[RFC,6/6] KVM: x86/mmu: Avoid memslot lookup in mmu_try_to_unsync_pages

Message ID	20210813203504.2742757-7-dmatlack@google.com (mailing list archive)
State	New, archived
Headers	show Return-Path: <kvm-owner@kernel.org> Date: Fri, 13 Aug 2021 20:35:04 +0000 In-Reply-To: <20210813203504.2742757-1-dmatlack@google.com> Message-Id: <20210813203504.2742757-7-dmatlack@google.com> Mime-Version: 1.0 References: <20210813203504.2742757-1-dmatlack@google.com> Subject: [RFC PATCH 6/6] KVM: x86/mmu: Avoid memslot lookup in mmu_try_to_unsync_pages From: David Matlack <dmatlack@google.com> To: Paolo Bonzini <pbonzini@redhat.com> Cc: kvm@vger.kernel.org, Ben Gardon <bgardon@google.com>, Joerg Roedel <joro@8bytes.org>, Jim Mattson <jmattson@google.com>, Wanpeng Li <wanpengli@tencent.com>, Vitaly Kuznetsov <vkuznets@redhat.com>, Sean Christopherson <seanjc@google.com>, David Matlack <dmatlack@google.com> Content-Type: text/plain; charset="UTF-8" Precedence: bulk
Series	Pass memslot around during page fault handling \| expand [RFC,0/6] Pass memslot around during page fault handling [RFC,1/6] KVM: x86/mmu: Rename try_async_pf to kvm_faultin_pfn in comment [RFC,2/6] KVM: x86/mmu: Fold rmap_recycle into rmap_add [RFC,3/6] KVM: x86/mmu: Pass the memslot around via struct kvm_page_fault [RFC,4/6] KVM: x86/mmu: Avoid memslot lookup in page_fault_handle_page_track [RFC,5/6] KVM: x86/mmu: Avoid memslot lookup in rmap_add [RFC,6/6] KVM: x86/mmu: Avoid memslot lookup in mmu_try_to_unsync_pages

diff --git a/arch/x86/include/asm/kvm_page_track.h b/arch/x86/include/asm/kvm_page_track.h index 8766adb52a73..be76dda0952b 100644 --- a/arch/x86/include/asm/kvm_page_track.h +++ b/arch/x86/include/asm/kvm_page_track.h @@ -59,8 +59,6 @@ void kvm_slot_page_track_add_page(struct kvm *kvm, void kvm_slot_page_track_remove_page(struct kvm *kvm, struct kvm_memory_slot *slot, gfn_t gfn, enum kvm_page_track_mode mode); -bool kvm_page_track_is_active(struct kvm_vcpu *vcpu, gfn_t gfn, - enum kvm_page_track_mode mode); bool kvm_slot_page_track_is_active(struct kvm_memory_slot *slot, gfn_t gfn, enum kvm_page_track_mode mode); diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 41e2ef8ad09b..136056b13e15 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -2583,7 +2583,8 @@ static void kvm_unsync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp) * were marked unsync (or if there is no shadow page), -EPERM if the SPTE must * be write-protected. */ -int mmu_try_to_unsync_pages(struct kvm_vcpu *vcpu, gfn_t gfn, bool can_unsync) +int mmu_try_to_unsync_pages(struct kvm_vcpu *vcpu, struct kvm_memory_slot *slot, + gfn_t gfn, bool can_unsync) { struct kvm_mmu_page *sp; @@ -2592,7 +2593,7 @@ int mmu_try_to_unsync_pages(struct kvm_vcpu *vcpu, gfn_t gfn, bool can_unsync) * track machinery is used to write-protect upper-level shadow pages, * i.e. this guards the role.level == 4K assertion below! */ - if (kvm_page_track_is_active(vcpu, gfn, KVM_PAGE_TRACK_WRITE)) + if (kvm_slot_page_track_is_active(slot, gfn, KVM_PAGE_TRACK_WRITE)) return -EPERM; /* @@ -2654,8 +2655,8 @@ int mmu_try_to_unsync_pages(struct kvm_vcpu *vcpu, gfn_t gfn, bool can_unsync) return 0; } -static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep, - unsigned