From 0e3d0648bd903ff6cda7499f9349a2ce612bccb4 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Fri, 13 Nov 2015 11:52:45 +0100 Subject: [PATCH] KVM: x86: MMU: always set accessed bit in shadow PTEs Commit 7a1638ce4220 ("nEPT: Redefine EPT-specific link_shadow_page()", 2013-08-05) says: Since nEPT doesn't support A/D bit, we should not set those bit when building the shadow page table. but this is not necessary. Even though nEPT doesn't support A/D bits, and hence the vmcs12 EPT pointer will never enable them, we always use them for shadow page tables if available (see construct_eptp in vmx.c). So we can set the A/D bits freely in the shadow page table. This patch hence basically reverts commit 7a1638ce4220. Cc: Yang Zhang Cc: Takuya Yoshikawa Signed-off-by: Paolo Bonzini --- arch/x86/kvm/mmu.c | 9 +++------ arch/x86/kvm/paging_tmpl.h | 4 ++-- 2 files changed, 5 insertions(+), 8 deletions(-) diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index e7c2c14..276d2f2 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -2198,7 +2198,7 @@ static void shadow_walk_next(struct kvm_shadow_walk_iterator *iterator) return __shadow_walk_next(iterator, *iterator->sptep); } -static void link_shadow_page(u64 *sptep, struct kvm_mmu_page *sp, bool accessed) +static void link_shadow_page(u64 *sptep, struct kvm_mmu_page *sp) { u64 spte; @@ -2206,10 +2206,7 @@ static void link_shadow_page(u64 *sptep, struct kvm_mmu_page *sp, bool accessed) VMX_EPT_WRITABLE_MASK != PT_WRITABLE_MASK); spte = __pa(sp->spt) | PT_PRESENT_MASK | PT_WRITABLE_MASK | - shadow_user_mask | shadow_x_mask; - - if (accessed) - spte |= shadow_accessed_mask; + shadow_user_mask | shadow_x_mask | shadow_accessed_mask; mmu_spte_set(sptep, spte); } @@ -2740,7 +2737,7 @@ static int __direct_map(struct kvm_vcpu *vcpu, gpa_t v, int write, iterator.level - 1, 1, ACC_ALL, iterator.sptep); - link_shadow_page(iterator.sptep, sp, true); + link_shadow_page(iterator.sptep, sp); } } return emulate; diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h index 3058a22..d8fdc5c 100644 --- a/arch/x86/kvm/paging_tmpl.h +++ b/arch/x86/kvm/paging_tmpl.h @@ -598,7 +598,7 @@ static int FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr, goto out_gpte_changed; if (sp) - link_shadow_page(it.sptep, sp, PT_GUEST_ACCESSED_MASK); + link_shadow_page(it.sptep, sp); } for (; @@ -618,7 +618,7 @@ static int FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr, sp = kvm_mmu_get_page(vcpu, direct_gfn, addr, it.level-1, true, direct_access, it.sptep); - link_shadow_page(it.sptep, sp, PT_GUEST_ACCESSED_MASK); + link_shadow_page(it.sptep, sp); } clear_sp_write_flooding_count(it.sptep); -- 2.7.4