Introduce device aliases

This patch introduces the support for giving all devices a short,
unique name, henceforth known as a 'device alias'.  These aliases
are not set by the end user, instead being assigned by the hypervisor
if it decides it want to support this concept.

The QEMU driver sets them whenever using the -device arg syntax
and uses them for improved hotplug/hotunplug. it is the intent
that other APIs (block / interface stats & device hotplug) be
able to accept device alias names in the future.

The XML syntax is

   <alias name="video0"/>

This may appear in any type of device that supports device info.

* src/conf/domain_conf.c, src/conf/domain_conf.h: Add a 'alias'
  field to virDomainDeviceInfo struct & parse/format it in XML
* src/libvirt_private.syms: Export virDomainDefClearDeviceAliases
* src/qemu/qemu_conf.c: Replace use of "nic_name" field with the
  standard device alias
* src/qemu/qemu_driver.c: Clear device aliases at shutdown

src/conf/domain_conf.c

@@ -806,50 +806,61 @@ int virDomainDeviceInfoIsSet(virDomainDeviceInfoPtr info)
 {
     if (info->type != VIR_DOMAIN_DEVICE_ADDRESS_TYPE_NONE)
         return 1;
+    if (info->alias)
+        return 1;
     return 0;
 }
 
 
 void virDomainDeviceInfoClear(virDomainDeviceInfoPtr info)
 {
+    VIR_FREE(info->alias);
     memset(&info->addr, 0, sizeof(info->addr));
     info->type = VIR_DOMAIN_DEVICE_ADDRESS_TYPE_NONE;
 }
 
 
-static void virDomainDeviceInfoClearField(virDomainDeviceInfoPtr info)
+static void virDomainDeviceInfoClearField(virDomainDeviceInfoPtr info, int alias, int pciaddr)
 {
-    if (info->type == VIR_DOMAIN_DEVICE_ADDRESS_TYPE_PCI) {
+    if (alias)
+        VIR_FREE(info->alias);
+    if (pciaddr &&
+        info->type == VIR_DOMAIN_DEVICE_ADDRESS_TYPE_PCI) {
         memset(&info->addr, 0, sizeof(info->addr));
         info->type = VIR_DOMAIN_DEVICE_ADDRESS_TYPE_NONE;
     }
 }
 
 
-static void virDomainDefClearDeviceInfo(virDomainDefPtr def)
+static void virDomainDefClearDeviceInfo(virDomainDefPtr def, int alias, int pciaddr)
 {
     int i;
 
     for (i = 0; i < def->ndisks ; i++)
-        virDomainDeviceInfoClearField(&def->disks[i]->info);
+        virDomainDeviceInfoClearField(&def->disks[i]->info, alias, pciaddr);
     for (i = 0; i < def->nnets ; i++)
-        virDomainDeviceInfoClearField(&def->nets[i]->info);
+        virDomainDeviceInfoClearField(&def->nets[i]->info, alias, pciaddr);
     for (i = 0; i < def->nsounds ; i++)
-        virDomainDeviceInfoClearField(&def->sounds[i]->info);
+        virDomainDeviceInfoClearField(&def->sounds[i]->info, alias, pciaddr);
     for (i = 0; i < def->nhostdevs ; i++)
-        virDomainDeviceInfoClearField(&def->hostdevs[i]->info);
+        virDomainDeviceInfoClearField(&def->hostdevs[i]->info, alias, pciaddr);
     for (i = 0; i < def->nvideos ; i++)
-            virDomainDeviceInfoClearField(&def->videos[i]->info);
+            virDomainDeviceInfoClearField(&def->videos[i]->info, alias, pciaddr);
     for (i = 0; i < def->ncontrollers ; i++)
-            virDomainDeviceInfoClearField(&def->controllers[i]->info);
+            virDomainDeviceInfoClearField(&def->controllers[i]->info, alias, pciaddr);
     if (def->watchdog)
-        virDomainDeviceInfoClearField(&def->watchdog->info);
+        virDomainDeviceInfoClearField(&def->watchdog->info, alias, pciaddr);
 }
 
 
 void virDomainDefClearPCIAddresses(virDomainDefPtr def)
 {
-    virDomainDefClearDeviceInfo(def);
+    virDomainDefClearDeviceInfo(def, 0, 1);
+}
+
+void virDomainDefClearDeviceAliases(virDomainDefPtr def)
+{
+    virDomainDefClearDeviceInfo(def, 1, 0);
 }
 
