Re: [Xen-devel] AMD GPU passthrough in Xen

["Zytaruk, Kelly" <Kelly.Zytaruk@xxxxxxx>]

> Good to know there is interest from AMD into this area :-)

I am taking a personal interest in this and would like to improve AMD support 
and presence within the Xen community.

Gordan has also reported problems restarting a guest.  

I have been trying to reproduce the problem but have not had any luck.  As a 
secondary it restarts for me every time.  I don't know if I inadvertently made 
a change that indirectly fixed it in my code base or what the difference might 
be.

What Xen version are you testing with?

Thanks,
Kelly

> -----Original Message-----
> From: Sander Eikelenboom [mailto:linux@xxxxxxxxxxxxxx]
> Sent: Tuesday, September 23, 2014 9:45 AM
> To: Zytaruk, Kelly
> Cc: Peter Kay; xen-devel@xxxxxxxxxxxxx
> Subject: Re: [Xen-devel] AMD GPU passthrough in Xen
> 
> Good to know there is interest from AMD into this area :-)
> 
> I'm experimenting for a while with:
> 
> - xen-unstable (and thus xl)
> - latest kernels (both dom0 and domU)
> - qemu-xen
> - Radeon HD 6570
> - secondary passthrough
> - Debian linux (sid) with the opensource (in kernel) radeon driver
>   (i also tried fglrx with succes, but it's a real PITA to build with every
>   new kernel, so i ditched that)
> 
> It used to work, but something broke at the moment, but that could also be the
> changes to the systemd cruft that Debian jessie/sid is currently undergoing 
> (or
> something else since i regularly update all components).
> 
> The problems are mostly with restarting the domU, it differs a bit:
> - sometimes screen goes ok, sometimes it's garbage.
> - the radeon powercontrols only seem to work on the first boot and give errors
> on any subsequent one.
> 
> But when it works it does:
> - the powercontrol.
> - opengl and opencl benchmarks with (near) native results.
> - hardware video acceleration in xbmc for instance.
> 
> So one of the main problems at present seems to be proper resetting of the
> whole device on domain shutdown/start. I did do some experiments with the
> opensource radeon driver, but didn't get conclusive results out of that yet.
> 
> --
> Sander
> 
> Tuesday, September 23, 2014, 3:19:41 PM, you wrote:
> 
> > Hi Peter / Sander,
> 
> > Yes, I have AMD GPU passthru working as both primary and secondary
> passthru.  Secondary was easy but primary is a bit tricky.
> 
> > Getting on to your questions;
> 
> >> Is there any specific reason you're using Xen 4.2 rather than 4.4.1?
> 
> > I am working on a project that is based on Xen 4.2 (I can't say any more 
> > than
> that).  I have looked at some of the more recent versions just to check if 
> some
> of the bugs that I have seen have been fixed but I have not studied the newer
> versions in detail.  At some point in time in the future I would like will 
> make the
> jump to a more recent version but I don't know the scheduling of that.
> 
> >> In 4.2, using xl or xm?
> 
> > xl
> 
> >> qemu-traditional (with rombios) or "upstream"
> 
> > qemu-traditional
> 
> >> Primary or secondary passthrough?
> 
> > Both but I am focusing on secondary right now.
> 
> >> Presumably 64 bit versions of Windows?
> 
> > 32 bit and 64 bit Win7.  I have tested Win8.1 and it works but my
> > focus is currently Win7
> 
> >> I am quite willing to test various scenarios. I've a 6950, 6450 and 5450.
> 
> > Awesome.  My goal right now is obtaining stability on Xen 4.2.  Since 4.2 is
> past its feature cutoff I won't be able to submit any open source changes for 
> it.
> I would like to eventually work with the community to get passthru working 
> with
> a recent version of "upstream".
> 
> > Thanks,
> > Kelly
> 
> 
> 
> >> -----Original Message-----
> >> From: Sander Eikelenboom [mailto:linux@xxxxxxxxxxxxxx]
> >> Sent: Monday, September 22, 2014 8:38 AM
> >> To: Peter Kay
> >> Cc: xen-devel@xxxxxxxxxxxxx; Zytaruk, Kelly
> >> Subject: Re: [Xen-devel] AMD GPU passthrough in Xen
> >>
> >>
> >> Monday, September 22, 2014, 2:16:58 PM, you wrote:
> >>
> >> > Hi Kelly, list
> >>
> >> > I see you're having AMD GPU success with Xen 4 2 and Linux 3.4.9.
> >> > I've been
> >> less than successful getting passthrough working at all in Xen
> >> (although it's fine in KVM primary passthrough as long as the BIOS is
> >> supplied as a file). Could I confirm the following :
> >>
> >> > Is there any specific reason you're using Xen 4.2 rather than
> >> > 4.4.1? I know in
> >> some ways 4.4 suffers as it's now xl only and some of the xm
> >> functionality has not come across.
> >>
> >> > In 4.2, using xl or xm?
> >>
> >> Another interesting question/aspect would be qemu-traditional (with
> >> rombios) or "upstream" (with seabios) ?
> >>
> >> > Primary or secondary passthrough?
> >>
> >> > Presumably 64 bit versions of Windows?
> >>
> >> > My system is a bit old (Core2Quad) but as mentioned AMD passthrough
> >> > works
> >> in KVM but I've found it tricky in Xen.
> >>
> >> > I am quite willing to test various scenarios. I've a 6950, 6450 and 5450.
> >>
> >> > Thanks
> >>
> >> > Peter
> >>
> >>
> 
> 


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