.com> X-Mailer: git-send-email 2.42.0.820.g83a721a137-goog Message-ID: <20231027182217.3615211-20-seanjc@google.com> Subject: [PATCH v13 19/35] KVM: x86: Disallow hugepages when memory attributes are mixed From: Sean Christopherson To: Paolo Bonzini , Marc Zyngier , Oliver Upton , Huacai Chen , Michael Ellerman , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Sean Christopherson , Alexander Viro , Christian Brauner , "Matthew Wilcox (Oracle)" , Andrew Morton Cc: kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Xiaoyao Li , Xu Yilun , Chao Peng , Fuad Tabba , Jarkko Sakkinen , Anish Moorthy , David Matlack , Yu Zhang , Isaku Yamahata , " =?utf-8?q?Micka=C3=ABl_Sala?= =?utf-8?q?=C3=BCn?= " , Vlastimil Babka , Vishal Annapurve , Ackerley Tng , Maciej Szmigiero , David Hildenbrand , Quentin Perret , Michael Roth , Wang , Liam Merwick , Isaku Yamahata , "Kirill A . Shutemov" From: Chao Peng Disallow creating hugepages with mixed memory attributes, e.g. shared versus private, as mapping a hugepage in this case would allow the guest to access memory with the wrong attributes, e.g. overlaying private memory with a shared hugepage. Tracking whether or not attributes are mixed via the existing disallow_lpage field, but use the most significant bit in 'disallow_lpage' to indicate a hugepage has mixed attributes instead using the normal refcounting. Whether or not attributes are mixed is binary; either they are or they aren't. Attempting to squeeze that info into the refcount is unnecessarily complex as it would require knowing the previous state of the mixed count when updating attributes. Using a flag means KVM just needs to ensure the current status is reflected in the memslots. Signed-off-by: Chao Peng Co-developed-by: Sean Christopherson Signed-off-by: Sean Christopherson --- arch/x86/include/asm/kvm_host.h | 3 + arch/x86/kvm/mmu/mmu.c | 154 +++++++++++++++++++++++++++++++- arch/x86/kvm/x86.c | 4 + 3 files changed, 159 insertions(+), 2 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 31e84668014e..8d60e4745e8b 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -1836,6 +1836,9 @@ int kvm_mmu_create(struct kvm_vcpu *vcpu); void kvm_mmu_init_vm(struct kvm *kvm); void kvm_mmu_uninit_vm(struct kvm *kvm); +void kvm_mmu_init_memslot_memory_attributes(struct kvm *kvm, + struct kvm_memory_slot *slot); + void kvm_mmu_after_set_cpuid(struct kvm_vcpu *vcpu); void kvm_mmu_reset_context(struct kvm_vcpu *vcpu); void kvm_mmu_slot_remove_write_access(struct kvm *kvm, diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index d33657d61d80..4167d557c577 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -795,16 +795,26 @@ static struct kvm_lpage_info *lpage_info_slot(gfn_t gfn, return &slot->arch.lpage_info[level - 2][idx]; } +/* + * The most significant bit in disallow_lpage tracks whether or not memory + * attributes are mixed, i.e. not identical for all gfns at the current level. + * The lower order bits are used to refcount other cases where a hugepage is + * disallowed, e.g. if KVM has shadow a page table at the gfn. + */ +#define KVM_LPAGE_MIXED_FLAG BIT(31) + static void update_gfn_disallow_lpage_count(const struct kvm_memory_slot *slot, gfn_t gfn, int count) { struct kvm_lpage_info *linfo; - int i; + int old, i; for (i = PG_LEVEL_2M; i <= KVM_MAX_HUGEPAGE_LEVEL; ++i) { linfo = lpage_info_slot(gfn, slot, i); + + old = linfo->disallow_lpage; linfo->disallow_lpage += count; - WARN_ON_ONCE(linfo->disallow_lpage < 0); + WARN_ON_ONCE((old ^ linfo->disallow_lpage) & KVM_LPAGE_MIXED_FLAG); } } @@ -7161,3 +7171,143 @@ void kvm_mmu_pre_destroy_vm(struct kvm *kvm) if (kvm->arch.nx_huge_page_recovery_thread) kthread_stop(kvm->arch.nx_huge_page_recovery_thread); } + +#ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES +static bool hugepage_test_mixed(struct kvm_memory_slot *slot, gfn_t gfn, + int level) +{ + return lpage_info_slot(gfn, slot, level)->disallow_lpage & KVM_LPAGE_MIXED_FLAG; +} + +static void hugepage_clear_mixed(struct kvm_memory_slot *slot, gfn_t gfn, + int level) +{ + lpage_info_slot(gfn, slot, level)->disallow_lpage &= ~KVM_LPAGE_MIXED_FLAG; +} + +static void hugepage_set_mixed(struct kvm_memory_slot *slot, gfn_t gfn, + int level) +{ + lpage_info_slot(gfn, slot, level)->disallow_lpage |= KVM_LPAGE_MIXED_FLAG; +} + +static bool hugepage_has_attrs(struct kvm *kvm, struct kvm_memory_slot *slot, + gfn_t gfn, int level, unsigned long attrs) +{ + const unsigned long start = gfn; + const unsigned long end = start + KVM_PAGES_PER_HPAGE(level); + + if (level == PG_LEVEL_2M) + return kvm_range_has_memory_attributes(kvm, start, end, attrs); + + for (gfn = start; gfn < end; gfn += KVM_PAGES_PER_HPAGE(level - 1)) { + if (hugepage_test_mixed(slot, gfn, level - 1) || + attrs != kvm_get_memory_attributes(kvm, gfn)) + return false; + } + return true; +} + +bool kvm_arch_post_set_memory_attributes(struct kvm *kvm, + struct kvm_gfn_range *range) +{ + unsigned long attrs = range->arg.attributes; + struct kvm_memory_slot *slot = range->slot; + int level; + + lockdep_assert_held_write(&kvm->mmu_lock); + lockdep_assert_held(&kvm->slots_lock); + + /* + * Calculate which ranges can be mapped with hugepages even if the slot + * can't map memory PRIVATE. KVM mustn't create a SHARED hugepage over + * a range that has PRIVATE GFNs, and conversely converting a range to + * SHARED may now allow hugepages. + */ + if (WARN_ON_ONCE(!kvm_arch_has_private_mem(kvm))) + return false; + + /* + * The sequence matters here: upper levels consume the result of lower + * level's scanning. + */ + for (level = PG_LEVEL_2M; level <= KVM_MAX_HUGEPAGE_LEVEL; level++) { + gfn_t nr_pages = KVM_PAGES_PER_HPAGE(level); + gfn_t gfn = gfn_round_for_level(range->start, level); + + /* Process the head page if it straddles the range. */ + if (gfn != range->start || gfn + nr_pages > range->end) { + /* + * Skip mixed tracking if the aligned gfn isn't covered + * by the memslot, KVM can't use a hugepage due to the + * misaligned address regardless of memory attributes. + */ + if (gfn >= slot->base_gfn) { + if (hugepage_has_attrs(kvm, slot, gfn, level, attrs)) + hugepage_clear_mixed(slot, gfn, level); + else + hugepage_set_mixed(slot, gfn, level); + } + gfn += nr_pages; + } + + /* + * Pages entirely covered by the range are guaranteed to have + * only the attributes which were just set. + */ + for ( ; gfn + nr_pages <= range->end; gfn += nr_pages) + hugepage_clear_mixed(slot, gfn, level); + + /* + * Process the last tail page if it straddles the range and is + * contained by the memslot. Like the head page, KVM can't + * create a hugepage if the slot size is misaligned. + */ + if (gfn < range->end && + (gfn + nr_pages) <= (slot->base_gfn + slot->npages)) { + if (hugepage_has_attrs(kvm, slot, gfn, level, attrs)) + hugepage_clear_mixed(slot, gfn, level); + else + hugepage_set_mixed(slot, gfn, level); + } + } + return false; +} + +void kvm_mmu_init_memslot_memory_attributes(struct kvm *kvm, + struct kvm_memory_slot *slot) +{ + int level; + + if (!kvm_arch_has_private_mem(kvm)) + return; + + for (level = PG_LEVEL_2M; level <= KVM_MAX_HUGEPAGE_LEVEL; level++) { + /* + * Don't bother tracking mixed attributes for pages that can't + * be huge due to alignment, i.e. process only pages that are + * entirely contained by the memslot. + */ + gfn_t end = gfn_round_for_level(slot->base_gfn + slot->npages, level); + gfn_t start = gfn_round_for_level(slot->base_gfn, level); + gfn_t nr_pages = KVM_PAGES_PER_HPAGE(level); + gfn_t gfn; + + if (start < slot->base_gfn) + start += nr_pages; + + /* + * Unlike setting attributes, every potential hugepage needs to + * be manually checked as the attributes may already be mixed. + */ + for (gfn = start; gfn < end; gfn += nr_pages) { + unsigned long attrs = kvm_get_memory_attributes(kvm, gfn); + + if (hugepage_has_attrs(kvm, slot, gfn, level, attrs)) + hugepage_clear_mixed(slot, gfn, level); + else + hugepage_set_mixed(slot, gfn, level); + } + } +} +#endif diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index f41dbb1465a0..824b58b44382 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -12607,6 +12607,10 @@ static int kvm_alloc_memslot_metadata(struct kvm *kvm, } } +#ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES + kvm_mmu_init_memslot_memory_attributes(kvm, slot); +#endif + if (kvm_page_track_create_memslot(kvm, slot, npages)) goto out_free; From patchwork Fri Oct 27 18:22:02 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 13438889 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D54B63DFEC for ; 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Fri, 27 Oct 2023 11:23:05 -0700 (PDT) Reply-To: Sean Christopherson Date: Fri, 27 Oct 2023 11:22:02 -0700 In-Reply-To: <20231027182217.3615211-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20231027182217.3615211-1-seanjc@google.com> X-Mailer: git-send-email 2.42.0.820.g83a721a137-goog Message-ID: <20231027182217.3615211-21-seanjc@google.com> Subject: [PATCH v13 20/35] KVM: x86/mmu: Handle page fault for private memory From: Sean Christopherson To: Paolo Bonzini , Marc Zyngier , Oliver Upton , Huacai Chen , Michael Ellerman , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Sean Christopherson , Alexander Viro , Christian Brauner , "Matthew Wilcox (Oracle)" , Andrew Morton Cc: kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Xiaoyao Li , Xu Yilun , Chao Peng , Fuad Tabba , Jarkko Sakkinen , Anish Moorthy , David Matlack , Yu Zhang , Isaku Yamahata , " =?utf-8?q?Micka=C3=ABl_Sala?= =?utf-8?q?=C3=BCn?= " , Vlastimil Babka , Vishal Annapurve , Ackerley Tng , Maciej Szmigiero , David Hildenbrand , Quentin Perret , Michael Roth , Wang , Liam Merwick , Isaku Yamahata , "Kirill A . Shutemov" From: Chao Peng Add support for resolving page faults on guest private memory for VMs that differentiate between "shared" and "private" memory. For such VMs, KVM_MEM_PRIVATE memslots can include both fd-based private memory and hva-based shared memory, and KVM needs to map in the "correct" variant, i.e. KVM needs to map the gfn shared/private as appropriate based on the current state of the gfn's KVM_MEMORY_ATTRIBUTE_PRIVATE flag. For AMD's SEV-SNP and Intel's TDX, the guest effectively gets to request shared vs. private via a bit in the guest page tables, i.e. what the guest wants may conflict with the current memory attributes. To support such "implicit" conversion requests, exit to user with KVM_EXIT_MEMORY_FAULT to forward the request to userspace. Add a new flag for memory faults, KVM_MEMORY_EXIT_FLAG_PRIVATE, to communicate whether the guest wants to map memory as shared vs. private. Like KVM_MEMORY_ATTRIBUTE_PRIVATE, use bit 3 for flagging private memory so that KVM can use bits 0-2 for capturing RWX behavior if/when userspace needs such information, e.g. a likely user of KVM_EXIT_MEMORY_FAULT is to exit on missing mappings when handling guest page fault VM-Exits. In that case, userspace will want to know RWX information in order to correctly/precisely resolve the fault. Note, private memory *must* be backed by guest_memfd, i.e. shared mappings always come from the host userspace page tables, and private mappings always come from a guest_memfd instance. Co-developed-by: Yu Zhang Signed-off-by: Yu Zhang Signed-off-by: Chao Peng Co-developed-by: Sean Christopherson Signed-off-by: Sean Christopherson Reviewed-by: Fuad Tabba Tested-by: Fuad Tabba --- Documentation/virt/kvm/api.rst | 8 ++- arch/x86/kvm/mmu/mmu.c | 101 ++++++++++++++++++++++++++++++-- arch/x86/kvm/mmu/mmu_internal.h | 1 + include/linux/kvm_host.h | 8 ++- include/uapi/linux/kvm.h | 1 + 5 files changed, 110 insertions(+), 9 deletions(-) diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index 7f00c310c24a..38dc1fda4f45 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -6837,6 +6837,7 @@ spec refer, https://github.com/riscv/riscv-sbi-doc. /* KVM_EXIT_MEMORY_FAULT */ struct { + #define KVM_MEMORY_EXIT_FLAG_PRIVATE (1ULL << 3) __u64 flags; __u64 gpa; __u64 size; @@ -6845,8 +6846,11 @@ spec refer, https://github.com/riscv/riscv-sbi-doc. KVM_EXIT_MEMORY_FAULT indicates the vCPU has encountered a memory fault that could not be resolved by KVM. The 'gpa' and 'size' (in bytes) describe the guest physical address range [gpa, gpa + size) of the fault. The 'flags' field -describes properties of the faulting access that are likely pertinent. -Currently, no flags are defined. +describes properties of the faulting access that are likely pertinent: + + - KVM_MEMORY_EXIT_FLAG_PRIVATE - When set, indicates the memory fault occurred + on a private memory access. When clear, indicates the fault occurred on a + shared access. Note! KVM_EXIT_MEMORY_FAULT is unique among all KVM exit reasons in that it accompanies a return code of '-1', not '0'! errno will always be set to EFAULT diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 4167d557c577..c4e758f0aebb 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -3147,9 +3147,9 @@ static int host_pfn_mapping_level(struct kvm *kvm, gfn_t gfn, return level; } -int kvm_mmu_max_mapping_level(struct kvm *kvm, - const struct kvm_memory_slot *slot, gfn_t gfn, - int max_level) +static int __kvm_mmu_max_mapping_level(struct kvm *kvm, + const struct kvm_memory_slot *slot, + gfn_t gfn, int max_level, bool is_private) { struct kvm_lpage_info *linfo; int host_level; @@ -3161,6 +3161,9 @@ int kvm_mmu_max_mapping_level(struct kvm *kvm, break; } + if (is_private) + return max_level; + if (max_level == PG_LEVEL_4K) return PG_LEVEL_4K; @@ -3168,6 +3171,16 @@ int kvm_mmu_max_mapping_level(struct kvm *kvm, return min(host_level, max_level); } +int kvm_mmu_max_mapping_level(struct kvm *kvm, + const struct kvm_memory_slot *slot, gfn_t gfn, + int max_level) +{ + bool is_private = kvm_slot_can_be_private(slot) && + kvm_mem_is_private(kvm, gfn); + + return __kvm_mmu_max_mapping_level(kvm, slot, gfn, max_level, is_private); +} + void kvm_mmu_hugepage_adjust(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault) { struct kvm_memory_slot *slot = fault->slot; @@ -3188,8 +3201,9 @@ void kvm_mmu_hugepage_adjust(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault * Enforce the iTLB multihit workaround after capturing the requested * level, which will be used to do precise, accurate accounting. */ - fault->req_level = kvm_mmu_max_mapping_level(vcpu->kvm, slot, - fault->gfn, fault->max_level); + fault->req_level = __kvm_mmu_max_mapping_level(vcpu->kvm, slot, + fault->gfn, fault->max_level, + fault->is_private); if (fault->req_level == PG_LEVEL_4K || fault->huge_page_disallowed) return; @@ -4261,6 +4275,55 @@ void kvm_arch_async_page_ready(struct kvm_vcpu *vcpu, struct kvm_async_pf *work) kvm_mmu_do_page_fault(vcpu, work->cr2_or_gpa, 0, true, NULL); } +static inline u8 kvm_max_level_for_order(int order) +{ + BUILD_BUG_ON(KVM_MAX_HUGEPAGE_LEVEL > PG_LEVEL_1G); + + KVM_MMU_WARN_ON(order != KVM_HPAGE_GFN_SHIFT(PG_LEVEL_1G) && + order != KVM_HPAGE_GFN_SHIFT(PG_LEVEL_2M) && + order != KVM_HPAGE_GFN_SHIFT(PG_LEVEL_4K)); + + if (order >= KVM_HPAGE_GFN_SHIFT(PG_LEVEL_1G)) + return PG_LEVEL_1G; + + if (order >= KVM_HPAGE_GFN_SHIFT(PG_LEVEL_2M)) + return PG_LEVEL_2M; + + return PG_LEVEL_4K; +} + +static void kvm_mmu_prepare_memory_fault_exit(struct kvm_vcpu *vcpu, + struct kvm_page_fault *fault) +{ + kvm_prepare_memory_fault_exit(vcpu, fault->gfn << PAGE_SHIFT, + PAGE_SIZE, fault->write, fault->exec, + fault->is_private); +} + +static int kvm_faultin_pfn_private(struct kvm_vcpu *vcpu, + struct kvm_page_fault *fault) +{ + int max_order, r; + + if (!kvm_slot_can_be_private(fault->slot)) { + kvm_mmu_prepare_memory_fault_exit(vcpu, fault); + return -EFAULT; + } + + r = kvm_gmem_get_pfn(vcpu->kvm, fault->slot, fault->gfn, &fault->pfn, + &max_order); + if (r) { + kvm_mmu_prepare_memory_fault_exit(vcpu, fault); + return r; + } + + fault->max_level = min(kvm_max_level_for_order(max_order), + fault->max_level); + fault->map_writable = !