From 0f53b5b1c0baae4f949ac0721a55b7a2158dda01 Mon Sep 17 00:00:00 2001 From: Xiao Guangrong Date: Wed, 9 Mar 2011 15:43:51 +0800 Subject: [PATCH] KVM: MMU: cleanup pte write path This patch does: - call vcpu->arch.mmu.update_pte directly - use gfn_to_pfn_atomic in update_pte path The suggestion is from Avi. Signed-off-by: Xiao Guangrong Signed-off-by: Avi Kivity --- arch/x86/include/asm/kvm_host.h | 7 +--- arch/x86/kvm/mmu.c | 69 +++++++++++---------------------- arch/x86/kvm/paging_tmpl.h | 12 +++--- 3 files changed, 32 insertions(+), 56 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index f08314f303e0..c8af0991fdf0 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -255,6 +255,8 @@ struct kvm_mmu { int (*sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp); void (*invlpg)(struct kvm_vcpu *vcpu, gva_t gva); + void (*update_pte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp, + u64 *spte, const void *pte, unsigned long mmu_seq); hpa_t root_hpa; int root_level; int shadow_root_level; @@ -335,11 +337,6 @@ struct kvm_vcpu_arch { u64 *last_pte_updated; gfn_t last_pte_gfn; - struct { - pfn_t pfn; /* pfn corresponding to that gfn */ - unsigned long mmu_seq; - } update_pte; - struct fpu guest_fpu; u64 xcr0; diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index 83171fdd38a7..22fae7593ee7 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -1204,6 +1204,13 @@ static void nonpaging_invlpg(struct kvm_vcpu *vcpu, gva_t gva) { } +static void nonpaging_update_pte(struct kvm_vcpu *vcpu, + struct kvm_mmu_page *sp, u64 *spte, + const void *pte, unsigned long mmu_seq) +{ + WARN_ON(1); +} + #define KVM_PAGE_ARRAY_NR 16 struct kvm_mmu_pages { @@ -2796,6 +2803,7 @@ static int nonpaging_init_context(struct kvm_vcpu *vcpu, context->prefetch_page = nonpaging_prefetch_page; context->sync_page = nonpaging_sync_page; context->invlpg = nonpaging_invlpg; + context->update_pte = nonpaging_update_pte; context->root_level = 0; context->shadow_root_level = PT32E_ROOT_LEVEL; context->root_hpa = INVALID_PAGE; @@ -2925,6 +2933,7 @@ static int paging64_init_context_common(struct kvm_vcpu *vcpu, context->prefetch_page = paging64_prefetch_page; context->sync_page = paging64_sync_page; context->invlpg = paging64_invlpg; + context->update_pte = paging64_update_pte; context->free = paging_free; context->root_level = level; context->shadow_root_level = level; @@ -2953,6 +2962,7 @@ static int paging32_init_context(struct kvm_vcpu *vcpu, context->prefetch_page = paging32_prefetch_page; context->sync_page = paging32_sync_page; context->invlpg = paging32_invlpg; + context->update_pte = paging32_update_pte; context->root_level = PT32_ROOT_LEVEL; context->shadow_root_level = PT32E_ROOT_LEVEL; context->root_hpa = INVALID_PAGE; @@ -2977,6 +2987,7 @@ static int init_kvm_tdp_mmu(struct kvm_vcpu *vcpu) context->prefetch_page = nonpaging_prefetch_page; context->sync_page = nonpaging_sync_page; context->invlpg = nonpaging_invlpg; + context->update_pte = nonpaging_update_pte; context->shadow_root_level = kvm_x86_ops->get_tdp_level(); context->root_hpa = INVALID_PAGE; context->direct_map = true; @@ -3081,8 +3092,6 @@ static int init_kvm_nested_mmu(struct kvm_vcpu *vcpu) static int init_kvm_mmu(struct kvm_vcpu *vcpu) { - vcpu->arch.update_pte.pfn = bad_pfn; - if (mmu_is_nested(vcpu)) return init_kvm_nested_mmu(vcpu); else if (tdp_enabled) @@ -3156,7 +3165,7 @@ static void mmu_pte_write_zap_pte(struct kvm_vcpu *vcpu, static void mmu_pte_write_new_pte(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp, u64 *spte, - const void *new) + const void *new, unsigned long mmu_seq) { if (sp->role.level != PT_PAGE_TABLE_LEVEL) { ++vcpu->kvm->stat.mmu_pde_zapped; @@ -3164,10 +3173,7 @@ static void mmu_pte_write_new_pte(struct kvm_vcpu *vcpu, } ++vcpu->kvm->stat.mmu_pte_updated; - if (!sp->role.cr4_pae) - paging32_update_pte(vcpu, sp, spte, new); - else - paging64_update_pte(vcpu, sp, spte, new); + vcpu->arch.mmu.update_pte(vcpu, sp, spte, new, mmu_seq); } static bool need_remote_flush(u64 old, u64 new) @@ -3202,27 +3208,6 @@ static bool last_updated_pte_accessed(struct kvm_vcpu *vcpu) return !!