qemuBuildInterfaceCommandLine: Move vhostuser handling a bit further

The idea is to have function that does some checking of the
arguments at its beginning and then have one big switch for all
the interface types it supports. Each one of them generating the
corresponding part of the command line.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

src/qemu/qemu_command.c

@@ -7878,15 +7878,13 @@ qemuBuildInterfaceCommandLine(virCommandPtr cmd,
     if (!bootindex)
         bootindex = net->info.bootIndex;
 
-    if (actualType == VIR_DOMAIN_NET_TYPE_VHOSTUSER)
-        return qemuBuildVhostuserCommandLine(cmd, def, net, qemuCaps, bootindex);
-
     /* Currently nothing besides TAP devices supports multiqueue. */
     if (net->driver.virtio.queues > 0 &&
         !(actualType == VIR_DOMAIN_NET_TYPE_NETWORK ||
           actualType == VIR_DOMAIN_NET_TYPE_BRIDGE ||
           actualType == VIR_DOMAIN_NET_TYPE_DIRECT ||
-          actualType == VIR_DOMAIN_NET_TYPE_ETHERNET)) {
+          actualType == VIR_DOMAIN_NET_TYPE_ETHERNET ||
+          actualType == VIR_DOMAIN_NET_TYPE_VHOSTUSER)) {
         virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
                        _("Multiqueue network is not supported for: %s"),
                        virDomainNetTypeToString(actualType));
@@ -7966,6 +7964,9 @@ qemuBuildInterfaceCommandLine(virCommandPtr cmd,
          */
         ret = 0;
         goto cleanup;
+    } else if (actualType == VIR_DOMAIN_NET_TYPE_VHOSTUSER) {
+        ret = qemuBuildVhostuserCommandLine(cmd, def, net, qemuCaps, bootindex);
+        goto cleanup;
     }
 
     /* For types whose implementations use a netdev on the host, add

tests/qemuxml2argvdata/qemuxml2argv-net-vhostuser-fail.xml

+<domain type='qemu'>
+  <name>QEMUGuest1</name>
+  <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
+  <memory unit='KiB'>219136</memory>
+  <currentMemory unit='KiB'>219136</currentMemory>
+  <vcpu placement='static'>1</vcpu>
+  <os>
+    <type arch='i686' machine='pc'>hvm</type>
+    <boot dev='hd'/>
+  </os>
+  <clock offset='utc'/>
+  <on_poweroff>destroy</on_poweroff>
+  <on_reboot>restart</on_reboot>
+  <on_crash>destroy</on_crash>
+  <devices>
+    <emulator>/usr/bin/qemu</emulator>
+    <disk type='block' device='disk'>
+      <driver name='qemu' type='raw'/>
+      <source dev='/dev/HostVG/QEMUGuest1'/>
+      <target dev='hda' bus='ide'/>
+      <address type='drive' controller='0' bus='0' target='0' unit='0'/>
+    </disk>
+    <controller type='usb' index='0'/>
+    <controller type='ide' index='0'/>
+    <controller type='pci' index='0' model='pci-root'/>
+    <interface type='vhostuser'>
+      <mac address='52:54:00:ee:96:6b'/>
+      <source type='unix' path='/tmp/vhost0.sock' mode='server'/>
+      <model type='virtio'/>
+      <filterref filter='myfilter'/>
+      <backend tap='/dev/mytap'/>
+      <driver queues='4'/>
+    </interface>
+    <memballoon model='none'/>
+  </devices>
+</domain>

tests/qemuxml2argvtest.c

@@ -1071,6 +1071,9 @@ mymain(void)
     DO_TEST("net-vhostuser-multiq",
             QEMU_CAPS_NETDEV, QEMU_CAPS_VHOSTUSER_MULTIQUEUE);
     DO_TEST_FAILURE("net-vhostuser-multiq", QEMU_CAPS_NETDEV);
+    DO_TEST_FAILURE("net-vhostuser-fail",
+                    QEMU_CAPS_NETDEV,
+                    QEMU_CAPS_VHOSTUSER_MULTIQUEUE);
     DO_TEST("net-user", NONE);
     DO_TEST("net-virtio", NONE);
     DO_TEST("net-virtio-device",