From: Chao Peng <chao.p.peng@linux.intel.com> To: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, qemu-devel@nongnu.org Cc: Paolo Bonzini <pbonzini@redhat.com>, Jonathan Corbet <corbet@lwn.net>, Sean Christopherson <seanjc@google.com>, Vitaly Kuznetsov <vkuznets@redhat.com>, Wanpeng Li <wanpengli@tencent.com>, Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>, Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>, x86@kernel.org, "H . Peter Anvin" <hpa@zytor.com>, Hugh Dickins <hughd@google.com>, Jeff Layton <jlayton@kernel.org>, "J . Bruce Fields" <bfields@fieldses.org>, Andrew Morton <akpm@linux-foundation.org>, Yu Zhang <yu.c.zhang@linux.intel.com>, Chao Peng <chao.p.peng@linux.intel.com>, "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>, luto@kernel.org, jun.nakajima@intel.com, dave.hansen@intel.com, ak@linux.intel.com, david@redhat.com Subject: [PATCH v4 11/12] KVM: Zap existing KVM mappings when pages changed in the private fd Date: Tue, 18 Jan 2022 21:21:20 +0800 [thread overview] Message-ID: <20220118132121.31388-12-chao.p.peng@linux.intel.com> (raw) In-Reply-To: <20220118132121.31388-1-chao.p.peng@linux.intel.com> KVM gets notified when memory pages changed in the memory backing store. When userspace allocates the memory with fallocate() or frees memory with fallocate(FALLOC_FL_PUNCH_HOLE), memory backing store calls into KVM fallocate/invalidate callbacks respectively. To ensure KVM never maps both the private and shared variants of a GPA into the guest, in the fallocate callback, we should zap the existing shared mapping and in the invalidate callback we should zap the existing private mapping. In the callbacks, KVM firstly converts the offset range into the gfn_range and then calls existing kvm_unmap_gfn_range() which will zap the shared or private mapping. Both callbacks pass in a memslot reference but we need 'kvm' so add a reference in memslot structure. Signed-off-by: Yu Zhang <yu.c.zhang@linux.intel.com> Signed-off-by: Chao Peng <chao.p.peng@linux.intel.com> --- include/linux/kvm_host.h | 3 ++- virt/kvm/kvm_main.c | 36 ++++++++++++++++++++++++++++++++++++ 2 files changed, 38 insertions(+), 1 deletion(-) diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 667efe839767..117cf0da9c5e 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -235,7 +235,7 @@ 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 +#if defined(KVM_ARCH_WANT_MMU_NOTIFIER) || defined(CONFIG_MEMFILE_NOTIFIER) struct kvm_gfn_range { struct kvm_memory_slot *slot; gfn_t start; @@ -463,6 +463,7 @@ struct kvm_memory_slot { loff_t private_offset; struct memfile_pfn_ops *pfn_ops; struct memfile_notifier notifier; + struct kvm *kvm; }; static inline bool kvm_slot_is_private(const struct kvm_memory_slot *slot) diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 6b78ddef7880..10e553215618 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -847,8 +847,43 @@ static int kvm_init_mmu_notifier(struct kvm *kvm) #endif /* CONFIG_MMU_NOTIFIER && KVM_ARCH_WANT_MMU_NOTIFIER */ #ifdef CONFIG_MEMFILE_NOTIFIER +static void kvm_memfile_notifier_handler(struct memfile_notifier *notifier, + pgoff_t start, pgoff_t end) +{ + int idx; + struct kvm_memory_slot *slot = container_of(notifier, + struct kvm_memory_slot, + notifier); + struct