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

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

AMD has two sets of drivers.  One is our Legacy driver which supports HD4xxx 
and previous GPU families and the other is our current driver which supports 
HD5xxx and up.
Officially we don't support the Legacy driver anymore.  HD4850 is a very old 
product and there isn't much that I can do with it as the driver changed 
significantly between HD4xxx and HD5xxx. 

Please don't spend too much time on the HD4850.  It uses an entirely different 
driver and there have been a lot of fixes that have gone into the latest driver.

Thanks,
Kelly

> -----Original Message-----
> From: Gordan Bobic [mailto:gordan@xxxxxxxxxx]
> Sent: Wednesday, September 24, 2014 8:56 AM
> To: Zytaruk, Kelly
> Cc: Sander Eikelenboom; Peter Kay; xen-devel@xxxxxxxxxxxxx
> Subject: RE: [Xen-devel] AMD GPU passthrough in Xen
> 
> On 2014-09-24 13:12, Zytaruk, Kelly wrote:
> >> 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?
> 
> I mentioned this before, the behaviour is the same with various versions of 
> Xen
> between versions 4.2.0 and 4.3.1 (haven't tried more recent ones). Also with
> kernels between 3.8.x and 3.14.x.
> 
> I'll try to build another machine for testing and re-attempt with my old 
> HD4850 (I
> disposed of all my ATI cards apart from the HD6450 which I'm using in a
> different machine and the
> HD4850 which I kept because it's the latest generation of
> pre-R9 ATI cards that has dual DL-DVI outputs). Unfortunately, that may take a
> little while (days/weeks) to find time to do. :(
> 
> Note that the fact it's a HD4xxx series card means I won't be able to use
> particularly recent drivers as the support for those has been dropped a while
> back, IIRC.
> 
> And then there's the issue of the R9 class cards not working properly behind
> NF200 bridges (and all 7 of my PCIe slots are behind NF200 bridges), but I'll
> worry about that when I get any ATI card working reliably across reboots.
> 
> Gordan
> 
> >> -----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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