qemu: Unify generation of command line for virtio devices

A virtio device such as

  <controller type='scsi' model='virtio-scsi'/>

will be translated to one of four different QEMU devices
based on the address type. This behavior is the same for
all virtio devices, but unfortunately we have separate
ad-hoc code dealing with each and every one of them: not
only this is pointless duplication, but it turns out
that most of that code is not robust against new address
types being introduced and some of it is outright buggy.

Introduce a new function, qemuBuildVirtioDevStr(), which
deals with the issue in a generic fashion, and rewrite
all existing code to use it.

This fixes a bunch of issues such as virtio-serial-pci
being used with virtio-mmio addresses and virtio-gpu
not being usable at all with virtio-mmio addresses.

It also introduces a couple of minor regressions,
namely no longer erroring out when attempting to
use virtio-balloon and virtio-input devices with
virtio-s390 addresses; that said, virtio-s390 has
been superseded by virtio-ccw such a long time ago
that recent QEMU releases have dropped support for
the former entirely, so re-implementing such
device-specific validation is not worth it.
Signed-off-by: NAndrea Bolognani <abologna@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

src/qemu/qemu_command.c

@@ -397,6 +397,55 @@ qemuBuildDeviceAddressStr(virBufferPtr buf,
     return ret;
 }
 
+
+static int
+qemuBuildVirtioDevStr(virBufferPtr buf,
+                      const char *baseName,
+                      virDomainDeviceAddressType type)
+{
+    const char *implName = NULL;
+
+    switch (type) {
+    case VIR_DOMAIN_DEVICE_ADDRESS_TYPE_PCI:
+        implName = "pci";
+        break;
+
+    case VIR_DOMAIN_DEVICE_ADDRESS_TYPE_VIRTIO_MMIO:
+        implName = "device";
+        break;
+
+    case VIR_DOMAIN_DEVICE_ADDRESS_TYPE_CCW:
+        implName = "ccw";
+        break;
+
+    case VIR_DOMAIN_DEVICE_ADDRESS_TYPE_VIRTIO_S390:
+        implName = "s390";
+        break;
+
+    case VIR_DOMAIN_DEVICE_ADDRESS_TYPE_DRIVE:
+    case VIR_DOMAIN_DEVICE_ADDRESS_TYPE_VIRTIO_SERIAL:
+    case VIR_DOMAIN_DEVICE_ADDRESS_TYPE_CCID:
+    case VIR_DOMAIN_DEVICE_ADDRESS_TYPE_USB:
+    case VIR_DOMAIN_DEVICE_ADDRESS_TYPE_SPAPRVIO:
+    case VIR_DOMAIN_DEVICE_ADDRESS_TYPE_ISA:
+    case VIR_DOMAIN_DEVICE_ADDRESS_TYPE_DIMM:
+        virReportError(VIR_ERR_INTERNAL_ERROR,
+                       _("Unexpected address type for '%s'"), baseName);
+        return -1;
+
+    case VIR_DOMAIN_DEVICE_ADDRESS_TYPE_NONE:
+    case VIR_DOMAIN_DEVICE_ADDRESS_TYPE_LAST:
+    default:
+        virReportEnumRangeError(virDomainDeviceAddressType, type);
+        return -1;
+    }
+
+    virBufferAsprintf(buf, "%s-%s", baseName, implName);
+
+    return 0;
+}
+
+
 static int
 qemuBuildVirtioOptionsStr(virBufferPtr buf,
                           virDomainVirtioOptionsPtr virtio,
@@ -2002,17 +2051,8 @@ qemuBuildDiskDeviceStr(const virDomainDef *def,
         break;
 
     case VIR_DOMAIN_DISK_BUS_VIRTIO:
-        if (disk->info.type == VIR_DOMAIN_DEVICE_ADDRESS_TYPE_CCW) {
-            virBufferAddLit(&opt, "virtio-blk-ccw");
-        } else if (disk->info.type ==
-                   VIR_DOMAIN_DEVICE_ADDRESS_TYPE_VIRTIO_S390) {
-            virBufferAddLit(&opt, "virtio-blk-s390");
-        } else if (disk->info.type ==
-                   VIR_DOMAIN_DEVICE_ADDRESS_TYPE_VIRTIO_MMIO) {
-            virBufferAddLit(&opt, "virtio-blk-device");
-        } else {
-            virBufferAddLit(&opt, "virtio-blk-pci");
-        }
+        if (qemuBuildVirtioDevStr(&opt, "virtio-blk", disk->info.type) < 0)
+            goto error;
 
         if (disk->iothread)
             virBufferAsprintf(&opt, ",iothread=iothread%u", disk->iothread);
@@ -2546,10 +2586,8 @@ qemuBuildFSDevStr(const virDomainDef *def,
         goto error;
     }
 
