Re: GPU passthrough with Xen 4.2 on Ubuntu 12.04

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

On Wed, Aug 08, 2012 at 04:42:08PM +0300, Pasi Kärkkäinen wrote:
> On Wed, Aug 08, 2012 at 02:26:33PM +0100, Matthew Dean wrote:
> > 
> >    I've used the stock Ubuntu provided kernel which is version
> >    3.2.0-27-generic.  Dom0 is connected to a display via the intel integrated
> >    graphics.
> > 
> 
> You might want to try Linux 3.4.x or 3.5.x dom0 kernels aswell.

The v3.5.x has some issues right now with PCI passthrough. Not sure what - but
trying to figure it out.

> I think there has been some fixes in xen-pciback.
> 
> 
> > 
> >    When I boot the VM everything seems to work fine.  Windows picks up all
> >    three devices and I can install drivers for them.  The USB controller
> >    works flawlessly and I can use an attached mouse and keyboard.  The radeon
> >    card requires a restart after which an attached display comes to life and
> >    I have 3D acceleration.  Restarting the VM seems to work OK.  If however I
> >    shut down the VM I have no end of problems.  On any subsequent startup the
> >    vm struggles to get past the windows splash screen, waiting much longer
> >    than usual.  During this period dom0 is sluggish regarding mouse and
> >    keyboard input even though cpu and memory usage are very low.  When
> >    windows finally loads I have no active display and I have to view the VM
> >    via VNC.  In device manage I find that windows has disabled the GPU saying
> >    there are not enough resources to run the card.  From this point onwards I
> >    can do nothing to get the gpu working again aside from removing the
> >    device, manually deleting the drivers, and starting again.
> > 
> 
> Do you get any errors from Xen (xl dmesg), or from dom0 kernel (dmesg) ? 
> 
> Do you have a serial console? 
> 
> 
> >    Note that at this point I am only trying to do secondary passthrough
> >    though I would ideally like to get to the point of doing primary
> >    passthrough.  Adding the line gfx_passthru=1 at any point in all this to
> >    the machine config however just prevents the VM from booting entirely;
> >    when I VNC in all I get is a qemu prompt and I never get any ouput to the
> >    real display.
> > 
> 
> AMD/ATI primary passthru requires extra patches to Xen qemu-dm,
> those are not included out-of-the-box yet.
> 
> >    Any suggestions as to how to get this to work would be greatly appreciated
> >    as I've hit a bit of a brick wall.  I should also say that I have managed
> >    to get secondary passthrough working using Debian Wheezy and the
> >    repository version of xen 4.1.  In that case though Dom0 didn't boot
> >    reliably.
> > 
> 
> -- Pasi
> 
> 
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