1 files changed, 33 insertions, 2 deletions

diff --git a/arch/x86/kvm/mmu/spte.c b/arch/x86/kvm/mmu/spte.c
index 4739b53c9734..800b857b3a53 100644
--- a/arch/x86/kvm/mmu/spte.c
+++ b/arch/x86/kvm/mmu/spte.c
@@ -19,7 +19,7 @@
 #include <asm/memtype.h>
 #include <asm/vmx.h>
 
-static bool __read_mostly enable_mmio_caching = true;
+bool __read_mostly enable_mmio_caching = true;
 module_param_named(mmio_caching, enable_mmio_caching, bool, 0444);
 
 u64 __read_mostly shadow_host_writable_mask;
@@ -90,6 +90,34 @@ static bool kvm_is_mmio_pfn(kvm_pfn_t pfn)
 				     E820_TYPE_RAM);
 }
 
+/*
+ * Returns true if the SPTE has bits that may be set without holding mmu_lock.
+ * The caller is responsible for checking if the SPTE is shadow-present, and
+ * for determining whether or not the caller cares about non-leaf SPTEs.
+ */
+bool spte_has_volatile_bits(u64 spte)
+{
+	/*
+	 * Always atomically update spte if it can be updated
+	 * out of mmu-lock, it can ensure dirty bit is not lost,
+	 * also, it can help us to get a stable is_writable_pte()
+	 * to ensure tlb flush is not missed.
+	 */
+	if (!is_writable_pte(spte) && is_mmu_writable_spte(spte))
+		return true;
+
+	if (is_access_track_spte(spte))
+		return true;
+
+	if (spte_ad_enabled(spte)) {
+		if (!(spte & shadow_accessed_mask) ||
+		    (is_writable_pte(spte) && !(spte & shadow_dirty_mask)))
+			return true;
+	}
+
+	return false;
+}
+
 bool make_spte(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
 	       const struct kvm_memory_slot *slot,
 	       unsigned int pte_access, gfn_t gfn, kvm_pfn_t pfn,
@@ -139,7 +167,7 @@ bool make_spte(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
 	else
 		pte_access &= ~ACC_WRITE_MASK;
 
-	if (!kvm_is_mmio_pfn(pfn))
+	if (shadow_me_mask && !kvm_is_mmio_pfn(pfn))
 		spte |= shadow_me_mask;
 
 	spte |= (u64)pfn << PAGE_SHIFT;
@@ -351,6 +379,9 @@ void kvm_mmu_set_mmio_spte_mask(u64 mmio_value, u64 mmio_mask, u64 access_mask)
 	    WARN_ON(mmio_value && (REMOVED_SPTE & mmio_mask) == mmio_value))
 		mmio_value = 0;
 
+	if (!mmio_value)
+		enable_mmio_caching = false;
+
 	shadow_mmio_value = mmio_value;
 	shadow_mmio_mask  = mmio_mask;
 	shadow_mmio_access_mask = access_mask;