(fault->slot->flags & KVM_MEM_READONLY); + + return RET_PF_CONTINUE; +} + static int __kvm_faultin_pfn(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault) { struct kvm_memory_slot *slot = fault->slot; @@ -4293,6 +4356,14 @@ static int __kvm_faultin_pfn(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault return RET_PF_EMULATE; } + if (fault->is_private != kvm_mem_is_private(vcpu->kvm, fault->gfn)) { + kvm_mmu_prepare_memory_fault_exit(vcpu, fault); + return -EFAULT; + } + + if (fault->is_private) + return kvm_faultin_pfn_private(vcpu, fault); + async = false; fault->pfn = __gfn_to_pfn_memslot(slot, fault->gfn, false, false, &async, fault->write, &fault->map_writable, @@ -7173,6 +7244,26 @@ void kvm_mmu_pre_destroy_vm(struct kvm *kvm) } #ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES +bool kvm_arch_pre_set_memory_attributes(struct kvm *kvm, + struct kvm_gfn_range *range) +{ + /* + * Zap SPTEs even if the slot can't be mapped PRIVATE. KVM x86 only + * supports KVM_MEMORY_ATTRIBUTE_PRIVATE, and so it *seems* like KVM + * can simply ignore such slots. But if userspace is making memory + * PRIVATE, then KVM must prevent the guest from accessing the memory + * as shared. And if userspace is making memory SHARED and this point + * is reached, then at least one page within the range was previously + * PRIVATE, i.e. the slot's possible hugepage ranges are changing. + * Zapping SPTEs in this case ensures KVM will reassess whether or not + * a hugepage can be used for affected ranges. + */ + if (WARN_ON_ONCE(!kvm_arch_has_private_mem(kvm))) + return false; + + return kvm_unmap_gfn_range(kvm, range); +} + static bool hugepage_test_mixed(struct kvm_memory_slot *slot, gfn_t gfn, int level) { diff --git a/arch/x86/kvm/mmu/mmu_internal.h b/arch/x86/kvm/mmu/mmu_internal.h index decc1f153669..86c7cb692786 100644 --- a/arch/x86/kvm/mmu/mmu_internal.h +++ b/arch/x86/kvm/mmu/mmu_internal.h @@ -201,6 +201,7 @@ struct kvm_page_fault { /* Derived from mmu and global state. */ const bool is_tdp; + const bool is_private; const bool nx_huge_page_workaround_enabled; /* diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 7de93858054d..e3223cafd7db 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -2358,14 +2358,18 @@ static inline void kvm_account_pgtable_pages(void *virt, int nr) #define KVM_DIRTY_RING_MAX_ENTRIES 65536 static inline void kvm_prepare_memory_fault_exit(struct kvm_vcpu *vcpu, - gpa_t gpa, gpa_t size) + gpa_t gpa, gpa_t size, + bool is_write, bool is_exec, + bool is_private) { vcpu->run->exit_reason = KVM_EXIT_MEMORY_FAULT; vcpu->run->memory_fault.gpa = gpa; vcpu->run->memory_fault.size = size; - /* Flags are not (yet) defined or communicated to userspace. */ + /* RWX flags are not (yet) defined or communicated to userspace. */ vcpu->run->memory_fault.flags = 0; + if (is_private) + vcpu->run->memory_fault.flags |= KVM_MEMORY_EXIT_FLAG_PRIVATE; } #ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index 33d542de0a61..29e9eb51dec9 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -527,6 +527,7 @@ struct kvm_run { } notify; /* KVM_EXIT_MEMORY_FAULT */ struct { +#define KVM_MEMORY_EXIT_FLAG_PRIVATE (1ULL << 3) __u64 flags; __u64 gpa; __u64 size; From patchwork Fri Oct 27 18:22:03 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 13438884 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7A3603D995 for ; 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Fri, 27 Oct 2023 11:23:07 -0700 (PDT) Reply-To: Sean Christopherson Date: Fri, 27 Oct 2023 11:22:03 -0700 In-Reply-To: <20231027182217.3615211-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20231027182217.3615211-1-seanjc@google.com> X-Mailer: git-send-email 2.42.0.820.g83a721a137-goog Message-ID: <20231027182217.3615211-22-seanjc@google.com> Subject: [PATCH v13 21/35] KVM: Drop superfluous __KVM_VCPU_MULTIPLE_ADDRESS_SPACE macro From: Sean Christopherson To: Paolo Bonzini , Marc Zyngier , Oliver Upton , Huacai Chen , Michael Ellerman , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Sean Christopherson , Alexander Viro , Christian Brauner , "Matthew Wilcox (Oracle)" , Andrew Morton Cc: kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Xiaoyao Li , Xu Yilun , Chao Peng , Fuad Tabba , Jarkko Sakkinen , Anish Moorthy , David Matlack , Yu Zhang , Isaku Yamahata , " =?utf-8?q?Micka=C3=ABl_Sala?= =?utf-8?q?=C3=BCn?= " , Vlastimil Babka , Vishal Annapurve , Ackerley Tng , Maciej Szmigiero , David Hildenbrand , Quentin Perret , Michael Roth , Wang , Liam Merwick , Isaku Yamahata , "Kirill A . Shutemov" Drop __KVM_VCPU_MULTIPLE_ADDRESS_SPACE and instead check the value of KVM_ADDRESS_SPACE_NUM. No functional change intended. Reviewed-by: Paolo Bonzini Signed-off-by: Sean Christopherson Reviewed-by: Fuad Tabba Tested-by: Fuad Tabba --- arch/x86/include/asm/kvm_host.h | 1 - include/linux/kvm_host.h | 2 +- 2 files changed, 1 insertion(+), 2 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 8d60e4745e8b..6702f795c862 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -2124,7 +2124,6 @@ enum { #define HF_SMM_MASK (1 << 1) #define HF_SMM_INSIDE_NMI_MASK (1 << 2) -# define __KVM_VCPU_MULTIPLE_ADDRESS_SPACE # define KVM_ADDRESS_SPACE_NUM 2 # define kvm_arch_vcpu_memslots_id(vcpu) ((vcpu)->arch.hflags & HF_SMM_MASK ? 1 : 0) # define kvm_memslots_for_spte_role(kvm, role) __kvm_memslots(kvm, (role).smm) diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index e3223cafd7db..c3cfe08b1300 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -692,7 +692,7 @@ bool kvm_arch_irqchip_in_kernel(struct kvm *kvm); #define KVM_MEM_SLOTS_NUM SHRT_MAX #define KVM_USER_MEM_SLOTS (KVM_MEM_SLOTS_NUM - KVM_INTERNAL_MEM_SLOTS) -#ifndef __KVM_VCPU_MULTIPLE_ADDRESS_SPACE +#if KVM_ADDRESS_SPACE_NUM == 1 static inline int kvm_arch_vcpu_memslots_id(struct kvm_vcpu *vcpu) { return 0; From patchwork Fri Oct 27 18:22:04 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 13438882 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 996AA3D965 for ; Fri, 27 Oct 2023 18:23:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="110ec8J/" Received: from mail-pl1-x649.google.com (mail-pl1-x649.google.com [IPv6:2607:f8b0:4864:20::649]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B5D821BEE for ; 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bh=0auIV1DMPWYBI3KY46bLeGa1maTu7OZj6FOKCV8dRqg=; b=cjOrwsv2/X+3ysMrYRxTbpelZZQ6T9lr7io3f3hBjWawc9cvAElcRM9q/oorsI7wAu GHVlkc0OpXJQ3GvIW8i5XuMNTtiGTkyc/ZmnqYJzKqj0nzuG1mxxr17lRkQQkltRv34A Yo6kt2HmQXo/jLuGc5PHz2BA0ajY1ty33YA4AJMu7qo3+sW2kZGgbjKAtFvvCaCpLJjg MayA/zS7JORpfN0OjKwZJ5JTd+Hg7b+IYwlr0G67u7gML3FpMoA8eDnczYpwGE7CnDrJ 254kn1iUwgHf1JDosVnYAjdip15Anm+aSdM24VBUX9Fa9XwB6NbiA4QiSMFaDXmOvd+f Z1bQ== X-Gm-Message-State: AOJu0YxMshd5cySP1OZHiUiCNKL7x3pmGZ8q6Qka0AXYAtwbbGT3pvrv SLR+VfWSwK5xg+uNEMuoh4Vjhh4/pCY= X-Google-Smtp-Source: AGHT+IFXrC3xkKZRDGXkVrFPzvpR3eGICNasom3Cu9rgQoclWToIjhDbekkK9eVZvTfAymJIx68sMWa+w9w= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a17:902:ee05:b0:1c9:d358:b3db with SMTP id z5-20020a170902ee0500b001c9d358b3dbmr54518plb.11.1698430989341; Fri, 27 Oct 2023 11:23:09 -0700 (PDT) Reply-To: Sean Christopherson Date: Fri, 27 Oct 2023 11:22:04 -0700 In-Reply-To: <20231027182217.3615211-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20231027182217.3615211-1-seanjc@google.com> X-Mailer: git-send-email 2.42.0.820.g83a721a137-goog Message-ID: <20231027182217.3615211-23-seanjc@google.com> Subject: [PATCH v13 22/35] KVM: Allow arch code to track number of memslot address spaces per VM From: Sean Christopherson To: Paolo Bonzini , Marc Zyngier , Oliver Upton , Huacai Chen , Michael Ellerman , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Sean Christopherson , Alexander Viro , Christian Brauner , "Matthew Wilcox (Oracle)" , Andrew Morton Cc: kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Xiaoyao Li , Xu Yilun , Chao Peng , Fuad Tabba , Jarkko Sakkinen , Anish Moorthy , David Matlack , Yu Zhang , Isaku Yamahata , " =?utf-8?q?Micka=C3=ABl_Sala?= =?utf-8?q?=C3=BCn?= " , Vlastimil Babka , Vishal Annapurve , Ackerley Tng , Maciej Szmigiero , David Hildenbrand , Quentin Perret , Michael Roth , Wang , Liam Merwick , Isaku Yamahata , "Kirill A . Shutemov" Let x86 track the number of address spaces on a per-VM basis so that KVM can disallow SMM memslots for confidential VMs. Confidentials VMs are fundamentally incompatible with emulating SMM, which as the name suggests requires being able to read and write guest memory and register state. Disallowing SMM will simplify support for guest private memory, as KVM will not need to worry about tracking memory attributes for multiple address spaces (SMM is the only "non-default" address space across all architectures). Signed-off-by: Sean Christopherson Reviewed-by: Paolo Bonzini Reviewed-by: Fuad Tabba Tested-by: Fuad Tabba --- arch/powerpc/kvm/book3s_hv.c | 2 +- arch/x86/include/asm/kvm_host.h | 8 +++++++- arch/x86/kvm/debugfs.c | 2 +- arch/x86/kvm/mmu/mmu.c | 6 +++--- arch/x86/kvm/x86.c | 2 +- include/linux/kvm_host.h | 17 +++++++++++------ virt/kvm/dirty_ring.c | 2 +- virt/kvm/kvm_main.c | 26 ++++++++++++++------------ 8 files changed, 39 insertions(+), 26 deletions(-) diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c index 130bafdb1430..9b0eaa17275a 100644 --- a/arch/powerpc/kvm/book3s_hv.c +++ b/arch/powerpc/kvm/book3s_hv.c @@ -6084,7 +6084,7 @@ static int kvmhv_svm_off(struct kvm *kvm) } srcu_idx = srcu_read_lock(&kvm->srcu); - for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) { + for (i = 0; i < kvm_arch_nr_memslot_as_ids(kvm); i++) { struct kvm_memory_slot *memslot; struct kvm_memslots *slots = __kvm_memslots(kvm, i); int bkt; diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 6702f795c862..f9e8d5642069 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -2124,9 +2124,15 @@ enum { #define HF_SMM_MASK (1 << 1) #define HF_SMM_INSIDE_NMI_MASK (1 << 2) -# define KVM_ADDRESS_SPACE_NUM 2 +# define KVM_MAX_NR_ADDRESS_SPACES 2 # define kvm_arch_vcpu_memslots_id(vcpu) ((vcpu)->arch.hflags & HF_SMM_MASK ? 1 : 0) # define kvm_memslots_for_spte_role(kvm, role) __kvm_memslots(kvm, (role).smm) + +static inline int kvm_arch_nr_memslot_as_ids(struct kvm *kvm) +{ + return KVM_MAX_NR_ADDRESS_SPACES; +} + #else # define kvm_memslots_for_spte_role(kvm, role) __kvm_memslots(kvm, 0) #endif diff --git a/arch/x86/kvm/debugfs.c b/arch/x86/kvm/debugfs.c index ee8c4c3496ed..42026b3f3ff3 100644 --- a/arch/x86/kvm/debugfs.c +++ b/arch/x86/kvm/debugfs.c @@ -111,7 +111,7 @@ static int kvm_mmu_rmaps_stat_show(struct seq_file *m, void *v) mutex_lock(&kvm->slots_lock); write_lock(&kvm->mmu_lock); - for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) { + for (i = 0; i < kvm_arch_nr_memslot_as_ids(kvm); i++) { int bkt; slots = __kvm_memslots(kvm, i); diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index c4e758f0aebb..baeba8fc1c38 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -3755,7 +3755,7 @@ static int mmu_first_shadow_root_alloc(struct kvm *kvm) kvm_page_track_write_tracking_enabled(kvm)) goto out_success; - for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) { + for (i = 0; i < kvm_arch_nr_memslot_as_ids(kvm); i++) { slots = __kvm_memslots(kvm, i); kvm_for_each_memslot(slot, bkt, slots) { /* @@ -6294,7 +6294,7 @@ static bool kvm_rmap_zap_gfn_range(struct kvm *kvm, gfn_t gfn_start, gfn_t gfn_e if (!kvm_memslots_have_rmaps(kvm)) return flush; - for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) { + for (i = 0; i < kvm_arch_nr_memslot_as_ids(kvm); i++) { slots = __kvm_memslots(kvm, i); kvm_for_each_memslot_in_gfn_range(&iter, slots, gfn_start, gfn_end) { @@ -6791,7 +6791,7 @@ void kvm_mmu_invalidate_mmio_sptes(struct kvm *kvm, u64 gen) * modifier prior to checking for a wrap of the MMIO generation so * that a wrap in any address space is detected. */ - gen &= ~((u64)KVM_ADDRESS_SPACE_NUM - 1); + gen &= ~((u64)kvm_arch_nr_memslot_as_ids(kvm) - 1); /* * The very rare case: if the MMIO generation number has wrapped, diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 824b58b44382..c4d17727b199 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -12456,7 +12456,7 @@ void __user * __x86_set_memory_region(struct kvm *kvm, int id, gpa_t gpa, hva = slot->userspace_addr; } - for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) { + for (i = 0; i < kvm_arch_nr_memslot_as_ids(kvm); i++) { struct kvm_userspace_memory_region2 m; m.slot = id | (i << 16); diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index c3cfe08b1300..687589ce9f63 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -80,8 +80,8 @@ /* Two fragments for cross MMIO pages. */ #define KVM_MAX_MMIO_FRAGMENTS 2 -#ifndef KVM_ADDRESS_SPACE_NUM -#define KVM_ADDRESS_SPACE_NUM 1 +#ifndef KVM_MAX_NR_ADDRESS_SPACES +#define KVM_MAX_NR_ADDRESS_SPACES 1 #endif /* @@ -692,7 +692,12 @@ bool kvm_arch_irqchip_in_kernel(struct kvm *kvm); #define KVM_MEM_SLOTS_NUM SHRT_MAX #define KVM_USER_MEM_SLOTS (KVM_MEM_SLOTS_NUM - KVM_INTERNAL_MEM_SLOTS) -#if KVM_ADDRESS_SPACE_NUM == 1 +#if KVM_MAX_NR_ADDRESS_SPACES == 1 +static inline int kvm_arch_nr_memslot_as_ids(struct kvm *kvm) +{ + return KVM_MAX_NR_ADDRESS_SPACES; +} + static inline int kvm_arch_vcpu_memslots_id(struct kvm_vcpu *vcpu) { return 0; @@ -747,9 +752,9 @@ struct kvm { struct mm_struct *mm; /* userspace tied to this vm */ unsigned long nr_memslot_pages; /* The two memslot sets - active and inactive (per address space) */ - struct kvm_memslots __memslots[KVM_ADDRESS_SPACE_NUM][2]; + struct kvm_memslots __memslots[KVM_MAX_NR_ADDRESS_SPACES][2]; /* The current active memslot set for each address space */ - struct kvm_memslots __rcu *memslots[KVM_ADDRESS_SPACE_NUM]; + struct kvm_memslots __rcu *memslots[KVM_MAX_NR_ADDRESS_SPACES]; struct xarray vcpu_array; /* * Protected by slots_lock, but can be read outside if an @@ -1018,7 +1023,7 @@ void kvm_put_kvm_no_destroy(struct kvm *kvm); static inline struct kvm_memslots *__kvm_memslots(struct kvm *kvm, int as_id) { - as_id = array_index_nospec(as_id, KVM_ADDRESS_SPACE_NUM); + as_id = array_index_nospec(as_id, KVM_MAX_NR_ADDRESS_SPACES); return srcu_dereference_check(kvm->memslots[as_id], &kvm->srcu, lockdep_is_held(&kvm->slots_lock) || !refcount_read(&kvm->users_count)); diff --git a/virt/kvm/dirty_ring.c b/virt/kvm/dirty_ring.c index c1cd7dfe4a90..86d267db87bb 100644 --- a/virt/kvm/dirty_ring.c +++ b/virt/kvm/dirty_ring.c @@ -58,7 +58,7 @@ static void kvm_reset_dirty_gfn(struct kvm *kvm, u32 slot, u64 offset, u64 mask) as_id = slot >> 16; id = (u16)slot; - if (as_id >= KVM_ADDRESS_SPACE_NUM || id >= KVM_USER_MEM_SLOTS) + if (as_id >= kvm_arch_nr_memslot_as_ids(kvm) || id >= KVM_USER_MEM_SLOTS) return; memslot = id_to_memslot(__kvm_memslots(kvm, as_id), id); diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 5d1a2f1b4e94..23633984142f 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -615,7 +615,7 @@ static __always_inline kvm_mn_ret_t __kvm_handle_hva_range(struct kvm *kvm, idx = srcu_read_lock(&kvm->srcu); - for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) { + for (i = 0; i < kvm_arch_nr_memslot_as_ids(kvm); i++) { struct interval_tree_node *node; slots = __kvm_memslots(kvm, i); @@ -1248,7 +1248,7 @@ static struct kvm *kvm_create_vm(unsigned long type, const char *fdname) goto out_err_no_irq_srcu; refcount_set(&kvm->users_count, 1); - for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) { + for (i = 0; i < kvm_arch_nr_memslot_as_ids(kvm); i++) { for (j = 0; j < 2; j++) { slots = &kvm->__memslots[i][j]; @@ -1398,7 +1398,7 @@ static void kvm_destroy_vm(struct kvm *kvm) #endif kvm_arch_destroy_vm(kvm); kvm_destroy_devices(kvm); - for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) { + for (i = 0; i < kvm_arch_nr_memslot_as_ids(kvm); i++) { kvm_free_memslots(kvm, &kvm->__memslots[i][0]); kvm_free_memslots(kvm, &kvm->__memslots[i][1]); } @@ -1681,7 +1681,7 @@ static void kvm_swap_active_memslots(struct kvm *kvm, int as_id) * space 0 will use generations 0, 2, 4, ... while address space 1 will * use generations 1, 3, 5, ... */ - gen += KVM_ADDRESS_SPACE_NUM; + gen += kvm_arch_nr_memslot_as_ids(kvm); kvm_arch_memslots_updated(kvm, gen); @@ -2051,7 +2051,7 @@ int __kvm_set_memory_region(struct kvm *kvm, (mem->guest_memfd_offset & (PAGE_SIZE - 1) || mem->guest_memfd_offset + mem->memory_size < mem->guest_memfd_offset)) return -EINVAL; - if (as_id >= KVM_ADDRESS_SPACE_NUM || id >= KVM_MEM_SLOTS_NUM) + if (as_id >= kvm_arch_nr_memslot_as_ids(kvm) || id >= KVM_MEM_SLOTS_NUM) return -EINVAL; if (mem->guest_phys_addr + mem->memory_size < mem->guest_phys_addr) return -EINVAL; @@ -2187,7 +2187,7 @@ int kvm_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log, as_id = log->slot >> 16; id = (u16)log->slot; - if (as_id >= KVM_ADDRESS_SPACE_NUM || id >= KVM_USER_MEM_SLOTS) + if (as_id >= kvm_arch_nr_memslot_as_ids(kvm) || id >= KVM_USER_MEM_SLOTS) return -EINVAL; slots = __kvm_memslots(kvm, as_id); @@ -2249,7 +2249,7 @@ static int kvm_get_dirty_log_protect(struct kvm *kvm, struct kvm_dirty_log *log) as_id = log->slot >> 16; id = (u16)log->slot; - if (as_id >= KVM_ADDRESS_SPACE_NUM || id >= KVM_USER_MEM_SLOTS) + if (as_id >= kvm_arch_nr_memslot_as_ids(kvm) || id >= KVM_USER_MEM_SLOTS) return -EINVAL; slots = __kvm_memslots(kvm, as_id); @@ -2361,7 +2361,7 @@ static int kvm_clear_dirty_log_protect(struct kvm *kvm, as_id = log->slot >> 16; id = (u16)log->slot; - if (as_id >= KVM_ADDRESS_SPACE_NUM || id >= KVM_USER_MEM_SLOTS) + if (as_id >= kvm_arch_nr_memslot_as_ids(kvm) || id >= KVM_USER_MEM_SLOTS) return -EINVAL; if (log->first_page & 63) @@ -2502,7 +2502,7 @@ static __always_inline void kvm_handle_gfn_range(struct kvm *kvm, gfn_range.only_private = false; gfn_range.only_shared = false; - for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) { + for (i = 0; i < kvm_arch_nr_memslot_as_ids(kvm); i++) { slots = __kvm_memslots(kvm, i); kvm_for_each_memslot_in_gfn_range(&iter, slots, range->start, range->end) { @@ -4857,9 +4857,11 @@ static int kvm_vm_ioctl_check_extension_generic(struct kvm *kvm, long arg) case KVM_CAP_IRQ_ROUTING: return KVM_MAX_IRQ_ROUTES; #endif -#if KVM_ADDRESS_SPACE_NUM > 1 +#if KVM_MAX_NR_ADDRESS_SPACES > 1 case KVM_CAP_MULTI_ADDRESS_SPACE: - return KVM_ADDRESS_SPACE_NUM; + if (kvm) + return kvm_arch_nr_memslot_as_ids(kvm); + return KVM_MAX_NR_ADDRESS_SPACES; #endif case KVM_CAP_NR_MEMSLOTS: return KVM_USER_MEM_SLOTS; @@ -4967,7 +4969,7 @@ bool kvm_are_all_memslots_empty(struct kvm *kvm) lockdep_assert_held(&kvm->slots_lock); - for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) { + for (i = 0; i < kvm_arch_nr_memslot_as_ids(kvm); i++) { if (!kvm_memslots_empty(__kvm_memslots(kvm, i))) return false; } From patchwork Fri Oct 27 18:22:05 2023 Content-Type: text/plain; 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Fri, 27 Oct 2023 11:23:11 -0700 (PDT) Reply-To: Sean Christopherson Date: Fri, 27 Oct 2023 11:22:05 -0700 In-Reply-To: <20231027182217.3615211-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20231027182217.3615211-1-seanjc@google.com> X-Mailer: git-send-email 2.42.0.820.g83a721a137-goog Message-ID: <20231027182217.3615211-24-seanjc@google.com> Subject: [PATCH v13 23/35] KVM: x86: Add support for "protected VMs" that can utilize private memory From: Sean Christopherson To: Paolo Bonzini , Marc Zyngier , Oliver Upton , Huacai Chen , Michael Ellerman , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Sean Christopherson , Alexander Viro , Christian Brauner , "Matthew Wilcox (Oracle)" , Andrew Morton Cc: kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Xiaoyao Li , Xu Yilun , Chao Peng , Fuad Tabba , Jarkko Sakkinen , Anish Moorthy , David Matlack , Yu Zhang , Isaku Yamahata , " =?utf-8?q?Micka=C3=ABl_Sala?