int pte_access, int level, +static int set_spte(struct kvm_vcpu *vcpu, struct kvm_memory_slot *slot, + u64 *sptep, unsigned int pte_access, int level, gfn_t gfn, kvm_pfn_t pfn, bool speculative, bool can_unsync, bool host_writable) { @@ -2665,8 +2666,9 @@ static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep, sp = sptep_to_sp(sptep); - ret = make_spte(vcpu, pte_access, level, gfn, pfn, *sptep, speculative, - can_unsync, host_writable, sp_ad_disabled(sp), &spte); + ret = make_spte(vcpu, slot, pte_access, level, gfn, pfn, *sptep, + speculative, can_unsync, host_writable, + sp_ad_disabled(sp), &spte); if (spte & PT_WRITABLE_MASK) kvm_vcpu_mark_page_dirty(vcpu, gfn); @@ -2717,7 +2719,7 @@ static int mmu_set_spte(struct kvm_vcpu *vcpu, struct kvm_memory_slot *slot, was_rmapped = 1; } - set_spte_ret = set_spte(vcpu, sptep, pte_access, level, gfn, pfn, + set_spte_ret = set_spte(vcpu, slot, sptep, pte_access, level, gfn, pfn, speculative, true, host_writable); if (set_spte_ret & SET_SPTE_WRITE_PROTECTED_PT) { if (write_fault) diff --git a/arch/x86/kvm/mmu/mmu_internal.h b/arch/x86/kvm/mmu/mmu_internal.h index 658d8d228d43..e0c9c68ff617 100644 --- a/arch/x86/kvm/mmu/mmu_internal.h +++ b/arch/x86/kvm/mmu/mmu_internal.h @@ -116,7 +116,8 @@ static inline bool kvm_vcpu_ad_need_write_protect(struct kvm_vcpu *vcpu) kvm_x86_ops.cpu_dirty_log_size; } -int mmu_try_to_unsync_pages(struct kvm_vcpu *vcpu, gfn_t gfn, bool can_unsync); +int mmu_try_to_unsync_pages(struct kvm_vcpu *vcpu, struct kvm_memory_slot *slot, + gfn_t gfn, bool can_unsync); void kvm_mmu_gfn_disallow_lpage(const struct kvm_memory_slot *slot, gfn_t gfn); void kvm_mmu_gfn_allow_lpage(const struct kvm_memory_slot *slot, gfn_t gfn); diff --git a/arch/x86/kvm/mmu/page_track.c b/arch/x86/kvm/mmu/page_track.c index a9e2e02f2f4f..4179f4712152 100644 --- a/arch/x86/kvm/mmu/page_track.c +++ b/arch/x86/kvm/mmu/page_track.c @@ -136,6 +136,9 @@ void kvm_slot_page_track_remove_page(struct kvm *kvm, } EXPORT_SYMBOL_GPL(kvm_slot_page_track_remove_page); +/* + * check if the corresponding access on the specified guest page is tracked. + */ bool kvm_slot_page_track_is_active(struct kvm_memory_slot *slot, gfn_t gfn, enum kvm_page_track_mode mode) { @@ -151,17 +154,6 @@ bool kvm_slot_page_track_is_active(struct kvm_memory_slot *slot, gfn_t gfn, return !!READ_ONCE(slot->arch.gfn_track[mode][index]); } -/* - * check if the corresponding access on the specified guest page is tracked. - */ -bool kvm_page_track_is_active(struct kvm_vcpu *vcpu, gfn_t gfn, - enum kvm_page_track_mode mode) -{ - struct kvm_memory_slot *slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn); - - return kvm_slot_page_track_is_active(slot, gfn, mode); -} - void kvm_page_track_cleanup(struct kvm *kvm) { struct kvm_page_track_notifier_head *head; diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h index 653ca44afa58..f85786534d86 100644 --- a/arch/x86/kvm/mmu/paging_tmpl.h +++ b/arch/x86/kvm/mmu/paging_tmpl.h @@ -1086,6 +1086,7 @@ static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp) first_pte_gpa = FNAME(get_level1_sp_gpa)(sp); for (i = 0; i < PT64_ENT_PER_PAGE; i++) { + struct kvm_memory_slot *slot; unsigned pte_access; pt_element_t gpte; gpa_t