[vfio-users] vfio PCI passthrough NVIDIA K420 GPU problems

[Alex Williamson]

On Wed, Feb 24, 2016 at 2:45 PM, Daniel Pocock <daniel at pocock.pro> wrote:

>
>
> On 24/02/16 21:58, Alex Williamson wrote:
> >
> >
> > On Wed, Feb 24, 2016 at 1:26 PM, Bronek Kozicki <brok at spamcop.net
> > <mailto:brok at spamcop.net>> wrote:
> >
> >     On 24/02/2016 15:41, Daniel Pocock wrote:
> >
> >
> >
> >         Hi,
> >
> >         I'm trying to use PCI passthrough to give an NVIDIA GPU to a VM
> with
> >         qemu / KVM.  I've summarized my environment below and the error
> >         I get is
> >         near the bottom.  Any help would be appreciated.
> >
> >         There are a few guides I've been referring to already:
> >         https://wiki.debian.org/VGAPassthrough
> >
> https://www.pugetsystems.com/labs/articles/Multiheaded-NVIDIA-Gaming-using-Ubuntu-14-04-KVM-585/
> >         https://wiki.archlinux.org/index.php/PCI_passthrough_via_OVMF
> >         https://bbs.archlinux.org/viewtopic.php?id=162768
> >         http://www.linux-kvm.org/page/VGA_device_assignment
> >
> >
> >
> >     Hi Daniel
> >
> >
> >     I'm successfully passing through two Quadro M5000 (to two instances
> >     of Windows 10), looking at
> >
> http://us.download.nvidia.com/Windows/Quadro_Certified/361.91/361.91-win10-quadro-grid-release-notes.pdf
> >     (page 9) it is not obvious that this would work for either your K420
> >     or mine M5000. One gotcha - when starting Windows I do not see boot
> >     screen at all, only Windows logon scren after nVidia drivers had
> >     loaded. Explanation is in Alex's email sent to this list on 6th Feb
> >     2016, subject "No boot screen on Quadro M5000?" - basically passed
> >     through Quadro cards are meant to be secondary  only (I use them as
> >     only card, though). However this small quirk aside, this works for
> >     me very well.
> >
> >
> >
> > Unfortunately K420 falls into the gap of unsupported and unknown between
> > GeForce, which are clearly unsupported, but we know how to make them
> > work, and Quardo K2000+, which are supported.  Typically Quadro cards
> > don't work as primary like GeForce do, and the NVIDIA driver will pull a
> > Code 43 on them, so it probably requires some combination of secondary
> > plus hiding KVM & Hyper-v (or changing hyper-v vendor info) to make it
> > work.  I'll note though that K420 is a GK107GL, as is the K2000, so
> > x-pci-device-id might be an interesting experiment.  And of course, the
> > most important guide was missed from the list, the one at
> > vfio.blogspot.com <http://vfio.blogspot.com> ;)  Thanks,
> >
>
>
> Thanks for all the replies about this
>
> What do you mean by primary vs secondary, is that documented somewhere?
>  Do you mean I need some other card to be primary in the VM?
>
> I have two cards I can use for this VM, the K420 and a Quadro 2000.
>
> The Quadro 2000 is mentioned favorably in the Xen guide[1], am I likely
> to have more luck with that than the K420?  The Quadro 2000 is a HP card
> and HP provides a BIOS download[2] too.
>

In a secondary configuration, an emulated graphics is the primary graphics
and is used for pre-boot, early boot, and install for the VM.  Once
accelerated drivers are installed and enabled, the primary graphics is
generally disabled (automatically or manually depending on the guest OS).
In a primary graphics configuration, the assigned GPU is the primary,
typically exclusive, graphics for the VM.  The 2000 is probably more likely
to work because NVIDIA is potentially not explicitly preventing it from
working like they do for the K420 and GeForce cards.   It is a Fermi based
card though, so it's not something we would actually claim as supported by
NVIDIA.  Add it to the VM just as you would any other PCI assigned device,
keeping the emulated graphics configuration.  Thanks,

Alex
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