kvm_gfn_range gfn_range = { + .slot = slot, + .start = start - (slot->private_offset >> PAGE_SHIFT), + .end = end - (slot->private_offset >> PAGE_SHIFT), + .may_block = true, + }; + struct kvm *kvm = slot->kvm; + + gfn_range.start = max(gfn_range.start, slot->base_gfn); + gfn_range.end = min(gfn_range.end, slot->base_gfn + slot->npages); + + if (gfn_range.start >= gfn_range.end) + return; + + idx = srcu_read_lock(&kvm->srcu); + KVM_MMU_LOCK(kvm); + kvm_unmap_gfn_range(kvm, &gfn_range); + kvm_flush_remote_tlbs(kvm); + KVM_MMU_UNLOCK(kvm); + srcu_read_unlock(&kvm->srcu, idx); +} + +static struct memfile_notifier_ops kvm_memfile_notifier_ops = { + .invalidate = kvm_memfile_notifier_handler, + .fallocate = kvm_memfile_notifier_handler, +}; + static inline int kvm_memfile_register(struct kvm_memory_slot *slot) { + slot->notifier.ops = &kvm_memfile_notifier_ops; return memfile_register_notifier(file_inode(slot->private_file), &slot->notifier, &slot->pfn_ops); @@ -1969,6 +2004,7 @@ int __kvm_set_memory_region(struct kvm *kvm, new->private_file = file; new->private_offset = mem->flags & KVM_MEM_PRIVATE ? region_ext->private_offset : 0; + new->kvm = kvm; r = kvm_set_memslot(kvm, old, new, change); if (!r) -- 2.17.1
WARNING: multiple messages have this Message-ID (diff)
From: Chao Peng <chao.p.peng@linux.intel.com> To: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, qemu-devel@nongnu.org Cc: Wanpeng Li <wanpengli@tencent.com>, luto@kernel.org, david@redhat.com, "J . Bruce Fields" <bfields@fieldses.org>, dave.hansen@intel.com, "H . Peter Anvin" <hpa@zytor.com>, Chao Peng <chao.p.peng@linux.intel.com>, ak@linux.intel.com, Jonathan Corbet <corbet@lwn.net>, Joerg Roedel <joro@8bytes.org>, x86@kernel.org, Hugh Dickins <hughd@google.com>, Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>, jun.nakajima@intel.com, Thomas Gleixner <tglx@linutronix.de>, Vitaly Kuznetsov <vkuznets@redhat.com>, Jim Mattson <jmattson@google.com>, Sean Christopherson <seanjc@google.com>, Jeff Layton <jlayton@kernel.org>, Yu Zhang <yu.c.zhang@linux.intel.com>, Paolo Bonzini <pbonzini@redhat.com>, Andrew Morton <akpm@linux-foundation.org>, "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com> Subject: [PATCH v4 11/12] KVM: Zap existing KVM mappings when pages changed in the private fd Date: Tue, 18 Jan 2022 21:21:20 +0800 [thread overview] Message-ID: <20220118132121.31388-12-chao.p.peng@linux.intel.com> (raw) In-Reply-To: <20220118132121.31388-1-chao.p.peng@linux.intel.com> KVM gets notified when memory pages changed in the memory backing store. When userspace allocates the memory with fallocate() or frees memory with fallocate(FALLOC_FL_PUNCH_HOLE), memory backing store calls into KVM fallocate/invalidate callbacks respectively. To ensure KVM never maps both the private and shared variants of a GPA into the guest, in the fallocate callback, we should zap the existing shared mapping and in the invalidate callback we should zap the existing private mapping. In the callbacks, KVM firstly converts the offset range into the gfn_range and then calls existing kvm_unmap_gfn_range() which will zap the shared or private mapping. Both callbacks pass in a memslot reference but we need 'kvm' so add a reference in memslot structure. Signed-off-by: Yu Zhang <yu.c.zhang@linux.intel.com> Signed-off-by: Chao Peng <chao.p.peng@linux.intel.com> --- include/linux/kvm_host.h | 3 ++- virt/kvm/kvm_main.c | 36 ++++++++++++++++++++++++++++++++++++ 2 files changed, 38 insertions(+), 1 deletion(-) diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 667efe839767..117cf0da9c5e 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -235,7 +235,7 @@ 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 +#if defined(KVM_ARCH_WANT_MMU_NOTIFIER) || defined(CONFIG_MEMFILE_NOTIFIER) struct kvm_gfn_range { struct kvm_memory_slot *slot; gfn_t start; @@ -463,6 +463,7 @@ struct kvm_memory_slot { loff_t private_offset; struct memfile_pfn_ops *pfn_ops; struct memfile_notifier notifier; + struct kvm *kvm; }; static inline bool kvm_slot_is_private(const struct kvm_memory_slot *slot) diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 6b78ddef7880..10e553215618 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -847,8 +847,43 @@ static int kvm_init_mmu_notifier(struct kvm *kvm) #endif /* CONFIG_MMU_NOTIFIER && KVM_ARCH_WANT_MMU_NOTIFIER */ #ifdef CONFIG_MEMFILE_NOTIFIER +static void kvm_memfile_notifier_handler(struct memfile_notifier *notifier, + pgoff_t start, pgoff_t end) +{ + int idx; + struct kvm_memory_slot *slot = container_of(notifier, + struct kvm_memory_slot, + notifier); + struct kvm_gfn_range gfn_range = { + .slot = slot, + .start = start - (slot->private_offset >> PAGE_SHIFT), + .end = end - (slot->private_offset >> PAGE_SHIFT), + .may_block = true, + }; + struct kvm *kvm = slot->kvm; + + gfn_range.start = max(gfn_range.start, slot->base_gfn); + gfn_range.end = min(gfn_range.end, slot->base_gfn + slot->npages); + + if (gfn_range.start >= gfn_range.end) + return; + + idx = srcu_read_lock(&kvm->srcu); + KVM_MMU_LOCK(kvm); + kvm_unmap_gfn_range(kvm, &gfn_range); + kvm_flush_remote_tlbs(kvm); + KVM_MMU_UNLOCK(kvm); + srcu_read_unlock(&kvm->srcu, idx); +} + +static struct memfile_notifier_ops kvm_memfile_notifier_ops = { + .invalidate = kvm_memfile_notifier_handler, + .fallocate = kvm_memfile_notifier_handler, +}; + static inline int kvm_memfile_register(struct kvm_memory_slot *slot) { + slot->notifier.ops = &kvm_memfile_notifier_ops; return memfile_register_notifier(file_inode(slot->private_file), &slot->notifier, &slot->pfn_ops); @@ -1969,6 +2004,7 @@ int __kvm_set_memory_region(struct kvm *kvm, new->private_file = file; new->private_offset = mem->flags & KVM_MEM_PRIVATE ? region_ext->private_offset : 0; + new->kvm = kvm; r = kvm_set_memslot(kvm, old, new, change); if (!r) -- 2.17.1
next prev parent reply other threads:[~2022-01-18 13:23 UTC|newest] Thread overview: 92+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-01-18 13:21 [PATCH v4 00/12] KVM: mm: fd-based approach for supporting KVM guest private memory Chao Peng 2022-01-18 13:21 ` Chao Peng 2022-01-18 13:21 ` [PATCH v4 01/12] mm/shmem: Introduce F_SEAL_INACCESSIBLE Chao Peng 2022-01-18 13:21 ` Chao Peng 2022-02-07 12:24 ` Vlastimil Babka 2022-02-07 12:24 ` Vlastimil Babka 2022-02-17 12:56 ` Chao Peng 2022-02-17 12:56 ` Chao Peng 2022-02-11 23:33 ` Andy Lutomirski 2022-02-11 23:33 ` Andy Lutomirski 2022-02-17 13:06 ` Chao Peng 2022-02-17 13:06 ` Chao Peng 2022-02-17 19:09 ` Andy Lutomirski 2022-02-17 19:09 ` Andy Lutomirski 