From b2f1863533774a39b3cd5642c183ec842a897c9b Mon Sep 17 00:00:00 2001
From: "Daniel P. Berrange" <dan@berrange.com>
Date: Thu, 15 Jul 2010 14:02:42 +0100
Subject: [PATCH] Explicitly represent balloon device in XML and handle PCI
 address

To allow compatibility with older QEMU PCI device slot assignment
it is necessary to explicitly track the balloon device in the
XML. This introduces a new device

   <memballoon model='virtio|xen'/>

It can also have a PCI address, auto-assigned if necessary.

The memballoon will be automatically added to all Xen and QEMU
guests by default.

* docs/schemas/domain.rng: Add <memballoon> element
* src/conf/domain_conf.c, src/conf/domain_conf.h: parsing
  and formatting for memballoon device. Always add a memory
  balloon device to Xen/QEMU if none exists in XML
* src/libvirt_private.syms: Export memballoon model APIs
* src/qemu/qemu_conf.c, src/qemu/qemu_conf.h: Honour the
  PCI device address in memory balloon device
* tests/*: Update to test new functionality
---
 docs/schemas/domain.rng                       |  16 +++
 src/conf/domain_conf.c                        | 118 ++++++++++++++++++
 src/conf/domain_conf.h                        |  19 +++
 src/libvirt_private.syms                      |   2 +
 src/qemu/qemu_conf.c                          |  74 +++++++++--
 src/qemu/qemu_conf.h                          |   2 +
 src/qemu/qemu_driver.c                        |  37 +++++-
 tests/define-dev-segfault                     |   1 +
 .../qemuxml2argv-balloon-device.args          |   1 +
 .../qemuxml2argv-balloon-device.xml           |  25 ++++
 .../qemuxml2argv-boot-cdrom.xml               |   1 +
 .../qemuxml2argv-boot-floppy.xml              |   1 +
 .../qemuxml2argv-boot-network.xml             |   1 +
 .../qemuxml2argv-bootloader.xml               |   1 +
 .../qemuxml2argv-channel-guestfwd.xml         |   1 +
 .../qemuxml2argv-channel-virtio-auto.xml      |   1 +
 .../qemuxml2argv-channel-virtio.xml           |   1 +
 .../qemuxml2argv-clock-france.xml             |   1 +
 .../qemuxml2argv-clock-localtime.xml          |   1 +
 .../qemuxml2argv-clock-utc.xml                |   1 +
 .../qemuxml2argv-clock-variable.xml           |   1 +
 .../qemuxml2argv-console-compat-chardev.xml   |   1 +
 .../qemuxml2argv-console-compat.xml           |   1 +
 .../qemuxml2argv-disk-cdrom-empty.xml         |   1 +
 .../qemuxml2argv-disk-cdrom.xml               |   1 +
 .../qemuxml2argv-disk-drive-boot-cdrom.xml    |   1 +
 .../qemuxml2argv-disk-drive-boot-disk.xml     |   1 +
 .../qemuxml2argv-disk-drive-cache-v1-none.xml |   1 +
 .../qemuxml2argv-disk-drive-cache-v1-wb.xml   |   1 +
 .../qemuxml2argv-disk-drive-cache-v1-wt.xml   |   1 +
 .../qemuxml2argv-disk-drive-cache-v2-none.xml |   1 +
 .../qemuxml2argv-disk-drive-cache-v2-wb.xml   |   1 +
 .../qemuxml2argv-disk-drive-cache-v2-wt.xml   |   1 +
 ...2argv-disk-drive-error-policy-enospace.xml |   1 +
 ...uxml2argv-disk-drive-error-policy-stop.xml |   1 +
 .../qemuxml2argv-disk-drive-fat.xml           |   1 +
 .../qemuxml2argv-disk-drive-fmt-qcow.xml      |   1 +
 .../qemuxml2argv-disk-drive-readonly-disk.xml |   1 +
 .../qemuxml2argv-disk-drive-shared.xml        |   1 +
 .../qemuxml2argv-disk-floppy.xml              |   1 +
 .../qemuxml2argv-disk-many.xml                |   1 +
 .../qemuxml2argv-disk-usb-device.xml          |   1 +
 .../qemuxml2argv-disk-usb.xml                 |   1 +
 .../qemuxml2argv-disk-virtio.xml              |   1 +
 .../qemuxml2argv-disk-xenvbd.xml              |   1 +
 .../qemuxml2argv-encrypted-disk.xml           |   1 +
 .../qemuxml2argv-floppy-drive-fat.xml         |   1 +
 .../qemuxml2argv-graphics-sdl-fullscreen.xml  |   1 +
 .../qemuxml2argv-graphics-sdl.xml             |   1 +
 .../qemuxml2argv-graphics-vnc-sasl.xml        |   1 +
 .../qemuxml2argv-graphics-vnc-tls.xml         |   1 +
 .../qemuxml2argv-graphics-vnc.xml             |   1 +
 ...emuxml2argv-hostdev-pci-address-device.xml |   1 +
 .../qemuxml2argv-hostdev-pci-address.xml      |   1 +
 ...emuxml2argv-hostdev-usb-address-device.xml |   1 +
 .../qemuxml2argv-hostdev-usb-address.xml      |   1 +
 .../qemuxml2argv-hugepages.xml                |   1 +
 .../qemuxml2argv-input-usbmouse.xml           |   1 +
 .../qemuxml2argv-input-usbtablet.xml          |   1 +
 .../qemuxml2argv-input-xen.xml                |   1 +
 .../qemuxml2argv-machine-aliases1.xml         |   1 +
 .../qemuxml2argv-machine-aliases2.xml         |   1 +
 .../qemuxml2argvdata/qemuxml2argv-migrate.xml |   1 +
 .../qemuxml2argvdata/qemuxml2argv-minimal.xml |   1 +
 .../qemuxml2argv-misc-acpi.xml                |   1 +
 .../qemuxml2argv-misc-no-reboot.xml           |   1 +
 .../qemuxml2argv-misc-uuid.xml                |   1 +
 .../qemuxml2argv-net-eth-ifname.xml           |   1 +
 .../qemuxml2argv-net-eth-names.xml            |   1 +
 .../qemuxml2argvdata/qemuxml2argv-net-eth.xml |   1 +
 .../qemuxml2argv-net-user.xml                 |   1 +
 .../qemuxml2argv-net-virtio-device.xml        |   1 +
 .../qemuxml2argv-net-virtio-netdev.xml        |   1 +
 .../qemuxml2argv-net-virtio.xml               |   1 +
 .../qemuxml2argv-nographics-vga.xml           |   1 +
 .../qemuxml2argv-parallel-tcp-chardev.xml     |   1 +
 .../qemuxml2argv-parallel-tcp.xml             |   1 +
 .../qemuxml2argv-restore-v1.xml               |   1 +
 .../qemuxml2argv-restore-v2.xml               |   1 +
 .../qemuxml2argv-serial-dev-chardev.xml       |   1 +
 .../qemuxml2argv-serial-dev.xml               |   1 +
 .../qemuxml2argv-serial-file-chardev.xml      |   1 +
 .../qemuxml2argv-serial-file.xml              |   1 +
 .../qemuxml2argv-serial-many-chardev.xml      |   1 +
 .../qemuxml2argv-serial-many.xml              |   1 +
 .../qemuxml2argv-serial-pty-chardev.xml       |   1 +
 .../qemuxml2argv-serial-pty.xml               |   1 +
 .../qemuxml2argv-serial-tcp-chardev.xml       |   1 +
 ...qemuxml2argv-serial-tcp-telnet-chardev.xml |   1 +
 .../qemuxml2argv-serial-tcp-telnet.xml        |   1 +
 .../qemuxml2argv-serial-tcp.xml               |   1 +
 .../qemuxml2argv-serial-udp-chardev.xml       |   1 +
 .../qemuxml2argv-serial-udp.xml               |   1 +
 .../qemuxml2argv-serial-unix-chardev.xml      |   1 +
 .../qemuxml2argv-serial-unix.xml              |   1 +
 .../qemuxml2argv-serial-vc-chardev.xml        |   1 +
 .../qemuxml2argv-serial-vc.xml                |   1 +
 .../qemuxml2argv-sound-device.xml             |   1 +
 tests/qemuxml2argvdata/qemuxml2argv-sound.xml |   1 +
 .../qemuxml2argv-watchdog-device.xml          |   1 +
 .../qemuxml2argv-watchdog.xml                 |   1 +
 tests/qemuxml2argvtest.c                      |   2 +
 102 files changed, 377 insertions(+), 11 deletions(-)
 create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-balloon-device.args
 create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-balloon-device.xml