-    if (fs->info.type == VIR_DOMAIN_DEVICE_ADDRESS_TYPE_CCW)
-        virBufferAddLit(&opt, "virtio-9p-ccw");
-    else
-        virBufferAddLit(&opt, "virtio-9p-pci");
+    if (qemuBuildVirtioDevStr(&opt, "virtio-9p", fs->info.type) < 0)
+        goto error;
 
     virBufferAsprintf(&opt, ",id=%s", fs->info.alias);
     virBufferAsprintf(&opt, ",fsdev=%s%s",
@@ -2744,7 +2782,6 @@ qemuBuildControllerDevStr(const virDomainDef *domainDef,
                           int *nusbcontroller)
 {
     virBuffer buf = VIR_BUFFER_INITIALIZER;
-    int address_type = def->info.type;
 
     *devstr = NULL;
 
@@ -2752,19 +2789,8 @@ qemuBuildControllerDevStr(const virDomainDef *domainDef,
     case VIR_DOMAIN_CONTROLLER_TYPE_SCSI:
         switch ((virDomainControllerModelSCSI) def->model) {
         case VIR_DOMAIN_CONTROLLER_MODEL_SCSI_VIRTIO_SCSI:
-            switch (address_type) {
-            case VIR_DOMAIN_DEVICE_ADDRESS_TYPE_CCW:
-                virBufferAddLit(&buf, "virtio-scsi-ccw");
-                break;
-            case VIR_DOMAIN_DEVICE_ADDRESS_TYPE_VIRTIO_S390:
-                virBufferAddLit(&buf, "virtio-scsi-s390");
-                break;
-            case VIR_DOMAIN_DEVICE_ADDRESS_TYPE_VIRTIO_MMIO:
-                virBufferAddLit(&buf, "virtio-scsi-device");
-                break;
-            default:
-                virBufferAddLit(&buf, "virtio-scsi-pci");
-            }
+            if (qemuBuildVirtioDevStr(&buf, "virtio-scsi", def->info.type) < 0)
+                goto error;
 
             if (def->iothread) {
                 virBufferAsprintf(&buf, ",iothread=iothread%u",
@@ -2804,22 +2830,9 @@ qemuBuildControllerDevStr(const virDomainDef *domainDef,
         break;
 
     case VIR_DOMAIN_CONTROLLER_TYPE_VIRTIO_SERIAL:
-        switch (address_type) {
-        case VIR_DOMAIN_DEVICE_ADDRESS_TYPE_PCI:
-            virBufferAddLit(&buf, "virtio-serial-pci");
-            break;
-        case VIR_DOMAIN_DEVICE_ADDRESS_TYPE_CCW:
-            virBufferAddLit(&buf, "virtio-serial-ccw");
-            break;
-        case VIR_DOMAIN_DEVICE_ADDRESS_TYPE_VIRTIO_S390:
-            virBufferAddLit(&buf, "virtio-serial-s390");
-            break;
-        case VIR_DOMAIN_DEVICE_ADDRESS_TYPE_VIRTIO_MMIO:
-            virBufferAddLit(&buf, "virtio-serial-device");
-            break;
-        default:
-            virBufferAddLit(&buf, "virtio-serial");
-        }
+        if (qemuBuildVirtioDevStr(&buf, "virtio-serial", def->info.type) < 0)
+            goto error;
+
         virBufferAsprintf(&buf, ",id=%s", def->info.alias);
         if (def->opts.vioserial.ports != -1) {
             virBufferAsprintf(&buf, ",max_ports=%d",
@@ -3517,24 +3530,18 @@ qemuBuildNicDevStr(virDomainDefPtr def,
                    virQEMUCapsPtr qemuCaps)
 {
     virBuffer buf = VIR_BUFFER_INITIALIZER;
-    const char *nic = net->model;
     bool usingVirtio = false;
     char macaddr[VIR_MAC_STRING_BUFLEN];
 
     if (STREQ(net->model, "virtio")) {
-        if (net->info.type == VIR_DOMAIN_DEVICE_ADDRESS_TYPE_CCW)
-            nic = "virtio-net-ccw";
-        else if (net->info.type == VIR_DOMAIN_DEVICE_ADDRESS_TYPE_VIRTIO_S390)
-            nic = "virtio-net-s390";
-        else if (net->info.type == VIR_DOMAIN_DEVICE_ADDRESS_TYPE_VIRTIO_MMIO)
-            nic = "virtio-net-device";
-        else
-            nic = "virtio-net-pci";
+        if (qemuBuildVirtioDevStr(&buf, "virtio-net", net->info.type) < 0)
+            goto error;
 
         usingVirtio = true;
+    } else {
+        virBufferAddStr(&buf, net->model);
     }
 
-    virBufferAdd(&buf, nic, -1);
     if (usingVirtio && net->driver.virtio.txmode) {
         if (virQEMUCapsGet(qemuCaps, QEMU_CAPS_VIRTIO_TX_ALG)) {
             virBufferAddLit(&buf, ",tx=");
@@ -3929,21 +3936,9 @@ qemuBuildMemballoonCommandLine(virCommandPtr cmd,
         return -1;
     }
 