 
@@ -857,7 +868,8 @@ void virDomainDefClearPCIAddresses(virDomainDefPtr def)
  * @param address Device address to stringify
  */
 static int virDomainDeviceInfoFormat(virBufferPtr buf,
-                                     virDomainDeviceInfoPtr info)
+                                     virDomainDeviceInfoPtr info,
+                                     int flags)
 {
     if (!info) {
         virDomainReportError(NULL, VIR_ERR_INTERNAL_ERROR, "%s",
@@ -865,6 +877,11 @@ static int virDomainDeviceInfoFormat(virBufferPtr buf,
         return -1;
     }
 
+    if (info->alias &&
+        !(flags & VIR_DOMAIN_XML_INACTIVE)) {
+        virBufferVSprintf(buf, "      <alias name='%s'/>\n", info->alias);
+    }
+
     if (info->type == VIR_DOMAIN_DEVICE_ADDRESS_TYPE_NONE)
         return 0;
 
@@ -1044,10 +1061,11 @@ static int
 virDomainDeviceInfoParseXML(virConnectPtr conn,
                             xmlNodePtr node,
                             virDomainDeviceInfoPtr info,
-                            unsigned int flags ATTRIBUTE_UNUSED)
+                            int flags)
 {
     xmlNodePtr cur;
     xmlNodePtr address = NULL;
+    xmlNodePtr alias = NULL;
     char *type = NULL;
     int ret = -1;
 
@@ -1056,14 +1074,21 @@ virDomainDeviceInfoParseXML(virConnectPtr conn,
     cur = node->children;
     while (cur != NULL) {
         if (cur->type == XML_ELEMENT_NODE) {
-            if (address == NULL &&
-                xmlStrEqual(cur->name, BAD_CAST "address")) {
+            if (alias == NULL &&
+                !(flags & VIR_DOMAIN_XML_INACTIVE) &&
+                xmlStrEqual(cur->name, BAD_CAST "alias")) {
+                alias = cur;
+            } else if (address == NULL &&
+                       xmlStrEqual(cur->name, BAD_CAST "address")) {
                 address = cur;
             }
         }
         cur = cur->next;
     }
 
+    if (alias)
+        info->alias = virXMLPropString(alias, "name");
+
     if (!address)
         return 0;
 
@@ -1102,6 +1127,8 @@ virDomainDeviceInfoParseXML(virConnectPtr conn,
     ret = 0;
 
 cleanup:
+    if (ret == -1)
+        VIR_FREE(info->alias);
     VIR_FREE(type);
     return ret;
 }
@@ -1666,6 +1693,8 @@ virDomainNetDefParseXML(virConnectPtr conn,
             goto error;
         }
         def->info.type = VIR_DOMAIN_DEVICE_ADDRESS_TYPE_PCI;
+        def->info.alias = nic_name;
+        nic_name = NULL;
     } else {
         if (virDomainDeviceInfoParseXML(conn, node, &def->info, flags) < 0)
             goto error;
@@ -1680,9 +1709,8 @@ virDomainNetDefParseXML(virConnectPtr conn,
         goto error;
     }
 