diff --git a/docs/schemas/domain.rng b/docs/schemas/domain.rng
index 1d56f5b008..2ca0ad2b02 100644
--- a/docs/schemas/domain.rng
+++ b/docs/schemas/domain.rng
@@ -1310,6 +1310,19 @@
       </optional>
     </element>
   </define>
+  <define name="memballoon">
+    <element name="memballoon">
+      <attribute name="model">
+        <choice>
+          <value>virtio</value>
+          <value>xen</value>
+        </choice>
+      </attribute>
+      <optional>
+        <ref name="address"/>
+      </optional>
+    </element>
+  </define>
   <define name="parallel">
     <element name="parallel">
       <ref name="qemucdev"/>
@@ -1516,6 +1529,9 @@
         <optional>
           <ref name="watchdog"/>
         </optional>
+        <optional>
+          <ref name="memballoon"/>
+        </optional>
       </interleave>
     </element>
   </define>
diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
index f3b8cfa3a5..0feb0cd6bc 100644
--- a/src/conf/domain_conf.c
+++ b/src/conf/domain_conf.c
@@ -189,6 +189,10 @@ VIR_ENUM_IMPL(virDomainSoundModel, VIR_DOMAIN_SOUND_MODEL_LAST,
               "pcspk",
               "ac97")
 
+VIR_ENUM_IMPL(virDomainMemballoonModel, VIR_DOMAIN_MEMBALLOON_MODEL_LAST,
+              "virtio",
+              "xen");
+
 VIR_ENUM_IMPL(virDomainWatchdogModel, VIR_DOMAIN_WATCHDOG_MODEL_LAST,
               "i6300esb",
               "ib700")
@@ -567,6 +571,16 @@ void virDomainSoundDefFree(virDomainSoundDefPtr def)
     VIR_FREE(def);
 }
 
+void virDomainMemballoonDefFree(virDomainMemballoonDefPtr def)
+{
+    if (!def)
+        return;
+
+    virDomainDeviceInfoClear(&def->info);
+
+    VIR_FREE(def);
+}
+
 void virDomainWatchdogDefFree(virDomainWatchdogDefPtr def)
 {
     if (!def)
@@ -1001,6 +1015,9 @@ int virDomainDeviceInfoIterate(virDomainDefPtr def,
     if (def->watchdog)
         if (cb(def, &def->watchdog->info, opaque) < 0)
             return -1;
+    if (def->memballoon)
+        if (cb(def, &def->memballoon->info, opaque) < 0)
+            return -1;
     if (def->console)
         if (cb(def, &def->console->info, opaque) < 0)
             return -1;
@@ -3170,6 +3187,40 @@ error:
 }
 
 
+static virDomainMemballoonDefPtr
+virDomainMemballoonDefParseXML(const xmlNodePtr node,
+                               int flags)
+{
+    char *model;
+    virDomainMemballoonDefPtr def;
+
+    if (VIR_ALLOC(def) < 0) {
+        virReportOOMError();
+        return NULL;
+    }
+
+    model = virXMLPropString(node, "model");
+    if ((def->model = virDomainMemballoonModelTypeFromString(model)) < 0) {
+        virDomainReportError(VIR_ERR_INTERNAL_ERROR,
+                             _("unknown memory balloon model '%s'"), model);
+        goto error;
+    }
+
+    if (virDomainDeviceInfoParseXML(node, &def->info, flags) < 0)
+        goto error;
+
+cleanup:
+    VIR_FREE(model);
+
+    return def;
+
+error:
+    virDomainMemballoonDefFree(def);
+    def = NULL;
+    goto cleanup;
+}
+
+
 int
 virDomainVideoDefaultRAM(virDomainDefPtr def,
                          int type)
@@ -4634,6 +4685,41 @@ static virDomainDefPtr virDomainDefParseXML(virCapsPtr caps,
         VIR_FREE(nodes);
     }
 
+    /* analysis of the memballoon devices */
+    def->memballoon = NULL;
+    if ((n = virXPathNodeSet("./devices/memballoon", ctxt, &nodes)) < 0) {
+        virDomainReportError(VIR_ERR_INTERNAL_ERROR,
+                             "%s", _("cannot extract memory balloon devices"));
+        goto error;
+    }
+    if (n > 1) {
+        virDomainReportError (VIR_ERR_INTERNAL_ERROR,
+                              "%s", _("only a single memory balloon device is supported"));
+        goto error;
+    }
+    if (n > 0) {
+        virDomainMemballoonDefPtr memballoon =
+            virDomainMemballoonDefParseXML(nodes[0], flags);
+        if (!memballoon)
+            goto error;
+
+        def->memballoon = memballoon;
+        VIR_FREE(nodes);
+    } else {
+        if (def->virtType == VIR_DOMAIN_VIRT_XEN ||
+            def->virtType == VIR_DOMAIN_VIRT_QEMU ||
+            def->virtType == VIR_DOMAIN_VIRT_KQEMU ||
+            def->virtType == VIR_DOMAIN_VIRT_KVM) {
+            virDomainMemballoonDefPtr memballoon;
+            if (VIR_ALLOC(memballoon) < 0)
+                goto no_memory;
+            memballoon->model = def->virtType == VIR_DOMAIN_VIRT_XEN ?
+                VIR_DOMAIN_MEMBALLOON_MODEL_XEN :
+                VIR_DOMAIN_MEMBALLOON_MODEL_VIRTIO;
+            def->memballoon = memballoon;
+        }
+    }
+
     /* analysis of security label */
     if (virSecurityLabelDefParseXML(def, ctxt, flags) == -1)
         goto error;
@@ -5671,6 +5757,35 @@ virDomainSoundDefFormat(virBufferPtr buf,
 }
 
 
+static int
+virDomainMemballoonDefFormat(virBufferPtr buf,
+                             virDomainMemballoonDefPtr def,
+                             int flags)
+{
+    const char *model = virDomainMemballoonModelTypeToString(def->model);
+
+    if (!model) {
+        virDomainReportError(VIR_ERR_INTERNAL_ERROR,
+                             _("unexpected memballoon model %d"), def->model);
+        return -1;
+    }
+
+    virBufferVSprintf(buf, "    <memballoon model='%s'",
+                      model);
+
+    if (virDomainDeviceInfoIsSet(&def->info)) {
+        virBufferAddLit(buf, ">\n");
+        if (virDomainDeviceInfoFormat(buf, &def->info, flags) < 0)
+            return -1;
+        virBufferAddLit(buf, "    </memballoon>\n");
+    } else {
+        virBufferAddLit(buf, "/>\n");
+    }
+
+    return 0;
+}
+
+
 static int
 virDomainWatchdogDefFormat(virBufferPtr buf,
                            virDomainWatchdogDefPtr def,
@@ -6280,6 +6395,9 @@ char *virDomainDefFormat(virDomainDefPtr def,
     if (def->watchdog)
         virDomainWatchdogDefFormat (&buf, def->watchdog, flags);
 
