Merge "Fix detaching devices by alias with mdevs"

nova/tests/functional/regressions/test_bug_2074219.py

@@ -12,7 +12,6 @@
 # under the License.
 
 from nova.tests.fixtures import libvirt as fakelibvirt
-from nova.tests.functional.api import client
 from nova.tests.functional.libvirt import test_vgpu
 
 
@@ -61,13 +60,7 @@ class VGPUTestVolumeOPs(test_vgpu.VGPUTestBase):
         # Detach the volume from the instance
         # DELETE /servers/{server_id}/os-volume_attachments/{volume_id} is
         # async but as we are using CastAsCall it's sync in our func tests
-        # FIXME(sean-k-mooney): This test is currently broken because of
-        # bug 2074219
-        # self.api.delete_server_volume(
-        #     server_id, self.cinder.IMAGE_BACKED_VOL)
-        # self._wait_for_volume_detach(
-        #     server_id, self.cinder.IMAGE_BACKED_VOL)
-        error = self.assertRaises(
-            client.OpenStackApiException, self.api.delete_server_volume,
+        self.api.delete_server_volume(
+            server_id, self.cinder.IMAGE_BACKED_VOL)
+        self._wait_for_volume_detach(
             server_id, self.cinder.IMAGE_BACKED_VOL)
-        self.assertEqual(500, error.response.status_code)

nova/tests/unit/virt/libvirt/test_guest.py

@@ -308,6 +308,11 @@ class GuestTestCase(test.NoDBTestCase):
         <address domain='0x0000' bus='0x06' slot='0x12' function='0x6'/>
       </source>
     </hostdev>
+    <hostdev mode='subsystem' type='mdev' model='vfio-pci'>
+      <source>
+        <address uuid='c2177883-f1bb-47f0-914d-32a22e3a8804'/>
+      </source>
+    </hostdev>
     <interface type="bridge">
       <mac address="fa:16:3e:f9:af:ae"/>
       <model type="virtio"/>

nova/virt/libvirt/guest.py

@@ -414,7 +414,7 @@ class Guest(object):
     def get_device_by_alias(self, devalias, devtype=None,
                             from_persistent_config=False):
         for dev in self.get_all_devices(devtype):
-            if dev.alias == devalias:
+            if hasattr(dev, 'alias') and dev.alias == devalias:
                 return dev
 
     def get_all_devices(

releasenotes/notes/bug-2074219-937d6404c1cbb04c.yaml

@@ -0,0 +1,17 @@
+---
+fixes:
+  - |
+    During the Caracal cycle the libvirt driver was enhanced to support using
+    device aliases to detach devices from a domain.
+    I1dfe4ad3df81bc810835af9b09cfc6c06e9a5388
+    This introduced a regression for instance with vgpus.
+    A prior bugfix https://bugs.launchpad.net/nova/+bug/1942345
+    addressed the symptom without correcting the underlying problem.
+    A related bug for mdev devices was later reported.
+    https://bugs.launchpad.net/nova/+bug/2074219
+    When this feature was added nova introduced a helper method
+    to get device via the alias because the libvirt api does not provide one
+    natively. That helper function assumed all devices would have an alias
+    attribute. That assumption was not valid and had now been corrected.
+    As a result detaching a volume from an instance with vgpus should now
+    be possible and this class of bug should no longer happen.