From 947da53830690cbd77d7f2b625d0df1f161ffd54 Mon Sep 17 00:00:00 2001 From: Avi Kivity Date: Tue, 18 Mar 2008 11:05:52 +0200 Subject: [PATCH] KVM: MMU: Set the accessed bit on non-speculative shadow ptes If we populate a shadow pte due to a fault (and not speculatively due to a pte write) then we can set the accessed bit on it, as we know it will be set immediately on the next guest instruction. This saves a read-modify-write operation. Signed-off-by: Avi Kivity --- arch/x86/kvm/mmu.c | 8 +++++--- arch/x86/kvm/paging_tmpl.h | 4 ++-- 2 files changed, 7 insertions(+), 5 deletions(-) diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index 072e9422c9..a5872b3c46 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -1020,7 +1020,7 @@ static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *shadow_pte, unsigned pt_access, unsigned pte_access, int user_fault, int write_fault, int dirty, int *ptwrite, int largepage, gfn_t gfn, - struct page *page) + struct page *page, bool speculative) { u64 spte; int was_rmapped = 0; @@ -1061,6 +1061,8 @@ static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *shadow_pte, * demand paging). */ spte = PT_PRESENT_MASK | PT_DIRTY_MASK; + if (!speculative) + pte_access |= PT_ACCESSED_MASK; if (!dirty) pte_access &= ~ACC_WRITE_MASK; if (!(pte_access & ACC_EXEC_MASK)) @@ -1148,13 +1150,13 @@ static int __direct_map(struct kvm_vcpu *vcpu, gpa_t v, int write, if (level == 1) { mmu_set_spte(vcpu, &table[index], ACC_ALL, ACC_ALL, - 0, write, 1, &pt_write, 0, gfn, page); + 0, write, 1, &pt_write, 0, gfn, page, false); return pt_write; } if (largepage && level == 2) { mmu_set_spte(vcpu, &table[index], ACC_ALL, ACC_ALL, - 0, write, 1, &pt_write, 1, gfn, page); + 0, write, 1, &pt_write, 1, gfn, page, false); return pt_write; } diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h index 57abbd0911..e9ae5dba72 100644 --- a/arch/x86/kvm/paging_tmpl.h +++ b/arch/x86/kvm/paging_tmpl.h @@ -266,7 +266,7 @@ static void FNAME(update_pte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *page, get_page(npage); mmu_set_spte(vcpu, spte, page->role.access, pte_access, 0, 0, gpte & PT_DIRTY_MASK, NULL, largepage, gpte_to_gfn(gpte), - npage); + npage, true); } /* @@ -349,7 +349,7 @@ static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr, mmu_set_spte(vcpu, shadow_ent, access, walker->pte_access & access, user_fault, write_fault, walker->ptes[walker->level-1] & PT_DIRTY_MASK, - ptwrite, largepage, walker->gfn, page); + ptwrite, largepage, walker->gfn, page, false); return shadow_ent; } -- 2.39.5