+    if (def->memballoon)
+        virDomainMemballoonDefFormat (&buf, def->memballoon, flags);
+
     virBufferAddLit(&buf, "  </devices>\n");
 
     if (def->seclabel.model) {
diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h
index d46869e44f..5e08aa196b 100644
--- a/src/conf/domain_conf.h
+++ b/src/conf/domain_conf.h
@@ -560,6 +560,22 @@ struct _virDomainHostdevDef {
     virDomainDeviceInfo info; /* Guest address */
 };
 
+
+enum {
+    VIR_DOMAIN_MEMBALLOON_MODEL_VIRTIO,
+    VIR_DOMAIN_MEMBALLOON_MODEL_XEN,
+
+    VIR_DOMAIN_MEMBALLOON_MODEL_LAST
+};
+
+typedef struct _virDomainMemballoonDef virDomainMemballoonDef;
+typedef virDomainMemballoonDef *virDomainMemballoonDefPtr;
+struct _virDomainMemballoonDef {
+    int model;
+    virDomainDeviceInfo info;
+};
+
+
 /* Flags for the 'type' field in next struct */
 enum virDomainDeviceType {
     VIR_DOMAIN_DEVICE_DISK,
@@ -871,6 +887,7 @@ struct _virDomainDef {
     virDomainChrDefPtr console;
     virSecurityLabelDef seclabel;
     virDomainWatchdogDefPtr watchdog;
+    virDomainMemballoonDefPtr memballoon;
     virCPUDefPtr cpu;
 };
 
@@ -931,6 +948,7 @@ void virDomainFSDefFree(virDomainFSDefPtr def);
 void virDomainNetDefFree(virDomainNetDefPtr def);
 void virDomainChrDefFree(virDomainChrDefPtr def);
 void virDomainSoundDefFree(virDomainSoundDefPtr def);
+void virDomainMemballoonDefFree(virDomainMemballoonDefPtr def);
 void virDomainWatchdogDefFree(virDomainWatchdogDefPtr def);
 void virDomainVideoDefFree(virDomainVideoDefPtr def);
 void virDomainHostdevDefFree(virDomainHostdevDefPtr def);
@@ -1109,6 +1127,7 @@ VIR_ENUM_DECL(virDomainNet)
 VIR_ENUM_DECL(virDomainChrTarget)
 VIR_ENUM_DECL(virDomainChr)
 VIR_ENUM_DECL(virDomainSoundModel)
+VIR_ENUM_DECL(virDomainMemballoonModel)
 VIR_ENUM_DECL(virDomainWatchdogModel)
 VIR_ENUM_DECL(virDomainWatchdogAction)
 VIR_ENUM_DECL(virDomainVideo)
diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index b5f36953bb..3573da17a9 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -170,6 +170,8 @@ virDomainSaveStatus;
 virDomainSoundDefFree;
 virDomainSoundModelTypeFromString;
 virDomainSoundModelTypeToString;
+virDomainMemballoonModelTypeFromString;
+virDomainMemballoonModelTypeToString;
 virDomainWatchdogModelTypeFromString;
 virDomainWatchdogModelTypeToString;
 virDomainWatchdogActionTypeFromString;
diff --git a/src/qemu/qemu_conf.c b/src/qemu/qemu_conf.c
index d89e065e22..ae345fb5fc 100644
--- a/src/qemu/qemu_conf.c
+++ b/src/qemu/qemu_conf.c
@@ -2023,6 +2023,10 @@ qemuAssignDeviceAliases(virDomainDefPtr def, unsigned long long qemuCmdFlags)
         if (virAsprintf(&def->watchdog->info.alias, "watchdog%d", 0) < 0)
             goto no_memory;
     }
+    if (def->memballoon) {
+        if (virAsprintf(&def->memballoon->info.alias, "balloon%d", 0) < 0)
+            goto no_memory;
+    }
 
     return 0;
 
@@ -2296,8 +2300,17 @@ qemuAssignDevicePCISlots(virDomainDefPtr def, qemuDomainPCIAddressSetPtr addrs)
     }
 
     /* VirtIO balloon always at slot 3 by default */
-    if (qemuDomainPCIAddressReserveSlot(addrs, 3) < 0)
-        goto error;
+    if (def->memballoon &&
+        def->memballoon->model == VIR_DOMAIN_MEMBALLOON_MODEL_VIRTIO &&
+        def->memballoon->info.type == VIR_DOMAIN_DEVICE_ADDRESS_TYPE_NONE) {
+        def->memballoon->info.type = VIR_DOMAIN_DEVICE_ADDRESS_TYPE_PCI;
+        def->memballoon->info.addr.pci.domain = 0;
+        def->memballoon->info.addr.pci.bus = 0;
+        def->memballoon->info.addr.pci.slot = 3;
+        def->memballoon->info.addr.pci.function = 0;
+        if (qemuDomainPCIAddressReserveSlot(addrs, 3) < 0)
+            goto error;
+    }
 
     for (i = 0; i < def->ndisks ; i++) {
         if (def->disks[i]->info.type != VIR_DOMAIN_DEVICE_ADDRESS_TYPE_NONE)
@@ -2912,6 +2925,29 @@ error:
 }
 
 
+char *
+qemuBuildMemballoonDevStr(virDomainMemballoonDefPtr dev)
+{
+    virBuffer buf = VIR_BUFFER_INITIALIZER;
+
+    virBufferAddLit(&buf, "virtio-balloon-pci");
+    virBufferVSprintf(&buf, ",id=%s", dev->info.alias);
+    if (qemuBuildDeviceAddressStr(&buf, &dev->info) < 0)
+        goto error;
+
+    if (virBufferError(&buf)) {
+        virReportOOMError();
+        goto error;
+    }
+
+    return virBufferContentAndReset(&buf);
+
+error:
+    virBufferFreeAndReset(&buf);
+    return NULL;
+}
+
+
 char *
 qemuBuildUSBInputDevStr(virDomainInputDefPtr dev)
 {
@@ -4771,12 +4807,25 @@ int qemudBuildCommandLine(virConnectPtr conn,
      * NB: Earlier we declared that VirtIO balloon will always be in
      * slot 0x3 on bus 0x0
      */
-    if (qemuCmdFlags & QEMUD_CMD_FLAG_DEVICE) {
-        ADD_ARG_LIT("-device");
-        ADD_ARG_LIT("virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x3");
-    } else if (qemuCmdFlags & QEMUD_CMD_FLAG_BALLOON) {
-        ADD_ARG_LIT("-balloon");
-        ADD_ARG_LIT("virtio");
+    if (def->memballoon) {
+        if (def->memballoon->model != VIR_DOMAIN_MEMBALLOON_MODEL_VIRTIO) {
+            qemuReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+                            _("Memory balloon device type '%s' is not supported by this version of qemu"),
+                            virDomainMemballoonModelTypeToString(def->memballoon->model));
+            goto error;
+        }
+        if (qemuCmdFlags & QEMUD_CMD_FLAG_DEVICE) {
+            char *optstr;
+            ADD_ARG_LIT("-device");
+
+            optstr = qemuBuildMemballoonDevStr(def->memballoon);
+            if (!optstr)
+                goto error;
+            ADD_ARG(optstr);
+        } else if (qemuCmdFlags & QEMUD_CMD_FLAG_BALLOON) {
+            ADD_ARG_LIT("-balloon");
+            ADD_ARG_LIT("virtio");
+        }
     }
 
     if (current_snapshot && current_snapshot->def->active) {
@@ -6346,6 +6395,15 @@ virDomainDefPtr qemuParseCommandLine(virCapsPtr caps,
         def->videos[def->nvideos++] = vid;
     }
 
