diff --git a/nova/tests/functional/regressions/test_bug_1951656.py b/nova/tests/functional/regressions/test_bug_1951656.py
index 9aad191072c4..d705ff6fe315 100644
--- a/nova/tests/functional/regressions/test_bug_1951656.py
+++ b/nova/tests/functional/regressions/test_bug_1951656.py
@@ -63,21 +63,11 @@ class VGPUTestsLibvirt7_7(test_vgpu.VGPUTestBase):
flavor_id=self.flavor, host=self.compute1.host,
networks='auto', expected_state='ACTIVE')
- # TODO(sbauza): Modify this once bug #1851656 is fixed.
- # mdev_name2uuid() raises a badly formed hexadecimal UUID string error
- self.assertRaises(ValueError,
- self.assert_mdev_usage,
- self.compute1, expected_amount=1)
+ self.assert_mdev_usage(self.compute1, expected_amount=1)
- # Now, the problem is that we can't create new instances with VGPUs
- # from this host.
- server = self._create_server(
+ self._create_server(
image_uuid='155d900f-4e14-4e4c-a73d-069cbf4541e6',
flavor_id=self.flavor, host=self.compute1.host,
- networks='auto', expected_state='ERROR')
- # The error is due to a bad mdev name parsing
- self.assertIn('fault', server)
- # since we only have one host, we have a RescheduledException as this
- # service was creating an exception and we can't use another one.
- self.assertIn('Exceeded maximum number of retries',
- server['fault']['message'])
+ networks='auto', expected_state='ACTIVE')
+
+ self.assert_mdev_usage(self.compute1, expected_amount=2)
diff --git a/nova/tests/unit/virt/libvirt/test_config.py b/nova/tests/unit/virt/libvirt/test_config.py
index c4c9359dd838..4a8aa027a917 100644
--- a/nova/tests/unit/virt/libvirt/test_config.py
+++ b/nova/tests/unit/virt/libvirt/test_config.py
@@ -3181,6 +3181,32 @@ class LibvirtConfigNodeDeviceTest(LibvirtConfigBaseTest):
config.LibvirtConfigNodeDeviceMdevInformation)
self.assertEqual("nvidia-11", obj.mdev_information.type)
self.assertEqual(12, obj.mdev_information.iommu_group)
+ self.assertIsNone(obj.mdev_information.uuid)
+
+ def test_config_mdev_device_uuid(self):
+ xmlin = """
+
+ mdev_b2107403_110c_45b0_af87_32cc91597b8a_0000_41_00_0
+ /sys/devices/pci0000:40/0000:40:03.1/0000:41:00.0/b2107403-110c-45b0-af87-32cc91597b8a
+ pci_0000_41_00_0
+
+ vfio_mdev
+
+
+
+ b2107403-110c-45b0-af87-32cc91597b8a
+
+
+ """
+
+ obj = config.LibvirtConfigNodeDevice()
+ obj.parse_str(xmlin)
+ self.assertIsInstance(obj.mdev_information,
+ config.LibvirtConfigNodeDeviceMdevInformation)
+ self.assertEqual("nvidia-442", obj.mdev_information.type)
+ self.assertEqual(57, obj.mdev_information.iommu_group)
+ self.assertEqual("b2107403-110c-45b0-af87-32cc91597b8a",
+ obj.mdev_information.uuid)
def test_config_vdpa_device(self):
xmlin = """
diff --git a/nova/virt/libvirt/config.py b/nova/virt/libvirt/config.py
index 3d91c325c397..0db2dc6b679f 100644
--- a/nova/virt/libvirt/config.py
+++ b/nova/virt/libvirt/config.py
@@ -3382,6 +3382,7 @@ class LibvirtConfigNodeDeviceMdevInformation(LibvirtConfigObject):
root_name="capability", **kwargs)
self.type = None
self.iommu_group = None
+ self.uuid = None
def parse_dom(self, xmldoc):
super(LibvirtConfigNodeDeviceMdevInformation,
@@ -3391,6 +3392,8 @@ class LibvirtConfigNodeDeviceMdevInformation(LibvirtConfigObject):
self.type = c.get('id')
if c.tag == "iommuGroup":
self.iommu_group = int(c.get('number'))
+ if c.tag == "uuid":
+ self.uuid = c.text
class LibvirtConfigNodeDeviceVpdCap(LibvirtConfigObject):
diff --git a/nova/virt/libvirt/driver.py b/nova/virt/libvirt/driver.py
index be458dbd5b77..e2471074377b 100644
--- a/nova/virt/libvirt/driver.py
+++ b/nova/virt/libvirt/driver.py
@@ -8227,15 +8227,52 @@ class LibvirtDriver(driver.ComputeDriver):
def _get_mediated_device_information(self, devname):
"""Returns a dict of a mediated device."""