= =?utf-8?q?=C3=BCn?= " , Vlastimil Babka , Vishal Annapurve , Ackerley Tng , Maciej Szmigiero , David Hildenbrand , Quentin Perret , Michael Roth , Wang , Liam Merwick , Isaku Yamahata , "Kirill A . Shutemov" Add a new x86 VM type, KVM_X86_SW_PROTECTED_VM, to serve as a development and testing vehicle for Confidential (CoCo) VMs, and potentially to even become a "real" product in the distant future, e.g. a la pKVM. The private memory support in KVM x86 is aimed at AMD's SEV-SNP and Intel's TDX, but those technologies are extremely complex (understatement), difficult to debug, don't support running as nested guests, and require hardware that's isn't universally accessible. I.e. relying SEV-SNP or TDX for maintaining guest private memory isn't a realistic option. At the very least, KVM_X86_SW_PROTECTED_VM will enable a variety of selftests for guest_memfd and private memory support without requiring unique hardware. Signed-off-by: Sean Christopherson Reviewed-by: Paolo Bonzini Reviewed-by: Fuad Tabba Tested-by: Fuad Tabba --- Documentation/virt/kvm/api.rst | 32 ++++++++++++++++++++++++++++++++ arch/x86/include/asm/kvm_host.h | 15 +++++++++------ arch/x86/include/uapi/asm/kvm.h | 3 +++ arch/x86/kvm/Kconfig | 12 ++++++++++++ arch/x86/kvm/mmu/mmu_internal.h | 1 + arch/x86/kvm/x86.c | 16 +++++++++++++++- include/uapi/linux/kvm.h | 1 + virt/kvm/Kconfig | 5 +++++ 8 files changed, 78 insertions(+), 7 deletions(-) diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index 38dc1fda4f45..00029436ac5b 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -147,10 +147,29 @@ described as 'basic' will be available. The new VM has no virtual cpus and no memory. You probably want to use 0 as machine type. +X86: +^^^^ + +Supported X86 VM types can be queried via KVM_CAP_VM_TYPES. + +S390: +^^^^^ + In order to create user controlled virtual machines on S390, check KVM_CAP_S390_UCONTROL and use the flag KVM_VM_S390_UCONTROL as privileged user (CAP_SYS_ADMIN). +MIPS: +^^^^^ + +To use hardware assisted virtualization on MIPS (VZ ASE) rather than +the default trap & emulate implementation (which changes the virtual +memory layout to fit in user mode), check KVM_CAP_MIPS_VZ and use the +flag KVM_VM_MIPS_VZ. + +ARM64: +^^^^^^ + On arm64, the physical address size for a VM (IPA Size limit) is limited to 40bits by default. The limit can be configured if the host supports the extension KVM_CAP_ARM_VM_IPA_SIZE. When supported, use @@ -8650,6 +8669,19 @@ block sizes is exposed in KVM_CAP_ARM_SUPPORTED_BLOCK_SIZES as a 64-bit bitmap (each bit describing a block size). The default value is 0, to disable the eager page splitting. +8.41 KVM_CAP_VM_TYPES +--------------------- + +:Capability: KVM_CAP_MEMORY_ATTRIBUTES +:Architectures: x86 +:Type: system ioctl + +This capability returns a bitmap of support VM types. The 1-setting of bit @n +means the VM type with value @n is supported. Possible values of @n are:: + + #define KVM_X86_DEFAULT_VM 0 + #define KVM_X86_SW_PROTECTED_VM 1 + 9. Known KVM API problems ========================= diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index f9e8d5642069..dff10051e9b6 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -1244,6 +1244,7 @@ enum kvm_apicv_inhibit { }; struct kvm_arch { + unsigned long vm_type; unsigned long n_used_mmu_pages; unsigned long n_requested_mmu_pages; unsigned long n_max_mmu_pages; @@ -2077,6 +2078,12 @@ void kvm_mmu_new_pgd(struct kvm_vcpu *vcpu, gpa_t new_pgd); void kvm_configure_mmu(bool enable_tdp, int tdp_forced_root_level, int tdp_max_root_level, int tdp_huge_page_level); +#ifdef CONFIG_KVM_PRIVATE_MEM +#define kvm_arch_has_private_mem(kvm) ((kvm)->arch.vm_type != KVM_X86_DEFAULT_VM) +#else +#define kvm_arch_has_private_mem(kvm) false +#endif + static inline u16 kvm_read_ldt(void) { u16 ldt; @@ -2125,14 +2132,10 @@ enum { #define HF_SMM_INSIDE_NMI_MASK (1 << 2) # define KVM_MAX_NR_ADDRESS_SPACES 2 +/* SMM is currently unsupported for guests with private memory. */ +# define kvm_arch_nr_memslot_as_ids(kvm) (kvm_arch_has_private_mem(kvm) ? 1 : 2) # define kvm_arch_vcpu_memslots_id(vcpu) ((vcpu)->arch.hflags & HF_SMM_MASK ? 1 : 0) # define kvm_memslots_for_spte_role(kvm, role) __kvm_memslots(kvm, (role).smm) - -static inline int kvm_arch_nr_memslot_as_ids(struct kvm *kvm) -{ - return KVM_MAX_NR_ADDRESS_SPACES; -} - #else # define kvm_memslots_for_spte_role(kvm, role) __kvm_memslots(kvm, 0) #endif diff --git a/arch/x86/include/uapi/asm/kvm.h b/arch/x86/include/uapi/asm/kvm.h index 1a6a1f987949..a448d0964fc0 100644 --- a/arch/x86/include/uapi/asm/kvm.h +++ b/arch/x86/include/uapi/asm/kvm.h @@ -562,4 +562,7 @@ struct kvm_pmu_event_filter { /* x86-specific KVM_EXIT_HYPERCALL flags. */ #define KVM_EXIT_HYPERCALL_LONG_MODE BIT(0) +#define KVM_X86_DEFAULT_VM 0 +#define KVM_X86_SW_PROTECTED_VM 1 + #endif /* _ASM_X86_KVM_H */ diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig index 091b74599c22..8452ed0228cb 100644 --- a/arch/x86/kvm/Kconfig +++ b/arch/x86/kvm/Kconfig @@ -77,6 +77,18 @@ config KVM_WERROR If in doubt, say "N". +config KVM_SW_PROTECTED_VM + bool "Enable support for KVM software-protected VMs" + depends on EXPERT + depends on X86_64 + select KVM_GENERIC_PRIVATE_MEM + help + Enable support for KVM software-protected VMs. Currently "protected" + means the VM can be backed with memory provided by + KVM_CREATE_GUEST_MEMFD. + + If unsure, say "N". + config KVM_INTEL tristate "KVM for Intel (and compatible) processors support" depends on KVM && IA32_FEAT_CTL diff --git a/arch/x86/kvm/mmu/mmu_internal.h b/arch/x86/kvm/mmu/mmu_internal.h index 86c7cb692786..b66a7d47e0e4 100644 --- a/arch/x86/kvm/mmu/mmu_internal.h +++ b/arch/x86/kvm/mmu/mmu_internal.h @@ -297,6 +297,7 @@ static inline int kvm_mmu_do_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, .max_level = KVM_MAX_HUGEPAGE_LEVEL, .req_level = PG_LEVEL_4K, .goal_level = PG_LEVEL_4K, + .is_private = kvm_mem_is_private(vcpu->kvm, cr2_or_gpa >> PAGE_SHIFT), }; int r; diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index c4d17727b199..e3eb608b6692 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -4441,6 +4441,13 @@ static int kvm_ioctl_get_supported_hv_cpuid(struct kvm_vcpu *vcpu, return 0; } +static bool kvm_is_vm_type_supported(unsigned long type) +{ + return type == KVM_X86_DEFAULT_VM || + (type == KVM_X86_SW_PROTECTED_VM && + IS_ENABLED(CONFIG_KVM_SW_PROTECTED_VM) && tdp_enabled); +} + int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) { int r = 0; @@ -4632,6 +4639,11 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) case KVM_CAP_X86_NOTIFY_VMEXIT: r = kvm_caps.has_notify_vmexit; break; + case KVM_CAP_VM_TYPES: + r = BIT(KVM_X86_DEFAULT_VM); + if (kvm_is_vm_type_supported(KVM_X86_SW_PROTECTED_VM)) + r |= BIT(KVM_X86_SW_PROTECTED_VM); + break; default: break; } @@ -12314,9 +12326,11 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) int ret; unsigned long flags; - if (type) + if (!kvm_is_vm_type_supported(type)) return -EINVAL; + kvm->arch.vm_type = type; + ret = kvm_page_track_init(kvm); if (ret) goto out; diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index 29e9eb51dec9..5b5820d19e71 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -1218,6 +1218,7 @@ struct kvm_ppc_resize_hpt { #define KVM_CAP_MEMORY_FAULT_INFO 231 #define KVM_CAP_MEMORY_ATTRIBUTES 232 #define KVM_CAP_GUEST_MEMFD 233 +#define KVM_CAP_VM_TYPES 234 #ifdef KVM_CAP_IRQ_ROUTING diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig index 08afef022db9..2c964586aa14 100644 --- a/virt/kvm/Kconfig +++ b/virt/kvm/Kconfig @@ -104,3 +104,8 @@ config KVM_GENERIC_MEMORY_ATTRIBUTES config KVM_PRIVATE_MEM select XARRAY_MULTI bool + +config KVM_GENERIC_PRIVATE_MEM + select KVM_GENERIC_MEMORY_ATTRIBUTES + select KVM_PRIVATE_MEM + bool From patchwork Fri Oct 27 18:22:06 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 13438895 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A57A93DFE4 for ; 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Fri, 27 Oct 2023 11:23:13 -0700 (PDT) Reply-To: Sean Christopherson Date: Fri, 27 Oct 2023 11:22:06 -0700 In-Reply-To: <20231027182217.3615211-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20231027182217.3615211-1-seanjc@google.com> X-Mailer: git-send-email 2.42.0.820.g83a721a137-goog Message-ID: <20231027182217.3615211-25-seanjc@google.com> Subject: [PATCH v13 24/35] KVM: selftests: Drop unused kvm_userspace_memory_region_find() helper From: Sean Christopherson To: Paolo Bonzini , Marc Zyngier , Oliver Upton , Huacai Chen , Michael Ellerman , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Sean Christopherson , Alexander Viro , Christian Brauner , "Matthew Wilcox (Oracle)" , Andrew Morton Cc: kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Xiaoyao Li , Xu Yilun , Chao Peng , Fuad Tabba , Jarkko Sakkinen , Anish Moorthy , David Matlack , Yu Zhang , Isaku Yamahata , " =?utf-8?q?Micka=C3=ABl_Sala?= =?utf-8?q?=C3=BCn?= " , Vlastimil Babka , Vishal Annapurve , Ackerley Tng , Maciej Szmigiero , David Hildenbrand , Quentin Perret , Michael Roth , Wang , Liam Merwick , Isaku Yamahata , "Kirill A . Shutemov" Drop kvm_userspace_memory_region_find(), it's unused and a terrible API (probably why it's unused). If anything outside of kvm_util.c needs to get at the memslot, userspace_mem_region_find() can be exposed to give others full access to all memory region/slot information. Signed-off-by: Sean Christopherson --- .../selftests/kvm/include/kvm_util_base.h | 4 --- tools/testing/selftests/kvm/lib/kvm_util.c | 29 ------------------- 2 files changed, 33 deletions(-) diff --git a/tools/testing/selftests/kvm/include/kvm_util_base.h b/tools/testing/selftests/kvm/include/kvm_util_base.h index a18db6a7b3cf..967eaaeacd75 100644 --- a/tools/testing/selftests/kvm/include/kvm_util_base.h +++ b/tools/testing/selftests/kvm/include/kvm_util_base.h @@ -776,10 +776,6 @@ vm_adjust_num_guest_pages(enum vm_guest_mode mode, unsigned int num_guest_pages) return n; } -struct kvm_userspace_memory_region * -kvm_userspace_memory_region_find(struct kvm_vm *vm, uint64_t start, - uint64_t end); - #define sync_global_to_guest(vm, g) ({ \ typeof(g) *_p = addr_gva2hva(vm, (vm_vaddr_t)&(g)); \ memcpy(_p, &(g), sizeof(g)); \ diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c index 7a8af1821f5d..f09295d56c23 100644 --- a/tools/testing/selftests/kvm/lib/kvm_util.c +++ b/tools/testing/selftests/kvm/lib/kvm_util.c @@ -590,35 +590,6 @@ userspace_mem_region_find(struct kvm_vm *vm, uint64_t start, uint64_t end) return NULL; } -/* - * KVM Userspace Memory Region Find - * - * Input Args: - * vm - Virtual Machine - * start - Starting VM physical address - * end - Ending VM physical address, inclusive. - * - * Output Args: None - * - * Return: - * Pointer to overlapping region, NULL if no such region. - * - * Public interface to userspace_mem_region_find. Allows tests to look up - * the memslot datastructure for a given range of guest physical memory. - */ -struct kvm_userspace_memory_region * -kvm_userspace_memory_region_find(struct kvm_vm *vm, uint64_t start, - uint64_t end) -{ - struct userspace_mem_region *region; - - region = userspace_mem_region_find(vm, start, end); - if (!region) - return NULL; - - return ®ion->region; -} - __weak void vcpu_arch_free(struct kvm_vcpu *vcpu) { From patchwork Fri Oct 27 18:22:07 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 13438885 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 120F03D968 for ; Fri, 27 Oct 2023 18:23:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="gLlOH8MK" Received: from mail-pl1-x64a.google.com (mail-pl1-x64a.google.com [IPv6:2607:f8b0:4864:20::64a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1006B1737 for ; Fri, 27 Oct 2023 11:23:17 -0700 (PDT) Received: by mail-pl1-x64a.google.com with SMTP id d9443c01a7336-1cc23f2226bso7022495ad.2 for ; Fri, 27 Oct 2023 11:23:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1698430995; x=1699035795; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:from:to:cc:subject:date:message-id:reply-to; bh=ZNZtzA/linIp+2GMXA1XUg0X+u1GFwKPof82zA2ctug=; b=gLlOH8MK3JtiCu2Fg8c51YiTnb6iJg2CSQ4bj2TE0KGfvIBwFD3XmecHQUmxdGEq+D aTchzWYKFNoTTGYXG4xMpZU4iePcqX9x4SuxBGb//TR7iSh+du4hnNWRuIKRd0PQbNr+ JX+I5wPsMXUl9grWCrjjI7tWfSFl8pVjB8ErLuodsuWY50LOT8gnJtFCHO58x7nraElM JWIc710ypUu5PtYGkP1cnxh0AGxnZjxFecEk1RztjtAJ9YzW983Mkgzo3VVVa88Xh10s 0jlmilGQFzk68bH/pZckJy+noZfndKiIpzOZYIvQZSaHuInKOWTgTCnfOLtQlClIQP3q 72pA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1698430995; x=1699035795; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=ZNZtzA/linIp+2GMXA1XUg0X+u1GFwKPof82zA2ctug=; b=qT3KDeH2hw1ilPf6UjEoESbERzfK589uClPPQkXGEVrprf+NIWOXThBvgdpXJsx4JC op4dHk8itmiX2Z9W4y1f0LpoOpuC+UznsOL6PqNUupjf+jHXdVIfSIiiEZsYEWWQj6m9 jY2+CEtJYs9KDbzyrGM1GqcfD5t/jOGmRHLYo4Rgsyk6ZylSDKNy9zErKTH9kl/jHMIj BukoA5se0HPvYAy6kQT4I2CGZweo8q6b3squ2AU1IYyf4gGryqUZHbGxido0ouq2ygYH OxskXYjjNxvYdg0ce+h/sGOXk9rnlXI0cpMBS08UwxwXi7sGxPbXoOwUkJu4W6Sw3y8J e3Lw== X-Gm-Message-State: AOJu0YzWFNeI1bztoyTSYB0fgC7BpI4kE3qeeJPTZB4WqYmSyu6XHMC4 QbNPxYVLmXiVkASWpRatxr1cINMV/lw= X-Google-Smtp-Source: AGHT+IFgEK+vNYv/vNHgA3JkDytYkMCwP8RspbM7NAIhoWJ8dWWtLUmat77zU+/1XadLWoCAT7TkthpzXqU= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a17:902:f809:b0:1cc:2a6f:ab91 with SMTP id ix9-20020a170902f80900b001cc2a6fab91mr26127plb.0.1698430994917; Fri, 27 Oct 2023 11:23:14 -0700 (PDT) Reply-To: Sean Christopherson Date: Fri, 27 Oct 2023 11:22:07 -0700 In-Reply-To: <20231027182217.3615211-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20231027182217.3615211-1-seanjc@google.com> X-Mailer: git-send-email 2.42.0.820.g83a721a137-goog Message-ID: <20231027182217.3615211-26-seanjc@google.com> Subject: [PATCH v13 25/35] KVM: selftests: Convert lib's mem regions to KVM_SET_USER_MEMORY_REGION2 From: Sean Christopherson To: Paolo Bonzini , Marc Zyngier , Oliver Upton , Huacai Chen , Michael Ellerman , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Sean Christopherson , Alexander Viro , Christian Brauner , "Matthew Wilcox (Oracle)" , Andrew Morton Cc: kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Xiaoyao Li , Xu Yilun , Chao Peng , Fuad Tabba , Jarkko Sakkinen , Anish Moorthy , David Matlack , Yu Zhang , Isaku Yamahata , " =?utf-8?q?Micka=C3=ABl_Sala?= =?utf-8?q?=C3=BCn?