KVM: nVMX: validate eptp pointer

Let's reuse the function introduced with eptp switching.

We don't explicitly have to check against enable_ept_ad_bits, as this
is implicitly done when checking against nested_vmx_ept_caps in
valid_ept_address().
Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/vmx.c

@@ -9721,18 +9721,15 @@ static unsigned long nested_ept_get_cr3(struct kvm_vcpu *vcpu)
 
 static int nested_ept_init_mmu_context(struct kvm_vcpu *vcpu)
 {
-	bool wants_ad;
-
 	WARN_ON(mmu_is_nested(vcpu));
-	wants_ad = nested_ept_ad_enabled(vcpu);
-	if (wants_ad && !enable_ept_ad_bits)
+	if (!valid_ept_address(vcpu, nested_ept_get_cr3(vcpu)))
 		return 1;
 
 	kvm_mmu_unload(vcpu);
 	kvm_init_shadow_ept_mmu(vcpu,
 			to_vmx(vcpu)->nested.nested_vmx_ept_caps &
 			VMX_EPT_EXECUTE_ONLY_BIT,
-			wants_ad);
+			nested_ept_ad_enabled(vcpu));
 	vcpu->arch.mmu.set_cr3           = vmx_set_cr3;
 	vcpu->arch.mmu.get_cr3           = nested_ept_get_cr3;
 	vcpu->arch.mmu.inject_page_fault = nested_ept_inject_page_fault;