Question on SRIOV vf -> pf mapping

[Ryan Stone]

This isn't possible in general.  When PCI Passthrough is in use, the VF
driver will run in the context of the VM's kernel and there is no device_t
corresponding to the PF at all.  If you're looking to pass information from
the PF down to the VF, then you need to establish some kind of
device-mediated side-channel to pass the information from host to guest.