[vfio-users] vga pass-thru and different gfx cards.

[Alex Williamson]

Please reply-all, adding the list back.

On Thu, Sep 10, 2015 at 12:44 PM, Torbjorn Jansson <
torbjorn.jansson at mbox200.swipnet.se> wrote:

> On 2015-09-10 19:47, Alex Williamson wrote:
>
>> On Thu, Sep 10, 2015 at 10:47 AM, Torbjorn Jansson <
>> torbjorn.jansson at mbox200.swipnet.se> wrote:
>>
>> Hello all.
>>>
>>> first of all a big thanks to alex willamsons and his blog series about
>>> getting a graphic card passed thru to a vm.
>>> without those i wouldn't have been able to get it to work (more or less)
>>>
>>> first some hw info about my linux box where i'm using vfio & kvm:
>>> asus p8Z77-v le with 16gb ram and at the moment i'm using a nvidia gt610
>>> card from asus but i have also tried a gtx570.
>>>
>>> i got it to work after a bit of reading alex blogs and a lot of testing.
>>> i use the built in intel gfx card for the host since that is no good for
>>> anything else and the gt610 is passed thru to a win7 vm.
>>>
>>> first problem i have is that vga pass-thru only works one time after a
>>> cold boot.
>>> if i try to restart the vm or just power it of and on again i get a hard
>>> lockup of the host.
>>> this is the most annoying problem.
>>>
>>>
>> It's not clear to me why there are numerous reports of reset problems on
>> nvidia.  AFAIK, there's no broken hardware for nvidia in this space like
>> there is for AMD.  So if you're having reset problems, maybe it's because
>> you're not binding both GPU and audio functions to vfio-pci and therefore
>> vfio-pci can't do a bus reset on VM reset.  Maybe your motherboard freaks
>> out on the bus reset.  Maybe it's a ROM issue like Blank suggests.
>>
>>
> both functions are bound to pci-stub via grub command line using:
> pci-stub.ids=
>
> i forgot to say, i'm unfortunately stuck on linux kernel 4.0.4 due to
> issues with drivers for a dvb card.
> and my distro is fedora 22


pci-stub is only to prevent host driver from binding to the device,
eventually the device needs to get bound to vfio-pci or else you're not
using vfio to do the assignment.


> at least with uefi i assume i would be able to get rid of the vgaarb patch
>>> fixing vaapi/vdpau support.
>>>
>>>
>> Yes.
>>
>>
> good, that would be one problem less.
> does it matter if the host bios does not support uefi but the vm would,
> like win 8+ ?


No
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