[vfio-users] GPU passthrough: device does not support requested feature x-vga

[Alex Williamson]

On Tue, 31 Mar 2020 21:35:33 +0300
Артем Семенов <artem.semenov at jarillolabs.com> wrote:

> Hello!
> 
> I try to passthrough GPU to the virtual machine (qemu). I've tried 
> different variants:
> 
> -device vfio-pci,host=02:00.0,bus=root.1,addr=00.0,multifunction=on,x-vga=on
> 
> or
> 
> -device vfio-pci,host=02:00.0,x-vga=on
> 
> and other but in any case I get error:
> 
> vfio 0000:02:00.0: failed getting region info for VGA region index 8: 
> Invalid argument
> device does not support requested feature x-vga
> 
> dmesg contains:
> 
> [  844.599821] vfio_ecap_init: 0000:02:00.0 hiding ecap 0x1e at 0x258
> [  844.599860] vfio_ecap_init: 0000:02:00.0 hiding ecap 0x19 at 0x900
> 
> If I remove x-vga=on option then qemu works but there is no signal from 
> GPU (black screen).
> 
> It looks like http://vfio.blogspot.com/2014/08/vfiovga-faq.html
> 
> "Question 3:
> 
> I have Intel host graphics, when I start the VM I don't get any output 
> on the assigned VGA monitor... "
> 
> I've tried to use 2 versions of the kernel: 4.19 and 5.4 - no difference.
> 
> Moterboard: ASUS PRIME H370-A.
> GPU: ASUS Turbo GeForce RTX 2060 Super.
> 
> What could be the cause of this problem?

Is your host kernel built with CONFIG_VFIO_PCI_VGA=y?  Are you
disabling that support with the disable_vga=1 module option of
vfio-pci?  Thanks,

Alex