qemu-system-x86_64: NVMM: Mem Assist Failed [gpa=0xfffffff0]

Hello.

I'm here to try to use netbsd with my current graphic hardware. Ascertained that my GPUs are too new to be used with NetBSD 9.2,I have installed the OS108 derivative "distribution" based on NetBSD 9.1-stable. I think that it worked. Now I'm using xfce4 at 1024x768 resolution,but for now it's good because I can't do this with the 9.2. Anyway,now I could do what I wanted to try for a long time : some experimentation with qemu and nvmm on netbsd. Below you can see what are the parameters that I've used to boot a linux vm.

On NetBSD 9.1-STABLE / OS108 :

qemu-system-x86_64 -accel nvmm \
-cpu max -smp cpus=4 -m 8G \
-drive if=pflash,format=raw,readonly=on,file=/usr/pkg/share/qemu/edk2-x86_64-code.fd \
-drive id=cdrom,if=none,media=cdrom,file=/home/marietto/Downloads/vm/ubuntu-22.04-desktop-amd64.iso \
-drive file=/home/marietto/Downloads/vm/jammy.img,if=none,id=disk0 \
-object rng-random,filename=/dev/urandom,id=viornd0 \
-device virtio-rng-pci,rng=viornd0 \
-netdev user,id=vioif0 -device virtio-net-pci,netdev=vioif0 \
-audiodev oss,id=oss,out.dev=/dev/audio,in.dev=/dev/audio \
-device ac97,audiodev=oss \
-display sdl,gl=on -vga vmware \
-usb -device usb-mouse,bus=usb-bus.0

WARNING: Image format was not specified for '/home/marietto/Downloads/vm/jammy.img' and probing guessed raw.
Automatically detecting the format is dangerous for raw images, write operations on block 0 will be restricted.
Specify the 'raw' format explicitly to remove the restrictions.
NetBSD Virtual Machine Monitor accelerator is operational

Unfortunately here it crashes :

qemu-system-x86_64: NVMM: Mem Assist Failed [gpa=0xfffffff0]
qemu-system-x86_64: NVMM: Failed to execute a VCPU.
[1] Abort trap (core dumped) qemu-system-x86_64 -accel nvmm -cpu max -smp c...

Surfing on the net a little bit,I found an interesting post regarding shit specific bug :

http://mail-index.netbsd.org/current-users/2020/08/24/msg039417.html

Robert Nestor says : "with -bios /usr/pkg/share/ovmf/OVMFX64.fd \ it boots just fine.

@Robert Nestor : have you been able to fix this bug ?

I would like to try to do the same as you,but I don't know where I can grab the file "OVMFX64.fd" because it is not stored in any place on my system. Thanks.

Mario.