= " , Vlastimil Babka , Vishal Annapurve , Ackerley Tng , Maciej Szmigiero , David Hildenbrand , Quentin Perret , Michael Roth , Wang , Liam Merwick , Isaku Yamahata , "Kirill A . Shutemov" Use KVM_SET_USER_MEMORY_REGION2 throughout KVM's selftests library so that support for guest private memory can be added without needing an entirely separate set of helpers. Note, this obviously makes selftests backwards-incompatible with older KVM versions from this point forward. Signed-off-by: Sean Christopherson --- .../selftests/kvm/include/kvm_util_base.h | 2 +- tools/testing/selftests/kvm/lib/kvm_util.c | 19 ++++++++++--------- 2 files changed, 11 insertions(+), 10 deletions(-) diff --git a/tools/testing/selftests/kvm/include/kvm_util_base.h b/tools/testing/selftests/kvm/include/kvm_util_base.h index 967eaaeacd75..9f144841c2ee 100644 --- a/tools/testing/selftests/kvm/include/kvm_util_base.h +++ b/tools/testing/selftests/kvm/include/kvm_util_base.h @@ -44,7 +44,7 @@ typedef uint64_t vm_paddr_t; /* Virtual Machine (Guest) physical address */ typedef uint64_t vm_vaddr_t; /* Virtual Machine (Guest) virtual address */ struct userspace_mem_region { - struct kvm_userspace_memory_region region; + struct kvm_userspace_memory_region2 region; struct sparsebit *unused_phy_pages; int fd; off_t offset; diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c index f09295d56c23..3676b37bea38 100644 --- a/tools/testing/selftests/kvm/lib/kvm_util.c +++ b/tools/testing/selftests/kvm/lib/kvm_util.c @@ -453,8 +453,9 @@ void kvm_vm_restart(struct kvm_vm *vmp) vm_create_irqchip(vmp); hash_for_each(vmp->regions.slot_hash, ctr, region, slot_node) { - int ret = ioctl(vmp->fd, KVM_SET_USER_MEMORY_REGION, ®ion->region); - TEST_ASSERT(ret == 0, "KVM_SET_USER_MEMORY_REGION IOCTL failed,\n" + int ret = ioctl(vmp->fd, KVM_SET_USER_MEMORY_REGION2, ®ion->region); + + TEST_ASSERT(ret == 0, "KVM_SET_USER_MEMORY_REGION2 IOCTL failed,\n" " rc: %i errno: %i\n" " slot: %u flags: 0x%x\n" " guest_phys_addr: 0x%llx size: 0x%llx", @@ -657,7 +658,7 @@ static void __vm_mem_region_delete(struct kvm_vm *vm, } region->region.memory_size = 0; - vm_ioctl(vm, KVM_SET_USER_MEMORY_REGION, ®ion->region); + vm_ioctl(vm, KVM_SET_USER_MEMORY_REGION2, ®ion->region); sparsebit_free(®ion->unused_phy_pages); ret = munmap(region->mmap_start, region->mmap_size); @@ -1014,8 +1015,8 @@ void vm_userspace_mem_region_add(struct kvm_vm *vm, region->region.guest_phys_addr = guest_paddr; region->region.memory_size = npages * vm->page_size; region->region.userspace_addr = (uintptr_t) region->host_mem; - ret = __vm_ioctl(vm, KVM_SET_USER_MEMORY_REGION, ®ion->region); - TEST_ASSERT(ret == 0, "KVM_SET_USER_MEMORY_REGION IOCTL failed,\n" + ret = __vm_ioctl(vm, KVM_SET_USER_MEMORY_REGION2, ®ion->region); + TEST_ASSERT(ret == 0, "KVM_SET_USER_MEMORY_REGION2 IOCTL failed,\n" " rc: %i errno: %i\n" " slot: %u flags: 0x%x\n" " guest_phys_addr: 0x%lx size: 0x%lx", @@ -1097,9 +1098,9 @@ void vm_mem_region_set_flags(struct kvm_vm *vm, uint32_t slot, uint32_t flags) region->region.flags = flags; - ret = __vm_ioctl(vm, KVM_SET_USER_MEMORY_REGION, ®ion->region); + ret = __vm_ioctl(vm, KVM_SET_USER_MEMORY_REGION2, ®ion->region); - TEST_ASSERT(ret == 0, "KVM_SET_USER_MEMORY_REGION IOCTL failed,\n" + TEST_ASSERT(ret == 0, "KVM_SET_USER_MEMORY_REGION2 IOCTL failed,\n" " rc: %i errno: %i slot: %u flags: 0x%x", ret, errno, slot, flags); } @@ -1127,9 +1128,9 @@ void vm_mem_region_move(struct kvm_vm *vm, uint32_t slot, uint64_t new_gpa) region->region.guest_phys_addr = new_gpa; - ret = __vm_ioctl(vm, KVM_SET_USER_MEMORY_REGION, ®ion->region); + ret = __vm_ioctl(vm, KVM_SET_USER_MEMORY_REGION2, ®ion->region); - TEST_ASSERT(!ret, "KVM_SET_USER_MEMORY_REGION failed\n" + TEST_ASSERT(!ret, "KVM_SET_USER_MEMORY_REGION2 failed\n" "ret: %i errno: %i slot: %u new_gpa: 0x%lx", ret, errno, slot, new_gpa); } From patchwork Fri Oct 27 18:22:08 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 13438888 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CA1163DFEB for ; Fri, 27 Oct 2023 18:23:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="E1Gjgb/o" Received: from mail-yb1-xb4a.google.com (mail-yb1-xb4a.google.com [IPv6:2607:f8b0:4864:20::b4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F293E1FF3 for ; Fri, 27 Oct 2023 11:23:17 -0700 (PDT) Received: by mail-yb1-xb4a.google.com with SMTP id 3f1490d57ef6-da0737dcb26so1813512276.3 for ; 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b=nMiHC7N6vTK83Y6QYAhJt79QCJ3o6jFOhkRLdTRY2s9mNuraenYJX2HosKSn1W6idx W8JnMKyi4Bp4Iyj0h6BHCu828TmljCo3yyNGfe3xLN49jIPJd3A3b+LR+obJYAVTzNvD uNusQHgthd/yipgdcaeCnbB+G7g989oHuUTexzPGly/QF/S8JIENp54VGLRzLHAb+LEV Sakcq5dn+tcKcobCX3Ve1rsKon+XSAVVL3U8hzrPNd02cQybD4nzUNORlYkFDxX3jybw 9S4JTggUMAE/tOQEG7nUWxdbSJJas0hO+ObKvNhDhCa9tGF+JGPJ2KD1CgTUsEVYGGzp 64Rg== X-Gm-Message-State: AOJu0YzdAUj4D0PsoxFK+CEtvrNa1LzePcwQzR3V1/HRydYy4IYd90dO f/UXkf+b2U7Rb76HX8NuiO1yBB+uVg4= X-Google-Smtp-Source: AGHT+IFVwKsM7vhHHbindB36SAJ//dsM5jy6/DD1JTv8kubZidgUJZpq/2shomqVAZOPrnOCRBDGbJqIEWs= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a05:6902:1782:b0:d81:582b:4661 with SMTP id ca2-20020a056902178200b00d81582b4661mr65203ybb.8.1698430996901; Fri, 27 Oct 2023 11:23:16 -0700 (PDT) Reply-To: Sean Christopherson Date: Fri, 27 Oct 2023 11:22:08 -0700 In-Reply-To: <20231027182217.3615211-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20231027182217.3615211-1-seanjc@google.com> X-Mailer: git-send-email 2.42.0.820.g83a721a137-goog Message-ID: <20231027182217.3615211-27-seanjc@google.com> Subject: [PATCH v13 26/35] KVM: selftests: Add support for creating private memslots From: Sean Christopherson To: Paolo Bonzini , Marc Zyngier , Oliver Upton , Huacai Chen , Michael Ellerman , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Sean Christopherson , Alexander Viro , Christian Brauner , "Matthew Wilcox (Oracle)" , Andrew Morton Cc: kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Xiaoyao Li , Xu Yilun , Chao Peng , Fuad Tabba , Jarkko Sakkinen , Anish Moorthy , David Matlack , Yu Zhang , Isaku Yamahata , " =?utf-8?q?Micka=C3=ABl_Sala?= =?utf-8?q?=C3=BCn?= " , Vlastimil Babka , Vishal Annapurve , Ackerley Tng , Maciej Szmigiero , David Hildenbrand , Quentin Perret , Michael Roth , Wang , Liam Merwick , Isaku Yamahata , "Kirill A . Shutemov" Add support for creating "private" memslots via KVM_CREATE_GUEST_MEMFD and KVM_SET_USER_MEMORY_REGION2. Make vm_userspace_mem_region_add() a wrapper to its effective replacement, vm_mem_add(), so that private memslots are fully opt-in, i.e. don't require update all tests that add memory regions. Pivot on the KVM_MEM_PRIVATE flag instead of the validity of the "gmem" file descriptor so that simple tests can let vm_mem_add() do the heavy lifting of creating the guest memfd, but also allow the caller to pass in an explicit fd+offset so that fancier tests can do things like back multiple memslots with a single file. If the caller passes in a fd, dup() the fd so that (a) __vm_mem_region_delete() can close the fd associated with the memory region without needing yet another flag, and (b) so that the caller can safely close its copy of the fd without having to first destroy memslots. Co-developed-by: Ackerley Tng Signed-off-by: Ackerley Tng Signed-off-by: Sean Christopherson --- .../selftests/kvm/include/kvm_util_base.h | 23 +++++ .../testing/selftests/kvm/include/test_util.h | 5 ++ tools/testing/selftests/kvm/lib/kvm_util.c | 85 ++++++++++++------- 3 files changed, 82 insertions(+), 31 deletions(-) diff --git a/tools/testing/selftests/kvm/include/kvm_util_base.h b/tools/testing/selftests/kvm/include/kvm_util_base.h index 9f144841c2ee..9f861182c02a 100644 --- a/tools/testing/selftests/kvm/include/kvm_util_base.h +++ b/tools/testing/selftests/kvm/include/kvm_util_base.h @@ -431,6 +431,26 @@ static inline uint64_t vm_get_stat(struct kvm_vm *vm, const char *stat_name) void vm_create_irqchip(struct kvm_vm *vm); +static inline int __vm_create_guest_memfd(struct kvm_vm *vm, uint64_t size, + uint64_t flags) +{ + struct kvm_create_guest_memfd guest_memfd = { + .size = size, + .flags = flags, + }; + + return __vm_ioctl(vm, KVM_CREATE_GUEST_MEMFD, &guest_memfd); +} + +static inline int vm_create_guest_memfd(struct kvm_vm *vm, uint64_t size, + uint64_t flags) +{ + int fd = __vm_create_guest_memfd(vm, size, flags); + + TEST_ASSERT(fd >= 0, KVM_IOCTL_ERROR(KVM_CREATE_GUEST_MEMFD, fd)); + return fd; +} + void vm_set_user_memory_region(struct kvm_vm *vm, uint32_t slot, uint32_t flags, uint64_t gpa, uint64_t size, void *hva); int __vm_set_user_memory_region(struct kvm_vm *vm, uint32_t slot, uint32_t flags, @@ -439,6 +459,9 @@ void vm_userspace_mem_region_add(struct kvm_vm *vm, enum vm_mem_backing_src_type src_type, uint64_t guest_paddr, uint32_t slot, uint64_t npages, uint32_t flags); +void vm_mem_add(struct kvm_vm *vm, enum vm_mem_backing_src_type src_type, + uint64_t guest_paddr, uint32_t slot, uint64_t npages, + uint32_t flags, int guest_memfd_fd, uint64_t guest_memfd_offset); void vm_mem_region_set_flags(struct kvm_vm *vm, uint32_t slot, uint32_t flags); void vm_mem_region_move(struct kvm_vm *vm, uint32_t slot, uint64_t new_gpa); diff --git a/tools/testing/selftests/kvm/include/test_util.h b/tools/testing/selftests/kvm/include/test_util.h index 7e614adc6cf4..7257f2243ab9 100644 --- a/tools/testing/selftests/kvm/include/test_util.h +++ b/tools/testing/selftests/kvm/include/test_util.h @@ -142,6 +142,11 @@ static inline bool backing_src_is_shared(enum vm_mem_backing_src_type t) return vm_mem_backing_src_alias(t)->flag & MAP_SHARED; } +static inline bool backing_src_can_be_huge(enum vm_mem_backing_src_type t) +{ + return t != VM_MEM_SRC_ANONYMOUS && t != VM_MEM_SRC_SHMEM; +} + /* Aligns x up to the next multiple of size. Size must be a power of 2. */ static inline uint64_t align_up(uint64_t x, uint64_t size) { diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c index 3676b37bea38..45050f54701a 100644 --- a/tools/testing/selftests/kvm/lib/kvm_util.c +++ b/tools/testing/selftests/kvm/lib/kvm_util.c @@ -669,6 +669,8 @@ static void __vm_mem_region_delete(struct kvm_vm *vm, TEST_ASSERT(!ret, __KVM_SYSCALL_ERROR("munmap()", ret)); close(region->fd); } + if (region->region.guest_memfd >= 0) + close(region->region.guest_memfd); free(region); } @@ -870,36 +872,15 @@ void vm_set_user_memory_region(struct kvm_vm *vm, uint32_t slot, uint32_t flags, errno, strerror(errno)); } -/* - * VM Userspace Memory Region Add - * - * Input Args: - * vm - Virtual Machine - * src_type - Storage source for this region. - * NULL to use anonymous memory. - * guest_paddr - Starting guest physical address - * slot - KVM region slot - * npages - Number of physical pages - * flags - KVM memory region flags (e.g. KVM_MEM_LOG_DIRTY_PAGES) - * - * Output Args: None - * - * Return: None - * - * Allocates a memory area of the number of pages specified by npages - * and maps it to the VM specified by vm, at a starting physical address - * given by guest_paddr. The region is created with a KVM region slot - * given by slot, which must be unique and < KVM_MEM_SLOTS_NUM. The - * region is created with the flags given by flags. - */ -void vm_userspace_mem_region_add(struct kvm_vm *vm, - enum vm_mem_backing_src_type src_type, - uint64_t guest_paddr, uint32_t slot, uint64_t npages, - uint32_t flags) +/* FIXME: This thing needs to be ripped apart and rewritten. */ +void vm_mem_add(struct kvm_vm *vm, enum vm_mem_backing_src_type src_type, + uint64_t guest_paddr, uint32_t slot, uint64_t npages, + uint32_t flags, int guest_memfd, uint64_t guest_memfd_offset) { int ret; struct userspace_mem_region *region; size_t backing_src_pagesz = get_backing_src_pagesz(src_type); + size_t mem_size = npages * vm->page_size; size_t alignment; TEST_ASSERT(vm_adjust_num_guest_pages(vm->mode, npages) == npages, @@ -952,7 +933,7 @@ void vm_userspace_mem_region_add(struct kvm_vm *vm, /* Allocate and initialize new mem region structure. */ region = calloc(1, sizeof(*region)); TEST_ASSERT(region != NULL, "Insufficient Memory"); - region->mmap_size = npages * vm->page_size; + region->mmap_size = mem_size; #ifdef __s390x__ /* On s390x, the host address must be aligned to 1M (due to PGSTEs) */ @@ -999,14 +980,47 @@ void vm_userspace_mem_region_add(struct kvm_vm *vm, /* As needed perform madvise */ if ((src_type == VM_MEM_SRC_ANONYMOUS || src_type == VM_MEM_SRC_ANONYMOUS_THP) && thp_configured()) { - ret = madvise(region->host_mem, npages * vm->page_size, + ret = madvise(region->host_mem, mem_size, src_type == VM_MEM_SRC_ANONYMOUS ? MADV_NOHUGEPAGE : MADV_HUGEPAGE); TEST_ASSERT(ret == 0, "madvise failed, addr: %p length: 0x%lx src_type: %s", - region->host_mem, npages * vm->page_size, + region->host_mem, mem_size, vm_mem_backing_src_alias(src_type)->name); } region->backing_src_type = src_type; + + if (flags & KVM_MEM_PRIVATE) { + if (guest_memfd < 0) { + uint32_t guest_memfd_flags = 0; + + /* + * Allow hugepages for the guest memfd backing if the + * "normal" backing is allowed/required to be huge. + */ + if (src_type != VM_MEM_SRC_ANONYMOUS && + src_type != VM_MEM_SRC_SHMEM) + guest_memfd_flags |= KVM_GUEST_MEMFD_ALLOW_HUGEPAGE; + + TEST_ASSERT(!guest_memfd_offset, + "Offset must be zero when creating new guest_memfd"); + guest_memfd = vm_create_guest_memfd(vm, mem_size, guest_memfd_flags); + } else { + /* + * Install a unique fd for each memslot so that the fd + * can be closed when the region is deleted without + * needing to track if the fd is owned by the framework + * or by the caller. + */ + guest_memfd = dup(guest_memfd); + TEST_ASSERT(guest_memfd >= 0, __KVM_SYSCALL_ERROR("dup()", guest_memfd)); + } + + region->region.guest_memfd = guest_memfd; + region->region.guest_memfd_offset = guest_memfd_offset; + } else { + region->region.guest_memfd = -1; + } + region->unused_phy_pages = sparsebit_alloc(); sparsebit_set_num(region->unused_phy_pages, guest_paddr >> vm->page_shift, npages); @@ -1019,9 +1033,10 @@ void vm_userspace_mem_region_add(struct kvm_vm *vm, TEST_ASSERT(ret == 0, "KVM_SET_USER_MEMORY_REGION2 IOCTL failed,\n" " rc: %i errno: %i\n" " slot: %u flags: 0x%x\n" - " guest_phys_addr: 0x%lx size: 0x%lx", + " guest_phys_addr: 0x%lx size: 0x%lx guest_memfd: %d\n", ret, errno, slot, flags, - guest_paddr, (uint64_t) region->region.memory_size); + guest_paddr, (uint64_t) region->region.memory_size, + region->region.guest_memfd); /* Add to quick lookup data structures */ vm_userspace_mem_region_gpa_insert(&vm->regions.gpa_tree, region); @@ -1042,6 +1057,14 @@ void vm_userspace_mem_region_add(struct kvm_vm *vm, } } +void vm_userspace_mem_region_add(struct kvm_vm *vm, + enum vm_mem_backing_src_type src_type, + uint64_t guest_paddr, uint32_t slot, + uint64_t npages, uint32_t flags) +{ + vm_mem_add(vm, src_type, guest_paddr, slot, npages, flags, -1, 0); +} + /* * Memslot to region * From patchwork Fri Oct 27 18:22:09 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 13438896 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 92EDE3DFE1 for ; Fri, 27 Oct 2023 18:25:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="ix2AfYCW" Received: from mail-yb1-xb49.google.com (mail-yb1-xb49.google.com [IPv6:2607:f8b0:4864:20::b49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 62E9B2108 for ; Fri, 27 Oct 2023 11:23:20 -0700 (PDT) Received: by mail-yb1-xb49.google.com with SMTP id 3f1490d57ef6-da0c7d27fb0so1329291276.1 for ; Fri, 27 Oct 2023 11:23:20 -0700 (PDT) DKIM-Signature: v=1; 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Fri, 27 Oct 2023 11:23:18 -0700 (PDT) Reply-To: Sean Christopherson Date: Fri, 27 Oct 2023 11:22:09 -0700 In-Reply-To: <20231027182217.3615211-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20231027182217.3615211-1-seanjc@google.com> X-Mailer: git-send-email 2.42.0.820.g83a721a137-goog Message-ID: <20231027182217.3615211-28-seanjc@google.com> Subject: [PATCH v13 27/35] KVM: selftests: Add helpers to convert guest memory b/w private and shared From: Sean Christopherson To: Paolo Bonzini , Marc Zyngier , Oliver Upton , Huacai Chen , Michael Ellerman , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Sean Christopherson , Alexander Viro , Christian Brauner , "Matthew Wilcox (Oracle)" , Andrew Morton Cc: kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Xiaoyao Li , Xu Yilun , Chao Peng , Fuad Tabba , Jarkko Sakkinen , Anish Moorthy , David Matlack , Yu Zhang , Isaku Yamahata , " =?utf-8?q?Micka=C3=ABl_Sala?= =?utf-8?q?=C3=BCn?