1 files changed, 20 insertions, 1 deletions

diff --git a/drivers/kvm/mmu.c b/drivers/kvm/mmu.c
index 069ce83f018e..d347e895736e 100644
--- a/drivers/kvm/mmu.c
+++ b/drivers/kvm/mmu.c
@@ -692,6 +692,15 @@ static void kvm_mmu_put_page(struct kvm_mmu_page *page,
         mmu_page_remove_parent_pte(page, parent_pte);
 }
 
+static void kvm_mmu_reset_last_pte_updated(struct kvm *kvm)
+{
+        int i;
+
+        for (i = 0; i < KVM_MAX_VCPUS; ++i)
+                if (kvm->vcpus[i])
+                        kvm->vcpus[i]->last_pte_updated = NULL;
+}
+
 static void kvm_mmu_zap_page(struct kvm *kvm,
                              struct kvm_mmu_page *page)
 {
@@ -717,6 +726,7 @@ static void kvm_mmu_zap_page(struct kvm *kvm,
                 kvm_mmu_free_page(kvm, page);
         } else
                 list_move(&page->link, &kvm->active_mmu_pages);
+        kvm_mmu_reset_last_pte_updated(kvm);
 }
 
 static int kvm_mmu_unprotect_page(struct kvm_vcpu *vcpu, gfn_t gfn)
@@ -1140,6 +1150,13 @@ static void mmu_pte_write_new_pte(struct kvm_vcpu *vcpu,
                                     offset_in_pte);
 }
 
+static bool last_updated_pte_accessed(struct kvm_vcpu *vcpu)
+{
+        u64 *spte = vcpu->last_pte_updated;
+
+        return !!(spte && (*spte & PT_ACCESSED_MASK));
+}
+
 void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
                        const u8 *new, int bytes)
 {
@@ -1160,13 +1177,15 @@ void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
 
         pgprintk("%s: gpa %llx bytes %d\n", __FUNCTION__, gpa, bytes);
         kvm_mmu_audit(vcpu, "pre pte write");
-        if (gfn == vcpu->last_pt_write_gfn) {
+        if (gfn == vcpu->last_pt_write_gfn
+            && !last_updated_pte_accessed(vcpu)) {
                 ++vcpu->last_pt_write_count;
                 if (vcpu->last_pt_write_count >= 3)
                         flooded = 1;
         } else {
                 vcpu->last_pt_write_gfn = gfn;
                 vcpu->last_pt_write_count = 1;
+                vcpu->last_pte_updated = NULL;
         }
         index = kvm_page_table_hashfn(gfn) % KVM_NUM_MMU_PAGES;
         bucket = &vcpu->kvm->mmu_page_hash[index];