conf: Add VM Generation ID parse/format support

The VM Generation ID is a mechanism to provide a unique 128-bit, cryptographically random, and integer value identifier known as the GUID (Globally Unique Identifier) to the guest OS. The value is used to help notify the guest operating system when the virtual machine is executed with a different configuration. This patch adds support for a new "genid" XML element similar to the "uuid" element. The "genid" element can have two forms "<genid/>" or "<genid>$GUID</genid>". If the $GUID is not provided, libvirt will generate one and save it in the XML. Since adding support for a generated GUID (or UUID like) value to be displayed modifying the xml2xml test to include virrandommock.so is necessary since it will generate a "known" value. Signed-off-by: John Ferlan <jferlan@redhat.com> ACKed-by: Michal Privoznik <mprivozn@redhat.com>
2024-12-22 17:34:18 +03:00 · 2018-04-09 12:10:02 -04:00 · 2018-04-09 12:10:02 -04:00 · b50efe97ad
commit b50efe97ad
parent c7151b0e4d
11 changed files with 290 additions and 1 deletions
--- a/docs/formatdomain.html.in
+++ b/docs/formatdomain.html.in
@ -34,6 +34,7 @@
 &lt;domain type='kvm' id='1'&gt;
  &lt;name&gt;MyGuest&lt;/name&gt;
  &lt;uuid&gt;4dea22b3-1d52-d8f3-2516-782e98ab3fa0&lt;/uuid&gt;
+  &lt;genid&gt;43dc0cf8-809b-4adb-9bea-a9abb5f3d90e&lt;/genid&gt;
  &lt;title&gt;A short description - title - of the domain&lt;/title&gt;
  &lt;description&gt;Some human readable description&lt;/description&gt;
  &lt;metadata&gt;
@ -61,6 +62,32 @@
        specification. <span class="since">Since 0.0.1, sysinfo
        since 0.8.7</span></dd>

+      <dt><code>genid</code></dt>
+      <dd><span class="since">Since 4.4.0</span>, the <code>genid</code>
+        element can be used to add a Virtual Machine Generation ID which
+        exposes a 128-bit, cryptographically random, integer value identifier,
+        referred to as a Globally Unique Identifier (GUID) using the same
+        format as the <code>uuid</code>. The value is used to help notify
+        the guest operating system when the virtual machine is re-executing
+        something that has already executed before, such as:
+
+        <ul>
+          <li>VM starts executing a snapshot</li>
+          <li>VM is recovered from backup</li>
+          <li>VM is failover in a disaster recovery environment</li>
+          <li>VM is imported, copied, or cloned</li>
+        </ul>
+
+        The guest operating system notices the change and is then able to
+        react as appropriate by marking its copies of distributed databases
+        as dirty, re-initializing its random number generator, etc.
+
+        <p>
+        The libvirt XML parser will accept both a provided GUID value
+        or just &lt;genid/&gt; in which case a GUID will be generated
+        and saved in the XML. For the transitions such as above, libvirt
+        will change the GUID before re-executing.</p></dd>
+
      <dt><code>title</code></dt>
      <dd>The optional element <code>title</code> provides space for a
        short description of the domain. The title should not contain
--- a/docs/schemas/domaincommon.rng
+++ b/docs/schemas/domaincommon.rng
@ -502,6 +502,14 @@
          <ref name="UUID"/>
        </element>
      </optional>
+      <optional>
+        <element name="genid">
+          <choice>
+            <ref name="UUID"/>
+            <empty/>
+          </choice>
+        </element>
+      </optional>
    </interleave>
  </define>
  <define name="idmap">
--- a/src/conf/domain_conf.c
+++ b/src/conf/domain_conf.c
@ -18920,6 +18920,34 @@ virDomainDefParseXML(xmlDocPtr xml,
        VIR_FREE(tmp);
    }

+    /* Extract domain genid - a genid can either be provided or generated */
+    if ((n = virXPathNodeSet("./genid", ctxt, &nodes)) < 0)
+        goto error;
+
+    if (n > 0) {
+        if (n != 1) {
+            virReportError(VIR_ERR_XML_ERROR, "%s",
+                           _("element 'genid' can only appear once"));
+            goto error;
+        }
+        def->genidRequested = true;
+        if (!(tmp = virXPathString("string(./genid)", ctxt))) {
+            if (virUUIDGenerate(def->genid) < 0) {
+                virReportError(VIR_ERR_INTERNAL_ERROR,
+                               "%s", _("Failed to generate genid"));
+                goto error;
+            }
+            def->genidGenerated = true;
+        } else {
+            if (virUUIDParse(tmp, def->genid) < 0) {
+                virReportError(VIR_ERR_INTERNAL_ERROR,
+                               "%s", _("malformed genid element"));
+                goto error;
+            }
+        }
+    }
+    VIR_FREE(nodes);
+
    /* Extract short description of domain (title) */
    def->title = virXPathString("string(./title[1])", ctxt);
    if (def->title && strchr(def->title, '\n')) {
@ -22034,6 +22062,25 @@ virDomainDefCheckABIStabilityFlags(virDomainDefPtr src,
        goto error;
    }