+    if (!def->memballoon) {
+        virDomainMemballoonDefPtr memballoon;
+        if (VIR_ALLOC(memballoon) < 0)
+            goto no_memory;
+        memballoon->model = VIR_DOMAIN_MEMBALLOON_MODEL_VIRTIO;
+
+        def->memballoon = memballoon;
+    }
+
     VIR_FREE(nics);
 
     if (!def->name) {
diff --git a/src/qemu/qemu_conf.h b/src/qemu/qemu_conf.h
index ea10f8592c..ca4559f5f0 100644
--- a/src/qemu/qemu_conf.h
+++ b/src/qemu/qemu_conf.h
@@ -243,6 +243,8 @@ char * qemuBuildControllerDevStr(virDomainControllerDefPtr def);
 
 char * qemuBuildWatchdogDevStr(virDomainWatchdogDefPtr dev);
 
+char * qemuBuildMemballoonDevStr(virDomainMemballoonDefPtr dev);
+
 char * qemuBuildUSBInputDevStr(virDomainInputDefPtr dev);
 
 char * qemuBuildSoundDevStr(virDomainSoundDefPtr sound);
diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 92b98479ab..6c7852882f 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -2360,6 +2360,8 @@ cleanup:
 
 #define QEMU_PCI_PRODUCT_DISK_VIRTIO 0x1001
 
+#define QEMU_PCI_PRODUCT_BALLOON_VIRTIO 0x1002
+
 #define QEMU_PCI_PRODUCT_NIC_NE2K     0x8029
 #define QEMU_PCI_PRODUCT_NIC_PCNET    0x2000
 #define QEMU_PCI_PRODUCT_NIC_RTL8139  0x8139
@@ -2568,6 +2570,25 @@ qemuGetPCIWatchdogVendorProduct(virDomainWatchdogDefPtr def,
 }
 
 
+static int
+qemuGetPCIMemballoonVendorProduct(virDomainMemballoonDefPtr def,
+                                  unsigned *vendor,
+                                  unsigned *product)
+{
+    switch (def->model) {
+    case VIR_DOMAIN_MEMBALLOON_MODEL_VIRTIO:
+        *vendor = QEMU_PCI_VENDOR_REDHAT;
+        *product = QEMU_PCI_PRODUCT_BALLOON_VIRTIO;
+        break;
+
+    default:
+        return -1;
+    }
+
+    return 0;
+}
+
+
 /*
  * This entire method assumes that PCI devices in 'info pci'
  * match ordering of devices specified on the command line
@@ -2649,7 +2670,7 @@ qemuDetectPCIAddresses(virDomainObjPtr vm,
             continue;
 
         if (qemuAssignNextPCIAddress(&(vm->def->sounds[i]->info),
-                                     vendor, product,
+                                    vendor, product,
                                      addrs,  naddrs) < 0) {
             qemuReportError(VIR_ERR_INTERNAL_ERROR,
                             _("cannot find PCI address for sound adapter %s"),
@@ -2671,6 +2692,18 @@ qemuDetectPCIAddresses(virDomainObjPtr vm,
         }
     }
 
+    if (vm->def->memballoon &&
+        qemuGetPCIMemballoonVendorProduct(vm->def->memballoon, &vendor, &product) == 0) {
+        if (qemuAssignNextPCIAddress(&(vm->def->memballoon->info),
+                                     vendor, product,
+                                     addrs, naddrs) < 0) {
+            qemuReportError(VIR_ERR_INTERNAL_ERROR,
+                            _("cannot find PCI address for balloon %s"),
+                            virDomainMemballoonModelTypeToString(vm->def->memballoon->model));
+            return -1;
+        }
+    }
+
     /* XXX console (virtio) */
 
 
@@ -2678,8 +2711,6 @@ qemuDetectPCIAddresses(virDomainObjPtr vm,
 
     /* XXX USB controller ? */
 
-    /* XXXX virtio balloon ? */
-
     /* XXX what about other PCI devices (ie bridges) */
 
