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 <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 7a22eb8..b432a71 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2207,11 +2207,6 @@
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 @@
}
}
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 @@
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 @@
++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;