From patchwork Thu Sep 15 14:29:13 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chao Peng X-Patchwork-Id: 12977494 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id A9932ECAAA1 for ; Thu, 15 Sep 2022 14:44:57 +0000 (UTC) Received: from localhost ([::1]:52870 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1oYq6q-0008RK-Q1 for qemu-devel@archiver.kernel.org; Thu, 15 Sep 2022 10:44:56 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:45986) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oYpxe-0005IE-18 for qemu-devel@nongnu.org; Thu, 15 Sep 2022 10:35:27 -0400 Received: from mga18.intel.com ([134.134.136.126]:49753) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oYpxb-00018Q-Qd for qemu-devel@nongnu.org; Thu, 15 Sep 2022 10:35:25 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1663252523; x=1694788523; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=vo7O6JJ0Mt3TYlCfYDqCaXE1DrArKMV3xwA8EiMd43o=; b=fqbFgqcRZdUhMwse+y4C9MiC8S9V5xGqnIyuRV83nLPw83W0zBGvLX4z beyR+p/mmAeM4XfR+tAWPA5ooZSwlZtbCtVooaE2n/UKrSlhnuCCaGxWx qSTfTaBJ9oo5+lcOmty0EIbfsIv3Ulb7UWToJxsuLn7Guwa4pwZCBu9E8 tdJNjok9+KcJbZxFwrvdpPyIHAhQRCaw0aBdnLw73d72mDQbFh2WbRZ7X PO73K1g/91cArkoZjzYUS3UNYBWcRZx3S1uglvw1mRJNtdFLKw39G+Km1 2S+6PFvyrnQlu/PPo7DHrwIZZtwd5Ey4w8zs40kueiJgcXfyqUuOtmWfU Q==; X-IronPort-AV: E=McAfee;i="6500,9779,10470"; a="281759484" X-IronPort-AV: E=Sophos;i="5.93,318,1654585200"; d="scan'208";a="281759484" Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by orsmga106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Sep 2022 07:35:21 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.93,318,1654585200"; d="scan'208";a="945977274" Received: from chaop.bj.intel.com ([10.240.193.75]) by fmsmga005.fm.intel.com with ESMTP; 15 Sep 2022 07:35:11 -0700 From: Chao Peng To: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-api@vger.kernel.org, linux-doc@vger.kernel.org, qemu-devel@nongnu.org Cc: Paolo Bonzini , Jonathan Corbet , Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org, "H . Peter Anvin" , Hugh Dickins , Jeff Layton , "J . Bruce Fields" , Andrew Morton , Shuah Khan , Mike Rapoport , Steven Price , "Maciej S . Szmigiero" , Vlastimil Babka , Vishal Annapurve , Yu Zhang , Chao Peng , "Kirill A . Shutemov" , luto@kernel.org, jun.nakajima@intel.com, dave.hansen@intel.com, ak@linux.intel.com, david@redhat.com, aarcange@redhat.com, ddutile@redhat.com, dhildenb@redhat.com, Quentin Perret , Michael Roth , mhocko@suse.com, Muchun Song , wei.w.wang@intel.com Subject: [PATCH v8 8/8] KVM: Enable and expose KVM_MEM_PRIVATE Date: Thu, 15 Sep 2022 22:29:13 +0800 Message-Id: <20220915142913.2213336-9-chao.p.peng@linux.intel.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220915142913.2213336-1-chao.p.peng@linux.intel.com> References: <20220915142913.2213336-1-chao.p.peng@linux.intel.com> MIME-Version: 1.0 Received-SPF: none client-ip=134.134.136.126; envelope-from=chao.p.peng@linux.intel.com; helo=mga18.intel.com X-Spam_score_int: -19 X-Spam_score: -2.0 X-Spam_bar: -- X-Spam_report: (-2.0 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_EF=-0.1, SPF_HELO_NONE=0.001, SPF_NONE=0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Expose KVM_MEM_PRIVATE and memslot fields private_fd/offset to userspace. KVM will register/unregister private memslot to fd-based memory backing store and response to invalidation event from inaccessible_notifier to zap the existing memory mappings in the secondary page table. Whether KVM_MEM_PRIVATE is actually exposed to userspace is determined by architecture code which can turn on it by overriding the default kvm_arch_has_private_mem(). A 'kvm' reference is added in memslot structure since in inaccessible_notifier callback we can only obtain a memslot reference but 'kvm' is needed to do the zapping. Co-developed-by: Yu Zhang Signed-off-by: Yu Zhang Signed-off-by: Chao Peng --- include/linux/kvm_host.h | 1 + virt/kvm/kvm_main.c | 116 +++++++++++++++++++++++++++++++++++++-- 2 files changed, 111 insertions(+), 6 deletions(-) diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index b9906cdf468b..cb4eefac709c 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -589,6 +589,7 @@ struct kvm_memory_slot { struct file *private_file; loff_t private_offset; struct inaccessible_notifier notifier; + struct kvm *kvm; }; static inline bool kvm_slot_can_be_private(const struct kvm_memory_slot *slot) diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 97d893f7482c..87e239d35b96 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -983,6 +983,57 @@ static int