Add QEMU support for virtio channel

Support virtio-serial controller and virtio channel in QEMU backend.
Will output
the following for virtio-serial controller:

-device
virtio-serial-pci,id=virtio-serial0,bus=pci.0,addr=0x4,max_ports=16,vectors=4

and the following for a virtio channel:

-chardev pty,id=channel0 \
-device
virtserialport,bus=virtio-serial0.0,chardev=channel0,name=org.linux-kvm.port.0

* src/qemu/qemu_conf.c: Add argument output for virtio
* tests/qemuxml2argvtest.c
  tests/qemuxml2argvdata/qemuxml2argv-channel-virtio.args: Add test for
  QEMU command line generation

src/qemu/qemu_conf.c

@@ -2180,7 +2180,6 @@ qemuAssignDevicePCISlots(virDomainDefPtr def, qemuDomainPCIAddressSetPtr addrs)
     }
     for (i = 0; i < def->nchannels ; i++) {
         /* Nada - none are PCI based (yet) */
-        /* XXX virtio-serial will need one */
     }
     if (def->watchdog &&
         def->watchdog->info.type == VIR_DOMAIN_DEVICE_ADDRESS_TYPE_NONE) {
@@ -2477,6 +2476,24 @@ qemuBuildControllerDevStr(virDomainControllerDefPtr def)
         virBufferVSprintf(&buf, ",id=scsi%d", def->idx);
         break;
 
+    case VIR_DOMAIN_CONTROLLER_TYPE_VIRTIO_SERIAL:
+        if (def->info.type == VIR_DOMAIN_DEVICE_ADDRESS_TYPE_PCI) {
+            virBufferAddLit(&buf, "virtio-serial-pci");
+        } else {
+            virBufferAddLit(&buf, "virtio-serial");
+        }
+        virBufferVSprintf(&buf, ",id=" QEMU_VIRTIO_SERIAL_PREFIX "%d",
+                          def->idx);
+        if (def->opts.vioserial.ports != -1) {
+            virBufferVSprintf(&buf, ",max_ports=%d",
+                              def->opts.vioserial.ports);
+        }
+        if (def->opts.vioserial.vectors != -1) {
+            virBufferVSprintf(&buf, ",vectors=%d",
+                              def->opts.vioserial.vectors);
+        }
+        break;
+
     /* We always get an IDE controller, whether we want it or not. */
     case VIR_DOMAIN_CONTROLLER_TYPE_IDE:
     default:
@@ -2981,6 +2998,45 @@ error:
 }
 
 
+char *
+qemuBuildVirtioSerialPortDevStr(virDomainChrDefPtr dev)
+{
+    virBuffer buf = VIR_BUFFER_INITIALIZER;
+    virBufferAddLit(&buf, "virtserialport");
+
+    if (dev->info.type != VIR_DOMAIN_DEVICE_ADDRESS_TYPE_NONE) {
+        /* Check it's a virtio-serial address */
+        if (dev->info.type !=
+            VIR_DOMAIN_DEVICE_ADDRESS_TYPE_VIRTIO_SERIAL)
+        {
+            qemuReportError(VIR_ERR_INTERNAL_ERROR,
+                            _("virtio serial device has invalid address type"));
+            goto error;
+        }
+
+        virBufferVSprintf(&buf,
+                          ",bus=" QEMU_VIRTIO_SERIAL_PREFIX "%d.%d",
+                          dev->info.addr.vioserial.controller,
+                          dev->info.addr.vioserial.bus);
+    }
+
+    virBufferVSprintf(&buf, ",chardev=%s", dev->info.alias);
+    if (dev->target.name) {
+        virBufferVSprintf(&buf, ",name=%s", dev->target.name);
+    }
+    if (virBufferError(&buf)) {
+        virReportOOMError();
+        goto error;
+    }
+
+    return virBufferContentAndReset(&buf);
+
+error:
+    virBufferFreeAndReset(&buf);
+    return NULL;
+}
+
+
 static int
 qemuBuildCpuArgStr(const struct qemud_driver *driver,
                    const virDomainDefPtr def,
@@ -3842,6 +3898,25 @@ int qemudBuildCommandLine(virConnectPtr conn,
             }
             VIR_FREE(addr);
             ADD_ARG(devstr);
+            break;
+
+        case VIR_DOMAIN_CHR_TARGET_TYPE_VIRTIO:
+            if (!(qemuCmdFlags & QEMUD_CMD_FLAG_DEVICE)) {
+                qemuReportError(VIR_ERR_NO_SUPPORT, "%s",
+                    _("virtio channel requires QEMU to support -device"));
+                goto error;
+            }
+
+            ADD_ARG_LIT("-chardev");
+            if (!(devstr = qemuBuildChrChardevStr(channel)))
+                goto error;
+            ADD_ARG(devstr);
+
+            ADD_ARG_LIT("-device");
+            if (!(devstr = qemuBuildVirtioSerialPortDevStr(channel)))
+                goto error;
+            ADD_ARG(devstr);
+            break;
         }
     }
 

src/qemu/qemu_conf.h

@@ -158,6 +158,7 @@ typedef qemuDomainPCIAddressSet *qemuDomainPCIAddressSetPtr;
 #define QEMU_CONFIG_FORMAT_ARGV "qemu-argv"
 
 #define QEMU_DRIVE_HOST_PREFIX "drive-"
+#define QEMU_VIRTIO_SERIAL_PREFIX "virtio-serial"
 
 #define qemuReportError(code, fmt...)                                   \
     virReportErrorHelper(NULL, VIR_FROM_QEMU, code, __FILE__,           \
@@ -234,6 +235,8 @@ char * qemuBuildChrChardevStr(virDomainChrDefPtr dev);
 /* Legacy, pre device support */
 char * qemuBuildChrArgStr(virDomainChrDefPtr dev, const char *prefix);
 
+char * qemuBuildVirtioSerialPortDevStr(virDomainChrDefPtr dev);
+
 /* Legacy, pre device support */
 char * qemuBuildUSBHostdevUsbDevStr(virDomainHostdevDefPtr dev);
 /* Current, best practice */

tests/qemuxml2argvdata/qemuxml2argv-channel-virtio.args

@@ -0,0 +1 @@
+LC_ALL=C PATH=/bin HOME=/home/test USER=test LOGNAME=test /usr/bin/qemu -S -M pc -m 214 -smp 1 -nographic -nodefaults -monitor unix:/tmp/test-monitor,server,nowait -no-acpi -boot c -device virtio-serial-pci,id=virtio-serial0,max_ports=16,vectors=4,bus=pci.0,addr=0x4 -device virtio-serial-pci,id=virtio-serial1,bus=pci.0,addr=0xa -hda /dev/HostVG/QEMUGuest1 -chardev pty,id=channel0 -device virtserialport,chardev=channel0,name=org.linux-kvm.port.0 -chardev pty,id=channel1 -device virtserialport,bus=virtio-serial1.0,chardev=channel1,name=org.linux-kvm.port.1 -usb -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x3

tests/qemuxml2argvtest.c

@@ -318,6 +318,7 @@ mymain(int argc, char **argv)
     DO_TEST("console-compat-chardev", QEMUD_CMD_FLAG_CHARDEV|QEMUD_CMD_FLAG_DEVICE);
 
     DO_TEST("channel-guestfwd", QEMUD_CMD_FLAG_CHARDEV|QEMUD_CMD_FLAG_DEVICE);
+    DO_TEST("channel-virtio", QEMUD_CMD_FLAG_DEVICE);
 
     DO_TEST("watchdog", 0);
     DO_TEST("watchdog-device", QEMUD_CMD_FLAG_DEVICE);