From patchwork Fri Dec 2 06:13:45 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chao Peng X-Patchwork-Id: 13062274 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 52CE9C4167B for ; Fri, 2 Dec 2022 06:21:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232424AbiLBGVS (ORCPT ); Fri, 2 Dec 2022 01:21:18 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41654 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232373AbiLBGTv (ORCPT ); Fri, 2 Dec 2022 01:19:51 -0500 Received: from mga07.intel.com (mga07.intel.com [134.134.136.100]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9851BDC87B; Thu, 1 Dec 2022 22:19:35 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1669961975; x=1701497975; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=uHWX+bmiWvi8twUa4xphTJMpG6518qs7AwJd83WeEzU=; b=neER6hXwszKZmJo5Xf9ZHwNJi8SXZby48D/dsHSEQ8ESYqTovGJVEPdx W9vuXtnBcWwm2OQUr84St0qiuCN5cgQtqJk2EFlNzhx9AWUGXyJh2cA3P zZQpXw2bzfYRtSRKY2/+01mJUGyNzK+yftE1am7Mq8AOaK1FuKeyF3hLp RXQxU6msQC7Al8AzVVqU559SvjdzFmfGiiTSyQvQa2ZwTO4glkV2gxCs8 osIGkJxIEPEGWY7kCxXGpY/hk0SYWi77Xk/DZ9Yv0iik+1b4aZWMCrGz6 0JH/S/G7FDMmzWGy08XB5wt6yn5LsyxbNAy5XQZQ+DiZHHHPtIRZyRDjC g==; X-IronPort-AV: E=McAfee;i="6500,9779,10548"; a="380170654" X-IronPort-AV: E=Sophos;i="5.96,210,1665471600"; d="scan'208";a="380170654" Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by orsmga105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Dec 2022 22:19:34 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6500,9779,10548"; a="733698745" X-IronPort-AV: E=Sophos;i="5.96,210,1665471600"; d="scan'208";a="733698745" Received: from chaop.bj.intel.com ([10.240.193.75]) by FMSMGA003.fm.intel.com with ESMTP; 01 Dec 2022 22:19:23 -0800 From: Chao Peng To: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-arch@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 , Arnd Bergmann , Naoya Horiguchi , Miaohe Lin , 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 , tabba@google.com, Michael Roth , mhocko@suse.com, wei.w.wang@intel.com Subject: [PATCH v10 7/9] KVM: Update lpage info when private/shared memory are mixed Date: Fri, 2 Dec 2022 14:13:45 +0800 Message-Id: <20221202061347.1070246-8-chao.p.peng@linux.intel.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20221202061347.1070246-1-chao.p.peng@linux.intel.com> References: <20221202061347.1070246-1-chao.p.peng@linux.intel.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org A large page with mixed private/shared subpages can't be mapped as large page since its sub private/shared pages are from different memory backends and may also treated by architecture differently. When private/shared memory are mixed in a large page, the current lpage_info is not sufficient to decide whether the page can be mapped as large page or not and additional private/shared mixed information is needed. Tracking this 'mixed' information with the current 'count' like disallow_lpage is a bit challenge so reserve a bit in 'disallow_lpage' to indicate a large page has mixed private/share subpages and update this 'mixed' bit whenever the memory attribute is changed between private and shared. Signed-off-by: Chao Peng --- arch/x86/include/asm/kvm_host.h | 8 ++ arch/x86/kvm/mmu/mmu.c | 134 +++++++++++++++++++++++++++++++- arch/x86/kvm/x86.c | 2 + include/linux/kvm_host.h | 19 +++++ virt/kvm/kvm_main.c | 9 ++- 5 files changed, 169 insertions(+), 3 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 