Comment 3 for bug 1915255

This is a real issue because the Cavium ThunderX hardware violates an assumtion we have with regards to PF having netdevs if VF do.
we just need to re add this try excpet that was removed.
https://review.opendev.org/c/openstack/nova/+/739131/12/nova/virt/libvirt/driver.py#b6957

it was orginally removed as we are only looking at the sub set of VFs that are nics
but since the Cavium ThunderX does not assing a PF to all VFs
per https://bugs.launchpad.net/charm-nova-compute/+bug/1771662

we need to catch the exception in this case as we did before.

this means that minium bandwidth based QOS cannot be implemented on this hardware as we rely on the PF netdev name to correlate the bandwidth between nova and neutron but other functionality shoudl work. The only way to support min bandwith qos on thsi hardware would be to altere the nic driver or enhance nova/neutron to support using the PF pci address instead of the parent netdev name.