pte_gpa; @@ -1135,7 +1136,8 @@ static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp) host_writable = sp->spt[i] & shadow_host_writable_mask; - set_spte_ret |= set_spte(vcpu, &sp->spt[i], + slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn); + set_spte_ret |= set_spte(vcpu, slot, &sp->spt[i], pte_access, PG_LEVEL_4K, gfn, spte_to_pfn(sp->spt[i]), true, false, host_writable); diff --git a/arch/x86/kvm/mmu/spte.c b/arch/x86/kvm/mmu/spte.c index 3e97cdb13eb7..5f0c99532a96 100644 --- a/arch/x86/kvm/mmu/spte.c +++ b/arch/x86/kvm/mmu/spte.c @@ -89,10 +89,11 @@ static bool kvm_is_mmio_pfn(kvm_pfn_t pfn) E820_TYPE_RAM); } -int make_spte(struct kvm_vcpu *vcpu, unsigned int pte_access, int level, - gfn_t gfn, kvm_pfn_t pfn, u64 old_spte, bool speculative, - bool can_unsync, bool host_writable, bool ad_disabled, - u64 *new_spte) +int make_spte(struct kvm_vcpu *vcpu, struct kvm_memory_slot *slot, + unsigned int pte_access, int level, + gfn_t gfn, kvm_pfn_t pfn, + u64 old_spte, bool speculative, bool can_unsync, + bool host_writable, bool ad_disabled, u64 *new_spte) { u64 spte = SPTE_MMU_PRESENT_MASK; int ret = 0; @@ -159,7 +160,7 @@ int make_spte(struct kvm_vcpu *vcpu, unsigned int pte_access, int level, * e.g. it's write-tracked (upper-level SPs) or has one or more * shadow pages and unsync'ing pages is not allowed. */ - if (mmu_try_to_unsync_pages(vcpu, gfn, can_unsync)) { + if (mmu_try_to_unsync_pages(vcpu, slot, gfn, can_unsync)) { pgprintk("%s: found shadow page for %llx, marking ro\n", __func__, gfn); ret |= SET_SPTE_WRITE_PROTECTED_PT; diff --git a/arch/x86/kvm/mmu/spte.h b/arch/x86/kvm/mmu/spte.h index eb7b227fc6cf..6d2446f4c591 100644 --- a/arch/x86/kvm/mmu/spte.h +++ b/arch/x86/kvm/mmu/spte.h @@ -339,10 +339,11 @@ static inline u64 get_mmio_spte_generation(u64 spte) #define SET_SPTE_NEED_REMOTE_TLB_FLUSH BIT(1) #define SET_SPTE_SPURIOUS BIT(2) -int make_spte(struct kvm_vcpu *vcpu, unsigned int pte_access, int level, - gfn_t gfn, kvm_pfn_t pfn, u64 old_spte, bool speculative, - bool can_unsync, bool host_writable, bool ad_disabled, - u64 *new_spte); +int make_spte(struct kvm_vcpu *vcpu, struct kvm_memory_slot *slot, + unsigned int pte_access, int level, + gfn_t gfn, kvm_pfn_t pfn, + u64 old_spte, bool speculative, bool can_unsync, + bool host_writable, bool ad_disabled, u64 *new_spte); u64 make_nonleaf_spte(u64 *child_pt, bool ad_disabled); u64 make_mmio_spte(struct kvm_vcpu *vcpu, u64 gfn, unsigned int access); u64 mark_spte_for_access_track(u64 spte); diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c index 6f733a68d750..cd72184327a4 100644 --- a/arch/x86/kvm/mmu/tdp_mmu.c +++ b/arch/x86/kvm/mmu/tdp_mmu.c @@ -927,7 +927,7 @@ static int tdp_mmu_map_handle_target_level(struct kvm_vcpu *vcpu, if (unlikely(is_noslot_pfn(fault->pfn))) new_spte = make_mmio_spte(vcpu, iter->gfn, ACC_ALL); else - make_spte_ret = make_spte(vcpu, ACC_ALL, iter->level, iter->gfn, + make_spte_ret = make_spte(vcpu, fault->slot, ACC_ALL, iter->level, iter->gfn, fault->pfn, iter->old_spte, fault->prefault, true, fault->map_writable, !shadow_accessed_mask, &new_spte);

[RFC,6/6] KVM: x86/mmu: Avoid memslot lookup in mmu_try_to_unsync_pages

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