Xen users - Aug 2012 - Nvidia: card fails to work in EITHER dom0 or domU -- any advice?

Hi all,

I have a Nvidia GeForce GTX 680 that I''d like to use in a Xen
configuration.  I don''t care if it''s used by dom0 or by a
linux domU guest,
either would be OK for my purposes.  Since getting this card, I''ve
experimented with Linux 3.4.6 and Xen 4.1.2 and determined the following:

1. The card works correctly under a linux kernel without Xen running.

2. The Nvidia proprietary drivers do not function in a dom0 setting,
because PAT is disabled in the dom0 kernel.  The driver detects this and
refuses to run.

3. Using PCI passthrough to a domU linux VM does not work either -- the
Nvidia proprietary driver does not recognize the card in the guest.  Not
sure why, but I suspect some resource the card uses is not being passed
through correctly.  (I can pass an AMD card to a domU without problems.)

I know that the Nvidia proprietary driver doesn''t officially support
Xen,
so getting it to work in dom0 might be futile, even if the PAT issue is
resolved.  So my main hope is to get passthrough to a guest working
correctly.  Any suggestions?  Is Xen 4.2 more likely to work for my use
case?

(The nouveau driver is not an option for me because I require OpenGL 3.2+
features, and last I checked, it doesn''t support the GTX 680 anyway.)

Brian


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On Thu, Aug 30, 2012 at 03:37:23PM -0700, Brian Johnson
wrote:
>    Hi all,
>    I have a Nvidia GeForce GTX 680 that I''d like to use in a Xen
>    configuration.  I don''t care if it''s used by dom0 or
by a linux domU
>    guest, either would be OK for my purposes.  Since getting this card,
I''ve
>    experimented with Linux 3.4.6 and Xen 4.1.2 and determined the
following:
>    1. The card works correctly under a linux kernel without Xen running.
>    2. The Nvidia proprietary drivers do not function in a dom0 setting,
>    because PAT is disabled in the dom0 kernel.  The driver detects this and
>    refuses to run.
>
Hmmm.. maybe Konrad (cc) can tell more about the PAT stuff. 
>    3. Using PCI passthrough to a domU linux VM does not work either -- the
>    Nvidia proprietary driver does not recognize the card in the guest.  Not
>    sure why, but I suspect some resource the card uses is not being passed
>    through correctly.  (I can pass an AMD card to a domU without problems.)
>    I know that the Nvidia proprietary driver doesn''t officially
support Xen,
>    so getting it to work in dom0 might be futile, even if the PAT issue is
>    resolved.  So my main hope is to get passthrough to a guest working
>    correctly.  Any suggestions?  Is Xen 4.2 more likely to work for my use
>    case?
>
You probably need the Nvidia vga passthru patches for Xen. 
Those patches are not yet merged to Xen, so they''re out-of-tree.

>    (The nouveau driver is not an option for me because I require OpenGL
3.2+
>    features, and last I checked, it doesn''t support the GTX 680
anyway.)
>    Brian
-- Pasi

On Thu, Sep 06, 2012 at 06:11:57PM +0300, Pasi Kärkkäinen
wrote:
> On Thu, Aug 30, 2012 at 03:37:23PM -0700, Brian Johnson wrote:
> >    Hi all,
> >    I have a Nvidia GeForce GTX 680 that I''d like to use in a
Xen
> >    configuration.  I don''t care if it''s used by dom0
or by a linux domU
> >    guest, either would be OK for my purposes.  Since getting this
card, I''ve
> >    experimented with Linux 3.4.6 and Xen 4.1.2 and determined the
following:
> >    1. The card works correctly under a linux kernel without Xen
running.
> >    2. The Nvidia proprietary drivers do not function in a dom0
setting,
> >    because PAT is disabled in the dom0 kernel.  The driver detects
this and
> >    refuses to run.
> >
> 
> Hmmm.. maybe Konrad (cc) can tell more about the PAT stuff. 
You could revert one patch and insert two other ones that make PAT work.

Look at
http://lists.xen.org/archives/html/xen-devel/2012-05/msg02277.html

ah, but the resolution never got copied.

If you can revert 8eaffa67b43e99ae581622c5133e20b0f48bcef1
and merge git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen.git
stable/for-x86


Or here:
https://groups.google.com/forum/?fromgroups=#!topic/qubes-devel/MyVtKaKfqIM
> 
> >    3. Using PCI passthrough to a domU linux VM does not work either --
the
> >    Nvidia proprietary driver does not recognize the card in the guest.
Not
> >    sure why, but I suspect some resource the card uses is not being
passed
> >    through correctly.  (I can pass an AMD card to a domU without
problems.)
> >    I know that the Nvidia proprietary driver doesn''t
officially support Xen,
> >    so getting it to work in dom0 might be futile, even if the PAT
issue is
> >    resolved.  So my main hope is to get passthrough to a guest working
> >    correctly.  Any suggestions?  Is Xen 4.2 more likely to work for my
use
> >    case?
> >
> 
> You probably need the Nvidia vga passthru patches for Xen. 
> Those patches are not yet merged to Xen, so they''re out-of-tree.
> 
> 
> >    (The nouveau driver is not an option for me because I require
OpenGL 3.2+
> >    features, and last I checked, it doesn''t support the GTX
680 anyway.)
> >    Brian
> 
> -- Pasi