KVM: VMX: Always return old for clear_flush_young() when using EPT

As well as discard fake accessed bit and dirty bit of EPT.

Signed-off-by: Sheng Yang <sheng.yang@intel.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

arch/x86/kvm/mmu.c

@@ -711,6 +711,10 @@ static int kvm_age_rmapp(struct kvm *kvm, unsigned long *rmapp)
 	u64 *spte;
 	int young = 0;
 
+	/* always return old for EPT */
+	if (!shadow_accessed_mask)
+		return 0;
+
 	spte = rmap_next(kvm, rmapp, NULL);
 	while (spte) {
 		int _young;