= " , Vlastimil Babka , Vishal Annapurve , Ackerley Tng , Maciej Szmigiero , David Hildenbrand , Quentin Perret , Michael Roth , Wang , Liam Merwick , Isaku Yamahata , "Kirill A . Shutemov" From: Vishal Annapurve Add helpers to convert memory between private and shared via KVM's memory attributes, as well as helpers to free/allocate guest_memfd memory via fallocate(). Userspace, i.e. tests, is NOT required to do fallocate() when converting memory, as the attributes are the single source of true. Provide allocate() helpers so that tests can mimic a userspace that frees private memory on conversion, e.g. to prioritize memory usage over performance. Signed-off-by: Vishal Annapurve Co-developed-by: Sean Christopherson Signed-off-by: Sean Christopherson Reviewed-by: Fuad Tabba Tested-by: Fuad Tabba --- .../selftests/kvm/include/kvm_util_base.h | 48 +++++++++++++++++++ tools/testing/selftests/kvm/lib/kvm_util.c | 28 +++++++++++ 2 files changed, 76 insertions(+) diff --git a/tools/testing/selftests/kvm/include/kvm_util_base.h b/tools/testing/selftests/kvm/include/kvm_util_base.h index 9f861182c02a..1441fca6c273 100644 --- a/tools/testing/selftests/kvm/include/kvm_util_base.h +++ b/tools/testing/selftests/kvm/include/kvm_util_base.h @@ -333,6 +333,54 @@ static inline void vm_enable_cap(struct kvm_vm *vm, uint32_t cap, uint64_t arg0) vm_ioctl(vm, KVM_ENABLE_CAP, &enable_cap); } +static inline void vm_set_memory_attributes(struct kvm_vm *vm, uint64_t gpa, + uint64_t size, uint64_t attributes) +{ + struct kvm_memory_attributes attr = { + .attributes = attributes, + .address = gpa, + .size = size, + .flags = 0, + }; + + /* + * KVM_SET_MEMORY_ATTRIBUTES overwrites _all_ attributes. These flows + * need significant enhancements to support multiple attributes. + */ + TEST_ASSERT(!attributes || attributes == KVM_MEMORY_ATTRIBUTE_PRIVATE, + "Update me to support multiple attributes!"); + + vm_ioctl(vm, KVM_SET_MEMORY_ATTRIBUTES, &attr); +} + + +static inline void vm_mem_set_private(struct kvm_vm *vm, uint64_t gpa, + uint64_t size) +{ + vm_set_memory_attributes(vm, gpa, size, KVM_MEMORY_ATTRIBUTE_PRIVATE); +} + +static inline void vm_mem_set_shared(struct kvm_vm *vm, uint64_t gpa, + uint64_t size) +{ + vm_set_memory_attributes(vm, gpa, size, 0); +} + +void vm_guest_mem_fallocate(struct kvm_vm *vm, uint64_t gpa, uint64_t size, + bool punch_hole); + +static inline void vm_guest_mem_punch_hole(struct kvm_vm *vm, uint64_t gpa, + uint64_t size) +{ + vm_guest_mem_fallocate(vm, gpa, size, true); +} + +static inline void vm_guest_mem_allocate(struct kvm_vm *vm, uint64_t gpa, + uint64_t size) +{ + vm_guest_mem_fallocate(vm, gpa, size, false); +} + void vm_enable_dirty_ring(struct kvm_vm *vm, uint32_t ring_size); const char *vm_guest_mode_string(uint32_t i); diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c index 45050f54701a..a140aee8d0f5 100644 --- a/tools/testing/selftests/kvm/lib/kvm_util.c +++ b/tools/testing/selftests/kvm/lib/kvm_util.c @@ -1176,6 +1176,34 @@ void vm_mem_region_delete(struct kvm_vm *vm, uint32_t slot) __vm_mem_region_delete(vm, memslot2region(vm, slot), true); } +void vm_guest_mem_fallocate(struct kvm_vm *vm, uint64_t base, uint64_t size, + bool punch_hole) +{ + const int mode = FALLOC_FL_KEEP_SIZE | (punch_hole ? FALLOC_FL_PUNCH_HOLE : 0); + struct userspace_mem_region *region; + uint64_t end = base + size; + uint64_t gpa, len; + off_t fd_offset; + int ret; + + for (gpa = base; gpa < end; gpa += len) { + uint64_t offset; + + region = userspace_mem_region_find(vm, gpa, gpa); + TEST_ASSERT(region && region->region.flags & KVM_MEM_PRIVATE, + "Private memory region not found for GPA 0x%lx", gpa); + + offset = (gpa - region->region.guest_phys_addr); + fd_offset = region->region.guest_memfd_offset + offset; + len = min_t(uint64_t, end - gpa, region->region.memory_size - offset); + + ret = fallocate(region->region.guest_memfd, mode, fd_offset, len); + TEST_ASSERT(!ret, "fallocate() failed to %s at %lx (len = %lu), fd = %d, mode = %x, offset = %lx\n", + punch_hole ? "punch hole" : "allocate", gpa, len, + region->region.guest_memfd, mode, fd_offset); + } +} + /* Returns the size of a vCPU's kvm_run structure. */ static int vcpu_mmap_sz(void) { From patchwork Fri Oct 27 18:22:10 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 13438886 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id F33B43DFE0 for ; Fri, 27 Oct 2023 18:23:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="OsCynHN7" Received: from mail-yw1-x1149.google.com (mail-yw1-x1149.google.com [IPv6:2607:f8b0:4864:20::1149]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E6D8710F7 for ; Fri, 27 Oct 2023 11:23:22 -0700 (PDT) Received: by mail-yw1-x1149.google.com with SMTP id 00721157ae682-5a7af69a4baso20633657b3.0 for ; Fri, 27 Oct 2023 11:23:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1698431001; x=1699035801; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:from:to:cc:subject:date:message-id:reply-to; bh=Xz8kt0PqFUxEdWsVGTpKhvh/0bAOqOlDGpUeOhSMn4Y=; b=OsCynHN7e3GIf2nZlVgAAzL9xfgOe12HvGyzelq0BaqcPUkHjvUGv7V/t3p6u/QB5d XzbYUd3YxZB2GRFVjllNEhiSazwuH/T3RNc6rH72ctO3WrZBN+veVNBuhn6IKD73e2lE tvOgu+tn7gQjA86uFzMPe6yMKXMdLIW0AUJchrmYdRKq9wuJUcOiZRVkaJikGs4e037u eGQyoS7vy7aj5G3ebzZqFOuVT1Fz0WFlWN1E7+z9ix0Ikl3DYEhE3/8c/6mXqXlqmroo 4STkfpkHlkT/WIoWMIgbr8caZb/C5xe2b2Ti6oPQHUchCsnWKeY1kEFlI9aHTOebf/zw EJVg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1698431001; x=1699035801; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=Xz8kt0PqFUxEdWsVGTpKhvh/0bAOqOlDGpUeOhSMn4Y=; b=XwCdhk3H2q0gVpm/eT60sz6E+wn21S68Q0ojMUriJgJCWveEEQVS/U7Sm7SwWsakyI tcOZlenXEYbqswS5FQ5cLEeDC6KZ2HsSwHf59WSszO9TNoOd/fTk7GCKkCGTiIZ/KzS7 9DlzfASYcVqXQV5Q0delWYvCQYac1coMNDDFnmdEbAvuJAd7A0B5rIy+GNyWgT1UJaq+ ZolnFzuW0Hgw5TV/v+tSpybPwg6Uz3M8I/jmft0TLZT++gtbYGR6LneetYvjl0mumWwG T5GHYgqSgld+BW7DaNxqDlPZKBfwSYLqqbOD6eD4nPcxlFiQdDC7ziIpMLAmH7EaoCBI ceGg== X-Gm-Message-State: AOJu0Yzr/rURbMPinWADyvZByZh58TsxPwMPM5qnDNsrZqjl/46f4/WC lQhOdrwOwZpaIYgTmKtuZ0au9sH0eo0= X-Google-Smtp-Source: AGHT+IElp9q5EmMXm2ScJmYLrQOoQHqoyljn7k2kapIAuiZd/nyrTEs2J8MXUI1aCi13+9HebXd80A1xuUo= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a0d:e653:0:b0:5a7:be10:461d with SMTP id p80-20020a0de653000000b005a7be10461dmr68754ywe.2.1698431001067; Fri, 27 Oct 2023 11:23:21 -0700 (PDT) Reply-To: Sean Christopherson Date: Fri, 27 Oct 2023 11:22:10 -0700 In-Reply-To: <20231027182217.3615211-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20231027182217.3615211-1-seanjc@google.com> X-Mailer: git-send-email 2.42.0.820.g83a721a137-goog Message-ID: <20231027182217.3615211-29-seanjc@google.com> Subject: [PATCH v13 28/35] KVM: selftests: Add helpers to do KVM_HC_MAP_GPA_RANGE hypercalls (x86) From: Sean Christopherson To: Paolo Bonzini , Marc Zyngier , Oliver Upton , Huacai Chen , Michael Ellerman , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Sean Christopherson , Alexander Viro , Christian Brauner , "Matthew Wilcox (Oracle)" , Andrew Morton Cc: kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Xiaoyao Li , Xu Yilun , Chao Peng , Fuad Tabba , Jarkko Sakkinen , Anish Moorthy , David Matlack , Yu Zhang , Isaku Yamahata , " =?utf-8?q?Micka=C3=ABl_Sala?= =?utf-8?q?=C3=BCn?= " , Vlastimil Babka , Vishal Annapurve , Ackerley Tng , Maciej Szmigiero , David Hildenbrand , Quentin Perret , Michael Roth , Wang , Liam Merwick , Isaku Yamahata , "Kirill A . Shutemov" From: Vishal Annapurve Add helpers for x86 guests to invoke the KVM_HC_MAP_GPA_RANGE hypercall, which KVM will forward to userspace and thus can be used by tests to coordinate private<=>shared conversions between host userspace code and guest code. Signed-off-by: Vishal Annapurve [sean: drop shared/private helpers (let tests specify flags)] Signed-off-by: Sean Christopherson --- .../selftests/kvm/include/x86_64/processor.h | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/tools/testing/selftests/kvm/include/x86_64/processor.h b/tools/testing/selftests/kvm/include/x86_64/processor.h index 25bc61dac5fb..a84863503fcb 100644 --- a/tools/testing/selftests/kvm/include/x86_64/processor.h +++ b/tools/testing/selftests/kvm/include/x86_64/processor.h @@ -15,6 +15,7 @@ #include #include +#include #include #include "../kvm_util.h" @@ -1194,6 +1195,20 @@ uint64_t kvm_hypercall(uint64_t nr, uint64_t a0, uint64_t a1, uint64_t a2, uint64_t __xen_hypercall(uint64_t nr, uint64_t a0, void *a1); void xen_hypercall(uint64_t nr, uint64_t a0, void *a1); +static inline uint64_t __kvm_hypercall_map_gpa_range(uint64_t gpa, + uint64_t size, uint64_t flags) +{ + return kvm_hypercall(KVM_HC_MAP_GPA_RANGE, gpa, size >> PAGE_SHIFT, flags, 0); +} + +static inline void kvm_hypercall_map_gpa_range(uint64_t gpa, uint64_t size, + uint64_t flags) +{ + uint64_t ret = __kvm_hypercall_map_gpa_range(gpa, size, flags); + + GUEST_ASSERT(!ret); +} + void __vm_xsave_require_permission(uint64_t xfeature, const char *name); #define vm_xsave_require_permission(xfeature) \ From patchwork Fri Oct 27 18:22:11 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 13438891 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7DB2A3DFE1 for ; Fri, 27 Oct 2023 18:24:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="1fkcR/pN" Received: from mail-pl1-x649.google.com (mail-pl1-x649.google.com [IPv6:2607:f8b0:4864:20::649]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EDCE72118 for ; 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bh=jQSVyWKl4uOIPgy0IGoz6RV6+SA994mJdxIjj30CSy8=; b=c7XwI5XKDTIpK9vc95kDvC+QfYF70wBn0iDjksZpsGL2IoPE+Jp54r+YIIgNm8KAYe qjEEtZbhXECnuoIxDLlJm9mfVAg3fVR/zIdveBe5/cJNAtceCJzhMJIg4CIstNoh2hmU FKKdvKLRhkd+WpdAACEWWNHZWGtVjRtfsr3017MRJwQjS6gCPnvz54fw1+vzfJk3tS5b HIkqWFDxYY/f3Y3eiX8mCpLR/5kTHR7iSm6Pp5fK16fsPl+zbgPnf1TnEI+Q0MJPSqv2 FZy2dOZpxW0YP+aEYPPwdOaBCHzoinB9UXAX3rObY1aMN+ZHt8N3NsNFJzV1cz3s5f90 zmXw== X-Gm-Message-State: AOJu0YzzLc5RDNrcZMGMs8IsRhwPNnQXUjhwN+y3u57n/RhAla46zNGi HqPCAG/RXMsHASsFhecp3kJtTp+4Lbk= X-Google-Smtp-Source: AGHT+IEPiReV3cx4w9TLV/sbeNO6eERW1W7R7I/92aij3c451hoquFxemYBSOe8iuKYscw30iX2x6gNTTBQ= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a17:903:18d:b0:1cc:2183:b380 with SMTP id z13-20020a170903018d00b001cc2183b380mr55116plg.8.1698431003083; Fri, 27 Oct 2023 11:23:23 -0700 (PDT) Reply-To: Sean Christopherson Date: Fri, 27 Oct 2023 11:22:11 -0700 In-Reply-To: <20231027182217.3615211-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20231027182217.3615211-1-seanjc@google.com> X-Mailer: git-send-email 2.42.0.820.g83a721a137-goog Message-ID: <20231027182217.3615211-30-seanjc@google.com> Subject: [PATCH v13 29/35] KVM: selftests: Introduce VM "shape" to allow tests to specify the VM type From: Sean Christopherson To: Paolo Bonzini , Marc Zyngier , Oliver Upton , Huacai Chen , Michael Ellerman , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Sean Christopherson , Alexander Viro , Christian Brauner , "Matthew Wilcox (Oracle)" , Andrew Morton Cc: kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Xiaoyao Li , Xu Yilun , Chao Peng , Fuad Tabba , Jarkko Sakkinen , Anish Moorthy , David Matlack , Yu Zhang , Isaku Yamahata , " =?utf-8?q?Micka=C3=ABl_Sala?= =?utf-8?q?=C3=BCn?= " , Vlastimil Babka , Vishal Annapurve , Ackerley Tng , Maciej Szmigiero , David Hildenbrand , Quentin Perret , Michael Roth , Wang , Liam Merwick , Isaku Yamahata , "Kirill A . Shutemov" Add a "vm_shape" structure to encapsulate the selftests-defined "mode", along with the KVM-defined "type" for use when creating a new VM. "mode" tracks physical and virtual address properties, as well as the preferred backing memory type, while "type" corresponds to the VM type. Taking the VM type will allow adding tests for KVM_CREATE_GUEST_MEMFD, a.k.a. guest private memory, without needing an entirely separate set of helpers. Guest private memory is effectively usable only by confidential VM types, and it's expected that x86 will double down and require unique VM types for TDX and SNP guests. Signed-off-by: Sean Christopherson --- tools/testing/selftests/kvm/dirty_log_test.c | 2 +- .../selftests/kvm/include/kvm_util_base.h | 54 +++++++++++++++---- .../selftests/kvm/kvm_page_table_test.c | 2 +- tools/testing/selftests/kvm/lib/kvm_util.c | 43 +++++++-------- tools/testing/selftests/kvm/lib/memstress.c | 3 +- .../kvm/x86_64/ucna_injection_test.c | 2 +- 6 files changed, 72 insertions(+), 34 deletions(-) diff --git a/tools/testing/selftests/kvm/dirty_log_test.c b/tools/testing/selftests/kvm/dirty_log_test.c index 936f3a8d1b83..6cbecf499767 100644 --- a/tools/testing/selftests/kvm/dirty_log_test.c +++ b/tools/testing/selftests/kvm/dirty_log_test.c @@ -699,7 +699,7 @@ static struct kvm_vm *create_vm(enum vm_guest_mode mode, struct kvm_vcpu **vcpu, pr_info("Testing guest mode: %s\n", vm_guest_mode_string(mode)); - vm = __vm_create(mode, 1, extra_mem_pages); + vm = __vm_create(VM_SHAPE(mode), 1, extra_mem_pages); log_mode_create_vm_done(vm); *vcpu = vm_vcpu_add(vm, 0, guest_code); diff --git a/tools/testing/selftests/kvm/include/kvm_util_base.h b/tools/testing/selftests/kvm/include/kvm_util_base.h index 1441fca6c273..157508c071f3 100644 --- a/tools/testing/selftests/kvm/include/kvm_util_base.h +++ b/tools/testing/selftests/kvm/include/kvm_util_base.h @@ -188,6 +188,23 @@ enum vm_guest_mode { NUM_VM_MODES, }; +struct vm_shape { + enum vm_guest_mode mode; + unsigned int type; +}; + +#define VM_TYPE_DEFAULT 0 + +#define VM_SHAPE(__mode) \ +({ \ + struct vm_shape shape = { \ + .mode = (__mode), \ + .type = VM_TYPE_DEFAULT \ + }; \ + \ + shape; \ +}) + #if defined(__aarch64__) extern enum vm_guest_mode vm_mode_default; @@ -220,6 +237,8 @@ extern enum vm_guest_mode vm_mode_default; #endif +#define VM_SHAPE_DEFAULT VM_SHAPE(VM_MODE_DEFAULT) + #define MIN_PAGE_SIZE (1U << MIN_PAGE_SHIFT) #define PTES_PER_MIN_PAGE ptes_per_page(MIN_PAGE_SIZE) @@ -784,21 +803,21 @@ vm_paddr_t vm_alloc_page_table(struct kvm_vm *vm); * __vm_create() does NOT create vCPUs, @nr_runnable_vcpus is used purely to * calculate the amount of memory needed for per-vCPU data, e.g. stacks. */ -struct kvm_vm *____vm_create(enum vm_guest_mode mode); -struct kvm_vm *__vm_create(enum vm_guest_mode mode, uint32_t nr_runnable_vcpus, +struct kvm_vm *____vm_create(struct vm_shape shape); +struct kvm_vm *__vm_create(struct vm_shape shape, uint32_t nr_runnable_vcpus, uint64_t nr_extra_pages); static inline struct kvm_vm *vm_create_barebones(void) { - return ____vm_create(VM_MODE_DEFAULT); + return ____vm_create(VM_SHAPE_DEFAULT); } static inline struct kvm_vm *vm_create(uint32_t nr_runnable_vcpus) { - return __vm_create(VM_MODE_DEFAULT, nr_runnable_vcpus, 0); + return __vm_create(VM_SHAPE_DEFAULT, nr_runnable_vcpus, 0); } -struct kvm_vm *__vm_create_with_vcpus(enum vm_guest_mode mode, uint32_t nr_vcpus, +struct kvm_vm *__vm_create_with_vcpus(struct vm_shape shape, uint32_t nr_vcpus, uint64_t extra_mem_pages, void *guest_code, struct kvm_vcpu *vcpus[]); @@ -806,17 +825,27 @@ static inline struct kvm_vm *vm_create_with_vcpus(uint32_t nr_vcpus, void *guest_code, struct kvm_vcpu *vcpus[]) { - return __vm_create_with_vcpus(VM_MODE_DEFAULT, nr_vcpus, 0, + return __vm_create_with_vcpus(VM_SHAPE_DEFAULT, nr_vcpus, 0, guest_code, vcpus); } + +struct kvm_vm *__vm_create_shape_with_one_vcpu(struct vm_shape shape, + struct kvm_vcpu **vcpu, + uint64_t extra_mem_pages, + void *guest_code); + /* * Create a VM with a single vCPU with reasonable defaults and @extra_mem_pages * additional pages of guest memory. Returns the VM and vCPU (via out param). */ -struct kvm_vm *__vm_create_with_one_vcpu(struct kvm_vcpu **vcpu, - uint64_t extra_mem_pages, - void *guest_code); +static inline struct kvm_vm *__vm_create_with_one_vcpu(struct kvm_vcpu **vcpu, + uint64_t extra_mem_pages, + void *guest_code) +{ + return __vm_create_shape_with_one_vcpu(VM_SHAPE_DEFAULT, vcpu, + extra_mem_pages, guest_code); +} static inline struct kvm_vm *vm_create_with_one_vcpu(struct kvm_vcpu **vcpu, void *guest_code) @@ -824,6 +853,13 @@ static inline struct kvm_vm *vm_create_with_one_vcpu(struct kvm_vcpu **vcpu, return __vm_create_with_one_vcpu(vcpu, 0, guest_code); } +static inline struct kvm_vm *vm_create_shape_with_one_vcpu(struct vm_shape shape, + struct kvm_vcpu **vcpu, + void *guest_code) +{ + return __vm_create_shape_with_one_vcpu(shape, vcpu, 0, guest_code); +} + struct kvm_vcpu *vm_recreate_with_one_vcpu(struct kvm_vm *vm); void kvm_pin_this_task_to_pcpu(uint32_t pcpu); diff --git a/tools/testing/selftests/kvm/kvm_page_table_test.c b/tools/testing/selftests/kvm/kvm_page_table_test.c index 69f26d80c821..e37dc9c21888 100644 --- a/tools/testing/selftests/kvm/kvm_page_table_test.c +++ b/tools/testing/selftests/kvm/kvm_page_table_test.c @@ -254,7 +254,7 @@ static struct kvm_vm *pre_init_before_test(enum vm_guest_mode mode, void *arg) /* Create a VM with enough guest pages */ guest_num_pages = test_mem_size / guest_page_size; - vm = __vm_create_with_vcpus(mode, nr_vcpus, guest_num_pages, + vm = __vm_create_with_vcpus(VM_SHAPE(mode), nr_vcpus, guest_num_pages, guest_code, test_args.vcpus); /* Align down GPA of the testing memslot */ diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c index a140aee8d0f5..52b131e3aca5 100644 --- a/tools/testing/selftests/kvm/lib/kvm_util.c +++ b/tools/testing/selftests/kvm/lib/kvm_util.c @@ -209,7 +209,7 @@ __weak void vm_vaddr_populate_bitmap(struct kvm_vm *vm) (1ULL << (vm->va_bits - 1)) >> vm->page_shift); } -struct kvm_vm *____vm_create(enum vm_guest_mode mode) +struct kvm_vm *____vm_create(struct vm_shape shape) { struct kvm_vm *vm; @@ -221,13 +221,13 @@ struct kvm_vm *____vm_create(enum vm_guest_mode mode) vm->regions.hva_tree = RB_ROOT; hash_init(vm->regions.slot_hash); - vm->mode = mode; - vm->type = 0; + vm->mode = shape.mode; + vm->type = shape.type; - vm->pa_bits = vm_guest_mode_params[mode].pa_bits; - vm->va_bits = vm_guest_mode_params[mode].va_bits; - vm->page_size = vm_guest_mode_params[mode].page_size; - vm->page_shift = vm_guest_mode_params[mode].page_shift; + vm->pa_bits = vm_guest_mode_params[vm->mode].pa_bits; + vm->va_bits = vm_guest_mode_params[vm->mode].va_bits; + vm->page_size = vm_guest_mode_params[vm->mode].page_size; + vm->page_shift = vm_guest_mode_params[vm->mode].page_shift; /* Setup mode specific traits. */ switch (vm->mode) { @@ -265,7 +265,7 @@ struct kvm_vm *____vm_create(enum vm_guest_mode mode) /* * Ignore KVM support for 5-level paging (vm->va_bits == 57), * it doesn't take effect unless a CR4.LA57 is set, which it - * isn't for this VM_MODE. + * isn't for this mode (48-bit virtual address space). */ TEST_ASSERT(vm->va_bits == 48 || vm->va_bits == 57, "Linear address width (%d bits) not supported", @@ -285,10 +285,11 @@ struct kvm_vm *____vm_create(enum vm_guest_mode mode) vm->pgtable_levels = 5; break; default: - TEST_FAIL("Unknown guest mode, mode: 0x%x", mode); + TEST_FAIL("Unknown guest mode: 0x%x", vm->mode); } #ifdef __aarch64__ + TEST_ASSERT(!vm->type, "ARM doesn't support test-provided types"); if (vm->pa_bits != 40) vm->type = KVM_VM_TYPE_ARM_IPA_SIZE(vm->pa_bits); #endif @@ -347,19 +348,19 @@ static uint64_t vm_nr_pages_required(enum vm_guest_mode mode, return vm_adjust_num_guest_pages(mode, nr_pages); } -struct kvm_vm *__vm_create(enum vm_guest_mode mode, uint32_t nr_runnable_vcpus, +struct kvm_vm *__vm_create(struct vm_shape shape, uint32_t nr_runnable_vcpus, uint64_t nr_extra_pages) { - uint64_t nr_pages = vm_nr_pages_required(mode, nr_runnable_vcpus, + uint64_t nr_pages = vm_nr_pages_required(shape.mode, nr_runnable_vcpus, nr_extra_pages); struct userspace_mem_region *slot0; struct kvm_vm *vm; int i; - pr_debug("%s: mode='%s' pages='%ld'\n", __func__, - vm_guest_mode_string(mode), nr_pages); + pr_debug("%s: mode='%s' type='%d', pages='%ld'\n", __func__, + vm_guest_mode_string(shape.mode), shape.type, nr_pages); - vm = ____vm_create(mode); + vm = ____vm_create(shape); vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS, 0, 0, nr_pages, 0); for (i = 0; i < NR_MEM_REGIONS; i++) @@ -400,7 +401,7 @@ struct kvm_vm *__vm_create(enum vm_guest_mode mode, uint32_t nr_runnable_vcpus, * extra_mem_pages is only used to calculate the maximum page table size, * no real memory allocation for non-slot0 memory in this function. */ -struct kvm_vm *__vm_create_with_vcpus(enum vm_guest_mode mode, uint32_t nr_vcpus, +struct kvm_vm *__vm_create_with_vcpus(struct vm_shape shape, uint32_t nr_vcpus, uint64_t extra_mem_pages, void *guest_code, struct kvm_vcpu *vcpus[]) { @@ -409,7 +410,7 @@ struct kvm_vm *__vm_create_with_vcpus(enum vm_guest_mode mode, uint32_t nr_vcpus TEST_ASSERT(!nr_vcpus || vcpus, "Must provide vCPU array"); - vm = __vm_create(mode, nr_vcpus, extra_mem_pages); + vm = __vm_create(shape, nr_vcpus, extra_mem_pages); for (i = 0; i < nr_vcpus; ++i) vcpus[i] = vm_vcpu_add(vm, i, guest_code); @@ -417,15 +418,15 @@ struct kvm_vm *__vm_create_with_vcpus(enum vm_guest_mode mode, uint32_t nr_vcpus return vm; } -struct kvm_vm *__vm_create_with_one_vcpu(struct kvm_vcpu **vcpu, - uint64_t extra_mem_pages, - void *guest_code) +struct kvm_vm *__vm_create_shape_with_one_vcpu(struct vm_shape shape, + struct kvm_vcpu **vcpu, + uint64_t extra_mem_pages, + void *guest_code) { struct kvm_vcpu *vcpus[1]; struct kvm_vm *vm; - vm = __vm_create_with_vcpus(VM_MODE_DEFAULT, 1, extra_mem_pages, - guest_code, vcpus); + vm = __vm_create_with_vcpus(shape, 1, extra_mem_pages, guest_code, vcpus); *vcpu = vcpus[0]; return vm; diff --git a/tools/testing/selftests/kvm/lib/memstress.c b/tools/testing/selftests/kvm/lib/memstress.c index df457452d146..d05487e5a371 100644 --- a/tools/testing/selftests/kvm/lib/memstress.c +++ b/tools/testing/selftests/kvm/lib/memstress.c @@ -168,7 +168,8 @@ struct kvm_vm *memstress_create_vm(enum vm_guest_mode mode, int nr_vcpus, * The memory is also added to memslot 0, but that's a benign side * effect as KVM allows aliasing HVAs in meslots. */ - vm = __vm_create_with_vcpus(mode, nr_vcpus, slot0_pages + guest_num_pages, + vm = __vm_create_with_vcpus(VM_SHAPE(mode), nr_vcpus, + slot0_pages + guest_num_pages, memstress_guest_code, vcpus); args->vm = vm; diff --git a/tools/testing/selftests/kvm/x86_64/ucna_injection_test.c b/tools/testing/selftests/kvm/x86_64/ucna_injection_test.c index 85f34ca7e49e..0ed32ec903d0 100644 --- a/tools/testing/selftests/kvm/x86_64/ucna_injection_test.c +++ b/tools/testing/selftests/kvm/x86_64/ucna_injection_test.c @@ -271,7 +271,7 @@ int main(int argc, char *argv[]) kvm_check_cap(KVM_CAP_MCE); - vm = __vm_create(VM_MODE_DEFAULT, 3, 0); + vm = __vm_create(VM_SHAPE_DEFAULT, 3, 0); kvm_ioctl(vm->kvm_fd, KVM_X86_GET_MCE_CAP_SUPPORTED, &supported_mcg_caps); From patchwork Fri Oct 27 18:22:12 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 13438887 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BA0CE3DFE1 for ; Fri, 27 Oct 2023 18:23:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="rsKK6rbA" Received: from mail-yw1-x114a.google.com (mail-yw1-x114a.google.com [IPv6:2607:f8b0:4864:20::114a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6A474198E for ; Fri, 27 Oct 2023 11:23:26 -0700 (PDT) Received: by mail-yw1-x114a.google.com with SMTP id 00721157ae682-5a7b9e83b70so22729477b3.0 for ; 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Shutemov" Add GUEST_SYNC[1-6]() so that tests can pass the maximum amount of information supported via ucall(), without needing to resort to shared memory. Signed-off-by: Sean Christopherson --- tools/testing/selftests/kvm/include/ucall_common.h | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/tools/testing/selftests/kvm/include/ucall_common.h b/tools/testing/selftests/kvm/include/ucall_common.h index ce33d306c2cb..0fb472a5a058 100644 --- a/tools/testing/selftests/kvm/include/ucall_common.h +++ b/tools/testing/selftests/kvm/include/ucall_common.h @@ -52,6 +52,17 @@ int ucall_nr_pages_required(uint64_t page_size); #define GUEST_SYNC_ARGS(stage, arg1, arg2, arg3, arg4) \ ucall(UCALL_SYNC, 6, "hello", stage, arg1, arg2, arg3, arg4) #define GUEST_SYNC(stage) ucall(UCALL_SYNC, 2, "hello", stage) +#define GUEST_SYNC1(arg0) ucall(UCALL_SYNC, 1, arg0) +#define GUEST_SYNC2(arg0, arg1) ucall(UCALL_SYNC, 2, arg0, arg1) +#define GUEST_SYNC3(arg0, arg1, arg2) \ + ucall(UCALL_SYNC, 3, arg0, arg1, arg2) +#define GUEST_SYNC4(arg0, arg1, arg2, arg3) \ + ucall(UCALL_SYNC, 4, arg0, arg1, arg2, arg3) +#define GUEST_SYNC5(arg0, arg1, arg2, arg3, arg4) \ + ucall(UCALL_SYNC, 5, arg0, arg1, arg2, arg3, arg4) +#define GUEST_SYNC6(arg0, arg1, arg2, arg3, arg4, arg5) \ + ucall(UCALL_SYNC, 6, arg0, arg1, arg2, arg3, arg4, arg5) + #define GUEST_PRINTF(_fmt, _args...) ucall_fmt(UCALL_PRINTF, _fmt, ##_args) #define GUEST_DONE() ucall(UCALL_DONE, 0) From patchwork Fri Oct 27 18:22:13 2023 Content-Type: text/plain; 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Fri, 27 Oct 2023 11:23:26 -0700 (PDT) Reply-To: Sean Christopherson Date: Fri, 27 Oct 2023 11:22:13 -0700 In-Reply-To: <20231027182217.3615211-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20231027182217.3615211-1-seanjc@google.com> X-Mailer: git-send-email 2.42.0.820.g83a721a137-goog Message-ID: <20231027182217.3615211-32-seanjc@google.com> Subject: [PATCH v13 31/35] KVM: selftests: Add x86-only selftest for private memory conversions From: Sean Christopherson To: Paolo Bonzini , Marc Zyngier , Oliver Upton , Huacai Chen , Michael Ellerman , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Sean Christopherson , Alexander Viro , Christian Brauner , "Matthew Wilcox (Oracle)" , Andrew Morton Cc: kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Xiaoyao Li , Xu Yilun , Chao Peng , Fuad Tabba , Jarkko Sakkinen , Anish Moorthy , David Matlack , Yu Zhang , Isaku Yamahata , " =?utf-8?q?Micka=C3=ABl_Sala?= =?utf-8?q?=C3=BCn?= " , Vlastimil Babka , Vishal Annapurve , Ackerley Tng , Maciej Szmigiero , David Hildenbrand , Quentin Perret , Michael Roth , Wang , Liam Merwick , Isaku Yamahata , "Kirill A . Shutemov" From: Vishal Annapurve Add a selftest to exercise implicit/explicit conversion functionality within KVM and verify: - Shared memory is visible to host userspace - Private memory is not visible to host userspace - Host userspace and guest can communicate over shared memory - Data in shared backing is preserved across conversions (test's host userspace doesn't free the data) - Private memory is bound to the lifetime of the VM Ideally, KVM's selftests infrastructure would be reworked to allow backing a single region of guest memory with multiple memslots for _all_ backing types and shapes, i.e. ideally the code for using a single backing fd across multiple memslots would work for "regular" memory as well. But sadly, support for KVM_CREATE_GUEST_MEMFD has languished for far too long, and overhauling selftests' memslots infrastructure would likely open a can of worms, i.e. delay things even further. In addition to the more obvious tests, verify that PUNCH_HOLE actually frees memory. Directly verifying that KVM frees memory is impractical, if it's even possible, so instead indirectly verify memory is freed by asserting that the guest reads zeroes after a PUNCH_HOLE. E.g. if KVM zaps SPTEs but doesn't actually punch a hole in the inode, the subsequent read will still see the previous value. And obviously punching a hole shouldn't cause explosions. Let the user specify the number of memslots in the private mem conversion test, i.e. don't require the number of memslots to be '1' or "nr_vcpus". Creating more memslots than vCPUs is particularly interesting, e.g. it can result in a single KVM_SET_MEMORY_ATTRIBUTES spanning multiple memslots. To keep the math reasonable, align each vCPU's chunk to at least 2MiB (the size is 2MiB+4KiB), and require the total size to be cleanly divisible by the number of memslots. The goal is to be able to validate that KVM plays nice with multiple memslots, being able to create a truly arbitrary number of memslots doesn't add meaningful value, i.e. isn't worth the cost. Intentionally don't take a requirement on KVM_CAP_GUEST_MEMFD, KVM_CAP_MEMORY_FAULT_INFO, KVM_MEMORY_ATTRIBUTE_PRIVATE, etc., as it's a KVM bug to advertise KVM_X86_SW_PROTECTED_VM without its prerequisites. Signed-off-by: Vishal Annapurve Co-developed-by: Ackerley Tng Signed-off-by: Ackerley Tng Co-developed-by: Sean Christopherson Signed-off-by: Sean Christopherson --- tools/testing/selftests/kvm/Makefile | 1 + .../kvm/x86_64/private_mem_conversions_test.c | 487 ++++++++++++++++++ 2 files changed, 488 insertions(+) create mode 100644 tools/testing/selftests/kvm/x86_64/private_mem_conversions_test.c diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile index a3bb36fb3cfc..b709a52d5cdb 100644 --- a/tools/testing/selftests/kvm/Makefile +++ b/tools/testing/selftests/kvm/Makefile @@ -81,6 +81,7 @@ TEST_GEN_PROGS_x86_64 += x86_64/monitor_mwait_test TEST_GEN_PROGS_x86_64 += x86_64/nested_exceptions_test TEST_GEN_PROGS_x86_64 += x86_64/platform_info_test TEST_GEN_PROGS_x86_64 += x86_64/pmu_event_filter_test +TEST_GEN_PROGS_x86_64 += x86_64/private_mem_conversions_test TEST_GEN_PROGS_x86_64 += x86_64/set_boot_cpu_id TEST_GEN_PROGS_x86_64 += x86_64/set_sregs_test TEST_GEN_PROGS_x86_64 += x86_64/smaller_maxphyaddr_emulation_test diff --git a/tools/testing/selftests/kvm/x86_64/private_mem_conversions_test.c b/tools/testing/selftests/kvm/x86_64/private_mem_conversions_test.c new file mode 100644 index 000000000000..be311944e90a --- /dev/null +++ b/tools/testing/selftests/kvm/x86_64/private_mem_conversions_test.c @@ -0,0 +1,487 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2022, Google LLC. + */ +#define _GNU_SOURCE /* for program_invocation_short_name */ +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include +#include +#include +#include + +#include +#include +#include + +#define BASE_DATA_SLOT 10 +#define BASE_DATA_GPA ((uint64_t)(1ull << 32)) +#define PER_CPU_DATA_SIZE ((uint64_t)(SZ_2M + PAGE_SIZE)) + +/* Horrific macro so that the line info is captured accurately :-( */ +#define memcmp_g(gpa, pattern, size) \ +do { \ + uint8_t *mem = (uint8_t *)gpa; \ + size_t i; \ + \ + for (i = 0; i < size; i++) \ + __GUEST_ASSERT(mem[i] == pattern, \ + "Guest expected 0x%x at offset %lu (gpa 0x%llx), got 0x%x", \ + pattern, i, gpa + i, mem[i]); \ +} while (0) + +static void memcmp_h(uint8_t *mem, uint64_t gpa, uint8_t pattern, size_t size) +{ + size_t i; + + for (i = 0; i < size; i++) + TEST_ASSERT(mem[i] == pattern, + "Host expected 0x%x at gpa 0x%lx, got 0x%x", + pattern, gpa + i, mem[i]); +} + +/* + * Run memory conversion tests with explicit conversion: + * Execute KVM hypercall to map/unmap gpa range which will cause userspace exit + * to back/unback private memory. Subsequent accesses by guest to the gpa range + * will not cause exit to userspace. + * + * Test memory conversion scenarios with following steps: + * 1) Access private memory using private access and verify that memory contents + * are not visible to userspace. + * 2) Convert memory to shared using explicit conversions and ensure that + * userspace is able to access the shared regions. + * 3) Convert memory back to private using explicit conversions and ensure that + * userspace is again not able to access converted private regions. + */ + +#define GUEST_STAGE(o, s) { .offset = o, .size = s } + +enum ucall_syncs { + SYNC_SHARED, + SYNC_PRIVATE, +}; + +static void guest_sync_shared(uint64_t gpa, uint64_t size, + uint8_t current_pattern, uint8_t new_pattern) +{ + GUEST_SYNC5(SYNC_SHARED, gpa, size, current_pattern, new_pattern); +} + +static void guest_sync_private(uint64_t gpa, uint64_t size, uint8_t pattern) +{ + GUEST_SYNC4(SYNC_PRIVATE, gpa, size, pattern); +} + +/* Arbitrary values, KVM doesn't care about the attribute flags. */ +#define MAP_GPA_SET_ATTRIBUTES BIT(0) +#define MAP_GPA_SHARED BIT(1) +#define MAP_GPA_DO_FALLOCATE BIT(2) + +static void guest_map_mem(uint64_t gpa, uint64_t size, bool map_shared, + bool do_fallocate) +{ + uint64_t flags = MAP_GPA_SET_ATTRIBUTES; + + if (map_shared) + flags |= MAP_GPA_SHARED; + if (do_fallocate) + flags |= MAP_GPA_DO_FALLOCATE; + kvm_hypercall_map_gpa_range(gpa, size, flags); +} + +static void guest_map_shared(uint64_t gpa, uint64_t size, bool do_fallocate) +{ + guest_map_mem(gpa, size, true, do_fallocate); +} + +static void guest_map_private(uint64_t gpa, uint64_t size, bool do_fallocate) +{ + guest_map_mem(gpa, size, false, do_fallocate); +} + +struct { + uint64_t offset; + uint64_t size; +} static const test_ranges[] = { + GUEST_STAGE(0, PAGE_SIZE), + GUEST_STAGE(0, SZ_2M), + GUEST_STAGE(PAGE_SIZE, PAGE_SIZE), + GUEST_STAGE(PAGE_SIZE, SZ_2M), + GUEST_STAGE(SZ_2M, PAGE_SIZE), +}; + +static void guest_test_explicit_conversion(uint64_t base_gpa, bool do_fallocate) +{ + const uint8_t def_p = 0xaa; + const uint8_t init_p = 0xcc; + uint64_t j; + int i; + + /* Memory should be shared by default. */ + memset((void *)base_gpa, def_p, PER_CPU_DATA_SIZE); + memcmp_g(base_gpa, def_p, PER_CPU_DATA_SIZE); + guest_sync_shared(base_gpa, PER_CPU_DATA_SIZE, def_p, init_p); + + memcmp_g(base_gpa, init_p, PER_CPU_DATA_SIZE); + + for (i = 0; i < ARRAY_SIZE(test_ranges); i++) { + uint64_t gpa = base_gpa + test_ranges[i].offset; + uint64_t size = test_ranges[i].size; + uint8_t p1 = 0x11; + uint8_t p2 = 0x22; + uint8_t p3 = 0x33; + uint8_t p4 = 0x44; + + /* + * Set the test region to pattern one to differentiate it from + * the data range as a whole (contains the initial pattern). + */ + memset((void *)gpa, p1, size); + + /* + * Convert to private, set and verify the private data, and + * then verify that the rest of the data (map shared) still + * holds the initial pattern, and that the host always sees the + * shared memory (initial pattern). Unlike shared memory, + * punching a hole in private memory is destructive, i.e. + * previous values aren't guaranteed to be preserved. + */ + guest_map_private(gpa, size, do_fallocate); + + if (size > PAGE_SIZE) { + memset((void *)gpa, p2, PAGE_SIZE); + goto skip; + } + + memset((void *)gpa, p2, size); + guest_sync_private(gpa, size, p1); + + /* + * Verify that the private memory was set to pattern two, and + * that shared memory still holds the initial pattern. + */ + memcmp_g(gpa, p2, size); + if (gpa > base_gpa) + memcmp_g(base_gpa, init_p, gpa - base_gpa); + if (gpa + size < base_gpa + PER_CPU_DATA_SIZE) + memcmp_g(gpa + size, init_p, + (base_gpa + PER_CPU_DATA_SIZE) - (gpa + size)); + + /* + * Convert odd-number page frames back to shared to verify KVM + * also correctly handles holes in private ranges. + */ + for (j = 0; j < size; j += PAGE_SIZE) { + if ((j >> PAGE_SHIFT) & 1) { + guest_map_shared(gpa + j, PAGE_SIZE, do_fallocate); + guest_sync_shared(gpa + j, PAGE_SIZE, p1, p3); + + memcmp_g(gpa + j, p3, PAGE_SIZE); + } else { + guest_sync_private(gpa + j, PAGE_SIZE, p1); + } + } + +skip: + /* + * Convert the entire region back to shared, explicitly write + * pattern three to fill in the even-number frames before + * asking the host to verify (and write pattern four). + */ + guest_map_shared(gpa, size, do_fallocate); + memset((void *)gpa, p3, size); + guest_sync_shared(gpa, size, p3, p4); + memcmp_g(gpa, p4, size); + + /* Reset the shared memory back to the initial pattern. */ + memset((void *)gpa, init_p, size); + + /* + * Free (via PUNCH_HOLE) *all* private memory so that the next + * iteration starts from a clean slate, e.g. with respect to + * whether or not there are pages/folios in guest_mem. + */ + guest_map_shared(base_gpa, PER_CPU_DATA_SIZE, true); + } +} + +static void guest_punch_hole(uint64_t gpa, uint64_t size) +{ + /* "Mapping" memory shared via fallocate() is done via PUNCH_HOLE. */ + uint64_t flags = MAP_GPA_SHARED | MAP_GPA_DO_FALLOCATE; + + kvm_hypercall_map_gpa_range(gpa, size, flags); +} + +/* + * Test that PUNCH_HOLE actually frees memory by punching holes without doing a + * proper conversion. Freeing (PUNCH_HOLE) should zap SPTEs, and reallocating + * (subsequent fault) should zero memory. + */ +static void guest_test_punch_hole(uint64_t base_gpa, bool precise) +{ + const uint8_t init_p = 0xcc; + int i; + + /* + * Convert the entire range to private, this testcase is all about + * punching holes in guest_memfd, i.e. shared mappings aren't needed. + */ + guest_map_private(base_gpa, PER_CPU_DATA_SIZE, false); + + for (i = 0; i < ARRAY_SIZE(test_ranges); i++) { + uint64_t gpa = base_gpa + test_ranges[i].offset; + uint64_t size = test_ranges[i].size; + + /* + * Free all memory before each iteration, even for the !precise + * case where the memory will be faulted back in. Freeing and + * reallocating should obviously work, and freeing all memory + * minimizes the probability of cross-testcase influence. + */ + guest_punch_hole(base_gpa, PER_CPU_DATA_SIZE); + + /* Fault-in and initialize memory, and verify the pattern. */ + if (precise) { + memset((void *)gpa, init_p, size); + memcmp_g(gpa, init_p, size); + } else { + memset((void *)base_gpa, init_p, PER_CPU_DATA_SIZE); + memcmp_g(base_gpa, init_p, PER_CPU_DATA_SIZE); + } + + /* + * Punch a hole at the target range and verify that reads from + * the guest succeed and return zeroes. + */ + guest_punch_hole(gpa, size); + memcmp_g(gpa, 0, size); + } +} + +static void guest_code(uint64_t base_gpa) +{ + /* + * Run the conversion test twice, with and without doing fallocate() on + * the guest_memfd backing when converting between shared and private. + */ + guest_test_explicit_conversion(base_gpa, false); + guest_test_explicit_conversion(base_gpa, true); + + /* + * Run the PUNCH_HOLE test twice too, once with the entire guest_memfd + * faulted in, once with only the target range faulted in. + */ + guest_test_punch_hole(base_gpa, false); + guest_test_punch_hole(base_gpa, true); + GUEST_DONE(); +} + +static void handle_exit_hypercall(struct kvm_vcpu *vcpu) +{ + struct kvm_run *run = vcpu->run; + uint64_t gpa = run->hypercall.args[0]; + uint64_t size = run->hypercall.args[1] * PAGE_SIZE; + bool set_attributes = run->hypercall.args[2] & MAP_GPA_SET_ATTRIBUTES; + bool map_shared = run->hypercall.args[2] & MAP_GPA_SHARED; + bool do_fallocate = run->hypercall.args[2] & MAP_GPA_DO_FALLOCATE; + struct kvm_vm *vm = vcpu->vm; + + TEST_ASSERT(run->hypercall.nr == KVM_HC_MAP_GPA_RANGE, + "Wanted MAP_GPA_RANGE (%u), got '%llu'", + KVM_HC_MAP_GPA_RANGE, run->hypercall.nr); + + if (do_fallocate) + vm_guest_mem_fallocate(vm, gpa, size, map_shared); + + if (set_attributes) + vm_set_memory_attributes(vm, gpa, size, + map_shared ? 