1 files changed, 28 insertions, 19 deletions

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index c07b9a200bc8..ff95d418750d 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -307,24 +307,42 @@ static bool spte_has_volatile_bits(u64 spte)
         if (!is_shadow_present_pte(spte))
                 return false;
 
-        if (spte & shadow_accessed_mask)
+        if ((spte & shadow_accessed_mask) &&
+              (!is_writable_pte(spte) || (spte & shadow_dirty_mask)))
                 return false;
 
         return true;
 }
 
+static bool spte_is_bit_cleared(u64 old_spte, u64 new_spte, u64 bit_mask)
+{
+        return (old_spte & bit_mask) && !(new_spte & bit_mask);
+}
+
 static void update_spte(u64 *sptep, u64 new_spte)
 {
-        u64 old_spte;
+        u64 mask, old_spte = *sptep;
+
+        WARN_ON(!is_rmap_spte(new_spte));
 
-        if (!shadow_accessed_mask || (new_spte & shadow_accessed_mask) ||
-              !is_rmap_spte(*sptep))
+        new_spte |= old_spte & shadow_dirty_mask;
+
+        mask = shadow_accessed_mask;
+        if (is_writable_pte(old_spte))
+                mask |= shadow_dirty_mask;
+
+        if (!spte_has_volatile_bits(old_spte) || (new_spte & mask) == mask)
                 __set_spte(sptep, new_spte);
-        else {
+        else
                 old_spte = __xchg_spte(sptep, new_spte);
-                if (old_spte & shadow_accessed_mask)
-                        kvm_set_pfn_accessed(spte_to_pfn(old_spte));
-        }
+
+        if (!shadow_accessed_mask)
+                return;
+
+        if (spte_is_bit_cleared(old_spte, new_spte, shadow_accessed_mask))
+                kvm_set_pfn_accessed(spte_to_pfn(old_spte));
+        if (spte_is_bit_cleared(old_spte, new_spte, shadow_dirty_mask))
+                kvm_set_pfn_dirty(spte_to_pfn(old_spte));
 }
 
 static int mmu_topup_memory_cache(struct kvm_mmu_memory_cache *cache,
@@ -704,7 +722,7 @@ static void set_spte_track_bits(u64 *sptep, u64 new_spte)
         pfn = spte_to_pfn(old_spte);
         if (!shadow_accessed_mask || old_spte & shadow_accessed_mask)
                 kvm_set_pfn_accessed(pfn);
-        if (is_writable_pte(old_spte))
+        if (!shadow_dirty_mask || (old_spte & shadow_dirty_mask))
                 kvm_set_pfn_dirty(pfn);
 }
 
@@ -759,13 +777,6 @@ static int rmap_write_protect(struct kvm *kvm, u64 gfn)
                 }
                 spte = rmap_next(kvm, rmapp, spte);
         }
-        if (write_protected) {
-                pfn_t pfn;
-
-                spte = rmap_next(kvm, rmapp, NULL);
-                pfn = spte_to_pfn(*spte);
-                kvm_set_pfn_dirty(pfn);
-        }
 
         /* check for huge page mappings */
         for (i = PT_DIRECTORY_LEVEL;
@@ -1938,7 +1949,7 @@ static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
          * whether the guest actually used the pte (in order to detect
          * demand paging).
          */
-        spte = shadow_base_present_pte | shadow_dirty_mask;
+        spte = shadow_base_present_pte;
         if (!speculative)
                 spte |= shadow_accessed_mask;
         if (!dirty)
@@ -1999,8 +2010,6 @@ static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
                 mark_page_dirty(vcpu->kvm, gfn);
 
 set_pte:
-        if (is_writable_pte(*sptep) && !is_writable_pte(spte))
-                kvm_set_pfn_dirty(pfn);
         update_spte(sptep, spte);
 done:
         return ret;