-    def->nic_name = nic_name;
     def->hostnet_name = hostnet_name;
-    nic_name = hostnet_name = NULL;
+    hostnet_name = NULL;
 
     def->vlan = -1;
     if (vlan && virStrToLong_i(vlan, NULL, 10, &def->vlan) < 0) {
@@ -2930,6 +2958,10 @@ virDomainHostdevDefParseXML(virConnectPtr conn,
                         if (virDomainHostdevSubsysPciDefParseXML(conn, cur, def, flags) < 0)
                             goto error;
                 }
+            } else if (xmlStrEqual(cur->name, BAD_CAST "address")) {
+            } else {
+                virDomainReportError(conn, VIR_ERR_INTERNAL_ERROR,
+                                     _("unknown node %s"), cur->name);
             }
         }
         cur = cur->next;
@@ -4499,7 +4531,8 @@ virDomainLifecycleDefFormat(virConnectPtr conn,
 static int
 virDomainDiskDefFormat(virConnectPtr conn,
                        virBufferPtr buf,
-                       virDomainDiskDefPtr def)
+                       virDomainDiskDefPtr def,
+                       int flags)
 {
     const char *type = virDomainDiskTypeToString(def->type);
     const char *device = virDomainDiskDeviceTypeToString(def->device);
@@ -4576,7 +4609,7 @@ virDomainDiskDefFormat(virConnectPtr conn,
         virStorageEncryptionFormat(conn, buf, def->encryption) < 0)
         return -1;
 
-    if (virDomainDeviceInfoFormat(buf, &def->info) < 0)
+    if (virDomainDeviceInfoFormat(buf, &def->info, flags) < 0)
         return -1;
 
     virBufferAddLit(buf, "    </disk>\n");
@@ -4587,7 +4620,8 @@ virDomainDiskDefFormat(virConnectPtr conn,
 static int
 virDomainControllerDefFormat(virConnectPtr conn,
                              virBufferPtr buf,
-                             virDomainControllerDefPtr def)
+                             virDomainControllerDefPtr def,
+                             int flags)
 {
     const char *type = virDomainControllerTypeToString(def->type);
 
@@ -4603,7 +4637,7 @@ virDomainControllerDefFormat(virConnectPtr conn,
 
     if (virDomainDeviceInfoIsSet(&def->info)) {
         virBufferAddLit(buf, ">\n");
-        if (virDomainDeviceInfoFormat(buf, &def->info) < 0)
+        if (virDomainDeviceInfoFormat(buf, &def->info, flags) < 0)
             return -1;
         virBufferAddLit(buf, "    </controller>\n");
     } else {
@@ -4749,7 +4783,7 @@ virDomainNetDefFormat(virConnectPtr conn,
         virBufferAddLit(buf, "/>\n");
     }
 
-    if (virDomainDeviceInfoFormat(buf, &def->info) < 0)
+    if (virDomainDeviceInfoFormat(buf, &def->info, flags) < 0)
         return -1;
 
     virBufferAddLit(buf, "    </interface>\n");
@@ -4912,7 +4946,8 @@ cleanup:
 static int
 virDomainSoundDefFormat(virConnectPtr conn,
                         virBufferPtr buf,
-                        virDomainSoundDefPtr def)
+                        virDomainSoundDefPtr def,
+                        int flags)
 {
     const char *model = virDomainSoundModelTypeToString(def->model);
 
@@ -4927,7 +4962,7 @@ virDomainSoundDefFormat(virConnectPtr conn,
 
     if (virDomainDeviceInfoIsSet(&def->info)) {
         virBufferAddLit(buf, ">\n");
-        if (virDomainDeviceInfoFormat(buf, &def->info) < 0)
+        if (virDomainDeviceInfoFormat(buf, &def->info, flags) < 0)
             return -1;
         virBufferAddLit(buf, "    </sound>\n");
     } else {
@@ -4941,7 +4976,8 @@ virDomainSoundDefFormat(virConnectPtr conn,
 static int
 virDomainWatchdogDefFormat(virConnectPtr conn,
                            virBufferPtr buf,
-                           virDomainWatchdogDefPtr def)
+                           virDomainWatchdogDefPtr def,
+                           int flags)
 {
     const char *model = virDomainWatchdogModelTypeToString (def->model);
     const char *action = virDomainWatchdogActionTypeToString (def->action);
@@ -4963,7 +4999,7 @@ virDomainWatchdogDefFormat(virConnectPtr conn,
 
