[vfio-users] vfio-pci with amd gpu in kernel 4.14.10+

[P. Pronk]

Alex, thank you for your advice. I checked the ubuntu kernel build logs
and I couldnt find differences in build config for the pci-stub,
vfio-pci and amdgpu modules or the build method in general.

Your next advice of adding the softdep workaround does seem to work. Not
sure if its related (probably not), but I was also able to remove the
stub/vfio kernel parameters in grub and now only have the vfio-pci ids
and the softdep listed in modprobe.d/vfio-pci.conf (for others coming
across this, dont forget to update your initramfs after adding the
softdep line).
I am still not sure why adding the softdep is necessary in v4.14.10+
btw, maybe its something ubuntu specific but at least its working again :)

Cheers, Pim

On 12/01/18 17:38, Alex Williamson wrote:
> On Fri, 12 Jan 2018 10:45:57 +0100
> "P. Pronk" <vfio at pronk.nl> wrote:
>
>> Thanks for the tips, swapping the cards is not an option as I use a uatx
>> board but also use all the other pcie ports which would be blocked by
>> the rx480 otherwise. Adding the vfio-pci module to initramfs doesnt make
>> any difference unfortunately.
>> You cant set which gpu is the primary on an Asus board. It just uses the
>> one in the first pcie slot and you have no other choice, thats why I
>> said I made a mistake buying Asus ;)
>>
>> But everything works as intended in v4.14.9, it 'just' doesnt anymore
>> since v4.14.10
>>
>> @Alex, do you maybe have any suggestions? Unfortunately I am having some
>> difficulties understanding the changelog of kernel v4.14.10 and their
>> possible impact on my problem.
> Both pci-stub.ids and vfio-pci.ids require that the pci-stub or
> vfio-pci driver are loaded before the potentially conflicting driver.
> Did your kernel perhaps change pci-stub from a builtin driver to a
> module between these releases?  You could possibly use a softdep to get
> vfio-pci loaded before amdgpu, something like
>
> softdep amdgpu pre: vfio-pci
>
> in modprobe.d.  Thanks,
>
> Alex

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://listman.redhat.com/archives/vfio-users/attachments/20180112/e9819b80/attachment.htm>