     return 0;
diff --git a/tests/define-dev-segfault b/tests/define-dev-segfault
index e0b953ad84..7a9a7b6fc6 100755
--- a/tests/define-dev-segfault
+++ b/tests/define-dev-segfault
@@ -59,6 +59,7 @@ cat <<\EOF > D.xml || fail=1
     </console>
     <sound model='pcspk'/>
     <sound model='es1370'/>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
 EOF
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-balloon-device.args b/tests/qemuxml2argvdata/qemuxml2argv-balloon-device.args
new file mode 100644
index 0000000000..0a481d6bb3
--- /dev/null
+++ b/tests/qemuxml2argvdata/qemuxml2argv-balloon-device.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 -nodefconfig -nodefaults -monitor unix:/tmp/test-monitor,server,nowait -no-acpi -boot c -hda /dev/HostVG/QEMUGuest1 -usb -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x12
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-balloon-device.xml b/tests/qemuxml2argvdata/qemuxml2argv-balloon-device.xml
new file mode 100644
index 0000000000..274eb8b008
--- /dev/null
+++ b/tests/qemuxml2argvdata/qemuxml2argv-balloon-device.xml
@@ -0,0 +1,25 @@
+<domain type='qemu'>
+  <name>QEMUGuest1</name>
+  <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
+  <memory>219200</memory>
+  <currentMemory>219200</currentMemory>
+  <vcpu>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'>
+      <source dev='/dev/HostVG/QEMUGuest1'/>
+      <target dev='hda' bus='ide'/>
+    </disk>
+    <memballoon model='virtio'>
+      <address type='pci' domain='0' bus='0' slot='18' function='0'/>
+    </memballoon>
+  </devices>
+</domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-boot-cdrom.xml b/tests/qemuxml2argvdata/qemuxml2argv-boot-cdrom.xml
index cf0d3df58c..410e6f9551 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-boot-cdrom.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-boot-cdrom.xml
@@ -21,5 +21,6 @@
       <address type='drive' controller='0' bus='1' unit='0'/>
     </disk>
     <controller type='ide' index='0'/>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-boot-floppy.xml b/tests/qemuxml2argvdata/qemuxml2argv-boot-floppy.xml
index cf3c5a8fd5..ad8bae226d 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-boot-floppy.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-boot-floppy.xml
@@ -26,5 +26,6 @@
     </disk>
     <controller type='fdc' index='0'/>
     <controller type='ide' index='0'/>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-boot-network.xml b/tests/qemuxml2argvdata/qemuxml2argv-boot-network.xml
index a28372dc3e..b1b77218d1 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-boot-network.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-boot-network.xml
@@ -20,5 +20,6 @@
       <address type='drive' controller='0' bus='0' unit='0'/>
     </disk>
     <controller type='ide' index='0'/>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-bootloader.xml b/tests/qemuxml2argvdata/qemuxml2argv-bootloader.xml
index 4af280c5f1..af19b3b7a0 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-bootloader.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-bootloader.xml
@@ -21,5 +21,6 @@
       <address type='drive' controller='0' bus='1' unit='0'/>
     </disk>
     <controller type='ide' index='0'/>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-channel-guestfwd.xml b/tests/qemuxml2argvdata/qemuxml2argv-channel-guestfwd.xml
index 8963350fad..b3c56b1dcd 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-channel-guestfwd.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-channel-guestfwd.xml
@@ -24,5 +24,6 @@
       <source path='/tmp/guestfwd'/>
       <target type='guestfwd' address='10.0.2.1' port='4600'/>
     </channel>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-channel-virtio-auto.xml b/tests/qemuxml2argvdata/qemuxml2argv-channel-virtio-auto.xml
index 6e3458f1de..afd73f42e7 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-channel-virtio-auto.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-channel-virtio-auto.xml
@@ -47,5 +47,6 @@
       <target type='virtio' name='org.linux-kvm.port.lla'/>
       <address type='virtio-serial' controller='2' bus='0'/>
     </channel>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-channel-virtio.xml b/tests/qemuxml2argvdata/qemuxml2argv-channel-virtio.xml
index e597c407e4..2dbb59697f 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-channel-virtio.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-channel-virtio.xml
@@ -27,5 +27,6 @@
       <target type='virtio' name='org.linux-kvm.port.foo'/>
       <address type='virtio-serial' controller='1' bus='0' port='3'/>
     </channel>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-clock-france.xml b/tests/qemuxml2argvdata/qemuxml2argv-clock-france.xml
index 157fdfb3de..8794492300 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-clock-france.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-clock-france.xml
@@ -20,5 +20,6 @@
       <address type='drive' controller='0' bus='0' unit='0'/>
     </disk>
     <controller type='ide' index='0'/>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-clock-localtime.xml b/tests/qemuxml2argvdata/qemuxml2argv-clock-localtime.xml
index 345ae22e9b..786d0c70e8 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-clock-localtime.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-clock-localtime.xml
@@ -20,5 +20,6 @@
       <address type='drive' controller='0' bus='0' unit='0'/>
     </disk>
     <controller type='ide' index='0'/>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-clock-utc.xml b/tests/qemuxml2argvdata/qemuxml2argv-clock-utc.xml
index 533ea59b30..ed91e37a12 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-clock-utc.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-clock-utc.xml
@@ -20,5 +20,6 @@
       <address type='drive' controller='0' bus='0' unit='0'/>
     </disk>
     <controller type='ide' index='0'/>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-clock-variable.xml b/tests/qemuxml2argvdata/qemuxml2argv-clock-variable.xml
index fa20b27374..41818d25eb 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-clock-variable.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-clock-variable.xml
@@ -20,5 +20,6 @@
       <address type='drive' controller='0' bus='0' unit='0'/>
     </disk>
     <controller type='ide' index='0'/>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-console-compat-chardev.xml b/tests/qemuxml2argvdata/qemuxml2argv-console-compat-chardev.xml
index df694c78cd..611ddb8d7b 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-console-compat-chardev.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-console-compat-chardev.xml
@@ -26,5 +26,6 @@
     <console type='pty'>
       <target port='0'/>
     </console>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-console-compat.xml b/tests/qemuxml2argvdata/qemuxml2argv-console-compat.xml
index df694c78cd..611ddb8d7b 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-console-compat.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-console-compat.xml
@@ -26,5 +26,6 @@
     <console type='pty'>
       <target port='0'/>
     </console>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-disk-cdrom-empty.xml b/tests/qemuxml2argvdata/qemuxml2argv-disk-cdrom-empty.xml
index addbbf1166..1b18d613d1 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-disk-cdrom-empty.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-disk-cdrom-empty.xml
@@ -25,5 +25,6 @@
       <address type='drive' controller='0' bus='1' unit='0'/>
     </disk>
     <controller type='ide' index='0'/>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-disk-cdrom.xml b/tests/qemuxml2argvdata/qemuxml2argv-disk-cdrom.xml
index 9c10551c41..061b196ba9 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-disk-cdrom.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-disk-cdrom.xml
@@ -26,5 +26,6 @@
       <address type='drive' controller='0' bus='1' unit='0'/>
     </disk>
     <controller type='ide' index='0'/>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-boot-cdrom.xml b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-boot-cdrom.xml
index 736e189e7c..0994a4986e 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-boot-cdrom.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-boot-cdrom.xml
@@ -25,5 +25,6 @@
       <address type='drive' controller='0' bus='1' unit='0'/>
     </disk>
     <controller type='ide' index='0'/>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-boot-disk.xml b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-boot-disk.xml
index c379f31855..9762f5aef4 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-boot-disk.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-boot-disk.xml
@@ -25,5 +25,6 @@
       <address type='drive' controller='0' bus='1' unit='0'/>
     </disk>
     <controller type='ide' index='0'/>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-cache-v1-none.xml b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-cache-v1-none.xml
index e689d9cad2..0b2f512ecd 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-cache-v1-none.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-cache-v1-none.xml
@@ -28,5 +28,6 @@
       <address type='drive' controller='0' bus='1' unit='0'/>
     </disk>
     <controller type='ide' index='0'/>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-cache-v1-wb.xml b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-cache-v1-wb.xml
index be00c4c81c..a43808618d 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-cache-v1-wb.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-cache-v1-wb.xml
@@ -28,5 +28,6 @@
       <address type='drive' controller='0' bus='1' unit='0'/>
     </disk>
     <controller type='ide' index='0'/>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-cache-v1-wt.xml b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-cache-v1-wt.xml
index edf776a399..29012a854d 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-cache-v1-wt.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-cache-v1-wt.xml
