q35 with BIOS as that is the cluster default with >4.3.
Running the dmesg messages through my mind as I remember them, the vio hardware may be all
PCIe based, which would explain why this won't work on a virtual FX 440FX system,
because those didn't have PCIe support AFAIK.
Any special reason why you'd want them based on 440FX?
And I also tested with GhostBSD, which is still 12.* based, and that doesn't seem to
have vio support, at least I could not see a hard disk there, which confirms your
observation there.