KVM: VMX: Use EPT Access bit in response to memory notifiers

Signed-off-by: Haitao Shan <haitao.shan@intel.com>
Signed-off-by: Xudong Hao <xudong.hao@intel.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

arch/x86/kvm/mmu.c

@@ -1242,7 +1242,8 @@ static int kvm_age_rmapp(struct kvm *kvm, unsigned long *rmapp,
 	int young = 0;
 
 	/*
-	 * Emulate the accessed bit for EPT, by checking if this page has
+	 * In case of absence of EPT Access and Dirty Bits supports,
+	 * emulate the accessed bit for EPT, by checking if this page has
 	 * an EPT mapping, and clearing it if it does. On the next access,
 	 * a new EPT mapping will be established.
 	 * This has some overhead, but not as much as the cost of swapping
@@ -1253,11 +1254,12 @@ static int kvm_age_rmapp(struct kvm *kvm, unsigned long *rmapp,
 
 	for (sptep = rmap_get_first(*rmapp, &iter); sptep;
 	     sptep = rmap_get_next(&iter)) {
-		BUG_ON(!(*sptep & PT_PRESENT_MASK));
+		BUG_ON(!is_shadow_present_pte(*sptep));
 
-		if (*sptep & PT_ACCESSED_MASK) {
+		if (*sptep & shadow_accessed_mask) {
 			young = 1;
-			clear_bit(PT_ACCESSED_SHIFT, (unsigned long *)sptep);
+			clear_bit((ffs(shadow_accessed_mask) - 1),
+				 (unsigned long *)sptep);
 		}
 	}
 
@@ -1281,9 +1283,9 @@ static int kvm_test_age_rmapp(struct kvm *kvm, unsigned long *rmapp,
 
 	for (sptep = rmap_get_first(*rmapp, &iter); sptep;
 	     sptep = rmap_get_next(&iter)) {
-		BUG_ON(!(*sptep & PT_PRESENT_MASK));
+		BUG_ON(!is_shadow_present_pte(*sptep));
 
-		if (*sptep & PT_ACCESSED_MASK) {
+		if (*sptep & shadow_accessed_mask) {
 			young = 1;
 			break;
 		}

arch/x86/kvm/vmx.c

@@ -7289,8 +7289,10 @@ static int __init vmx_init(void)
 	vmx_disable_intercept_for_msr(MSR_IA32_SYSENTER_EIP, false);
 
 	if (enable_ept) {
-		kvm_mmu_set_mask_ptes(0ull, 0ull, 0ull, 0ull,
-				VMX_EPT_EXECUTABLE_MASK);
+		kvm_mmu_set_mask_ptes(0ull,
+			(enable_ept_ad_bits) ? VMX_EPT_ACCESS_BIT : 0ull,
+			(enable_ept_ad_bits) ? VMX_EPT_DIRTY_BIT : 0ull,
+			0ull, VMX_EPT_EXECUTABLE_MASK);
 		ept_set_mmio_spte_mask();
 		kvm_enable_tdp();
 	} else