+    if (src->genidRequested != dst->genidRequested) {
+        virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
+                       _("Target domain requested genid does not match source"));
+        goto error;
+    }
+
+    if (src->genidRequested &&
+        memcmp(src->genid, dst->genid, VIR_UUID_BUFLEN) != 0) {
+        char guidsrc[VIR_UUID_STRING_BUFLEN];
+        char guiddst[VIR_UUID_STRING_BUFLEN];
+
+        virUUIDFormat(src->genid, guidsrc);
+        virUUIDFormat(dst->genid, guiddst);
+        virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+                       _("Target domain genid %s does not match source %s"),
+                       guiddst, guidsrc);
+        goto error;
+    }
+
    /* Not strictly ABI related, but we want to make sure domains
     * don't get silently re-named through the backdoor when passing
     * custom XML into various APIs, since this would create havoc
@ -26752,6 +26799,13 @@ virDomainDefFormatInternal(virDomainDefPtr def,
    virUUIDFormat(uuid, uuidstr);
    virBufferAsprintf(buf, "<uuid>%s</uuid>\n", uuidstr);

+    if (def->genidRequested) {
+        char genidstr[VIR_UUID_STRING_BUFLEN];
+
+        virUUIDFormat(def->genid, genidstr);
+        virBufferAsprintf(buf, "<genid>%s</genid>\n", genidstr);
+    }
+
    virBufferEscapeString(buf, "<title>%s</title>\n", def->title);

