KVM: nSVM: split nested_vmcb_check_controls

The authoritative state does not come from the VMCB once in guest mode,
but KVM_SET_NESTED_STATE can still perform checks on L1's provided SVM
controls because we get them from userspace.

Therefore, split out a function to do them.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/svm/nested.c

@@ -203,26 +203,31 @@ static bool nested_svm_vmrun_msrpm(struct vcpu_svm *svm)
 	return true;
 }
 
-static bool nested_vmcb_checks(struct vmcb *vmcb)
+static bool nested_vmcb_check_controls(struct vmcb_control_area *control)
 {
-	if ((vmcb->save.efer & EFER_SVME) == 0)
+	if ((control->intercept & (1ULL << INTERCEPT_VMRUN)) == 0)
 		return false;
 
-	if (((vmcb->save.cr0 & X86_CR0_CD) == 0) &&
-	    (vmcb->save.cr0 & X86_CR0_NW))
+	if (control->asid == 0)
 		return false;
 
-	if ((vmcb->control.intercept & (1ULL << INTERCEPT_VMRUN)) == 0)
+	if ((control->nested_ctl & SVM_NESTED_CTL_NP_ENABLE) &&
+	    !npt_enabled)
 		return false;
 
-	if (vmcb->control.asid == 0)
+	return true;
+}
+
+static bool nested_vmcb_checks(struct vmcb *vmcb)
+{
+	if ((vmcb->save.efer & EFER_SVME) == 0)
 		return false;
 
-	if ((vmcb->control.nested_ctl & SVM_NESTED_CTL_NP_ENABLE) &&
-	    !npt_enabled)
+	if (((vmcb->save.cr0 & X86_CR0_CD) == 0) &&
+	    (vmcb->save.cr0 & X86_CR0_NW))
 		return false;
 
-	return true;
+	return nested_vmcb_check_controls(&vmcb->control);
 }
 
 static void load_nested_vmcb_control(struct vcpu_svm *svm,