KVM: SVM: handle errors in vmrun emulation path appropriatly

If nested svm fails to load the msrpm the vmrun succeeds with the old
msrpm which is not correct. This patch changes the logic to roll back
to host mode in case the msrpm cannot be loaded.
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

arch/x86/kvm/svm.c

@@ -1874,6 +1874,7 @@ static int vmsave_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
 static int vmrun_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
 {
 	nsvm_printk("VMrun\n");
+
 	if (nested_svm_check_permissions(svm))
 		return 1;
 
@@ -1884,8 +1885,19 @@ static int vmrun_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
 		return 1;
 
 	if (!nested_svm_vmrun_msrpm(svm))
+		goto failed;
+
 	return 1;
 
+failed:
+
+	svm->vmcb->control.exit_code    = SVM_EXIT_ERR;
+	svm->vmcb->control.exit_code_hi = 0;
+	svm->vmcb->control.exit_info_1  = 0;
+	svm->vmcb->control.exit_info_2  = 0;
+
+	nested_svm_vmexit(svm);
+
 	return 1;
 }