From d01f8d5e02cc79998e3160f7ad545f77891b00e5 Mon Sep 17 00:00:00 2001 From: Xiao Guangrong Date: Thu, 22 Sep 2011 16:55:36 +0800 Subject: [PATCH] KVM: MMU: do not mark accessed bit on pte write path In current code, the accessed bit is always set when page fault occurred, do not need to set it on pte write path Signed-off-by: Xiao Guangrong Signed-off-by: Avi Kivity --- arch/x86/include/asm/kvm_host.h | 1 - arch/x86/kvm/mmu.c | 22 +--------------------- 2 files changed, 1 insertion(+), 22 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 4ceefa9567ed..f8ab0d760231 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -356,7 +356,6 @@ struct kvm_vcpu_arch { gfn_t last_pt_write_gfn; int last_pt_write_count; u64 *last_pte_updated; - gfn_t last_pte_gfn; struct fpu guest_fpu; u64 xcr0; diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index 7a22eb81b4ca..b432a71a1839 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -2207,11 +2207,6 @@ static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep, if (set_mmio_spte(sptep, gfn, pfn, pte_access)) return 0; - /* - * We don't set the accessed bit, since we sometimes want to see - * whether the guest actually used the pte (in order to detect - * demand paging). - */ spte = PT_PRESENT_MASK; if (!speculative) spte |= shadow_accessed_mask; @@ -2362,10 +2357,8 @@ static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep, } } kvm_release_pfn_clean(pfn); - if (speculative) { + if (speculative) vcpu->arch.last_pte_updated = sptep; - vcpu->arch.last_pte_gfn = gfn; - } } static void nonpaging_new_cr3(struct kvm_vcpu *vcpu) @@ -3533,18 +3526,6 @@ static bool last_updated_pte_accessed(struct kvm_vcpu *vcpu) return !!(spte && (*spte & shadow_accessed_mask)); } -static void kvm_mmu_access_page(struct kvm_vcpu *vcpu, gfn_t gfn) -{ - u64 *spte = vcpu->arch.last_pte_updated; - - if (spte - && vcpu->arch.last_pte_gfn == gfn - && shadow_accessed_mask - && !(*spte & shadow_accessed_mask) - && is_shadow_present_pte(*spte)) - set_bit(PT_ACCESSED_SHIFT, (unsigned long *)spte); -} - void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa, const u8 *new, int bytes, bool guest_initiated) @@ -3615,7 +3596,6 @@ void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa, ++vcpu->kvm->stat.mmu_pte_write; trace_kvm_mmu_audit(vcpu, AUDIT_PRE_PTE_WRITE); if (guest_initiated) { - kvm_mmu_access_page(vcpu, gfn); if (gfn == vcpu->arch.last_pt_write_gfn && !last_updated_pte_accessed(vcpu)) { ++vcpu->arch.last_pt_write_count; -- 2.34.1