2022-02-23 11:49 ` Chao Peng 2022-02-23 11:49 ` Chao Peng 2022-02-23 12:05 ` Steven Price 2022-02-23 12:05 ` Steven Price 2022-03-04 19:24 ` Andy Lutomirski 2022-03-04 19:24 ` Andy Lutomirski 2022-03-07 13:26 ` Chao Peng 2022-03-07 13:26 ` Chao Peng 2022-03-08 12:17 ` Paolo Bonzini 2022-03-08 12:17 ` Paolo Bonzini 2022-01-18 13:21 ` [PATCH v4 02/12] mm/memfd: Introduce MFD_INACCESSIBLE flag Chao Peng 2022-01-18 13:21 ` Chao Peng 2022-01-21 15:50 ` Steven Price 2022-01-21 15:50 ` Steven Price 2022-01-24 13:29 ` Chao Peng 2022-01-24 13:29 ` Chao Peng 2022-02-07 18:51 ` Vlastimil Babka 2022-02-07 18:51 ` Vlastimil Babka 2022-02-08 8:49 ` David Hildenbrand 2022-02-08 8:49 ` David Hildenbrand 2022-02-08 18:22 ` Mike Rapoport 2022-02-08 18:22 ` Mike Rapoport 2022-01-18 13:21 ` [PATCH v4 03/12] mm: Introduce memfile_notifier Chao Peng 2022-01-18 13:21 ` Chao Peng 2022-03-07 15:42 ` Vlastimil Babka 2022-03-07 15:42 ` Vlastimil Babka 2022-03-08 1:45 ` Chao Peng 2022-03-08 1:45 ` Chao Peng 2022-01-18 13:21 ` [PATCH v4 04/12] mm/shmem: Support memfile_notifier Chao Peng 2022-01-18 13:21 ` Chao Peng 2022-02-08 18:29 ` Mike Rapoport 2022-02-08 18:29 ` Mike Rapoport 2022-02-17 13:10 ` Chao Peng 2022-02-17 13:10 ` Chao Peng 2022-02-11 23:40 ` Andy Lutomirski 2022-02-11 23:40 ` Andy Lutomirski 2022-02-17 13:23 ` Chao Peng 2022-02-17 13:23 ` Chao Peng 2022-01-18 13:21 ` [PATCH v4 05/12] KVM: Extend the memslot to support fd-based private memory Chao Peng 2022-01-18 13:21 ` Chao Peng 2022-01-18 13:21 ` [PATCH v4 06/12] KVM: Use kvm_userspace_memory_region_ext Chao Peng 2022-01-18 13:21 ` Chao Peng 2022-01-18 13:21 ` [PATCH v4 07/12] KVM: Add KVM_EXIT_MEMORY_ERROR exit Chao Peng 2022-01-18 13:21 ` Chao Peng 2022-01-18 13:21 ` [PATCH v4 08/12] KVM: Use memfile_pfn_ops to obtain pfn for private pages Chao Peng 2022-01-18 13:21 ` Chao Peng 2022-01-18 13:21 ` [PATCH v4 09/12] KVM: Handle page fault for private memory Chao Peng 2022-01-18 13:21 ` Chao Peng 2022-01-18 13:21 ` [PATCH v4 10/12] KVM: Register private memslot to memory backing store Chao Peng 2022-01-18 13:21 ` Chao Peng 2022-01-18 13:21 ` Chao Peng [this message] 2022-01-18 13:21 ` [PATCH v4 11/12] KVM: Zap existing KVM mappings when pages changed in the private fd Chao Peng 2022-01-18 13:21 ` [PATCH v4 12/12] KVM: Expose KVM_MEM_PRIVATE Chao Peng 2022-01-18 13:21 ` Chao Peng 2022-01-25 20:20 ` Maciej S. Szmigiero 2022-01-25 20:20 ` Maciej S. Szmigiero 2022-02-17 13:45 ` Chao Peng 2022-02-17 13:45 ` Chao Peng 2022-02-22 1:16 ` Maciej S. Szmigiero 2022-02-22 1:16 ` Maciej S. Szmigiero 2022-02-23 12:00 ` Chao Peng 2022-02-23 12:00 ` Chao Peng 2022-02-23 18:32 ` Maciej S. Szmigiero 2022-02-23 18:32 ` Maciej S. Szmigiero 2022-02-24 8:07 ` Chao Peng 2022-02-24 8:07 ` Chao Peng 2022-01-28 16:47 ` [PATCH v4 00/12] KVM: mm: fd-based approach for supporting KVM guest private memory Steven Price 2022-01-28 16:47 ` Steven Price 2022-02-02 2:28 ` Nakajima, Jun 2022-02-02 2:28 ` Nakajima, Jun 2022-02-02 9:23 ` Steven Price 2022-02-02 9:23 ` Steven Price 2022-02-02 20:47 ` Nakajima, Jun 2022-02-02 20:47 ` Nakajima, Jun 2022-02-08 18:33 ` Mike Rapoport 2022-02-08 18:33 ` Mike Rapoport 2022-02-17 13:47 ` Chao Peng 2022-02-17 13:47 ` Chao Peng
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