0 : KVM_MEMORY_ATTRIBUTE_PRIVATE); + run->hypercall.ret = 0; +} + +static bool run_vcpus; + +static void *__test_mem_conversions(void *__vcpu) +{ + struct kvm_vcpu *vcpu = __vcpu; + struct kvm_run *run = vcpu->run; + struct kvm_vm *vm = vcpu->vm; + struct ucall uc; + + while (!READ_ONCE(run_vcpus)) + ; + + for ( ;; ) { + vcpu_run(vcpu); + + if (run->exit_reason == KVM_EXIT_HYPERCALL) { + handle_exit_hypercall(vcpu); + continue; + } + + TEST_ASSERT(run->exit_reason == KVM_EXIT_IO, + "Wanted KVM_EXIT_IO, got exit reason: %u (%s)", + run->exit_reason, exit_reason_str(run->exit_reason)); + + switch (get_ucall(vcpu, &uc)) { + case UCALL_ABORT: + REPORT_GUEST_ASSERT(uc); + case UCALL_SYNC: { + uint64_t gpa = uc.args[1]; + size_t size = uc.args[2]; + size_t i; + + TEST_ASSERT(uc.args[0] == SYNC_SHARED || + uc.args[0] == SYNC_PRIVATE, + "Unknown sync command '%ld'", uc.args[0]); + + for (i = 0; i < size; i += vm->page_size) { + size_t nr_bytes = min_t(size_t, vm->page_size, size - i); + uint8_t *hva = addr_gpa2hva(vm, gpa + i); + + /* In all cases, the host should observe the shared data. */ + memcmp_h(hva, gpa + i, uc.args[3], nr_bytes); + + /* For shared, write the new pattern to guest memory. */ + if (uc.args[0] == SYNC_SHARED) + memset(hva, uc.args[4], nr_bytes); + } + break; + } + case UCALL_DONE: + return NULL; + default: + TEST_FAIL("Unknown ucall 0x%lx.", uc.cmd); + } + } +} + +static void test_mem_conversions(enum vm_mem_backing_src_type src_type, uint32_t nr_vcpus, + uint32_t nr_memslots) +{ + /* + * Allocate enough memory so that each vCPU's chunk of memory can be + * naturally aligned with respect to the size of the backing store. + */ + const size_t alignment = max_t(size_t, SZ_2M, get_backing_src_pagesz(src_type)); + const size_t per_cpu_size = align_up(PER_CPU_DATA_SIZE, alignment); + const size_t memfd_size = per_cpu_size * nr_vcpus; + const size_t slot_size = memfd_size / nr_memslots; + struct kvm_vcpu *vcpus[KVM_MAX_VCPUS]; + pthread_t threads[KVM_MAX_VCPUS]; + uint64_t memfd_flags; + struct kvm_vm *vm; + int memfd, i, r; + + const struct vm_shape shape = { + .mode = VM_MODE_DEFAULT, + .type = KVM_X86_SW_PROTECTED_VM, + }; + + TEST_ASSERT(slot_size * nr_memslots == memfd_size, + "The memfd size (0x%lx) needs to be cleanly divisible by the number of memslots (%u)", + memfd_size, nr_memslots); + vm = __vm_create_with_vcpus(shape, nr_vcpus, 0, guest_code, vcpus); + + vm_enable_cap(vm, KVM_CAP_EXIT_HYPERCALL, (1 << KVM_HC_MAP_GPA_RANGE)); + + if (backing_src_can_be_huge(src_type)) + memfd_flags = KVM_GUEST_MEMFD_ALLOW_HUGEPAGE; + else + memfd_flags = 0; + memfd = vm_create_guest_memfd(vm, memfd_size, memfd_flags); + + for (i = 0; i < nr_memslots; i++) + vm_mem_add(vm, src_type, BASE_DATA_GPA + slot_size * i, + BASE_DATA_SLOT + i, slot_size / vm->page_size, + KVM_MEM_PRIVATE, memfd, slot_size * i); + + for (i = 0; i < nr_vcpus; i++) { + uint64_t gpa = BASE_DATA_GPA + i * per_cpu_size; + + vcpu_args_set(vcpus[i], 1, gpa); + + /* + * Map only what is needed so that an out-of-bounds access + * results #PF => SHUTDOWN instead of data corruption. + */ + virt_map(vm, gpa, gpa, PER_CPU_DATA_SIZE / vm->page_size); + + pthread_create(&threads[i], NULL, __test_mem_conversions, vcpus[i]); + } + + WRITE_ONCE(run_vcpus, true); + + for (i = 0; i < nr_vcpus; i++) + pthread_join(threads[i], NULL); + + kvm_vm_free(vm); + + /* + * Allocate and free memory from the guest_memfd after closing the VM + * fd. The guest_memfd is gifted a reference to its owning VM, i.e. + * should prevent the VM from being fully destroyed until the last + * reference to the guest_memfd is also put. + */ + r = fallocate(memfd, FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE, 0, memfd_size); + TEST_ASSERT(!r, __KVM_SYSCALL_ERROR("fallocate()", r)); + + r = fallocate(memfd, FALLOC_FL_KEEP_SIZE, 0, memfd_size); + TEST_ASSERT(!r, __KVM_SYSCALL_ERROR("fallocate()", r)); +} + +static void usage(const char *cmd) +{ + puts(""); + printf("usage: %s [-h] [-m nr_memslots] [-s mem_type] [-n nr_vcpus]\n", cmd); + puts(""); + backing_src_help("-s"); + puts(""); + puts(" -n: specify the number of vcpus (default: 1)"); + puts(""); + puts(" -m: specify the number of memslots (default: 1)"); + puts(""); +} + +int main(int argc, char *argv[]) +{ + enum vm_mem_backing_src_type src_type = DEFAULT_VM_MEM_SRC; + uint32_t nr_memslots = 1; + uint32_t nr_vcpus = 1; + int opt; + + TEST_REQUIRE(kvm_check_cap(KVM_CAP_VM_TYPES) & BIT(KVM_X86_SW_PROTECTED_VM)); + + while ((opt = getopt(argc, argv, "hm:s:n:")) != -1) { + switch (opt) { + case 's': + src_type = parse_backing_src_type(optarg); + break; + case 'n': + nr_vcpus = atoi_positive("nr_vcpus", optarg); + break; + case 'm': + nr_memslots = atoi_positive("nr_memslots", optarg); + break; + case 'h': + default: + usage(argv[0]); + exit(0); + } + } + + test_mem_conversions(src_type, nr_vcpus, nr_memslots); + + return 0; +} From patchwork Fri Oct 27 18:22:14 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 13438894 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CB2D03DFE0 for ; Fri, 27 Oct 2023 18:24:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="ct+ZvQnq" Received: from mail-yb1-xb49.google.com (mail-yb1-xb49.google.com [IPv6:2607:f8b0:4864:20::b49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2736D26AE for ; 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bh=rHCSEdVT91A5ySy8HWpIrikDyrYgztwmDmnD7EhGGWM=; b=sMJWJdfa6Ilxy5tvQKbqykIL0LSMWe9nWEASw8xpBsChhqydQnREWQEywbro2bquDq m9tVqxP3qkOiG0UNCcj22imJDw4yZ1ThUYKYXdwohqfVG59JelDcPZOn7i2p/M+1kaze lPRJxeE4i2Kb7Q+VEmaFVk4vluNrFptwBCTGLZ4udvtFG+8dEDa8WCbPBgYRu0lYhAv5 yr7J8CLKe6elLS3gmSlJpR0zIXojGlBLJacC+wUVR3li1KCC6lJPTkBLuqoMGhgajzpr Nr6IgOTaXSXWEoNAz3dg/AvQWWeOkfj8NPyz54jBM1aTQZcLO9yf3UcS427bULoCOk0U W7CA== X-Gm-Message-State: AOJu0YyP/hmtnLpitmnq89wGrvhZGE2HhicKwau1nKMjJn2KsK1/qtYG unrkrRA7aZsH51goAKF2/t/qoI+BWAM= X-Google-Smtp-Source: AGHT+IGBlPG7wn0887XfDb8cENXXLGU58G9yJP5jBeCkKIucbC9oYDwWXkdT4FgaevehYCQITd+4fshLciA= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a05:6902:565:b0:da0:c979:fd70 with SMTP id a5-20020a056902056500b00da0c979fd70mr69913ybt.9.1698431009012; Fri, 27 Oct 2023 11:23:29 -0700 (PDT) Reply-To: Sean Christopherson Date: Fri, 27 Oct 2023 11:22:14 -0700 In-Reply-To: <20231027182217.3615211-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20231027182217.3615211-1-seanjc@google.com> X-Mailer: git-send-email 2.42.0.820.g83a721a137-goog Message-ID: <20231027182217.3615211-33-seanjc@google.com> Subject: [PATCH v13 32/35] KVM: selftests: Add KVM_SET_USER_MEMORY_REGION2 helper From: Sean Christopherson To: Paolo Bonzini , Marc Zyngier , Oliver Upton , Huacai Chen , Michael Ellerman , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Sean Christopherson , Alexander Viro , Christian Brauner , "Matthew Wilcox (Oracle)" , Andrew Morton Cc: kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Xiaoyao Li , Xu Yilun , Chao Peng , Fuad Tabba , Jarkko Sakkinen , Anish Moorthy , David Matlack , Yu Zhang , Isaku Yamahata , " =?utf-8?q?Micka=C3=ABl_Sala?= =?utf-8?q?=C3=BCn?= " , Vlastimil Babka , Vishal Annapurve , Ackerley Tng , Maciej Szmigiero , David Hildenbrand , Quentin Perret , Michael Roth , Wang , Liam Merwick , Isaku Yamahata , "Kirill A . Shutemov" From: Chao Peng Add helpers to invoke KVM_SET_USER_MEMORY_REGION2 directly so that tests can validate of features that are unique to "version 2" of "set user memory region", e.g. do negative testing on gmem_fd and gmem_offset. Provide a raw version as well as an assert-success version to reduce the amount of boilerplate code need for basic usage. Signed-off-by: Chao Peng Signed-off-by: Ackerley Tng Signed-off-by: Sean Christopherson --- .../selftests/kvm/include/kvm_util_base.h | 7 +++++ tools/testing/selftests/kvm/lib/kvm_util.c | 29 +++++++++++++++++++ 2 files changed, 36 insertions(+) diff --git a/tools/testing/selftests/kvm/include/kvm_util_base.h b/tools/testing/selftests/kvm/include/kvm_util_base.h index 157508c071f3..8ec122f5fcc8 100644 --- a/tools/testing/selftests/kvm/include/kvm_util_base.h +++ b/tools/testing/selftests/kvm/include/kvm_util_base.h @@ -522,6 +522,13 @@ void vm_set_user_memory_region(struct kvm_vm *vm, uint32_t slot, uint32_t flags, uint64_t gpa, uint64_t size, void *hva); int __vm_set_user_memory_region(struct kvm_vm *vm, uint32_t slot, uint32_t flags, uint64_t gpa, uint64_t size, void *hva); +void vm_set_user_memory_region2(struct kvm_vm *vm, uint32_t slot, uint32_t flags, + uint64_t gpa, uint64_t size, void *hva, + uint32_t guest_memfd, uint64_t guest_memfd_offset); +int __vm_set_user_memory_region2(struct kvm_vm *vm, uint32_t slot, uint32_t flags, + uint64_t gpa, uint64_t size, void *hva, + uint32_t guest_memfd, uint64_t guest_memfd_offset); + void vm_userspace_mem_region_add(struct kvm_vm *vm, enum vm_mem_backing_src_type src_type, uint64_t guest_paddr, uint32_t slot, uint64_t npages, diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c index 52b131e3aca5..1620452c1cf7 100644 --- a/tools/testing/selftests/kvm/lib/kvm_util.c +++ b/tools/testing/selftests/kvm/lib/kvm_util.c @@ -873,6 +873,35 @@ void vm_set_user_memory_region(struct kvm_vm *vm, uint32_t slot, uint32_t flags, errno, strerror(errno)); } +int __vm_set_user_memory_region2(struct kvm_vm *vm, uint32_t slot, uint32_t flags, + uint64_t gpa, uint64_t size, void *hva, + uint32_t guest_memfd, uint64_t guest_memfd_offset) +{ + struct kvm_userspace_memory_region2 region = { + .slot = slot, + .flags = flags, + .guest_phys_addr = gpa, + .memory_size = size, + .userspace_addr = (uintptr_t)hva, + .guest_memfd = guest_memfd, + .guest_memfd_offset = guest_memfd_offset, + }; + + return ioctl(vm->fd, KVM_SET_USER_MEMORY_REGION2, ®ion); +} + +void vm_set_user_memory_region2(struct kvm_vm *vm, uint32_t slot, uint32_t flags, + uint64_t gpa, uint64_t size, void *hva, + uint32_t guest_memfd, uint64_t guest_memfd_offset) +{ + int ret = __vm_set_user_memory_region2(vm, slot, flags, gpa, size, hva, + guest_memfd, guest_memfd_offset); + + TEST_ASSERT(!ret, "KVM_SET_USER_MEMORY_REGION2 failed, errno = %d (%s)", + errno, strerror(errno)); +} + + /* FIXME: This thing needs to be ripped apart and rewritten. */ void vm_mem_add(struct kvm_vm *vm, enum vm_mem_backing_src_type src_type, uint64_t guest_paddr, uint32_t slot, uint64_t npages, From patchwork Fri Oct 27 18:22:15 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 13438892 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D84773DFE1 for ; 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Fri, 27 Oct 2023 11:23:31 -0700 (PDT) Reply-To: Sean Christopherson Date: Fri, 27 Oct 2023 11:22:15 -0700 In-Reply-To: <20231027182217.3615211-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20231027182217.3615211-1-seanjc@google.com> X-Mailer: git-send-email 2.42.0.820.g83a721a137-goog Message-ID: <20231027182217.3615211-34-seanjc@google.com> Subject: [PATCH v13 33/35] KVM: selftests: Expand set_memory_region_test to validate guest_memfd() From: Sean Christopherson To: Paolo Bonzini , Marc Zyngier , Oliver Upton , Huacai Chen , Michael Ellerman , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Sean Christopherson , Alexander Viro , Christian Brauner , "Matthew Wilcox (Oracle)" , Andrew Morton Cc: kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Xiaoyao Li , Xu Yilun , Chao Peng , Fuad Tabba , Jarkko Sakkinen , Anish Moorthy , David Matlack , Yu Zhang , Isaku Yamahata , " =?utf-8?q?Micka=C3=ABl_Sala?= =?utf-8?q?=C3=BCn?= " , Vlastimil Babka , Vishal Annapurve , Ackerley Tng , Maciej Szmigiero , David Hildenbrand , Quentin Perret , Michael Roth , Wang , Liam Merwick , Isaku Yamahata , "Kirill A . Shutemov" From: Chao Peng Expand set_memory_region_test to exercise various positive and negative testcases for private memory. - Non-guest_memfd() file descriptor for private memory - guest_memfd() from different VM - Overlapping bindings - Unaligned bindings Signed-off-by: Chao Peng Co-developed-by: Ackerley Tng Signed-off-by: Ackerley Tng [sean: trim the testcases to remove duplicate coverage] Signed-off-by: Sean Christopherson --- .../selftests/kvm/include/kvm_util_base.h | 10 ++ .../selftests/kvm/set_memory_region_test.c | 100 ++++++++++++++++++ 2 files changed, 110 insertions(+) diff --git a/tools/testing/selftests/kvm/include/kvm_util_base.h b/tools/testing/selftests/kvm/include/kvm_util_base.h index 8ec122f5fcc8..e4d2cd9218b2 100644 --- a/tools/testing/selftests/kvm/include/kvm_util_base.h +++ b/tools/testing/selftests/kvm/include/kvm_util_base.h @@ -819,6 +819,16 @@ static inline struct kvm_vm *vm_create_barebones(void) return ____vm_create(VM_SHAPE_DEFAULT); } +static inline struct kvm_vm *vm_create_barebones_protected_vm(void) +{ + const struct vm_shape shape = { + .mode = VM_MODE_DEFAULT, + .type = KVM_X86_SW_PROTECTED_VM, + }; + + return ____vm_create(shape); +} + static inline struct kvm_vm *vm_create(uint32_t nr_runnable_vcpus) { return __vm_create(VM_SHAPE_DEFAULT, nr_runnable_vcpus, 0); diff --git a/tools/testing/selftests/kvm/set_memory_region_test.c b/tools/testing/selftests/kvm/set_memory_region_test.c index b32960189f5f..ca83e3307a98 100644 --- a/tools/testing/selftests/kvm/set_memory_region_test.c +++ b/tools/testing/selftests/kvm/set_memory_region_test.c @@ -385,6 +385,98 @@ static void test_add_max_memory_regions(void) kvm_vm_free(vm); } + +static void test_invalid_guest_memfd(struct kvm_vm *vm, int memfd, + size_t offset, const char *msg) +{ + int r = __vm_set_user_memory_region2(vm, MEM_REGION_SLOT, KVM_MEM_PRIVATE, + MEM_REGION_GPA, MEM_REGION_SIZE, + 0, memfd, offset); + TEST_ASSERT(r == -1 && errno == EINVAL, "%s", msg); +} + +static void test_add_private_memory_region(void) +{ + struct kvm_vm *vm, *vm2; + int memfd, i; + + pr_info("Testing ADD of KVM_MEM_PRIVATE memory regions\n"); + + vm = vm_create_barebones_protected_vm(); + + test_invalid_guest_memfd(vm, vm->kvm_fd, 0, "KVM fd should fail"); + test_invalid_guest_memfd(vm, vm->fd, 0, "VM's fd should fail"); + + memfd = kvm_memfd_alloc(MEM_REGION_SIZE, false); + test_invalid_guest_memfd(vm, memfd, 0, "Regular memfd() should fail"); + close(memfd); + + vm2 = vm_create_barebones_protected_vm(); + memfd = vm_create_guest_memfd(vm2, MEM_REGION_SIZE, 0); + test_invalid_guest_memfd(vm, memfd, 0, "Other VM's guest_memfd() should fail"); + + vm_set_user_memory_region2(vm2, MEM_REGION_SLOT, KVM_MEM_PRIVATE, + MEM_REGION_GPA, MEM_REGION_SIZE, 0, memfd, 0); + close(memfd); + kvm_vm_free(vm2); + + memfd = vm_create_guest_memfd(vm, MEM_REGION_SIZE, 0); + for (i = 1; i < PAGE_SIZE; i++) + test_invalid_guest_memfd(vm, memfd, i, "Unaligned offset should fail"); + + vm_set_user_memory_region2(vm, MEM_REGION_SLOT, KVM_MEM_PRIVATE, + MEM_REGION_GPA, MEM_REGION_SIZE, 0, memfd, 0); + close(memfd); + + kvm_vm_free(vm); +} + +static void test_add_overlapping_private_memory_regions(void) +{ + struct kvm_vm *vm; + int memfd; + int r; + + pr_info("Testing ADD of overlapping KVM_MEM_PRIVATE memory regions\n"); + + vm = vm_create_barebones_protected_vm(); + + memfd = vm_create_guest_memfd(vm, MEM_REGION_SIZE * 4, 0); + + vm_set_user_memory_region2(vm, MEM_REGION_SLOT, KVM_MEM_PRIVATE, + MEM_REGION_GPA, MEM_REGION_SIZE * 2, 0, memfd, 0); + + vm_set_user_memory_region2(vm, MEM_REGION_SLOT + 1, KVM_MEM_PRIVATE, + MEM_REGION_GPA * 2, MEM_REGION_SIZE * 2, + 0, memfd, MEM_REGION_SIZE * 2); + + /* + * Delete the first memslot, and then attempt to recreate it except + * with a "bad" offset that results in overlap in the guest_memfd(). + */ + vm_set_user_memory_region2(vm, MEM_REGION_SLOT, KVM_MEM_PRIVATE, + MEM_REGION_GPA, 0, NULL, -1, 0); + + /* Overlap the front half of the other slot. */ + r = __vm_set_user_memory_region2(vm, MEM_REGION_SLOT, KVM_MEM_PRIVATE, + MEM_REGION_GPA * 2 - MEM_REGION_SIZE, + MEM_REGION_SIZE * 2, + 0, memfd, 0); + TEST_ASSERT(r == -1 && errno == EEXIST, "%s", + "Overlapping guest_memfd() bindings should fail with EEXIST"); + + /* And now the back half of the other slot. */ + r = __vm_set_user_memory_region2(vm, MEM_REGION_SLOT, KVM_MEM_PRIVATE, + MEM_REGION_GPA * 2 + MEM_REGION_SIZE, + MEM_REGION_SIZE * 2, + 0, memfd, 0); + TEST_ASSERT(r == -1 && errno == EEXIST, "%s", + "Overlapping guest_memfd() bindings should fail with EEXIST"); + + close(memfd); + kvm_vm_free(vm); +} + int main(int argc, char *argv[]) { #ifdef __x86_64__ @@ -401,6 +493,14 @@ int main(int argc, char *argv[]) test_add_max_memory_regions(); + if (kvm_has_cap(KVM_CAP_GUEST_MEMFD) && + (kvm_check_cap(KVM_CAP_VM_TYPES) & BIT(KVM_X86_SW_PROTECTED_VM))) { + test_add_private_memory_region(); + test_add_overlapping_private_memory_regions(); + } else { + pr_info("Skipping tests for KVM_MEM_PRIVATE memory regions\n"); + } + #ifdef __x86_64__ if (argc > 1) loops = atoi_positive("Number of iterations", argv[1]); From patchwork Fri Oct 27 18:22:16 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 13438893 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 138253DFE2 for ; 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Fri, 27 Oct 2023 11:23:33 -0700 (PDT) Reply-To: Sean Christopherson Date: Fri, 27 Oct 2023 11:22:16 -0700 In-Reply-To: <20231027182217.3615211-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20231027182217.3615211-1-seanjc@google.com> X-Mailer: git-send-email 2.42.0.820.g83a721a137-goog Message-ID: <20231027182217.3615211-35-seanjc@google.com> Subject: [PATCH v13 34/35] KVM: selftests: Add basic selftest for guest_memfd() From: Sean Christopherson To: Paolo Bonzini , Marc Zyngier , Oliver Upton , Huacai Chen , Michael Ellerman , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Sean Christopherson , Alexander Viro , Christian Brauner , "Matthew Wilcox (Oracle)" , Andrew Morton Cc: kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Xiaoyao Li , Xu Yilun , Chao Peng , Fuad Tabba , Jarkko Sakkinen , Anish Moorthy , David Matlack , Yu Zhang , Isaku Yamahata , " =?utf-8?q?Micka=C3=ABl_Sala?