This might never be done but I've put it in Jira to document it.

Nova is looking at eventually putting the ACPI index of a network device into the Metadata. From the guest, it'll then be possible to lookup the correct PCI device linked to that index, that is attached to a specific Neutron network.

This is to provide an alternative solution to the fix in https://issues.redhat.com/browse/OCPBUGS-19908