@@ -28,5 +28,6 @@
       <address type='drive' controller='0' bus='1' unit='0'/>
     </disk>
     <controller type='ide' index='0'/>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-cache-v2-none.xml b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-cache-v2-none.xml
index e689d9cad2..0b2f512ecd 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-cache-v2-none.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-cache-v2-none.xml
@@ -28,5 +28,6 @@
       <address type='drive' controller='0' bus='1' unit='0'/>
     </disk>
     <controller type='ide' index='0'/>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-cache-v2-wb.xml b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-cache-v2-wb.xml
index be00c4c81c..a43808618d 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-cache-v2-wb.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-cache-v2-wb.xml
@@ -28,5 +28,6 @@
       <address type='drive' controller='0' bus='1' unit='0'/>
     </disk>
     <controller type='ide' index='0'/>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-cache-v2-wt.xml b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-cache-v2-wt.xml
index edf776a399..29012a854d 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-cache-v2-wt.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-cache-v2-wt.xml
@@ -28,5 +28,6 @@
       <address type='drive' controller='0' bus='1' unit='0'/>
     </disk>
     <controller type='ide' index='0'/>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-error-policy-enospace.xml b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-error-policy-enospace.xml
index 8fe64d4bdf..b3e6de9947 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-error-policy-enospace.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-error-policy-enospace.xml
@@ -28,5 +28,6 @@
       <address type='drive' controller='0' bus='1' unit='0'/>
     </disk>
     <controller type='ide' index='0'/>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-error-policy-stop.xml b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-error-policy-stop.xml
index 67e23ccfe4..a4865026eb 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-error-policy-stop.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-error-policy-stop.xml
@@ -28,5 +28,6 @@
       <address type='drive' controller='0' bus='1' unit='0'/>
     </disk>
     <controller type='ide' index='0'/>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-fat.xml b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-fat.xml
index b2b1b4ec1e..a3491e770b 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-fat.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-fat.xml
@@ -22,5 +22,6 @@
       <address type='drive' controller='0' bus='0' unit='0'/>
     </disk>
     <controller type='ide' index='0'/>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-fmt-qcow.xml b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-fmt-qcow.xml
index 0b04e69d90..f2643bb09e 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-fmt-qcow.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-fmt-qcow.xml
@@ -28,5 +28,6 @@
       <address type='drive' controller='0' bus='1' unit='0'/>
     </disk>
     <controller type='ide' index='0'/>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-readonly-disk.xml b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-readonly-disk.xml
index 39c3a1ccfe..1f193c93cb 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-readonly-disk.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-readonly-disk.xml
@@ -26,5 +26,6 @@
        <address type='drive' controller='0' bus='1' unit='0'/>
     </disk>
     <controller type='ide' index='0'/>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-shared.xml b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-shared.xml
index 47afcd710c..27e741ae84 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-shared.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-shared.xml
@@ -30,5 +30,6 @@
       <address type='drive' controller='0' bus='1' unit='0'/>
     </disk>
     <controller type='ide' index='0'/>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-disk-floppy.xml b/tests/qemuxml2argvdata/qemuxml2argv-disk-floppy.xml
index 35474beb1e..c0a4a08384 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-disk-floppy.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-disk-floppy.xml
@@ -31,5 +31,6 @@
     </disk>
     <controller type='fdc' index='0'/>
     <controller type='ide' index='0'/>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-disk-many.xml b/tests/qemuxml2argvdata/qemuxml2argv-disk-many.xml
index 467fa5d65b..14f85cc72d 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-disk-many.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-disk-many.xml
@@ -35,5 +35,6 @@
       <address type='drive' controller='0' bus='1' unit='1'/>
     </disk>
     <controller type='ide' index='0'/>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-disk-usb-device.xml b/tests/qemuxml2argvdata/qemuxml2argv-disk-usb-device.xml
index d59e1c0a27..6d35eea5fc 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-disk-usb-device.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-disk-usb-device.xml
@@ -22,5 +22,6 @@
       <source file='/tmp/usbdisk.img'/>
       <target dev='sda' bus='usb'/>
     </disk>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-disk-usb.xml b/tests/qemuxml2argvdata/qemuxml2argv-disk-usb.xml
index 8148626ad5..79ab65422b 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-disk-usb.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-disk-usb.xml
@@ -24,5 +24,6 @@
       <target dev='sda' bus='usb'/>
     </disk>
     <controller type='ide' index='0'/>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-disk-virtio.xml b/tests/qemuxml2argvdata/qemuxml2argv-disk-virtio.xml
index 23930731f2..a8aae71b39 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-disk-virtio.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-disk-virtio.xml
@@ -34,5 +34,6 @@
       <target dev='vdb' bus='virtio'/>
     </disk>
     <controller type='ide' index='0'/>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-disk-xenvbd.xml b/tests/qemuxml2argvdata/qemuxml2argv-disk-xenvbd.xml
index 0c36457601..a3dd4c637b 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-disk-xenvbd.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-disk-xenvbd.xml
@@ -34,5 +34,6 @@
       <target dev='xvdg' bus='xen'/>
     </disk>
     <controller type='ide' index='0'/>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-encrypted-disk.xml b/tests/qemuxml2argvdata/qemuxml2argv-encrypted-disk.xml
index cb7b06d3d3..f5e5d74a89 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-encrypted-disk.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-encrypted-disk.xml
@@ -23,5 +23,6 @@
       </encryption>
       <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0'/>
     </disk>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-floppy-drive-fat.xml b/tests/qemuxml2argvdata/qemuxml2argv-floppy-drive-fat.xml
index 6da210d097..ec74bdddd6 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-floppy-drive-fat.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-floppy-drive-fat.xml
@@ -23,5 +23,6 @@
     </disk>
     <controller type='ide' index='0'/>
     <controller type='fdc' index='0'/>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-graphics-sdl-fullscreen.xml b/tests/qemuxml2argvdata/qemuxml2argv-graphics-sdl-fullscreen.xml
index dcecd47d3d..06b0539894 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-graphics-sdl-fullscreen.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-graphics-sdl-fullscreen.xml
@@ -25,5 +25,6 @@
     <video>
       <model type='cirrus' vram='9216' heads='1'/>
     </video>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-graphics-sdl.xml b/tests/qemuxml2argvdata/qemuxml2argv-graphics-sdl.xml
index f691bfeca5..16fd3badd4 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-graphics-sdl.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-graphics-sdl.xml
@@ -25,5 +25,6 @@
     <video>
       <model type='vga' vram='9216' heads='1'/>
     </video>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-graphics-vnc-sasl.xml b/tests/qemuxml2argvdata/qemuxml2argv-graphics-vnc-sasl.xml
index da0f3c68af..a07f87b139 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-graphics-vnc-sasl.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-graphics-vnc-sasl.xml
@@ -25,5 +25,6 @@
     <video>
       <model type='cirrus' vram='9216' heads='1'/>
     </video>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-graphics-vnc-tls.xml b/tests/qemuxml2argvdata/qemuxml2argv-graphics-vnc-tls.xml
index da0f3c68af..a07f87b139 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-graphics-vnc-tls.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-graphics-vnc-tls.xml
@@ -25,5 +25,6 @@
     <video>
       <model type='cirrus' vram='9216' heads='1'/>
     </video>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-graphics-vnc.xml b/tests/qemuxml2argvdata/qemuxml2argv-graphics-vnc.xml
index da0f3c68af..a07f87b139 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-graphics-vnc.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-graphics-vnc.xml
@@ -25,5 +25,6 @@
     <video>
       <model type='cirrus' vram='9216' heads='1'/>
     </video>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-hostdev-pci-address-device.xml b/tests/qemuxml2argvdata/qemuxml2argv-hostdev-pci-address-device.xml
index ac5ad47eca..711e3f8ca9 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-hostdev-pci-address-device.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-hostdev-pci-address-device.xml
@@ -23,5 +23,6 @@
         <address domain='0x0000' bus='0x06' slot='0x12' function='0x5'/>
       </source>
     </hostdev>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-hostdev-pci-address.xml b/tests/qemuxml2argvdata/qemuxml2argv-hostdev-pci-address.xml
