qemu: Add memoryBackingDir to qemuDomainObjPrivate

This way we _can_ (but do not, yet) remember the memory backing path for
running domains even after configuration change and daemon restart.

Signed-off-by: Martin Kletzander <mkletzan@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>

src/qemu/qemu_domain.c

@@ -1934,6 +1934,8 @@ qemuDomainObjPrivateDataClear(qemuDomainObjPrivate *priv)
     g_slist_free_full(g_steal_pointer(&priv->threadContextAliases), g_free);
 
     priv->migrationRecoverSetup = false;
+
+    g_clear_pointer(&priv->memoryBackingDir, g_free);
 }
 
 
@@ -2708,6 +2710,7 @@ qemuDomainObjPrivateXMLFormat(virBuffer *buf,
     virBufferEscapeString(buf, "<libDir path='%s'/>\n", priv->libDir);
     virBufferEscapeString(buf, "<channelTargetDir path='%s'/>\n",
                           priv->channelTargetDir);
+    virBufferEscapeString(buf, "<memoryBackingDir path='%s'/>\n", priv->memoryBackingDir);
 
     virCPUDefFormatBufFull(buf, priv->origCPU, NULL);
 
@@ -3429,6 +3432,8 @@ qemuDomainObjPrivateXMLParse(xmlXPathContextPtr ctxt,
         priv->channelTargetDir = tmp;
     tmp = NULL;
 
+    priv->memoryBackingDir = virXPathString("string(./memoryBackingDir/@path)", ctxt);
+
     qemuDomainSetPrivatePathsOld(driver, vm);
 
     if (virCPUDefParseXML(ctxt, "./cpu", VIR_CPU_TYPE_GUEST, &priv->origCPU,

src/qemu/qemu_domain.h

@@ -261,6 +261,8 @@ struct _qemuDomainObjPrivate {
 
     /* named file descriptor groups associated with the VM */
     GHashTable *fds;
+
+    char *memoryBackingDir;
 };
 
 #define QEMU_DOMAIN_PRIVATE(vm) \

tests/qemustatusxml2xmldata/memory-backing-dir-in.xml

@@ -0,0 +1,61 @@
+<domstatus state='running' reason='booted' pid='3803518'>
+  <taint flag='high-privileges'/>
+  <monitor path='/var/lib/libvirt/qemu/test.monitor' type='unix'/>
+  <vcpus>
+    <vcpu id='0' pid='3803519'/>
+  </vcpus>
+  <qemuCaps>
+    <flag name='vnet-hdr'/>
+    <flag name='qxl.vgamem_mb'/>
+    <flag name='qxl-vga.vgamem_mb'/>
+    <flag name='pc-dimm'/>
+  </qemuCaps>
+  <lockstate>testtest</lockstate>
+  <devices>
+    <device alias='balloon0'/>
+    <device alias='video0'/>
+    <device alias='serial0'/>
+    <device alias='net0'/>
+    <device alias='usb'/>
+  </devices>
+  <numad nodeset='0-2' cpuset='1,3'/>
+  <libDir path='/tmp'/>
+  <channelTargetDir path='/var/lib/libvirt/qemu/channel/target'/>
+  <memoryBackingDir path='/some/random/path/1-QEMUGuest1'/>
+  <allowReboot value='yes'/>
+  <nodename index='0'/>
+  <fdset index='0'/>
+  <blockjobs active='no'/>
+  <agentTimeout>-2</agentTimeout>
+  <domain type='qemu' id='1'>
+    <name>QEMUGuest1</name>
+    <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
+    <memory unit='KiB'>219136</memory>
+    <currentMemory unit='KiB'>219136</currentMemory>
+    <vcpu placement='static'>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-system-i386</emulator>
+      <controller type='usb' index='0'>
+        <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x2'/>
+      </controller>
+      <controller type='ide' index='0'>
+        <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x1'/>
+      </controller>
+      <controller type='pci' index='0' model='pci-root'/>
+      <input type='mouse' bus='ps2'/>
+      <input type='keyboard' bus='ps2'/>
+      <audio id='1' type='none'/>
+      <memballoon model='virtio'>
+        <address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x0'/>
+      </memballoon>
+    </devices>
+  </domain>
+</domstatus>

tests/qemustatusxml2xmldata/memory-backing-dir-out.xml

@@ -0,0 +1 @@
+memory-backing-dir-in.xml

tests/qemuxmlactivetest.c

@@ -248,6 +248,8 @@ mymain(void)
 
     DO_TEST_STATUS("backup-pull");
 
+    DO_TEST_STATUS("memory-backing-dir");
+
  cleanup:
     qemuTestDriverFree(&driver);