well you just need an efi firmware and I guess ovmf is the only one that the guy knew of (I actually do not now of any other aswell). if you boot qemu without any firmware it would emulate a real mode device which probably make it impossible to access the device correctly. (not verified or tested, since my rig never worked).
but you can install OVMF on any new linux distribution. and you probably don't need to patch it (at least on ubuntu 17.10, fedora 27+, arch linux...)
> OVMF is an open-source UEFI firmware for QEMU virtual machines. While it's possible to use SeaBIOS to get similar results to an actual PCI passthough, the setup process is different and it is generally preferable to use the EFI method if your hardware supports it.
Edit: Arch wiki (the best) writes something about it: https://wiki.archlinux.org/index.php/PCI_passthrough_via_OVM...
> OVMF is an open-source UEFI firmware for QEMU virtual machines. While it's possible to use SeaBIOS to get similar results to an actual PCI passthough, the setup process is different and it is generally preferable to use the EFI method if your hardware supports it.