KVM: nVMX: Move the checks for Host Control Registers and MSRs 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

@@ -2585,25 +2585,18 @@ static int nested_check_vm_entry_controls(struct kvm_vcpu *vcpu,
 	return 0;
 }
 
-static int nested_vmx_check_vmentry_prereqs(struct kvm_vcpu *vcpu,
-					    struct vmcs12 *vmcs12)
+/*
+ * Checks related to Host Control Registers and MSRs
+ */
+static int nested_check_host_control_regs(struct kvm_vcpu *vcpu,
+                                          struct vmcs12 *vmcs12)
 {
 	bool ia32e;
 
-	if (vmcs12->guest_activity_state != GUEST_ACTIVITY_ACTIVE &&
-	    vmcs12->guest_activity_state != GUEST_ACTIVITY_HLT)
-		return VMXERR_ENTRY_INVALID_CONTROL_FIELD;
-
-	if (nested_check_vm_execution_controls(vcpu, vmcs12) ||
-	    nested_check_vm_exit_controls(vcpu, vmcs12) ||
-	    nested_check_vm_entry_controls(vcpu, vmcs12))
-		return VMXERR_ENTRY_INVALID_CONTROL_FIELD;
-
 	if (!nested_host_cr0_valid(vcpu, vmcs12->host_cr0) ||
 	    !nested_host_cr4_valid(vcpu, vmcs12->host_cr4) ||
 	    !nested_cr3_valid(vcpu, vmcs12->host_cr3))
-		return VMXERR_ENTRY_INVALID_HOST_STATE_FIELD;
-
+		return -EINVAL;
 	/*
 	 * If the load IA32_EFER VM-exit control is 1, bits reserved in the
 	 * IA32_EFER MSR must be 0 in the field for that register. In addition,
@@ -2616,12 +2609,30 @@ static int nested_vmx_check_vmentry_prereqs(struct kvm_vcpu *vcpu,
 		if (!kvm_valid_efer(vcpu, vmcs12->host_ia32_efer) ||
 		    ia32e != !!(vmcs12->host_ia32_efer & EFER_LMA) ||
 		    ia32e != !!(vmcs12->host_ia32_efer & EFER_LME))
-			return VMXERR_ENTRY_INVALID_HOST_STATE_FIELD;
+			return -EINVAL;
 	}
 
 	return 0;
 }
 
+static int nested_vmx_check_vmentry_prereqs(struct kvm_vcpu *vcpu,
+					    struct vmcs12 *vmcs12)
+{
+	if (vmcs12->guest_activity_state != GUEST_ACTIVITY_ACTIVE &&
+	    vmcs12->guest_activity_state != GUEST_ACTIVITY_HLT)
+		return VMXERR_ENTRY_INVALID_CONTROL_FIELD;
+
+	if (nested_check_vm_execution_controls(vcpu, vmcs12) ||
+	    nested_check_vm_exit_controls(vcpu, vmcs12) ||
+	    nested_check_vm_entry_controls(vcpu, vmcs12))
+		return VMXERR_ENTRY_INVALID_CONTROL_FIELD;
+
+	if (nested_check_host_control_regs(vcpu, vmcs12))
+		return VMXERR_ENTRY_INVALID_HOST_STATE_FIELD;
+
+	return 0;
+}
+
 static int nested_vmx_check_vmcs_link_ptr(struct kvm_vcpu *vcpu,
 					  struct vmcs12 *vmcs12)
 {