qemu: Fix networking for ARM guests

Similar to the chardev bit, ARM boards depend on the old style '-net nic'
for actually instantiating net devices. But we can't block out
-netdev altogether since it's needed for upcoming virtio support.

And add tests for working ARM XML with console, disk, and networking.

src/qemu/qemu_command.c

@@ -417,6 +417,26 @@ cleanup:
     return ret;
 }
 
+static bool
+qemuDomainSupportsNicdev(virDomainDefPtr def, virQEMUCapsPtr qemuCaps)
+{
+    if (!virQEMUCapsGet(qemuCaps, QEMU_CAPS_DEVICE))
+        return false;
+
+    /* arm boards require legacy -net nic */
+    if (def->os.arch == VIR_ARCH_ARMV7L)
+        return false;
+
+    return true;
+}
+
+static bool
+qemuDomainSupportsNetdev(virDomainDefPtr def, virQEMUCapsPtr qemuCaps)
+{
+    if (!qemuDomainSupportsNicdev(def, qemuCaps))
+        return false;
+    return virQEMUCapsGet(qemuCaps, QEMU_CAPS_NETDEV);
+}
 
 /**
  * qemuOpenVhostNet:
@@ -454,8 +474,7 @@ qemuOpenVhostNet(virDomainDefPtr def,
      * option), don't try to open the device.
      */
     if (!(virQEMUCapsGet(qemuCaps, QEMU_CAPS_VHOST_NET) &&
-          virQEMUCapsGet(qemuCaps, QEMU_CAPS_NETDEV) &&
-          virQEMUCapsGet(qemuCaps, QEMU_CAPS_DEVICE))) {
+          qemuDomainSupportsNetdev(def, qemuCaps))) {
         if (net->driver.virtio.name == VIR_DOMAIN_NET_BACKEND_TYPE_VHOST) {
             virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
                            "%s", _("vhost-net is not supported with "
@@ -7335,8 +7354,7 @@ qemuBuildInterfaceCommandLine(virCommandPtr cmd,
      *
      * NB, no support for -netdev without use of -device
      */
-    if (virQEMUCapsGet(qemuCaps, QEMU_CAPS_NETDEV) &&
-        virQEMUCapsGet(qemuCaps, QEMU_CAPS_DEVICE)) {
+    if (qemuDomainSupportsNetdev(def, qemuCaps)) {
         if (!(host = qemuBuildHostNetStr(net, driver,
                                          ',', vlan,
                                          tapfdName, tapfdSize,
@@ -7344,7 +7362,7 @@ qemuBuildInterfaceCommandLine(virCommandPtr cmd,
             goto cleanup;
         virCommandAddArgList(cmd, "-netdev", host, NULL);
     }
-    if (virQEMUCapsGet(qemuCaps, QEMU_CAPS_DEVICE)) {
+    if (qemuDomainSupportsNicdev(def, qemuCaps)) {
         bool multiqueue = tapfdSize > 1 || vhostfdSize > 1;
 
         if (!(nic = qemuBuildNicDevStr(def, net, vlan, bootindex,
@@ -7356,8 +7374,7 @@ qemuBuildInterfaceCommandLine(virCommandPtr cmd,
             goto cleanup;
         virCommandAddArgList(cmd, "-net", nic, NULL);
     }
-    if (!(virQEMUCapsGet(qemuCaps, QEMU_CAPS_NETDEV) &&
-          virQEMUCapsGet(qemuCaps, QEMU_CAPS_DEVICE))) {
+    if (!qemuDomainSupportsNetdev(def, qemuCaps)) {
         if (!(host = qemuBuildHostNetStr(net, driver,
                                          ',', vlan,
                                          tapfdName, tapfdSize,
@@ -8408,8 +8425,7 @@ qemuBuildCommandLine(virConnectPtr conn,
             int vlan;
 
             /* VLANs are not used with -netdev, so don't record them */
-            if (virQEMUCapsGet(qemuCaps, QEMU_CAPS_NETDEV) &&
-                virQEMUCapsGet(qemuCaps, QEMU_CAPS_DEVICE))
+            if (qemuDomainSupportsNetdev(def, qemuCaps))
                 vlan = -1;
             else
                 vlan = i;

src/qemu/qemu_domain.c

@@ -799,6 +799,23 @@ qemuDomainDefPostParse(virDomainDefPtr def,
     return 0;
 }
 
