Comment 2 for bug 1983570

I think in sort term we should add a note about this limitation in https://docs.openstack.org/nova/latest/admin/pci-passthrough.html

To make this work is not trivial as we would need to enhance the PCI scheduling to support "physnet=None OR physnet=foobar" type of requests. We have multiple options here:
1) enhance InstancePCIRequest and the PciPassthroughFilter
2) wait for the pci-device-tracking-in-placement to start supporting neutron based SRIOV and factor this support into that work
3) start thinking about expressing the PCI request of a neutron port not via the InstancePCIRequest but via the port's resource_request. That field is directly translated to placement query and placement already supports OR relationship between traits (added in yoga).