qemuDomainAttachNetDevice: Explicitly list allowed types for hotplug

Instead of blindly claim support for hot-plugging of every
interface type out there we should copy approach we have for
device types: white listing supported types and explicitly error
out on unsupported ones.
For instance, trying to hotplug vhostuser interface results in
nothing usable from guest currently. vhostuser typed interfaces
require additional work on our side.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

src/qemu/qemu_hotplug.c

@@ -970,8 +970,9 @@ qemuDomainAttachNetDevice(virQEMUDriverPtr driver,
         return -1;
     }
 
-    if (actualType == VIR_DOMAIN_NET_TYPE_BRIDGE ||
-        actualType == VIR_DOMAIN_NET_TYPE_NETWORK) {
+    switch (actualType) {
+    case VIR_DOMAIN_NET_TYPE_BRIDGE:
+    case VIR_DOMAIN_NET_TYPE_NETWORK:
         tapfdSize = vhostfdSize = net->driver.virtio.queues;
         if (!tapfdSize)
             tapfdSize = vhostfdSize = 1;
@@ -988,7 +989,9 @@ qemuDomainAttachNetDevice(virQEMUDriverPtr driver,
         if (qemuInterfaceOpenVhostNet(vm->def, net, priv->qemuCaps,
                                       vhostfd, &vhostfdSize) < 0)
             goto cleanup;
-    } else if (actualType == VIR_DOMAIN_NET_TYPE_DIRECT) {
+        break;
+
+    case VIR_DOMAIN_NET_TYPE_DIRECT:
         tapfdSize = vhostfdSize = net->driver.virtio.queues;
         if (!tapfdSize)
             tapfdSize = vhostfdSize = 1;
@@ -1006,7 +1009,9 @@ qemuDomainAttachNetDevice(virQEMUDriverPtr driver,
         if (qemuInterfaceOpenVhostNet(vm->def, net, priv->qemuCaps,
                                       vhostfd, &vhostfdSize) < 0)
             goto cleanup;
-    } else if (actualType == VIR_DOMAIN_NET_TYPE_ETHERNET) {
+        break;
+
+    case VIR_DOMAIN_NET_TYPE_ETHERNET:
         tapfdSize = vhostfdSize = net->driver.virtio.queues;
         if (!tapfdSize)
             tapfdSize = vhostfdSize = 1;
@@ -1017,13 +1022,15 @@ qemuDomainAttachNetDevice(virQEMUDriverPtr driver,
             goto cleanup;
         memset(vhostfd, -1, sizeof(*vhostfd) * vhostfdSize);
         if (qemuInterfaceEthernetConnect(vm->def, driver, net,
-                                       tapfd, tapfdSize) < 0)
+                                         tapfd, tapfdSize) < 0)
             goto cleanup;
         iface_connected = true;
         if (qemuInterfaceOpenVhostNet(vm->def, net, priv->qemuCaps,
                                       vhostfd, &vhostfdSize) < 0)
             goto cleanup;
-    } else if (actualType == VIR_DOMAIN_NET_TYPE_HOSTDEV) {
+        break;
+
+    case VIR_DOMAIN_NET_TYPE_HOSTDEV:
         /* This is really a "smart hostdev", so it should be attached
          * as a hostdev (the hostdev code will reach over into the
          * netdev-specific code as appropriate), then also added to
@@ -1035,6 +1042,20 @@ qemuDomainAttachNetDevice(virQEMUDriverPtr driver,
         ret = qemuDomainAttachHostDevice(NULL, driver, vm,
                                          virDomainNetGetActualHostdev(net));
         goto cleanup;
+        break;
+
+    case VIR_DOMAIN_NET_TYPE_USER:
+    case VIR_DOMAIN_NET_TYPE_VHOSTUSER:
+    case VIR_DOMAIN_NET_TYPE_SERVER:
+    case VIR_DOMAIN_NET_TYPE_CLIENT:
+    case VIR_DOMAIN_NET_TYPE_MCAST:
+    case VIR_DOMAIN_NET_TYPE_INTERNAL:
+    case VIR_DOMAIN_NET_TYPE_UDP:
+    case VIR_DOMAIN_NET_TYPE_LAST:
+        virReportError(VIR_ERR_OPERATION_UNSUPPORTED,
+                       _("hotplug of interface type of %s is not implemented yet"),
+                       virDomainNetTypeToString(actualType));
+        goto cleanup;
     }
 
     /* Set device online immediately */