-    switch (def->memballoon->info.type) {
-        case VIR_DOMAIN_DEVICE_ADDRESS_TYPE_PCI:
-            virBufferAddLit(&buf, "virtio-balloon-pci");
-            break;
-        case VIR_DOMAIN_DEVICE_ADDRESS_TYPE_CCW:
-            virBufferAddLit(&buf, "virtio-balloon-ccw");
-            break;
-        case VIR_DOMAIN_DEVICE_ADDRESS_TYPE_VIRTIO_MMIO:
-            virBufferAddLit(&buf, "virtio-balloon-device");
-            break;
-        default:
-            virReportError(VIR_ERR_XML_ERROR,
-                           _("memballoon unsupported with address type '%s'"),
-                           virDomainDeviceAddressTypeToString(def->memballoon->info.type));
-            goto error;
+    if (qemuBuildVirtioDevStr(&buf, "virtio-balloon",
+                              def->memballoon->info.type) < 0) {
+        goto error;
     }
 
     virBufferAsprintf(&buf, ",id=%s", def->memballoon->info.alias);
@@ -4040,33 +4035,23 @@ qemuBuildVirtioInputDevStr(const virDomainDef *def,
                            virQEMUCapsPtr qemuCaps)
 {
     virBuffer buf = VIR_BUFFER_INITIALIZER;
-    const char *suffix;
-
-    if (dev->info.type == VIR_DOMAIN_DEVICE_ADDRESS_TYPE_PCI) {
-        suffix = "-pci";
-    } else if (dev->info.type == VIR_DOMAIN_DEVICE_ADDRESS_TYPE_CCW) {
-        suffix = "-ccw";
-    } else if (dev->info.type == VIR_DOMAIN_DEVICE_ADDRESS_TYPE_VIRTIO_MMIO) {
-        suffix = "-device";
-    } else {
-        virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
-                       _("unsupported address type %s for virtio input device"),
-                       virDomainDeviceAddressTypeToString(dev->info.type));
-        goto error;
-    }
 
     switch ((virDomainInputType)dev->type) {
     case VIR_DOMAIN_INPUT_TYPE_MOUSE:
-        virBufferAsprintf(&buf, "virtio-mouse%s", suffix);
+        if (qemuBuildVirtioDevStr(&buf, "virtio-mouse", dev->info.type) < 0)
+            goto error;
         break;
     case VIR_DOMAIN_INPUT_TYPE_TABLET:
-        virBufferAsprintf(&buf, "virtio-tablet%s", suffix);
+        if (qemuBuildVirtioDevStr(&buf, "virtio-tablet", dev->info.type) < 0)
+            goto error;
         break;
     case VIR_DOMAIN_INPUT_TYPE_KBD:
-        virBufferAsprintf(&buf, "virtio-keyboard%s", suffix);
+        if (qemuBuildVirtioDevStr(&buf, "virtio-keyboard", dev->info.type) < 0)
+            goto error;
         break;
     case VIR_DOMAIN_INPUT_TYPE_PASSTHROUGH:
-        virBufferAsprintf(&buf, "virtio-input-host%s", suffix);
+        if (qemuBuildVirtioDevStr(&buf, "virtio-input-host", dev->info.type) < 0)
+            goto error;
         break;
     case VIR_DOMAIN_INPUT_TYPE_LAST:
     default:
@@ -4378,10 +4363,8 @@ qemuBuildDeviceVideoStr(const virDomainDef *def,
     }
 
     if (STREQ(model, "virtio-gpu")) {
-        if (video->info.type == VIR_DOMAIN_DEVICE_ADDRESS_TYPE_CCW)
-            virBufferAsprintf(&buf, "%s-ccw", model);
-        else
-            virBufferAsprintf(&buf, "%s-pci", model);
+        if (qemuBuildVirtioDevStr(&buf, "virtio-gpu", video->info.type) < 0)
+            goto error;
     } else {
         virBufferAsprintf(&buf, "%s", model);
     }
@@ -5812,14 +5795,8 @@ qemuBuildRNGDevStr(const virDomainDef *def,
                                               dev->source.file))
         goto error;
 
-    if (dev->info.type == VIR_DOMAIN_DEVICE_ADDRESS_TYPE_CCW)
-        virBufferAddLit(&buf, "virtio-rng-ccw");
-    else if (dev->info.type == VIR_DOMAIN_DEVICE_ADDRESS_TYPE_VIRTIO_S390)
-        virBufferAddLit(&buf, "virtio-rng-s390");
-    else if (dev->info.type == VIR_DOMAIN_DEVICE_ADDRESS_TYPE_VIRTIO_MMIO)
-        virBufferAddLit(&buf, "virtio-rng-device");
-    else
-        virBufferAddLit(&buf, "virtio-rng-pci");
+    if (qemuBuildVirtioDevStr(&buf, "virtio-rng", dev->info.type) < 0)
+        goto error;
 
     virBufferAsprintf(&buf, ",rng=obj%s,id=%s",
                       dev->info.alias, dev->info.alias);