= =?utf-8?q?=C3=BCn?= " , Vlastimil Babka , Vishal Annapurve , Ackerley Tng , Maciej Szmigiero , David Hildenbrand , Quentin Perret , Michael Roth , Wang , Liam Merwick , Isaku Yamahata , "Kirill A . Shutemov" From: Chao Peng Add a selftest to verify the basic functionality of guest_memfd(): + file descriptor created with the guest_memfd() ioctl does not allow read/write/mmap operations + file size and block size as returned from fstat are as expected + fallocate on the fd checks that offset/length on fallocate(FALLOC_FL_PUNCH_HOLE) should be page aligned + invalid inputs (misaligned size, invalid flags) are rejected + file size and inode are unique (the innocuous-sounding anon_inode_getfile() backs all files with a single inode...) Signed-off-by: Chao Peng Co-developed-by: Ackerley Tng Signed-off-by: Ackerley Tng Co-developed-by: Paolo Bonzini Signed-off-by: Paolo Bonzini Co-developed-by: Sean Christopherson Signed-off-by: Sean Christopherson --- tools/testing/selftests/kvm/Makefile | 1 + .../testing/selftests/kvm/guest_memfd_test.c | 221 ++++++++++++++++++ 2 files changed, 222 insertions(+) create mode 100644 tools/testing/selftests/kvm/guest_memfd_test.c diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile index b709a52d5cdb..2b1ef809d73a 100644 --- a/tools/testing/selftests/kvm/Makefile +++ b/tools/testing/selftests/kvm/Makefile @@ -124,6 +124,7 @@ TEST_GEN_PROGS_x86_64 += access_tracking_perf_test TEST_GEN_PROGS_x86_64 += demand_paging_test TEST_GEN_PROGS_x86_64 += dirty_log_test TEST_GEN_PROGS_x86_64 += dirty_log_perf_test +TEST_GEN_PROGS_x86_64 += guest_memfd_test TEST_GEN_PROGS_x86_64 += guest_print_test TEST_GEN_PROGS_x86_64 += hardware_disable_test TEST_GEN_PROGS_x86_64 += kvm_create_max_vcpus diff --git a/tools/testing/selftests/kvm/guest_memfd_test.c b/tools/testing/selftests/kvm/guest_memfd_test.c new file mode 100644 index 000000000000..c15de9852316 --- /dev/null +++ b/tools/testing/selftests/kvm/guest_memfd_test.c @@ -0,0 +1,221 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright Intel Corporation, 2023 + * + * Author: Chao Peng + */ + +#define _GNU_SOURCE +#include "test_util.h" +#include "kvm_util_base.h" +#include +#include +#include +#include +#include + +#include +#include +#include +#include +#include +#include + +static void test_file_read_write(int fd) +{ + char buf[64]; + + TEST_ASSERT(read(fd, buf, sizeof(buf)) < 0, + "read on a guest_mem fd should fail"); + TEST_ASSERT(write(fd, buf, sizeof(buf)) < 0, + "write on a guest_mem fd should fail"); + TEST_ASSERT(pread(fd, buf, sizeof(buf), 0) < 0, + "pread on a guest_mem fd should fail"); + TEST_ASSERT(pwrite(fd, buf, sizeof(buf), 0) < 0, + "pwrite on a guest_mem fd should fail"); +} + +static void test_mmap(int fd, size_t page_size) +{ + char *mem; + + mem = mmap(NULL, page_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0); + TEST_ASSERT_EQ(mem, MAP_FAILED); +} + +static void test_file_size(int fd, size_t page_size, size_t total_size) +{ + struct stat sb; + int ret; + + ret = fstat(fd, &sb); + TEST_ASSERT(!ret, "fstat should succeed"); + TEST_ASSERT_EQ(sb.st_size, total_size); + TEST_ASSERT_EQ(sb.st_blksize, page_size); +} + +static void test_fallocate(int fd, size_t page_size, size_t total_size) +{ + int ret; + + ret = fallocate(fd, FALLOC_FL_KEEP_SIZE, 0, total_size); + TEST_ASSERT(!ret, "fallocate with aligned offset and size should succeed"); + + ret = fallocate(fd, FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE, + page_size - 1, page_size); + TEST_ASSERT(ret, "fallocate with unaligned offset should fail"); + + ret = fallocate(fd, FALLOC_FL_KEEP_SIZE, total_size, page_size); + TEST_ASSERT(ret, "fallocate beginning at total_size should fail"); + + ret = fallocate(fd, FALLOC_FL_KEEP_SIZE, total_size + page_size, page_size); + TEST_ASSERT(ret, "fallocate beginning after total_size should fail"); + + ret = fallocate(fd, FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE, + total_size, page_size); + TEST_ASSERT(!ret, "fallocate(PUNCH_HOLE) at total_size should succeed"); + + ret = fallocate(fd, FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE, + total_size + page_size, page_size); + TEST_ASSERT(!ret, "fallocate(PUNCH_HOLE) after total_size should succeed"); + + ret = fallocate(fd, FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE, + page_size, page_size - 1); + TEST_ASSERT(ret, "fallocate with unaligned size should fail"); + + ret = fallocate(fd, FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE, + page_size, page_size); + TEST_ASSERT(!ret, "fallocate(PUNCH_HOLE) with aligned offset and size should succeed"); + + ret = fallocate(fd, FALLOC_FL_KEEP_SIZE, page_size, page_size); + TEST_ASSERT(!ret, "fallocate to restore punched hole should succeed"); +} + +static void test_invalid_punch_hole(int fd, size_t page_size, size_t total_size) +{ + struct { + off_t offset; + off_t len; + } testcases[] = { + {0, 1}, + {0, page_size - 1}, + {0, page_size + 1}, + + {1, 1}, + {1, page_size - 1}, + {1, page_size}, + {1, page_size + 1}, + + {page_size, 1}, + {page_size, page_size - 1}, + {page_size, page_size + 1}, + }; + int ret, i; + + for (i = 0; i < ARRAY_SIZE(testcases); i++) { + ret = fallocate(fd, FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE, + testcases[i].offset, testcases[i].len); + TEST_ASSERT(ret == -1 && errno == EINVAL, + "PUNCH_HOLE with !PAGE_SIZE offset (%lx) and/or length (%lx) should fail", + testcases[i].offset, testcases[i].len); + } +} + +static void test_create_guest_memfd_invalid(struct kvm_vm *vm) +{ + uint64_t valid_flags = 0; + size_t page_size = getpagesize(); + uint64_t flag; + size_t size; + int fd; + + for (size = 1; size < page_size; size++) { + fd = __vm_create_guest_memfd(vm, size, 0); + TEST_ASSERT(fd == -1 && errno == EINVAL, + "guest_memfd() with non-page-aligned page size '0x%lx' should fail with EINVAL", + size); + } + + if (thp_configured()) { + for (size = page_size * 2; size < get_trans_hugepagesz(); size += page_size) { + fd = __vm_create_guest_memfd(vm, size, KVM_GUEST_MEMFD_ALLOW_HUGEPAGE); + TEST_ASSERT(fd == -1 && errno == EINVAL, + "guest_memfd() with non-hugepage-aligned page size '0x%lx' should fail with EINVAL", + size); + } + + valid_flags = KVM_GUEST_MEMFD_ALLOW_HUGEPAGE; + } + + for (flag = 1; flag; flag <<= 1) { + uint64_t bit; + + if (flag & valid_flags) + continue; + + fd = __vm_create_guest_memfd(vm, page_size, flag); + TEST_ASSERT(fd == -1 && errno == EINVAL, + "guest_memfd() with flag '0x%lx' should fail with EINVAL", + flag); + + for_each_set_bit(bit, &valid_flags, 64) { + fd = __vm_create_guest_memfd(vm, page_size, flag | BIT_ULL(bit)); + TEST_ASSERT(fd == -1 && errno == EINVAL, + "guest_memfd() with flags '0x%llx' should fail with EINVAL", + flag | BIT_ULL(bit)); + } + } +} + +static void test_create_guest_memfd_multiple(struct kvm_vm *vm) +{ + int fd1, fd2, ret; + struct stat st1, st2; + + fd1 = __vm_create_guest_memfd(vm, 4096, 0); + TEST_ASSERT(fd1 != -1, "memfd creation should succeed"); + + ret = fstat(fd1, &st1); + TEST_ASSERT(ret != -1, "memfd fstat should succeed"); + TEST_ASSERT(st1.st_size == 4096, "memfd st_size should match requested size"); + + fd2 = __vm_create_guest_memfd(vm, 8192, 0); + TEST_ASSERT(fd2 != -1, "memfd creation should succeed"); + + ret = fstat(fd2, &st2); + TEST_ASSERT(ret != -1, "memfd fstat should succeed"); + TEST_ASSERT(st2.st_size == 8192, "second memfd st_size should match requested size"); + + ret = fstat(fd1, &st1); + TEST_ASSERT(ret != -1, "memfd fstat should succeed"); + TEST_ASSERT(st1.st_size == 4096, "first memfd st_size should still match requested size"); + TEST_ASSERT(st1.st_ino != st2.st_ino, "different memfd should have different inode numbers"); +} + +int main(int argc, char *argv[]) +{ + size_t page_size; + size_t total_size; + int fd; + struct kvm_vm *vm; + + TEST_REQUIRE(kvm_has_cap(KVM_CAP_GUEST_MEMFD)); + + page_size = getpagesize(); + total_size = page_size * 4; + + vm = vm_create_barebones(); + + test_create_guest_memfd_invalid(vm); + test_create_guest_memfd_multiple(vm); + + fd = vm_create_guest_memfd(vm, total_size, 0); + + test_file_read_write(fd); + test_mmap(fd, page_size); + test_file_size(fd, page_size, total_size); + test_fallocate(fd, page_size, total_size); + test_invalid_punch_hole(fd, page_size, total_size); + + close(fd); +} From patchwork Fri Oct 27 18:22:17 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 13438890 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D5A3D3DFE1 for ; 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Fri, 27 Oct 2023 11:23:35 -0700 (PDT) Reply-To: Sean Christopherson Date: Fri, 27 Oct 2023 11:22:17 -0700 In-Reply-To: <20231027182217.3615211-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20231027182217.3615211-1-seanjc@google.com> X-Mailer: git-send-email 2.42.0.820.g83a721a137-goog Message-ID: <20231027182217.3615211-36-seanjc@google.com> Subject: [PATCH v13 35/35] KVM: selftests: Test KVM exit behavior for private memory/access From: Sean Christopherson To: Paolo Bonzini , Marc Zyngier , Oliver Upton , Huacai Chen , Michael Ellerman , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Sean Christopherson , Alexander Viro , Christian Brauner , "Matthew Wilcox (Oracle)" , Andrew Morton Cc: kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Xiaoyao Li , Xu Yilun , Chao Peng , Fuad Tabba , Jarkko Sakkinen , Anish Moorthy , David Matlack , Yu Zhang , Isaku Yamahata , " =?utf-8?q?Micka=C3=ABl_Sala?= =?utf-8?q?=C3=BCn?= " , Vlastimil Babka , Vishal Annapurve , Ackerley Tng , Maciej Szmigiero , David Hildenbrand , Quentin Perret , Michael Roth , Wang , Liam Merwick , Isaku Yamahata , "Kirill A . Shutemov" From: Ackerley Tng "Testing private access when memslot gets deleted" tests the behavior of KVM when a private memslot gets deleted while the VM is using the private memslot. When KVM looks up the deleted (slot = NULL) memslot, KVM should exit to userspace with KVM_EXIT_MEMORY_FAULT. In the second test, upon a private access to non-private memslot, KVM should also exit to userspace with KVM_EXIT_MEMORY_FAULT. Intentionally don't take a requirement on KVM_CAP_GUEST_MEMFD, KVM_CAP_MEMORY_FAULT_INFO, KVM_MEMORY_ATTRIBUTE_PRIVATE, etc., as it's a KVM bug to advertise KVM_X86_SW_PROTECTED_VM without its prerequisites. Signed-off-by: Ackerley Tng [sean: call out the similarities with set_memory_region_test] Signed-off-by: Sean Christopherson --- tools/testing/selftests/kvm/Makefile | 1 + .../kvm/x86_64/private_mem_kvm_exits_test.c | 120 ++++++++++++++++++ 2 files changed, 121 insertions(+) create mode 100644 tools/testing/selftests/kvm/x86_64/private_mem_kvm_exits_test.c diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile index 2b1ef809d73a..f7fdd8244547 100644 --- a/tools/testing/selftests/kvm/Makefile +++ b/tools/testing/selftests/kvm/Makefile @@ -82,6 +82,7 @@ TEST_GEN_PROGS_x86_64 += x86_64/nested_exceptions_test TEST_GEN_PROGS_x86_64 += x86_64/platform_info_test TEST_GEN_PROGS_x86_64 += x86_64/pmu_event_filter_test TEST_GEN_PROGS_x86_64 += x86_64/private_mem_conversions_test +TEST_GEN_PROGS_x86_64 += x86_64/private_mem_kvm_exits_test TEST_GEN_PROGS_x86_64 += x86_64/set_boot_cpu_id TEST_GEN_PROGS_x86_64 += x86_64/set_sregs_test TEST_GEN_PROGS_x86_64 += x86_64/smaller_maxphyaddr_emulation_test diff --git a/tools/testing/selftests/kvm/x86_64/private_mem_kvm_exits_test.c b/tools/testing/selftests/kvm/x86_64/private_mem_kvm_exits_test.c new file mode 100644 index 000000000000..7f7ca4475745 --- /dev/null +++ b/tools/testing/selftests/kvm/x86_64/private_mem_kvm_exits_test.c @@ -0,0 +1,120 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2022, Google LLC. + */ +#include +#include +#include + +#include "kvm_util.h" +#include "processor.h" +#include "test_util.h" + +/* Arbitrarily selected to avoid overlaps with anything else */ +#define EXITS_TEST_GVA 0xc0000000 +#define EXITS_TEST_GPA EXITS_TEST_GVA +#define EXITS_TEST_NPAGES 1 +#define EXITS_TEST_SIZE (EXITS_TEST_NPAGES * PAGE_SIZE) +#define EXITS_TEST_SLOT 10 + +static uint64_t guest_repeatedly_read(void) +{ + volatile uint64_t value; + + while (true) + value = *((uint64_t *) EXITS_TEST_GVA); + + return value; +} + +static uint32_t run_vcpu_get_exit_reason(struct kvm_vcpu *vcpu) +{ + int r; + + r = _vcpu_run(vcpu); + if (r) { + TEST_ASSERT(errno == EFAULT, KVM_IOCTL_ERROR(KVM_RUN, r)); + TEST_ASSERT_EQ(vcpu->run->exit_reason, KVM_EXIT_MEMORY_FAULT); + } + return vcpu->run->exit_reason; +} + +const struct vm_shape protected_vm_shape = { + .mode = VM_MODE_DEFAULT, + .type = KVM_X86_SW_PROTECTED_VM, +}; + +static void test_private_access_memslot_deleted(void) +{ + struct kvm_vm *vm; + struct kvm_vcpu *vcpu; + pthread_t vm_thread; + void *thread_return; + uint32_t exit_reason; + + vm = vm_create_shape_with_one_vcpu(protected_vm_shape, &vcpu, + guest_repeatedly_read); + + vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS, + EXITS_TEST_GPA, EXITS_TEST_SLOT, + EXITS_TEST_NPAGES, + KVM_MEM_PRIVATE); + + virt_map(vm, EXITS_TEST_GVA, EXITS_TEST_GPA, EXITS_TEST_NPAGES); + + /* Request to access page privately */ + vm_mem_set_private(vm, EXITS_TEST_GPA, EXITS_TEST_SIZE); + + pthread_create(&vm_thread, NULL, + (void *(*)(void *))run_vcpu_get_exit_reason, + (void *)vcpu); + + vm_mem_region_delete(vm, EXITS_TEST_SLOT); + + pthread_join(vm_thread, &thread_return); + exit_reason = (uint32_t)(uint64_t)thread_return; + + TEST_ASSERT_EQ(exit_reason, KVM_EXIT_MEMORY_FAULT); + TEST_ASSERT_EQ(vcpu->run->memory_fault.flags, KVM_MEMORY_EXIT_FLAG_PRIVATE); + TEST_ASSERT_EQ(vcpu->run->memory_fault.gpa, EXITS_TEST_GPA); + TEST_ASSERT_EQ(vcpu->run->memory_fault.size, EXITS_TEST_SIZE); + + kvm_vm_free(vm); +} + +static void test_private_access_memslot_not_private(void) +{ + struct kvm_vm *vm; + struct kvm_vcpu *vcpu; + uint32_t exit_reason; + + vm = vm_create_shape_with_one_vcpu(protected_vm_shape, &vcpu, + guest_repeatedly_read); + + /* Add a non-private memslot (flags = 0) */ + vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS, + EXITS_TEST_GPA, EXITS_TEST_SLOT, + EXITS_TEST_NPAGES, 0); + + virt_map(vm, EXITS_TEST_GVA, EXITS_TEST_GPA, EXITS_TEST_NPAGES); + + /* Request to access page privately */ + vm_mem_set_private(vm, EXITS_TEST_GPA, EXITS_TEST_SIZE); + + exit_reason = run_vcpu_get_exit_reason(vcpu); + + TEST_ASSERT_EQ(exit_reason, KVM_EXIT_MEMORY_FAULT); + TEST_ASSERT_EQ(vcpu->run->memory_fault.flags, KVM_MEMORY_EXIT_FLAG_PRIVATE); + TEST_ASSERT_EQ(vcpu->run->memory_fault.gpa, EXITS_TEST_GPA); + TEST_ASSERT_EQ(vcpu->run->memory_fault.size, EXITS_TEST_SIZE); + + kvm_vm_free(vm); +} + +int main(int argc, char *argv[]) +{ + TEST_REQUIRE(kvm_check_cap(KVM_CAP_VM_TYPES) & BIT(KVM_X86_SW_PROTECTED_VM)); + + test_private_access_memslot_deleted(); + test_private_access_memslot_not_private(); +}