qemu: Fix switch() statements for virDomainIOMMUModel

Ensure unexpected values are dealt with correctly, that
is by invoking virReportEnumRangeError() and immediately
returning a negative value to the caller.
Signed-off-by: NAndrea Bolognani <abologna@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

src/qemu/qemu_command.c

@@ -6961,8 +6961,12 @@ qemuBuildIOMMUCommandLine(virCommandPtr cmd,
             virBufferAsprintf(&opts, ",device-iotlb=%s",
                               virTristateSwitchTypeToString(iommu->iotlb));
         }
-    case VIR_DOMAIN_IOMMU_MODEL_LAST:
         break;
+
+    case VIR_DOMAIN_IOMMU_MODEL_LAST:
+    default:
+        virReportEnumRangeError(virDomainIOMMUModel, iommu->model);
+        return -1;
     }
     virCommandAddArg(cmd, "-device");
     virCommandAddArgBuffer(cmd, &opts);
@@ -7609,7 +7613,9 @@ qemuBuildMachineCommandLine(virCommandPtr cmd,
             virBufferAddLit(&buf, ",iommu=on");
             break;
         case VIR_DOMAIN_IOMMU_MODEL_LAST:
-            break;
+        default:
+            virReportEnumRangeError(virDomainIOMMUModel, def->iommu->model);
+            return -1;
         }
     }
 

src/qemu/qemu_domain.c

@@ -6138,6 +6138,7 @@ qemuDomainDeviceDefValidateIOMMU(const virDomainIOMMUDef *iommu,
     case VIR_DOMAIN_IOMMU_MODEL_LAST:
     default:
         virReportEnumRangeError(virDomainIOMMUModel, iommu->model);
+        return -1;
     }
 
     return 0;