index cb039af783..0347eeea19 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-hostdev-pci-address.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-hostdev-pci-address.xml
@@ -25,5 +25,6 @@
         <address domain='0x0000' bus='0x06' slot='0x12' function='0x5'/>
       </source>
     </hostdev>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-hostdev-usb-address-device.xml b/tests/qemuxml2argvdata/qemuxml2argv-hostdev-usb-address-device.xml
index 61bb2a2b2a..da2562e825 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-hostdev-usb-address-device.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-hostdev-usb-address-device.xml
@@ -23,5 +23,6 @@
         <address bus='14' device='6'/>
       </source>
     </hostdev>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-hostdev-usb-address.xml b/tests/qemuxml2argvdata/qemuxml2argv-hostdev-usb-address.xml
index c7d0d919f3..4391bf108e 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-hostdev-usb-address.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-hostdev-usb-address.xml
@@ -25,5 +25,6 @@
         <address bus='14' device='6'/>
       </source>
     </hostdev>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-hugepages.xml b/tests/qemuxml2argvdata/qemuxml2argv-hugepages.xml
index 2e4b75fa68..8ed7490eca 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-hugepages.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-hugepages.xml
@@ -23,5 +23,6 @@
       <address type='drive' controller='0' bus='0' unit='0'/>
     </disk>
     <controller type='ide' index='0'/>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-input-usbmouse.xml b/tests/qemuxml2argvdata/qemuxml2argv-input-usbmouse.xml
index 8603d1bcba..b76a895ee4 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-input-usbmouse.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-input-usbmouse.xml
@@ -21,5 +21,6 @@
     </disk>
     <controller type='ide' index='0'/>
     <input type='mouse' bus='usb'/>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-input-usbtablet.xml b/tests/qemuxml2argvdata/qemuxml2argv-input-usbtablet.xml
index 6c2a41b70a..a878f8c9a6 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-input-usbtablet.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-input-usbtablet.xml
@@ -21,5 +21,6 @@
     </disk>
     <controller type='ide' index='0'/>
     <input type='tablet' bus='usb'/>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-input-xen.xml b/tests/qemuxml2argvdata/qemuxml2argv-input-xen.xml
index 91dd79524c..0ea00c1bef 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-input-xen.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-input-xen.xml
@@ -25,5 +25,6 @@
     <video>
       <model type='xen' vram='4096' heads='1'/>
     </video>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-machine-aliases1.xml b/tests/qemuxml2argvdata/qemuxml2argv-machine-aliases1.xml
index 268954d0d9..9f3fc85ea8 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-machine-aliases1.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-machine-aliases1.xml
@@ -20,5 +20,6 @@
       <address type='drive' controller='0' bus='0' unit='0'/>
     </disk>
     <controller type='ide' index='0'/>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-machine-aliases2.xml b/tests/qemuxml2argvdata/qemuxml2argv-machine-aliases2.xml
index 354b1d5d7c..c57e64ce02 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-machine-aliases2.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-machine-aliases2.xml
@@ -20,5 +20,6 @@
       <address type='drive' controller='0' bus='0' unit='0'/>
     </disk>
     <controller type='ide' index='0'/>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-migrate.xml b/tests/qemuxml2argvdata/qemuxml2argv-migrate.xml
index 533ea59b30..ed91e37a12 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-migrate.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-migrate.xml
@@ -20,5 +20,6 @@
       <address type='drive' controller='0' bus='0' unit='0'/>
     </disk>
     <controller type='ide' index='0'/>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-minimal.xml b/tests/qemuxml2argvdata/qemuxml2argv-minimal.xml
index 334a9f99c3..8a13e47428 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-minimal.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-minimal.xml
@@ -20,5 +20,6 @@
       <address type='drive' controller='0' bus='0' unit='0'/>
     </disk>
     <controller type='ide' index='0'/>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-misc-acpi.xml b/tests/qemuxml2argvdata/qemuxml2argv-misc-acpi.xml
index 474832d053..c8e87b058d 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-misc-acpi.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-misc-acpi.xml
@@ -23,5 +23,6 @@
       <address type='drive' controller='0' bus='0' unit='0'/>
     </disk>
     <controller type='ide' index='0'/>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-misc-no-reboot.xml b/tests/qemuxml2argvdata/qemuxml2argv-misc-no-reboot.xml
index f75722ffcc..bb4f5f05a3 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-misc-no-reboot.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-misc-no-reboot.xml
@@ -20,5 +20,6 @@
       <address type='drive' controller='0' bus='0' unit='0'/>
     </disk>
     <controller type='ide' index='0'/>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-misc-uuid.xml b/tests/qemuxml2argvdata/qemuxml2argv-misc-uuid.xml
index 474832d053..c8e87b058d 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-misc-uuid.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-misc-uuid.xml
@@ -23,5 +23,6 @@
       <address type='drive' controller='0' bus='0' unit='0'/>
     </disk>
     <controller type='ide' index='0'/>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-net-eth-ifname.xml b/tests/qemuxml2argvdata/qemuxml2argv-net-eth-ifname.xml
index e24cd997ba..516957fc02 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-net-eth-ifname.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-net-eth-ifname.xml
@@ -25,5 +25,6 @@
       <script path='/etc/qemu-ifup'/>
       <target dev='nic02'/>
     </interface>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-net-eth-names.xml b/tests/qemuxml2argvdata/qemuxml2argv-net-eth-names.xml
index 105d3f6292..7875d0ccf8 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-net-eth-names.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-net-eth-names.xml
@@ -29,5 +29,6 @@
       <script path='/etc/qemu-ifup'/>
       <model type='e1000'/>
     </interface>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-net-eth.xml b/tests/qemuxml2argvdata/qemuxml2argv-net-eth.xml
index 27238fc75a..5d410b3753 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-net-eth.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-net-eth.xml
@@ -24,5 +24,6 @@
       <mac address='00:11:22:33:44:55'/>
       <script path='/etc/qemu-ifup'/>
     </interface>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-net-user.xml b/tests/qemuxml2argvdata/qemuxml2argv-net-user.xml
index 525593dc8c..ffc4a2ceb9 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-net-user.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-net-user.xml
@@ -23,5 +23,6 @@
     <interface type='user'>
       <mac address='00:11:22:33:44:55'/>
     </interface>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-net-virtio-device.xml b/tests/qemuxml2argvdata/qemuxml2argv-net-virtio-device.xml
index 5d34bd492c..e521796f9d 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-net-virtio-device.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-net-virtio-device.xml
@@ -22,5 +22,6 @@
       <mac address='00:11:22:33:44:55'/>
       <model type='virtio'/>
     </interface>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-net-virtio-netdev.xml b/tests/qemuxml2argvdata/qemuxml2argv-net-virtio-netdev.xml
index 5d34bd492c..e521796f9d 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-net-virtio-netdev.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-net-virtio-netdev.xml
@@ -22,5 +22,6 @@
       <mac address='00:11:22:33:44:55'/>
       <model type='virtio'/>
     </interface>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-net-virtio.xml b/tests/qemuxml2argvdata/qemuxml2argv-net-virtio.xml
index f8d9acfb6f..9b9c059ad0 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-net-virtio.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-net-virtio.xml
@@ -24,5 +24,6 @@
       <mac address='00:11:22:33:44:55'/>
       <model type='virtio'/>
     </interface>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-nographics-vga.xml b/tests/qemuxml2argvdata/qemuxml2argv-nographics-vga.xml
index 533ea59b30..ed91e37a12 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-nographics-vga.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-nographics-vga.xml
@@ -20,5 +20,6 @@
       <address type='drive' controller='0' bus='0' unit='0'/>
     </disk>
     <controller type='ide' index='0'/>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-parallel-tcp-chardev.xml b/tests/qemuxml2argvdata/qemuxml2argv-parallel-tcp-chardev.xml
index 96a1ca5a17..1093901da1 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-parallel-tcp-chardev.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-parallel-tcp-chardev.xml
@@ -25,5 +25,6 @@
       <protocol type='raw'/>
       <target port='0'/>
     </parallel>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-parallel-tcp.xml b/tests/qemuxml2argvdata/qemuxml2argv-parallel-tcp.xml
index 96a1ca5a17..1093901da1 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-parallel-tcp.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-parallel-tcp.xml
@@ -25,5 +25,6 @@
       <protocol type='raw'/>
       <target port='0'/>
     </parallel>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-restore-v1.xml b/tests/qemuxml2argvdata/qemuxml2argv-restore-v1.xml
index 533ea59b30..ed91e37a12 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-restore-v1.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-restore-v1.xml
