Parse alias from domain hostdev

In I16e7df6932bb7dff243706ee49338ba6b3782085 we missed that
LibvirtConfigGuestHostdevPCI is not a child class of
LibvirtConfigGuestInterface and therefore we missed parsing out the
alias field from the domain xml for hostdevs. The new libvirt driver
device detach logic[1] uses the alias as the identifier towards libvirt
so now hostdevs cannot be detached. This patch parses out the alias
field to fix the issue.

Closes-Bug: #1942345
Related-Bug: #1882521

[1] https://review.opendev.org/q/topic:bug/1882521

Change-Id: I30d30a772475cb82d0fd088f14a54a35646bd1dc
(cherry picked from commit b67b928)

Author: Balazs Gibizer

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

@@ -1604,6 +1604,24 @@ def test_parse_guest_hosdev_usb(self):
         self.assertEqual(obj.mode, 'subsystem')
         self.assertEqual(obj.type, 'usb')
 
+    def test_config_alias_parse(self):
+        xml = """
+            <hostdev mode='subsystem' type='pci' managed='yes'>
+                <driver name='vfio'/>
+                <source>
+                    <address domain='0x0000' bus='0x81' slot='0x00'
+                             function='0x1'/>
+                </source>
+                <alias name='hostdev1'/>
+                <address type='pci' domain='0x0000' bus='0x00' slot='0x05'
+                         function='0x0'/>
+            </hostdev>"""
+
+        xmldoc = etree.fromstring(xml)
+        obj = config.LibvirtConfigGuestHostdevPCI()
+        obj.parse_dom(xmldoc)
+        self.assertEqual('hostdev1', obj.alias)
+
 
 class LibvirtConfigGuestHostdevMDEV(LibvirtConfigBaseTest):
 

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

@@ -23433,15 +23433,23 @@ def test__detach_with_retry_persistent_success(self):
         # check that the internal event handling is cleaned up
         self.assertEqual(set(), drvr._device_event_handler._waiters)
 
-    @ddt.data(power_state.RUNNING, power_state.PAUSED)
-    def test__detach_with_retry_live_success(self, state):
+    @ddt.unpack
+    @ddt.data(
+        (power_state.RUNNING, vconfig.LibvirtConfigGuestDisk()),
+        (power_state.RUNNING, vconfig.LibvirtConfigGuestInterface()),
+        (power_state.RUNNING, vconfig.LibvirtConfigGuestHostdevPCI()),
+        (power_state.PAUSED, vconfig.LibvirtConfigGuestDisk()),
+        (power_state.PAUSED, vconfig.LibvirtConfigGuestInterface()),
+        (power_state.PAUSED, vconfig.LibvirtConfigGuestHostdevPCI()),
+    )
+    def test__detach_with_retry_live_success(self, state, device_class):
         """Test detach only from the live domain"""
         drvr = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
         mock_guest = mock.Mock(spec=libvirt_guest.Guest)
         mock_guest.get_power_state.return_value = state
         mock_guest.has_persistent_configuration.return_value = False
 
-        mock_dev = mock.Mock(spec=vconfig.LibvirtConfigGuestDisk)
+        mock_dev = mock.Mock(spec_set=device_class)
         mock_dev.alias = 'virtio-disk1'
 
         mock_get_device_conf_func = mock.Mock(

nova/virt/libvirt/config.py

@@ -2204,6 +2204,8 @@ def __init__(self, **kwargs):
         self.slot = None
         self.function = None
 
+        self.alias = None
+
     def __eq__(self, other):
         if not isinstance(other, LibvirtConfigGuestHostdevPCI):
             return False
@@ -2243,6 +2245,8 @@ def parse_dom(self, xmldoc):
                         self.bus = sub.get('bus')
                         self.slot = sub.get('slot')
                         self.function = sub.get('function')
+            elif c.tag == 'alias':
+                self.alias = c.get('name')
 
 
 class LibvirtConfigGuestHostdevMDEV(LibvirtConfigGuestHostdev):