(spte && (*spte & shadow_accessed_mask)); } -static void mmu_guess_page_from_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa, - u64 gpte) -{ - gfn_t gfn; - pfn_t pfn; - - if (!is_present_gpte(gpte)) - return; - gfn = (gpte & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT; - - vcpu->arch.update_pte.mmu_seq = vcpu->kvm->mmu_notifier_seq; - smp_rmb(); - pfn = gfn_to_pfn(vcpu->kvm, gfn); - - if (is_error_pfn(pfn)) { - kvm_release_pfn_clean(pfn); - return; - } - vcpu->arch.update_pte.pfn = pfn; -} - static void kvm_mmu_access_page(struct kvm_vcpu *vcpu, gfn_t gfn) { u64 *spte = vcpu->arch.last_pte_updated; @@ -3244,21 +3229,14 @@ void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa, struct kvm_mmu_page *sp; struct hlist_node *node; LIST_HEAD(invalid_list); - u64 entry, gentry; - u64 *spte; - unsigned offset = offset_in_page(gpa); - unsigned pte_size; - unsigned page_offset; - unsigned misaligned; - unsigned quadrant; - int level; - int flooded = 0; - int npte; - int r; - int invlpg_counter; + unsigned long mmu_seq; + u64 entry, gentry, *spte; + unsigned pte_size, page_offset, misaligned, quadrant, offset; + int level, npte, invlpg_counter, r, flooded = 0; bool remote_flush, local_flush, zap_page; zap_page = remote_flush = local_flush = false; + offset = offset_in_page(gpa); pgprintk("%s: gpa %llx bytes %d\n", __func__, gpa, bytes); @@ -3293,7 +3271,9 @@ void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa, break; } - mmu_guess_page_from_pte_write(vcpu, gpa, gentry); + mmu_seq = vcpu->kvm->mmu_notifier_seq; + smp_rmb(); + spin_lock(&vcpu->kvm->mmu_lock); if (atomic_read(&vcpu->kvm->arch.invlpg_counter) != invlpg_counter) gentry = 0; @@ -3365,7 +3345,8 @@ void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa, if (gentry && !((sp->role.word ^ vcpu->arch.mmu.base_role.word) & mask.word)) - mmu_pte_write_new_pte(vcpu, sp, spte, &gentry); + mmu_pte_write_new_pte(vcpu, sp, spte, &gentry, + mmu_seq); if (!remote_flush && need_remote_flush(entry, *spte)) remote_flush = true; ++spte; @@ -3375,10 +3356,6 @@ void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa, kvm_mmu_commit_zap_page(vcpu->kvm, &invalid_list); trace_kvm_mmu_audit(vcpu, AUDIT_POST_PTE_WRITE); spin_unlock(&vcpu->kvm->mmu_lock); - if (!is_error_pfn(vcpu->arch.update_pte.pfn)) { - kvm_release_pfn_clean(vcpu->arch.update_pte.pfn); - vcpu->arch.update_pte.pfn = bad_pfn; - } } int kvm_mmu_unprotect_page_virt(struct kvm_vcpu *vcpu, gva_t gva) diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h index 86eb8160bcb9..751405097d8c 100644 --- a/arch/x86/kvm/paging_tmpl.h +++ b/arch/x86/kvm/paging_tmpl.h @@ -325,7 +325,7 @@ no_present: } static void FNAME(update_pte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp, - u64 *spte, const void *pte) + u64 *spte, const void *pte, unsigned long mmu_seq) { pt_element_t gpte; unsigned pte_access; @@ -337,12 +337,14 @@ static void FNAME(update_pte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp, pgprintk("%s: gpte %llx spte %p\n", __func__, (u64)gpte, spte); pte_access = sp->role.access & FNAME(gpte_access)(vcpu, gpte); - pfn = vcpu->arch.update_pte.pfn; - if (is_error_pfn(pfn)) + pfn = gfn_to_pfn_atomic(vcpu->kvm, gpte_to_gfn(gpte)); + if (is_error_pfn(pfn)) { + kvm_release_pfn_clean(pfn); return; - if (mmu_notifier_retry(vcpu, vcpu->arch.update_pte.mmu_seq)) + } + if (mmu_notifier_retry(vcpu, mmu_seq)) return; - kvm_get_pfn(pfn); + /* * we call mmu_set_spte() with host_writable = true beacuse that * vcpu->arch.update_pte.pfn was fetched from get_user_pages(write = 1). -- 2.20.1