    virBufferEscapeString(buf, "<description>%s</description>\n",
--- a/src/conf/domain_conf.h
+++ b/src/conf/domain_conf.h
@ -2328,6 +2328,11 @@ struct _virDomainDef {
    virDomainVirtType virtType;
    int id;
    unsigned char uuid[VIR_UUID_BUFLEN];
+
+    unsigned char genid[VIR_UUID_BUFLEN];
+    bool genidRequested;
+    bool genidGenerated;
+
    char *name;
    char *title;
    char *description;
--- a/tests/qemuxml2argvdata/genid-auto.xml
+++ b/tests/qemuxml2argvdata/genid-auto.xml
@ -0,0 +1,32 @@
+<domain type='qemu' id='1'>
+  <name>QEMUGuest1</name>
+  <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
+  <genid/>
+  <memory unit='KiB'>219136</memory>
+  <currentMemory unit='KiB'>219136</currentMemory>
+  <vcpu placement='static'>1</vcpu>
+  <os>
+    <type arch='x86_64' machine='pc'>hvm</type>
+    <boot dev='hd'/>
+  </os>
+  <features>
+    <acpi/>
+  </features>
+  <clock offset='utc'/>
+  <on_poweroff>destroy</on_poweroff>
+  <on_reboot>restart</on_reboot>
+  <on_crash>destroy</on_crash>
+  <devices>
+    <emulator>/usr/bin/qemu-system-x86_64</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'/>
+    <memballoon model='none'/>
+  </devices>
+</domain>
--- a/tests/qemuxml2argvdata/genid.xml
+++ b/tests/qemuxml2argvdata/genid.xml
@ -0,0 +1,32 @@
+<domain type='qemu' id='1'>
+  <name>QEMUGuest1</name>
+  <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
+  <genid>e9392370-2917-565e-692b-d057f46512d6</genid>
+  <memory unit='KiB'>219136</memory>
+  <currentMemory unit='KiB'>219136</currentMemory>
+  <vcpu placement='static'>1</vcpu>
+  <os>
+    <type arch='x86_64' machine='pc'>hvm</type>
+    <boot dev='hd'/>
+  </os>
+  <features>
+    <acpi/>
+  </features>
+  <clock offset='utc'/>
+  <on_poweroff>destroy</on_poweroff>
+  <on_reboot>restart</on_reboot>
+  <on_crash>destroy</on_crash>
+  <devices>
+    <emulator>/usr/bin/qemu-system-x86_64</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'/>
+    <memballoon model='none'/>
+  </devices>
+</domain>
--- a/tests/qemuxml2xmloutdata/genid-active.xml
+++ b/tests/qemuxml2xmloutdata/genid-active.xml
@ -0,0 +1,32 @@
+<domain type='qemu' id='1'>
+  <name>QEMUGuest1</name>
+  <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
+  <genid>e9392370-2917-565e-692b-d057f46512d6</genid>
+  <memory unit='KiB'>219136</memory>
+  <currentMemory unit='KiB'>219136</currentMemory>
+  <vcpu placement='static'>1</vcpu>
+  <os>
+    <type arch='x86_64' machine='pc'>hvm</type>
+    <boot dev='hd'/>
+  </os>
+  <features>
+    <acpi/>
+  </features>
+  <clock offset='utc'/>
+  <on_poweroff>destroy</on_poweroff>
+  <on_reboot>restart</on_reboot>
+  <on_crash>destroy</on_crash>
+  <devices>
+    <emulator>/usr/bin/qemu-system-x86_64</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'/>
+    <memballoon model='none'/>
+  </devices>
+</domain>
--- a/tests/qemuxml2xmloutdata/genid-auto-active.xml
+++ b/tests/qemuxml2xmloutdata/genid-auto-active.xml
@ -0,0 +1,32 @@
+<domain type='qemu' id='1'>
+  <name>QEMUGuest1</name>
+  <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
+  <genid>00010203-0405-4607-8809-0a0b0c0d0e0f</genid>
+  <memory unit='KiB'>219136</memory>
+  <currentMemory unit='KiB'>219136</currentMemory>
+  <vcpu placement='static'>1</vcpu>
+  <os>
+    <type arch='x86_64' machine='pc'>hvm</type>
+    <boot dev='hd'/>
+  </os>
+  <features>
+    <acpi/>
+  </features>
+  <clock offset='utc'/>
+  <on_poweroff>destroy</on_poweroff>
+  <on_reboot>restart</on_reboot>
+  <on_crash>destroy</on_crash>
+  <devices>
+    <emulator>/usr/bin/qemu-system-x86_64</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'/>
+    <memballoon model='none'/>
+  </devices>
+</domain>
--- a/tests/qemuxml2xmloutdata/genid-auto-inactive.xml
+++ b/tests/qemuxml2xmloutdata/genid-auto-inactive.xml
@ -0,0 +1,32 @@
+<domain type='qemu'>
+  <name>QEMUGuest1</name>
+  <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
+  <genid>00010203-0405-4607-8809-0a0b0c0d0e0f</genid>
+  <memory unit='KiB'>219136</memory>
+  <currentMemory unit='KiB'>219136</currentMemory>
+  <vcpu placement='static'>1</vcpu>
+  <os>
+    <type arch='x86_64' machine='pc'>hvm</type>
+    <boot dev='hd'/>
+  </os>
+  <features>
+    <acpi/>
+  </features>
+  <clock offset='utc'/>
+  <on_poweroff>destroy</on_poweroff>
+  <on_reboot>restart</on_reboot>
+  <on_crash>destroy</on_crash>
+  <devices>
+    <emulator>/usr/bin/qemu-system-x86_64</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'/>
+    <memballoon model='none'/>
+  </devices>
+</domain>
--- a/tests/qemuxml2xmloutdata/genid-inactive.xml
+++ b/tests/qemuxml2xmloutdata/genid-inactive.xml
@ -0,0 +1,32 @@
+<domain type='qemu'>
+  <name>QEMUGuest1</name>
+  <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
+  <genid>e9392370-2917-565e-692b-d057f46512d6</genid>
+  <memory unit='KiB'>219136</memory>
+  <currentMemory unit='KiB'>219136</currentMemory>
+  <vcpu placement='static'>1</vcpu>
+  <os>
+    <type arch='x86_64' machine='pc'>hvm</type>
+    <boot dev='hd'/>
+  </os>
+  <features>
+    <acpi/>
+  </features>
+  <clock offset='utc'/>
+  <on_poweroff>destroy</on_poweroff>
+  <on_reboot>restart</on_reboot>
+  <on_crash>destroy</on_crash>
+  <devices>
+    <emulator>/usr/bin/qemu-system-x86_64</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'/>
+    <memballoon model='none'/>
+  </devices>
+</domain>
--- a/tests/qemuxml2xmltest.c
+++ b/tests/qemuxml2xmltest.c
@ -276,6 +276,8 @@ mymain(void)
    setenv("PATH", "/bin", 1);

    DO_TEST("minimal", NONE);
+    DO_TEST("genid", NONE);
+    DO_TEST("genid-auto", NONE);
    DO_TEST("machine-core-on", NONE);
    DO_TEST("machine-core-off", NONE);
    DO_TEST("machine-loadparm-multiple-disks-nets-s390", NONE);
@ -1220,7 +1222,8 @@ mymain(void)
 }

 VIR_TEST_MAIN_PRELOAD(mymain,
-                      abs_builddir "/.libs/virpcimock.so")
+                      abs_builddir "/.libs/virpcimock.so",
+                      abs_builddir "/.libs/virrandommock.so")

 #else