KVM: nVMX: Move the checks for Guest Non-Register States to a separate helper function

.. to improve readability and maintainability, and to align the code as per
the layout of the checks in chapter "VM Entries" in Intel SDM vol 3C.
Signed-off-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Reviewed-by: Mihai Carabas <mihai.carabas@oracle.com>
Reviewed-by: Mark Kanda <mark.kanda@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/vmx/nested.c

@@ -2615,13 +2615,21 @@ static int nested_check_host_control_regs(struct kvm_vcpu *vcpu,
 	return 0;
 }
 
-static int nested_vmx_check_vmentry_prereqs(struct kvm_vcpu *vcpu,
-					    struct vmcs12 *vmcs12)
+/*
+ * Checks related to Guest Non-register State
+ */
+static int nested_check_guest_non_reg_state(struct vmcs12 *vmcs12)
 {
 	if (vmcs12->guest_activity_state != GUEST_ACTIVITY_ACTIVE &&
 	    vmcs12->guest_activity_state != GUEST_ACTIVITY_HLT)
-		return VMXERR_ENTRY_INVALID_CONTROL_FIELD;
+		return -EINVAL;
+
+	return 0;
+}
 
+static int nested_vmx_check_vmentry_prereqs(struct kvm_vcpu *vcpu,
+					    struct vmcs12 *vmcs12)
+{
 	if (nested_check_vm_execution_controls(vcpu, vmcs12) ||
 	    nested_check_vm_exit_controls(vcpu, vmcs12) ||
 	    nested_check_vm_entry_controls(vcpu, vmcs12))
@@ -2630,6 +2638,9 @@ static int nested_vmx_check_vmentry_prereqs(struct kvm_vcpu *vcpu,
 	if (nested_check_host_control_regs(vcpu, vmcs12))
 		return VMXERR_ENTRY_INVALID_HOST_STATE_FIELD;
 
+	if (nested_check_guest_non_reg_state(vmcs12))
+		return VMXERR_ENTRY_INVALID_CONTROL_FIELD;
+
 	return 0;
 }