kvm_vm_ioctl_set_mem_attr(struct kvm *kvm, gpa_t gpa, gpa_t size, xa_erase(&kvm->mem_attr_array, index); return r; } + +static void kvm_private_notifier_invalidate(struct inaccessible_notifier *notifier, + pgoff_t start, pgoff_t end) +{ + struct kvm_memory_slot *slot = container_of(notifier, + struct kvm_memory_slot, + notifier); + unsigned long base_pgoff = slot->private_offset >> PAGE_SHIFT; + gfn_t start_gfn = slot->base_gfn; + gfn_t end_gfn = slot->base_gfn + slot->npages; + + + if (start > base_pgoff) + start_gfn = slot->base_gfn + start - base_pgoff; + + if (end < base_pgoff + slot->npages) + end_gfn = slot->base_gfn + end - base_pgoff; + + if (start_gfn >= end_gfn) + return; + + kvm_zap_gfn_range(slot->kvm, start_gfn, end_gfn); +} + +static struct inaccessible_notifier_ops kvm_private_notifier_ops = { + .invalidate = kvm_private_notifier_invalidate, +}; + +static inline void kvm_private_mem_register(struct kvm_memory_slot *slot) +{ + slot->notifier.ops = &kvm_private_notifier_ops; + inaccessible_register_notifier(slot->private_file, &slot->notifier); +} + +static inline void kvm_private_mem_unregister(struct kvm_memory_slot *slot) +{ + inaccessible_unregister_notifier(slot->private_file, &slot->notifier); +} + +#else /* !CONFIG_HAVE_KVM_PRIVATE_MEM */ + +static inline void kvm_private_mem_register(struct kvm_memory_slot *slot) +{ + WARN_ON_ONCE(1); +} + +static inline void kvm_private_mem_unregister(struct kvm_memory_slot *slot) +{ + WARN_ON_ONCE(1); +} + #endif /* CONFIG_HAVE_KVM_PRIVATE_MEM */ #ifdef CONFIG_HAVE_KVM_PM_NOTIFIER @@ -1029,6 +1080,11 @@ 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_private_mem_unregister(slot); + fput(slot->private_file); + } + kvm_destroy_dirty_bitmap(slot); kvm_arch_free_memslot(kvm, slot); @@ -1600,10 +1656,16 @@ bool __weak kvm_arch_has_private_mem(struct kvm *kvm) return false; } -static int check_memory_region_flags(const struct kvm_user_mem_region *mem) +static int check_memory_region_flags(struct kvm *kvm, + const struct kvm_user_mem_region *mem) { u32 valid_flags = KVM_MEM_LOG_DIRTY_PAGES; +#ifdef CONFIG_HAVE_KVM_PRIVATE_MEM + if (kvm_arch_has_private_mem(kvm)) + valid_flags |= KVM_MEM_PRIVATE; +#endif + #ifdef __KVM_HAVE_READONLY_MEM valid_flags |= KVM_MEM_READONLY; #endif @@ -1679,6 +1741,9 @@ static int kvm_prepare_memory_region(struct kvm *kvm, { int r; + if (change == KVM_MR_CREATE && new->flags & KVM_MEM_PRIVATE) + kvm_private_mem_register(new); + /* * If dirty logging is disabled, nullify the bitmap; the old bitmap * will be freed on "commit". If logging is enabled in both old and @@ -1707,6 +1772,9 @@ static int kvm_prepare_memory_region(struct kvm *kvm, if (r && new && new->dirty_bitmap && (!old || !old->dirty_bitmap)) kvm_destroy_dirty_bitmap(new); + if (r && change == KVM_MR_CREATE && new->flags & KVM_MEM_PRIVATE) + kvm_private_mem_unregister(new); + return r; } @@ -2004,7 +2072,7 @@ 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; @@ -2023,6 +2091,10 @@ 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->private_offset & (PAGE_SIZE - 1) || + mem->private_offset > U64_MAX - mem->memory_size)) + 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) @@ -2061,6 +2133,9 @@ 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)) @@ -2089,10 +2164,27 @@ 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) { + new->private_file = fget(mem->private_fd); + if (!new->private_file) { + r = -EINVAL; + goto out; + } + new->private_offset = mem->private_offset; + } + + new->kvm = kvm; r = kvm_set_memslot(kvm, old, new, change); if (r) - kfree(new); + goto out; + + return 0; + +out: + if (new->private_file) + fput(new->private_file); + kfree(new); return r; } EXPORT_SYMBOL_GPL(__kvm_set_memory_region); @@ -4747,16 +4839,28 @@ static long kvm_vm_ioctl(struct file *filp, } case KVM_SET_USER_MEMORY_REGION: { struct kvm_user_mem_region mem; - unsigned long size = sizeof(struct kvm_userspace_memory_region); + unsigned int flags_offset = offsetof(typeof(mem), flags); + unsigned long size; + u32 flags; kvm_sanity_check_user_mem_region_alias(); + memset(&mem, 0, sizeof(mem)); + r = -EFAULT; - if (copy_from_user(&mem, argp, size); + if (get_user(flags, (u32 __user *)(argp + flags_offset))) + goto out; + + if (flags & KVM_MEM_PRIVATE) + size = sizeof(struct kvm_userspace_memory_region_ext); + else + size = sizeof(struct kvm_userspace_memory_region); + + if (copy_from_user(&mem, argp, size)) goto out; r = -EINVAL; - if (mem.flags & KVM_MEM_PRIVATE) + if ((flags ^ mem.flags) & KVM_MEM_PRIVATE) goto out; r = kvm_vm_ioctl_set_memory_region(kvm, &mem);