     if (virDomainDeviceInfoIsSet(&def->info)) {
         virBufferAddLit(buf, ">\n");
-        if (virDomainDeviceInfoFormat(buf, &def->info) < 0)
+        if (virDomainDeviceInfoFormat(buf, &def->info, flags) < 0)
             return -1;
         virBufferAddLit(buf, "    </watchdog>\n");
     } else {
@@ -4989,7 +5025,8 @@ virDomainVideoAccelDefFormat(virBufferPtr buf,
 static int
 virDomainVideoDefFormat(virConnectPtr conn,
                         virBufferPtr buf,
-                        virDomainVideoDefPtr def)
+                        virDomainVideoDefPtr def,
+                        int flags)
 {
     const char *model = virDomainVideoTypeToString(def->type);
 
@@ -5014,7 +5051,7 @@ virDomainVideoDefFormat(virConnectPtr conn,
         virBufferAddLit(buf, "/>\n");
     }
 
-    if (virDomainDeviceInfoFormat(buf, &def->info) < 0)
+    if (virDomainDeviceInfoFormat(buf, &def->info, flags) < 0)
         return -1;
 
     virBufferAddLit(buf, "    </video>\n");
@@ -5146,7 +5183,8 @@ virDomainGraphicsDefFormat(virConnectPtr conn,
 static int
 virDomainHostdevDefFormat(virConnectPtr conn,
                           virBufferPtr buf,
-                          virDomainHostdevDefPtr def)
+                          virDomainHostdevDefPtr def,
+                          int flags)
 {
     const char *mode = virDomainHostdevModeTypeToString(def->mode);
     const char *type;
@@ -5190,7 +5228,7 @@ virDomainHostdevDefFormat(virConnectPtr conn,
 
     virBufferAddLit(buf, "      </source>\n");
 
-    if (virDomainDeviceInfoFormat(buf, &def->info) < 0)
+    if (virDomainDeviceInfoFormat(buf, &def->info, flags) < 0)
         return -1;
 
     virBufferAddLit(buf, "    </hostdev>\n");
@@ -5357,11 +5395,11 @@ char *virDomainDefFormat(virConnectPtr conn,
                               def->emulator);
 
     for (n = 0 ; n < def->ndisks ; n++)
-        if (virDomainDiskDefFormat(conn, &buf, def->disks[n]) < 0)
+        if (virDomainDiskDefFormat(conn, &buf, def->disks[n], flags) < 0)
             goto cleanup;
 
     for (n = 0 ; n < def->ncontrollers ; n++)
-        if (virDomainControllerDefFormat(conn, &buf, def->controllers[n]) < 0)
+        if (virDomainControllerDefFormat(conn, &buf, def->controllers[n], flags) < 0)
             goto cleanup;
 
     for (n = 0 ; n < def->nfss ; n++)
@@ -5421,19 +5459,19 @@ char *virDomainDefFormat(virConnectPtr conn,
     }
 
     for (n = 0 ; n < def->nsounds ; n++)
-        if (virDomainSoundDefFormat(conn, &buf, def->sounds[n]) < 0)
+        if (virDomainSoundDefFormat(conn, &buf, def->sounds[n], flags) < 0)
             goto cleanup;
 
     for (n = 0 ; n < def->nvideos ; n++)
-        if (virDomainVideoDefFormat(conn, &buf, def->videos[n]) < 0)
+        if (virDomainVideoDefFormat(conn, &buf, def->videos[n], flags) < 0)
             goto cleanup;
 
     for (n = 0 ; n < def->nhostdevs ; n++)
-        if (virDomainHostdevDefFormat(conn, &buf, def->hostdevs[n]) < 0)
+        if (virDomainHostdevDefFormat(conn, &buf, def->hostdevs[n], flags) < 0)
             goto cleanup;
 
     if (def->watchdog)
-        virDomainWatchdogDefFormat (conn, &buf, def->watchdog);
+        virDomainWatchdogDefFormat (conn, &buf, def->watchdog, flags);
 
     virBufferAddLit(&buf, "  </devices>\n");
 

src/conf/domain_conf.h

@@ -92,6 +92,7 @@ struct _virDomainDeviceDriveAddress {
 typedef struct _virDomainDeviceInfo virDomainDeviceInfo;
 typedef virDomainDeviceInfo *virDomainDeviceInfoPtr;
 struct _virDomainDeviceInfo {
+    char *alias;
     int type;
     union {
         virDomainDevicePCIAddress pci;
@@ -246,8 +247,6 @@ struct _virDomainNetDef {
     char *ifname;
     virDomainDeviceInfo info;
     /* XXX figure out how to remove this */
-    char *nic_name;
-    /* XXX figure out how to remove this */
     char *hostnet_name;
     /* XXX figure out how to remove this */
     int vlan;
@@ -737,6 +736,7 @@ int virDomainDeviceDriveAddressIsValid(virDomainDeviceDriveAddressPtr addr);
 int virDomainDeviceInfoIsSet(virDomainDeviceInfoPtr info);
 void virDomainDeviceInfoClear(virDomainDeviceInfoPtr info);
 void virDomainDefClearPCIAddresses(virDomainDefPtr def);
+void virDomainDefClearDeviceAliases(virDomainDefPtr def);
 
 void virDomainDefFree(virDomainDefPtr vm);
 void virDomainObjRef(virDomainObjPtr vm);

src/libvirt_private.syms

@@ -188,6 +188,7 @@ virDomainControllerDefFree;
 virDomainDeviceAddressTypeToString;
 virDomainDefAddDiskControllers;
 virDomainDefClearPCIAddresses;
+virDomainDefClearDeviceAliases;
 
 
 # domain_event.h

src/qemu/qemu_conf.c

@@ -1489,7 +1489,7 @@ qemuAssignNetNames(virDomainDefPtr def,
         if (def->nets[i] == net)
             continue;
 
-        if (!def->nets[i]->nic_name || !def->nets[i]->hostnet_name)
+        if (!def->nets[i]->info.alias || !def->nets[i]->hostnet_name)
             continue;
 
         if ((def->nets[i]->model == NULL && net->model == NULL) ||
@@ -1517,7 +1517,7 @@ qemuAssignNetNames(virDomainDefPtr def,
         return -1;
     }
 
-    net->nic_name = nic_name;
+    net->info.alias = nic_name;
     net->hostnet_name = hostnet_name;
 
     return 0;
@@ -1714,8 +1714,8 @@ qemuBuildNicStr(virConnectPtr conn,
                     vlan,
                     (net->model ? ",model=" : ""),
                     (net->model ? net->model : ""),
-                    (net->nic_name ? ",name=" : ""),
-                    (net->nic_name ? net->nic_name : "")) < 0) {
+                    (net->info.alias ? ",name=" : ""),
+                    (net->info.alias ? net->info.alias : "")) < 0) {
         virReportOOMError(conn);
         return -1;
     }

src/qemu/qemu_driver.c

@@ -3049,6 +3049,7 @@ static void qemudShutdownVMDaemon(virConnectPtr conn,
     }
 
     virDomainDefClearPCIAddresses(vm->def);
+    virDomainDefClearDeviceAliases(vm->def);
 
     if (qemuDomainSetAllDeviceOwnership(conn, driver, vm->def, 1) < 0)
         VIR_WARN("Failed to restore all device ownership for %s",