KVM: nVMX: introduce nested_get_vmcs12_pages

Introduce function nested_get_vmcs12_pages() to check the valid
of nested apic access page and virtual apic page earlier.
Signed-off-by: Wanpeng Li <wanpeng.li@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/vmx.c

@@ -7927,6 +7927,30 @@ static void vmx_inject_page_fault_nested(struct kvm_vcpu *vcpu,
 		kvm_inject_page_fault(vcpu, fault);
 }
 
+static bool nested_get_vmcs12_pages(struct kvm_vcpu *vcpu,
+					struct vmcs12 *vmcs12)
+{
+	struct vcpu_vmx *vmx = to_vmx(vcpu);
+
+	if (nested_cpu_has2(vmcs12, SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES)) {
+		if (!PAGE_ALIGNED(vmcs12->apic_access_addr))
+			/*TODO: Also verify bits beyond physical address width are 0*/
+			return false;
+
+		/*
+		 * Translate L1 physical address to host physical
+		 * address for vmcs02. Keep the page pinned, so this
+		 * physical address remains valid. We keep a reference
+		 * to it so we can release it later.
+		 */
+		if (vmx->nested.apic_access_page) /* shouldn't happen */
+			nested_release_page(vmx->nested.apic_access_page);
+		vmx->nested.apic_access_page =
+			nested_get_page(vcpu, vmcs12->apic_access_addr);
+	}
+	return true;
+}
+
 static void vmx_start_preemption_timer(struct kvm_vcpu *vcpu)
 {
 	u64 preemption_timeout = get_vmcs12(vcpu)->vmx_preemption_timer_value;
@@ -8072,16 +8096,6 @@ static void prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12)
 			exec_control |= vmcs12->secondary_vm_exec_control;
 
 		if (exec_control & SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES) {
-			/*
-			 * Translate L1 physical address to host physical
-			 * address for vmcs02. Keep the page pinned, so this
-			 * physical address remains valid. We keep a reference
-			 * to it so we can release it later.
-			 */
-			if (vmx->nested.apic_access_page) /* shouldn't happen */
-				nested_release_page(vmx->nested.apic_access_page);
-			vmx->nested.apic_access_page =
-				nested_get_page(vcpu, vmcs12->apic_access_addr);
 			/*
 			 * If translation failed, no matter: This feature asks
 			 * to exit when accessing the given address, and if it
@@ -8288,8 +8302,7 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch)
 		return 1;
 	}
 
-	if (nested_cpu_has2(vmcs12, SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES) &&
-			!PAGE_ALIGNED(vmcs12->apic_access_addr)) {
+	if (!nested_get_vmcs12_pages(vcpu, vmcs12)) {
 		/*TODO: Also verify bits beyond physical address width are 0*/
 		nested_vmx_failValid(vcpu, VMXERR_ENTRY_INVALID_CONTROL_FIELD);
 		return 1;