Arch Linux

eyes

Member

Registered: 2021-10-26

Posts: 25

QEMU vfio drivers not binding to GPU

hey lads ive been trying to set up GPU passthrough in a windows VM with qemu, following the wiki: https://wiki.archlinux.org/title/PCI_pa … h_via_OVMF
the wiki and every other guide ive found says to add the vfio kernel modules to load pre boot like so:

MODULES=(... vfio_pci vfio vfio_iommu_type1 vfio_virqfd ...)

i checked dmesg, and vfio is correctly loading:

sudo dmesg | grep -i vfio
[    1.716463] VFIO - User Level meta-driver version: 0.3

however its not being bound to my graphics card:

lspci -nnk | grep VGA -A 3
2f:00.0 VGA compatible controller [0300]: Advanced Micro Devices, Inc. [AMD/ATI] Navi 10 [Radeon RX 5600 OEM/5600 XT / 5700/5700 XT] [1002:731f] (rev c4)
    Subsystem: Advanced Micro Devices, Inc. [AMD/ATI] Reference RX 5700 XT [1002:0b36]
    Kernel driver in use: amdgpu
    Kernel modules: amdgpu

any ideas? as far as I can tell, the kernel seems to just sorta grab the first available driver. I tried to blacklist the amdgpu module by adding a file /etc/modprobe.d/amdgpu.conf which contained "blacklist amdgpu" but that just removed the "Kernel Modules" entry from the output of that lspci command, and left the "Kernel driver in use" still set to amdgpu. also, I couldn't start X.

Last edited by eyes (2022-02-27 21:32:41)

Lone_Wolf

Administrator

From: Netherlands, Europe

Registered: 2005-10-04

Posts: 15,065

Re: QEMU vfio drivers not binding to GPU

You did add vfio-pci.ids kernel parameters to the kernel bootline or in /etc/modprobe.d/vfio.conf ?

How many videocards does your machine have ?

The full ouput of that lspci command would help, also full dmesg and/or journalctl -b .

---

Disliking systemd intensely, but not satisfied with alternatives so focusing on taming systemd.

clean chroot building not flexible enough ?
Try clean chroot manager by graysky

eyes

Member

Registered: 2021-10-26

Posts: 25

Re: QEMU vfio drivers not binding to GPU

You did add vfio-pci.ids kernel parameters to the kernel bootline or in /etc/modprobe.d/vfio.conf ?

okay I added them to my kernel params and regenerated grub.cfg as well. kernel params look like this:

GRUB_CMDLINE_LINUX_DEFAULT="loglevel=3 quiet nordrand acpi_backlight=vendor amd_iommu=on vfio-pci.ids"

where previously vfio-pci.ids was not there. Dmesg says that "vfio-pci" is an invalid parameter for ids.

mkinitcpio.conf:

MODULES=(vfio vfio_iommu_type1 vfio_pci vfio_virqfd kvm-amd kvm)
BINARIES=()
FILES=()
HOOKS=(base udev autodetect modconf block filesystems keyboard fsck)

/etc/modprobe.d/vfio.conf:

options vfio=pci ids=1002:731f,1002:ab38

full lspci: http://ix.io/3QW1
full dmesg: http://ix.io/3QW6
can't give journalctl, using runit for my init system. (sorry for not mentioning this earlier)

qinohe

Member

From: Netherlands

Registered: 2012-06-20

Posts: 1,593

Re: QEMU vfio drivers not binding to GPU

GRUB_CMDLINE_LINUX_DEFAULT="loglevel=3 quiet nordrand acpi_backlight=vendor amd_iommu=on vfio-pci.ids"

Shouldn't that be 'vfio-pci' instead of 'vfio-pci.ids'?
edit:
or 'vfio_pci.ids=1002:731f'
/edit

And this;

/etc/modprobe.d/vfio.conf:

options vfio=pci ids=1002:731f,1002:ab38

options vfio_pci ids=1002:731f,1002:ab38

?

Last edited by qinohe (2022-02-27 20:17:19)

eyes

Member

Registered: 2021-10-26

Posts: 25

Re: QEMU vfio drivers not binding to GPU

Yep, I clearly made a typo with that equals sign. It all works... sort of. I have now realized that I do not have an integrated graphics card. Not sure why I thought I did. I guess passthrough is not an option for me, unfortunately. Thanks for the help.