@@ -20,5 +20,6 @@
       <address type='drive' controller='0' bus='0' unit='0'/>
     </disk>
     <controller type='ide' index='0'/>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-restore-v2.xml b/tests/qemuxml2argvdata/qemuxml2argv-restore-v2.xml
index 533ea59b30..ed91e37a12 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-restore-v2.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-restore-v2.xml
@@ -20,5 +20,6 @@
       <address type='drive' controller='0' bus='0' unit='0'/>
     </disk>
     <controller type='ide' index='0'/>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-serial-dev-chardev.xml b/tests/qemuxml2argvdata/qemuxml2argv-serial-dev-chardev.xml
index ae906c25bc..5d24986341 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-serial-dev-chardev.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-serial-dev-chardev.xml
@@ -28,5 +28,6 @@
       <source path='/dev/ttyS2'/>
       <target port='0'/>
     </console>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-serial-dev.xml b/tests/qemuxml2argvdata/qemuxml2argv-serial-dev.xml
index ae906c25bc..5d24986341 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-serial-dev.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-serial-dev.xml
@@ -28,5 +28,6 @@
       <source path='/dev/ttyS2'/>
       <target port='0'/>
     </console>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-serial-file-chardev.xml b/tests/qemuxml2argvdata/qemuxml2argv-serial-file-chardev.xml
index bdc483ffc7..98bc4ef70f 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-serial-file-chardev.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-serial-file-chardev.xml
@@ -28,5 +28,6 @@
       <source path='/tmp/serial.log'/>
       <target port='0'/>
     </console>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-serial-file.xml b/tests/qemuxml2argvdata/qemuxml2argv-serial-file.xml
index bdc483ffc7..98bc4ef70f 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-serial-file.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-serial-file.xml
@@ -28,5 +28,6 @@
       <source path='/tmp/serial.log'/>
       <target port='0'/>
     </console>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-serial-many-chardev.xml b/tests/qemuxml2argvdata/qemuxml2argv-serial-many-chardev.xml
index 38a9498faa..b121c5c72f 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-serial-many-chardev.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-serial-many-chardev.xml
@@ -30,5 +30,6 @@
     <console type='pty'>
       <target port='0'/>
     </console>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-serial-many.xml b/tests/qemuxml2argvdata/qemuxml2argv-serial-many.xml
index 38a9498faa..b121c5c72f 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-serial-many.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-serial-many.xml
@@ -30,5 +30,6 @@
     <console type='pty'>
       <target port='0'/>
     </console>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-serial-pty-chardev.xml b/tests/qemuxml2argvdata/qemuxml2argv-serial-pty-chardev.xml
index df694c78cd..611ddb8d7b 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-serial-pty-chardev.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-serial-pty-chardev.xml
@@ -26,5 +26,6 @@
     <console type='pty'>
       <target port='0'/>
     </console>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-serial-pty.xml b/tests/qemuxml2argvdata/qemuxml2argv-serial-pty.xml
index df694c78cd..611ddb8d7b 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-serial-pty.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-serial-pty.xml
@@ -26,5 +26,6 @@
     <console type='pty'>
       <target port='0'/>
     </console>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-serial-tcp-chardev.xml b/tests/qemuxml2argvdata/qemuxml2argv-serial-tcp-chardev.xml
index a8a3526713..286417e181 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-serial-tcp-chardev.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-serial-tcp-chardev.xml
@@ -30,5 +30,6 @@
       <protocol type='raw'/>
       <target port='0'/>
     </console>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-serial-tcp-telnet-chardev.xml b/tests/qemuxml2argvdata/qemuxml2argv-serial-tcp-telnet-chardev.xml
index fb8004214e..5aeceb0e8c 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-serial-tcp-telnet-chardev.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-serial-tcp-telnet-chardev.xml
@@ -30,5 +30,6 @@
       <protocol type='telnet'/>
       <target port='0'/>
     </console>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-serial-tcp-telnet.xml b/tests/qemuxml2argvdata/qemuxml2argv-serial-tcp-telnet.xml
index fb8004214e..5aeceb0e8c 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-serial-tcp-telnet.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-serial-tcp-telnet.xml
@@ -30,5 +30,6 @@
       <protocol type='telnet'/>
       <target port='0'/>
     </console>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-serial-tcp.xml b/tests/qemuxml2argvdata/qemuxml2argv-serial-tcp.xml
index a8a3526713..286417e181 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-serial-tcp.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-serial-tcp.xml
@@ -30,5 +30,6 @@
       <protocol type='raw'/>
       <target port='0'/>
     </console>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-serial-udp-chardev.xml b/tests/qemuxml2argvdata/qemuxml2argv-serial-udp-chardev.xml
index 01dba47c88..2c447389d5 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-serial-udp-chardev.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-serial-udp-chardev.xml
@@ -30,5 +30,6 @@
       <source mode='connect' host='127.0.0.1' service='9998'/>
       <target port='0'/>
     </console>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-serial-udp.xml b/tests/qemuxml2argvdata/qemuxml2argv-serial-udp.xml
index 01dba47c88..2c447389d5 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-serial-udp.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-serial-udp.xml
@@ -30,5 +30,6 @@
       <source mode='connect' host='127.0.0.1' service='9998'/>
       <target port='0'/>
     </console>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-serial-unix-chardev.xml b/tests/qemuxml2argvdata/qemuxml2argv-serial-unix-chardev.xml
index 7b90d7b3c5..2c07e94a0a 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-serial-unix-chardev.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-serial-unix-chardev.xml
@@ -28,5 +28,6 @@
       <source mode='connect' path='/tmp/serial.sock'/>
       <target port='0'/>
     </console>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-serial-unix.xml b/tests/qemuxml2argvdata/qemuxml2argv-serial-unix.xml
index 7b90d7b3c5..2c07e94a0a 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-serial-unix.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-serial-unix.xml
@@ -28,5 +28,6 @@
       <source mode='connect' path='/tmp/serial.sock'/>
       <target port='0'/>
     </console>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-serial-vc-chardev.xml b/tests/qemuxml2argvdata/qemuxml2argv-serial-vc-chardev.xml
index 76b3e2abc8..5b39736d5b 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-serial-vc-chardev.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-serial-vc-chardev.xml
@@ -26,5 +26,6 @@
     <console type='vc'>
       <target port='0'/>
     </console>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-serial-vc.xml b/tests/qemuxml2argvdata/qemuxml2argv-serial-vc.xml
index 76b3e2abc8..5b39736d5b 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-serial-vc.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-serial-vc.xml
@@ -26,5 +26,6 @@
     <console type='vc'>
       <target port='0'/>
     </console>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-sound-device.xml b/tests/qemuxml2argvdata/qemuxml2argv-sound-device.xml
index 8c33e6c90a..c7253462b2 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-sound-device.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-sound-device.xml
@@ -22,5 +22,6 @@
     <sound model='es1370'/>
     <sound model='sb16'/>
     <sound model='ac97'/>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-sound.xml b/tests/qemuxml2argvdata/qemuxml2argv-sound.xml
index 85f81cefaf..d34e0b3411 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-sound.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-sound.xml
@@ -24,5 +24,6 @@
     <sound model='es1370'/>
     <sound model='sb16'/>
     <sound model='ac97'/>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-watchdog-device.xml b/tests/qemuxml2argvdata/qemuxml2argv-watchdog-device.xml
index 9b2ffdf8b2..2dfc37e22e 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-watchdog-device.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-watchdog-device.xml
@@ -19,5 +19,6 @@
       <target dev='hda' bus='ide'/>
     </disk>
     <watchdog model='ib700' action='poweroff'/>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-watchdog.xml b/tests/qemuxml2argvdata/qemuxml2argv-watchdog.xml
index 07d2c14269..804dfd8935 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-watchdog.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-watchdog.xml
@@ -21,5 +21,6 @@
     </disk>
     <controller type='ide' index='0'/>
     <watchdog model='ib700' action='poweroff'/>
+    <memballoon model='virtio'/>
   </devices>
 </domain>
diff --git a/tests/qemuxml2argvtest.c b/tests/qemuxml2argvtest.c
index ad1379b5c6..24002b8f17 100644
--- a/tests/qemuxml2argvtest.c
+++ b/tests/qemuxml2argvtest.c
@@ -352,6 +352,8 @@ mymain(int argc, char **argv)
     DO_TEST("watchdog", 0);
     DO_TEST("watchdog-device", QEMUD_CMD_FLAG_DEVICE |
             QEMUD_CMD_FLAG_NODEFCONFIG);
+    DO_TEST("balloon-device", QEMUD_CMD_FLAG_DEVICE |
+            QEMUD_CMD_FLAG_NODEFCONFIG);
     DO_TEST("sound", 0);
     DO_TEST("sound-device", QEMUD_CMD_FLAG_DEVICE |
             QEMUD_CMD_FLAG_NODEFCONFIG);