- virtdev = self._host.device_lookup_by_name(devname)
+ # LP #1951656 - In Libvirt 7.7, the mdev name now includes the PCI
+ # address of the parent device (e.g. mdev__) due to
+ # the mdevctl allowing for multiple mediated devs having the same UUID
+ # defined (only one can be active at a time). Since the guest
+ # information doesn't have the parent ID, try to lookup which
+ # mediated device is available that matches the UUID. If multiple
+ # devices are found that match the UUID, then this is an error
+ # condition.
+ try:
+ virtdev = self._host.device_lookup_by_name(devname)
+ except libvirt.libvirtError as ex:
+ if ex.get_error_code() != libvirt.VIR_ERR_NO_NODE_DEVICE:
+ raise
+ mdevs = [dev for dev in self._host.list_mediated_devices()
+ if dev.startswith(devname)]
+ # If no matching devices are found, simply raise the original
+ # exception indicating that no devices are found.
+ if not mdevs:
+ raise
+ elif len(mdevs) > 1:
+ msg = ("The mediated device name %(devname)s refers to a UUID "
+ "that is present in multiple libvirt mediated devices. "
+ "Matching libvirt mediated devices are %(devices)s. "
+ "Mediated device UUIDs must be unique for Nova." %
+ {'devname': devname,
+ 'devices': ', '.join(mdevs)})
+ raise exception.InvalidLibvirtMdevConfig(reason=msg)
+
+ LOG.debug('Found requested device %s as %s. Using that.',
+ devname, mdevs[0])
+ virtdev = self._host.device_lookup_by_name(mdevs[0])
xmlstr = virtdev.XMLDesc(0)
cfgdev = vconfig.LibvirtConfigNodeDevice()
cfgdev.parse_str(xmlstr)
+ # Starting with Libvirt 7.3, the uuid information is available in the
+ # node device information. If its there, use that. Otherwise,
+ # fall back to the previous behavior of parsing the uuid from the
+ # devname.
+ if cfgdev.mdev_information.uuid:
+ mdev_uuid = cfgdev.mdev_information.uuid
+ else:
+ mdev_uuid = libvirt_utils.mdev_name2uuid(cfgdev.name)
device = {
"dev_id": cfgdev.name,
- # name is like mdev_00ead764_fdc0_46b6_8db9_2963f5c815b4
- "uuid": libvirt_utils.mdev_name2uuid(cfgdev.name),
+ "uuid": mdev_uuid,
# the physical GPU PCI device
"parent": cfgdev.parent,
"type": cfgdev.mdev_information.type,
diff --git a/nova/virt/libvirt/host.py b/nova/virt/libvirt/host.py
index 785acdcd186c..46435a9a7fd8 100644
--- a/nova/virt/libvirt/host.py
+++ b/nova/virt/libvirt/host.py
@@ -1566,7 +1566,7 @@ class Host(object):
def list_mediated_devices(self, flags=0):
"""Lookup mediated devices.
- :returns: a list of virNodeDevice instance
+ :returns: a list of strings with the name of the instance
"""
return self._list_devices("mdev", flags=flags)
diff --git a/nova/virt/libvirt/utils.py b/nova/virt/libvirt/utils.py
index c673818603cc..0675e4ac146d 100644
--- a/nova/virt/libvirt/utils.py
+++ b/nova/virt/libvirt/utils.py
@@ -575,17 +575,31 @@ def get_default_machine_type(arch: str) -> ty.Optional[str]:
def mdev_name2uuid(mdev_name: str) -> str:
- """Convert an mdev name (of the form mdev_) to a
- uuid (of the form 8-4-4-4-12).
+ """Convert an mdev name (of the form mdev_ or
+ mdev__) to a uuid
+ (of the form 8-4-4-4-12).
+
+ :param mdev_name: the name of the mdev to parse the UUID from
+ :returns: string containing the uuid
"""
- return str(uuid.UUID(mdev_name[5:].replace('_', '-')))
+ mdev_uuid = mdev_name[5:].replace('_', '-')
+ # Unconditionnally remove the PCI address from the name
+ mdev_uuid = mdev_uuid[:36]
+ return str(uuid.UUID(mdev_uuid))
-def mdev_uuid2name(mdev_uuid: str) -> str:
- """Convert an mdev uuid (of the form 8-4-4-4-12) to a name (of the form
- mdev_).
+def mdev_uuid2name(mdev_uuid: str, parent: str = None) -> str:
+ """Convert an mdev uuid (of the form 8-4-4-4-12) and optionally its parent
+ device to a name (of the form mdev_[_]).
+
+ :param mdev_uuid: the uuid of the mediated device
+ :param parent: the parent device id for the mediated device
+ :returns: name of the mdev to reference in libvirt
"""
- return "mdev_" + mdev_uuid.replace('-', '_')
+ name = "mdev_" + mdev_uuid.replace('-', '_')
+ if parent and parent.startswith('pci_'):
+ name = name + parent[4:]
+ return name
def get_flags_by_flavor_specs(flavor: 'objects.Flavor') -> ty.Set[str]: