Troubleshooting iGPU passthrough on Incus to Ubuntu guest

Incus
, ,
1

I’m trying to do GPU pass through on a NixOS 25.11 host running Incus and guest running ubuntu 24.04. I’m trying to pass the Intel Core Ultra 5 225 CPU’s (on a Asus B860-i mobo) integrated GPU but screen goes black when guest boots. I launch my system with kernelParams =intel_iommu=on iommu=pt vfio.ids=8086:7d67and kernelModules = vfio vfio_pci vfio_iommu_type1 i915

On host:

user@host:~#  lspci -nnk -d 8086:7d67
00:02.0 VGA compatible controller [0300]: Intel Corporation Arrow Lake-S [Intel Graphics] [8086:7d67] (rev 06)
        DeviceName: Onboard IGD
        Subsystem: ASUSTeK Computer Inc. Device [1043:88ef]
        Kernel driver in use: vfio-pci
        Kernel modules: i915, xe

On guest:

root@test2:~# lspci -nnk -d 1af4:1050
04:00.0 VGA compatible controller [0300]: Red Hat, Inc. Virtio 1.0 GPU [1af4:1050] (rev 01)
        Subsystem: Red Hat, Inc. Virtio 1.0 GPU [1af4:1100]
        Kernel driver in use: virtio-pci
root@test2:~# lspci -nnk -d 8086:7d67
06:00.0 VGA compatible controller [0300]: Intel Corporation Arrow Lake-U [Intel Graphics] [8086:7d67] (rev 06)
        Subsystem: ASUSTeK Computer Inc. Device [1043:88ef]
        Kernel driver in use: i915
        Kernel modules: i915, xe

Furthermore, the guest seems to fail on loading the driver:

root@test2:~# vainfo
error: XDG_RUNTIME_DIR is invalid or not set in the environment.
error: can't connect to X server!
libva info: VA-API version 1.23.0
libva info: Trying to open /usr/lib/x86_64-linux-gnu/dri/virtio_gpu_drv_video.so
libva info: Found init function __vaDriverInit_1_20
libva error: /usr/lib/x86_64-linux-gnu/dri/virtio_gpu_drv_video.so init failed
libva info: va_openDriver() returns 2
vaInitialize failed with error code 2 (resource allocation failed),exit


root@test2:~# ls /usr/lib/x86_64-linux-gnu/dri | grep -iE 'virtio|virgl|i915'
i915_dri.so
virtio_gpu_dri.so
virtio_gpu_drv_video.so
root@test2:~#

Anyone see anything fishy? Personally I find it odd I have 2 gpu’s on the guest?

2

In my case, when doing GPU passthrough on incus, I used a container instance.

With a multi-GPU setup (AMD & Nvidia), implementing a kernel blacklist was necessary to get it working.

1 Like
3

I only have one graphics controller - the iGPU one. Or do you mean it’s important to blacklist that too on bootup?

4

You’ll also very likely need to manually install the firmware package for your GPU.

5

If you only have a single GPU and want to use GPU passthrough, I recommended using a container instance instead.

6

I tinkered some tonight. And for the first time in weeks I finally got display working. It was either

  • blacklisting both graphics drivers in kernelParams (of host):
 module_blacklist=i915
 module_blacklist=xe

Thanks a bunch!

​…now I seem to have a new problem to hammer on. Mouse and keyboard is not working but I figured that’s also passthrough affair.

7

After some testing today, it’s clear i DON’T need the blacklisting xe/i915 drivers above. So so the romfile is enough: I managed to make that work with

  raw.qemu.conf: |-
    [device "dev-incus_gpu-1"]
    romfile = "/usr/share/kvm/idg.rom"
1 Like