I'm attempting to setup a Linux kvm machine. I'm running into some strange issues. a little background. the host machine is a uefi h170 board, that being said, I know that the MSI Radeon R7 240 supports uefi since prior to playing with kvm I had to install the host OS using it.

If I use seabios, pci passthrough works fine. I actually do the full windows install via a passed through mouse, keyboard and the monitor on the radeon card.

However, if I build the same machine with virt-manager and passthrough the video, it does not work.

If I use uefi via virt-manager or cli, video passthrough does not work.

Here is my working string (although I end up with two nics somehow!?)

qemu-system-x86_64 -enable-kvm -M q35 -m 3072 -cpu host \
-smp 2,sockets=1,cores=2,threads=1 \
-bios /usr/share/qemu/bios.bin -vga none \
-device virtio-scsi-pci,id=scsi \
-drive file=/srv/wip.img,format=raw,id=disk,if=none,cache=directsync,aio=native \
-device scsi-hd,drive=disk \
-cdrom /home/driz/win10.iso \
-device ioh3420,bus=pcie.0,addr=1c.0,multifunction=on,port=1,chassis=1,id=root.1 \
-device vfio-pci,host=01:00.0,bus=root.1,addr=00.0,multifunction=on,x-vga=on \
-device virtio-net-pci,mac=52:54:00:ea:c8:8d \
-usb -usbdevice host:040b:2000 -usbdevice host:046d:c01e -usbdevice host:0d8c:0014 \
-boot menu=on

Here is a test string that does not work

qemu-system-x86_64 -enable-kvm -M q35 -m 3072 -cpu host \
-smp 2,sockets=1,cores=2,threads=1 \
-mem-path /dev/hugepages \
-mem-prealloc \
-drive file=/srv/ovmf-x64/OVMF_CODE-pure-efi.fd,if=pflash,format=raw,unit=0,readonly=on \
-drive file=/srv/ovmf-x64/OVMF_VARS-pure-efi.fd,if=pflash,format=raw,unit=1 \
-device i82801b11-bridge,id=pci.1,bus=pcie.0,addr=0x1e \
-device pci-bridge,chassis_nr=2,id=pci.2,bus=pci.1,addr=0x0 \
-device virtio-scsi-pci,id=scsi0,bus=pci.2,addr=0x2 \
-drive file=/srv/wip2.img,format=raw,if=none,id=drive-scsi0-0-0-0 \
-device scsi-hd,bus=scsi0.0,channel=0,scsi-id=0,lun=0,drive=drive-scsi0-0-0-0,id=scsi0-0-0-0 \
-cdrom /srv/win10.iso \
-device virtio-net-pci,mac=52:54:00:ea:c8:8d \
-device vfio-pci,host=01:00.0,multifunction=on \
-nographic \
-usb -usbdevice host:040b:2000 -usbdevice host:046d:c01e -usbdevice host:0d8c:0014 \
-device virtio-balloon-pci,id=balloon0,bus=pci.2,addr=0x4 \
-boot menu=on

I've spent about 4 days working on this now and researching everywhere I can, and my kids are finally getting upset with the delays. any help is appreciated!

1 Answer 1


Manually specifying the video rom corrected the issue on the CLI version. In virsh you can define the rom (with an appropriate version) as shown below

     <rom file='/etc/fake/boot.bin'/>

on the cli

add romfile=/path/to/your/rom/romfile.rom to the end of your pci passthrough device

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