Handle new nodedev name for mediated devices

libvirt recently changed the nodedev names for mediated devices due to
the fact that mdevctl supports defining multiple mediated devices with
the same UUID as long as only one is active at a time. This means that
the nodedev name changed from the format 'mdev_$UUID' to the format
'mdev_$UUID_$PARENT'.

Unfortunately, virt-install was parsing the nodedev name to extract the
UUID of a mediated device. This fails with the new name format.
Fortunately, in libvirt 7.3.0, a <uuid> field was added to the xml
schema for mdev devices, so we can simply use this instead, and fall
back to the name parsing if it doesn't exist.

Signed-off-by: Jonathon Jongsma <jjongsma@redhat.com>

tests/data/testdriver/testdriver.xml

@@ -3725,4 +3725,18 @@ ba</description>
   </capability>
 </device>
 
+<device>
+  <name>mdev_35ceae7f_eea5_4f28_b7f3_7b12a3e62d3c_0000_06_00_0</name>
+  <path>/sys/devices/pci0000:00/0000:00:02.0/35ceae7f-eea5-4f28-b7f3-7b12a3e62d3c</path>
+  <parent>pci_0000_06_00_0</parent>
+  <driver>
+    <name>vfio_mdev</name>
+  </driver>
+ <capability type='mdev'>
+    <type id='nvidia-11'/>
+    <iommuGroup number='12'/>
+    <uuid>35ceae7f-eea5-4f28-b7f3-7b12a3e62d3c</uuid>
+  </capability>
+</device>
+
 </node>

tests/test_nodedev.py

@@ -8,6 +8,7 @@
 import os.path
 
 import pytest
+import libvirt
 
 from virtinst import Guest
 from virtinst import NodeDevice
@@ -154,6 +155,19 @@ def testPCIMdev():
     assert dev.parent == "pci_0000_06_00_0"
     assert dev.device_type == "mdev"
     assert dev.type_id == "nvidia-11"
+    assert dev.get_mdev_uuid() == "4b20d080-1b54-4048-85b3-a6a62d165c01"
+
+# libvirt <7.3.0 doesn't support <uuid> in the mdev node device xml
+@pytest.mark.skipif(libvirt.getVersion() < 7003000, reason="libvirt version doesn't support new mdev format")
+def testPCIMdevNewFormat():
+    conn = utils.URIs.open_testdriver_cached()
+    devname = "mdev_35ceae7f_eea5_4f28_b7f3_7b12a3e62d3c_0000_06_00_0"
+    dev = _nodeDevFromName(conn, devname)
+    assert dev.name == devname
+    assert dev.parent == "pci_0000_06_00_0"
+    assert dev.device_type == "mdev"
+    assert dev.type_id == "nvidia-11"
+    assert dev.get_mdev_uuid() == "35ceae7f-eea5-4f28-b7f3-7b12a3e62d3c"
 
 
 # NodeDevice 2 Device XML tests

virtinst/nodedev.py

@@ -94,6 +94,12 @@ class NodeDevice(XMLBuilder):
     device_type = XMLProperty("./capability/@type")
 
     def get_mdev_uuid(self):
+        # libvirt 7.3.0 added a <uuid> element to the nodedev xml for mdev
+        # types. For older versions, we unfortunately have to parse the nodedev
+        # name, which uses the format "mdev_$UUID_WITH_UNDERSCORES"
+        if self.uuid is not None:
+            return self.uuid
+
         return self.name[5:].replace('_', '-')
 
     def compare_to_hostdev(self, hostdev):
@@ -191,6 +197,7 @@ class NodeDevice(XMLBuilder):
 
     # type='mdev' options
     type_id = XMLProperty("./capability/type/@id")
+    uuid = XMLProperty("./capability/uuid")
 
 
 def _AddressStringToHostdev(conn, addrstr):