Proxmox NIC pass-through and machine type

I picked up a little Topton fanless server a while back, that comes with 4 x 2.5Gb Intel i226 NICs, and wanted to try running an OpenBSD VM on Proxmox with NIC pass-through. There are some fairly detailed instructions on servethehome.com, but one important thing I found they left out was the Proxmox "Machine" setting.

The default seems to be "i440fx", and with that default I was sort of seeing the NIC inside OpenBSD, but with dmesg entries like:

igc0 at pci0 dev 16 function 0 "Intel I226-V" rev 0x04: not enough msi-x vectors
igc0: unable to map msi-x vector 0

and the interface wouldn't actually show up in ifconfig

After finally finding some hints on the web that the q35 machine type adds PCIe support, I gave that a try and now the igc0 interface on OpenBSD seems to be working!