283cbb83d6ae..7772ab37ac89 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -38,6 +38,7 @@ #include #define __KVM_HAVE_ARCH_VCPU_DEBUGFS +#define __KVM_HAVE_ARCH_SET_MEMORY_ATTRIBUTES #define KVM_MAX_VCPUS 1024 @@ -1011,6 +1012,13 @@ struct kvm_vcpu_arch { #endif }; +/* + * Use a bit in disallow_lpage to indicate private/shared pages mixed at the + * level. The remaining bits are used as a reference count. + */ +#define KVM_LPAGE_PRIVATE_SHARED_MIXED (1U << 31) +#define KVM_LPAGE_COUNT_MAX ((1U << 31) - 1) + struct kvm_lpage_info { int disallow_lpage; }; diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index e2c70b5afa3e..2190fd8c95c0 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -763,11 +763,16 @@ static void update_gfn_disallow_lpage_count(const struct kvm_memory_slot *slot, { struct kvm_lpage_info *linfo; int i; + int disallow_count; for (i = PG_LEVEL_2M; i <= KVM_MAX_HUGEPAGE_LEVEL; ++i) { linfo = lpage_info_slot(gfn, slot, i); + + disallow_count = linfo->disallow_lpage & KVM_LPAGE_COUNT_MAX; + WARN_ON(disallow_count + count < 0 || + disallow_count > KVM_LPAGE_COUNT_MAX - count); + linfo->disallow_lpage += count; - WARN_ON(linfo->disallow_lpage < 0); } } @@ -6986,3 +6991,130 @@ 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); } + +static bool linfo_is_mixed(struct kvm_lpage_info *linfo) +{ + return linfo->disallow_lpage & KVM_LPAGE_PRIVATE_SHARED_MIXED; +} + +static void linfo_set_mixed(gfn_t gfn, struct kvm_memory_slot *slot, + int level, bool mixed) +{ + struct kvm_lpage_info *linfo = lpage_info_slot(gfn, slot, level); + + if (mixed) + linfo->disallow_lpage |= KVM_LPAGE_PRIVATE_SHARED_MIXED; + else + linfo->disallow_lpage &= ~KVM_LPAGE_PRIVATE_SHARED_MIXED; +} + +static bool is_expected_attr_entry(void *entry, unsigned long expected_attrs) +{ + bool expect_private = expected_attrs & KVM_MEMORY_ATTRIBUTE_PRIVATE; + + if (xa_to_value(entry) & KVM_MEMORY_ATTRIBUTE_PRIVATE) { + if (!expect_private) + return false; + } else if (expect_private) + return false; + + return true; +} + +static bool mem_attrs_mixed_2m(struct kvm *kvm, unsigned long attrs, + gfn_t start, gfn_t end) +{ + XA_STATE(xas, &kvm->mem_attr_array, start); + gfn_t gfn = start; + void *entry; + bool mixed = false; + + rcu_read_lock(); + entry = xas_load(&xas); + while (gfn < end) { + if (xas_retry(&xas, entry)) + continue; + + KVM_BUG_ON(gfn != xas.xa_index, kvm); + + if (!is_expected_attr_entry(entry, attrs)) { + mixed = true; + break; + } + + entry = xas_next(&xas); + gfn++; + } + + rcu_read_unlock(); + return mixed; +} + +static bool mem_attrs_mixed(struct kvm *kvm, struct kvm_memory_slot *slot, + int level, unsigned long attrs, + gfn_t start, gfn_t end) +{ + unsigned long gfn; + + if (level == PG_LEVEL_2M) + return mem_attrs_mixed_2m(kvm, attrs, start, end); + + for (gfn = start; gfn < end; gfn += KVM_PAGES_PER_HPAGE(level - 1)) + if (linfo_is_mixed(lpage_info_slot(gfn, slot, level - 1)) || + !is_expected_attr_entry(xa_load(&kvm->mem_attr_array, gfn), + attrs)) + return true; + return false; +} + +static void kvm_update_lpage_private_shared_mixed(struct kvm *kvm, + struct kvm_memory_slot *slot, + unsigned long attrs, + gfn_t start, gfn_t end) +{ + unsigned long pages, mask; + gfn_t gfn, gfn_end, first, last; + int level; + bool mixed; + + /* + * The sequence matters here: we set the higher level basing on the + * lower level's scanning result. + */ + for (level = PG_LEVEL_2M; level <= KVM_MAX_HUGEPAGE_LEVEL; level++) { + pages = KVM_PAGES_PER_HPAGE(level); + mask = ~(pages - 1); + first = start & mask; + last = (end - 1) & mask; + + /* + * We only need to scan the head and tail page, for middle pages + * we know they will not be mixed. + */ + gfn = max(first, slot->base_gfn); + gfn_end = min(first + pages, slot->base_gfn + slot->npages); + mixed = mem_attrs_mixed(kvm, slot, level, attrs, gfn, gfn_end); + linfo_set_mixed(gfn, slot, level, mixed); + + if (first == last) + return; + + for (gfn = first + pages; gfn < last; gfn += pages) + linfo_set_mixed(gfn, slot, level, false); + + gfn = last; + gfn_end = min(last + pages, slot->base_gfn + slot->npages); + mixed = mem_attrs_mixed(kvm, slot, level, attrs, gfn, gfn_end); + linfo_set_mixed(gfn, slot, level, mixed); + } +} + +void kvm_arch_set_memory_attributes(struct kvm *kvm, + struct kvm_memory_slot *slot, + unsigned long attrs, + gfn_t start, gfn_t end) +{ + if (kvm_slot_can_be_private(slot)) + kvm_update_lpage_private_shared_mixed(kvm, slot, attrs, + start, end); +} diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 9a07380f8d3c..5aefcff614d2 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -12362,6 +12362,8 @@ static int kvm_alloc_memslot_metadata(struct kvm *kvm, if ((slot->base_gfn + npages) & (KVM_PAGES_PER_HPAGE(level) - 1)) linfo[lpages - 1].disallow_lpage = 1; ugfn = slot->userspace_addr >> PAGE_SHIFT; + if (kvm_slot_can_be_private(slot)) + ugfn |= slot->restricted_offset >> PAGE_SHIFT; /* * If the gfn and userspace address are not aligned wrt each * other, disable large page support for this slot. diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 3331c0c92838..25099c94e770 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -592,6 +592,11 @@ struct kvm_memory_slot { struct restrictedmem_notifier notifier; }; +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; @@ -2316,4 +2321,18 @@ 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 +#ifdef __KVM_HAVE_ARCH_SET_MEMORY_ATTRIBUTES +void kvm_arch_set_memory_attributes(struct kvm *kvm, + struct kvm_memory_slot *slot, + unsigned long attrs, + gfn_t start, gfn_t end); +#else +static inline void kvm_arch_set_memory_attributes(struct kvm *kvm, + struct kvm_memory_slot *slot, + unsigned long attrs, + gfn_t start, gfn_t end) +{ +} +#endif /* __KVM_HAVE_ARCH_SET_MEMORY_ATTRIBUTES */ + #endif diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 4e1e1e113bf0..e107afea32f0 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -2354,7 +2354,8 @@ static u64 kvm_supported_mem_attributes(struct kvm *kvm) return 0; } -static void kvm_unmap_mem_range(struct kvm *kvm, gfn_t start, gfn_t end) +static void kvm_unmap_mem_range(struct kvm *kvm, gfn_t start, gfn_t end, + unsigned long attrs) { struct kvm_gfn_range gfn_range; struct kvm_memory_slot *slot; @@ -2378,6 +2379,10 @@ static void kvm_unmap_mem_range(struct kvm *kvm, gfn_t start, gfn_t end) gfn_range.slot = slot; r |= kvm_unmap_gfn_range(kvm, &gfn_range); + + kvm_arch_set_memory_attributes(kvm, slot, attrs, + gfn_range.start, + gfn_range.end); } } @@ -2427,7 +2432,7 @@ static int kvm_vm_ioctl_set_mem_attributes(struct kvm *kvm, idx = srcu_read_lock(&kvm->srcu); KVM_MMU_LOCK(kvm); if (i > start) - kvm_unmap_mem_range(kvm, start, i); + kvm_unmap_mem_range(kvm, start, i, attrs->attributes); kvm_mmu_invalidate_end(kvm); KVM_MMU_UNLOCK(kvm); srcu_read_unlock(&kvm->srcu, idx);