+static const char *
+qemuDomainDefaultNetModel(virDomainDefPtr def) {
+    if (def->os.arch == VIR_ARCH_S390 ||
+        def->os.arch == VIR_ARCH_S390X)
+        return "virtio";
+
+    if (def->os.arch == VIR_ARCH_ARMV7L) {
+        if (STREQ(def->os.machine, "versatilepb"))
+            return "smc91c111";
+
+        /* Incomplete. vexpress (and a few others) use this, but not all
+         * arm boards */
+        return "lan9118";
+    }
+
+    return "rtl8139";
+}
 
 static int
 qemuDomainDeviceDefPostParse(virDomainDeviceDefPtr dev,
@@ -814,8 +831,7 @@ qemuDomainDeviceDefPostParse(virDomainDeviceDefPtr dev,
         dev->data.net->type != VIR_DOMAIN_NET_TYPE_HOSTDEV &&
         !dev->data.net->model) {
         if (VIR_STRDUP(dev->data.net->model,
-                       def->os.arch == VIR_ARCH_S390 ||
-                       def->os.arch == VIR_ARCH_S390X ? "virtio" : "rtl8139") < 0)
+                       qemuDomainDefaultNetModel(def)) < 0)
             goto cleanup;
     }
 

tests/qemuxml2argvdata/qemuxml2argv-arm-vexpressa9-basic.args

+LC_ALL=C PATH=/bin HOME=/home/test USER=test LOGNAME=test QEMU_AUDIO_DRV=none \
+/usr/bin/qemu-system-arm -S -M vexpress-a9 -m 1024 -smp 1 -nographic \
+-nodefconfig -nodefaults -monitor unix:/tmp/test-monitor,server,nowait \
+-boot c -kernel /arm.kernel -initrd /arm.initrd -append \
+'console=ttyAMA0,115200n8 rw root=/dev/mmcblk0p3 rootwait physmap.enabled=0' \
+-dtb /arm.dtb -usb -drive file=/arm.raw,if=sd,index=0 \
+-net nic,macaddr=52:54:00:09:a4:37,vlan=0,model=lan9118,name=net0 \
+-net user,vlan=0,name=hostnet0 -serial pty

tests/qemuxml2argvdata/qemuxml2argv-arm-vexpressa9-basic.xml

+<domain type="qemu">
+  <name>armtest</name>
+  <uuid>496d7ea8-9739-544b-4ebd-ef08be936e6a</uuid>
+  <memory>1048576</memory>
+  <currentMemory>1048576</currentMemory>
+  <vcpu>1</vcpu>
+  <os>
+    <type arch="armv7l" machine="vexpress-a9">hvm</type>
+    <kernel>/arm.kernel</kernel>
+    <initrd>/arm.initrd</initrd>
+    <dtb>/arm.dtb</dtb>
+    <cmdline>console=ttyAMA0,115200n8 rw root=/dev/mmcblk0p3 rootwait physmap.enabled=0</cmdline>
+  </os>
+  <features>
+    <acpi/>
+    <apic/>
+    <pae/>
+  </features>
+  <clock offset="utc"/>
+  <on_poweroff>destroy</on_poweroff>
+  <on_reboot>restart</on_reboot>
+  <on_crash>restart</on_crash>
+  <devices>
+    <emulator>/usr/bin/qemu-system-arm</emulator>
+    <disk type='file' device='disk'>
+      <source file='/arm.raw'/>
+      <target dev='sda' bus='sd'/>
+    </disk>
+    <interface type='user'>
+      <mac address='52:54:00:09:a4:37'/>
+    </interface>
+    <console type='pty'/>
+  </devices>
+</domain>

tests/qemuxml2argvtest.c

@@ -1063,6 +1063,9 @@ mymain(void)
 
     DO_TEST("arm-vexpressa9-nodevs",
             QEMU_CAPS_DEVICE, QEMU_CAPS_NODEFCONFIG, QEMU_CAPS_DTB);
+    DO_TEST("arm-vexpressa9-basic",
+            QEMU_CAPS_DEVICE, QEMU_CAPS_NODEFCONFIG, QEMU_CAPS_DTB,
+            QEMU_CAPS_DRIVE);
 
     virObjectUnref(driver.config);
     virObjectUnref(driver.caps);