I agree with AW's general assessment that you need to decide if it's worth your time and risk to hardware in $'s before undertaking any sort of bios mod but if your just using the bios in qemu it should be relatively safe and potentially incredibly easy. The radeon UEFI GOP itself is generic so I think modding is not complex but since qemu / vfio / ovmf is a thing of limitless pain avoiding wonder you can probably get UEFI boot working in an EFI-only OVMF boot by using your card ROM as normal and appending the generic GOP as an option rom with the qemu command line addition of (for example):
You can get AMD gop option ROMS from the tool at the link below, searching on the web (where I just got the link below) or extracting them from whatever bios you like.
There's a simple bit of code you can run there to update your current bios .. but I just stripped the UEFI part out of my bios with a hex editor, and had qemu booting fine with the option-rom approach (and failing without) - I use a very recent version of the ovmf efi only rom/qemu/linux kernel though and my card is originally UEFI so your mileage may well vary. I used the newer 1.59 GOP vs 1.53 GOP in my card bios and checked version in the UEFI shell with the 'drivers' command then booted windows and re-installed my graphics drivers/ran heaven benchmark. It made no difference to anything as far as I could tell so I doubt the GOP matters much outside boot/reset.
I do recommend going the UEFI route for radeon guest/IGD on the host (as per the wonderful description on AW's blog) as I recently did this and had absolutely no trouble at all with 64 bit Win10 guest other than needing to use the bleeding edge qemu and kernel (I have skylake though). I will post a simple EFI only qemu command line example soon but had a few questions and wanted to read some of the upstream boards first to check I'm not time wasting/in the wrong place/missing the point somewhere. Compared to bare metal I'm seeing slight improvements in min frame rates and a reduction in time spent swearing at or fixing Windows of over 95%.
Big thanks to all the people that worked on this.
On 23/03/16 07:38, Zir Blazer wrote: