[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Xen-users] ATI VGA Passthrough / Xen 4.2 / Linux 3.8.10
On 05/09/2013 06:35 PM, Casey DeLorme wrote:
Thanks for posting the results Gordan, unfortunate that it isn't
working as well as we hoped.
I haven't given up _quite_ yet.
I discovered yesterday that it _looks liks_ one of my PCIe slots is
actually duff (two different GPUs both fail to detect properly in it
but work fine in other slots).
If it turns out to be a duff slot, there's no telling what else
might be duff on the motherboard and how it might affect various
things, even though several days of full load stability testing
passed.
So some more bare-metal testing seems to be called for - right now I
am not prepared to disregard the possibility that maybe I have a
hardware issue somewhere that despite EDAC and ECC on everything,
remains undetected and unreported in the logs.
I hope you manage to resolve it, though I feel the NF200 will be the
larger challenge.
I hope I'll resolve it, too, but right now I am not convinced that the
NF200 is actually the cause of my problems. My gut feeling says that if
I can get it working for 5 minutes at a time, something less fundamental
than the NF200 PCIe routers are the cause of the problems.
2) My motherboard's PCIe slots are behind NF200 PCIe bridges
(yes,
EVGA have decided in their infinite wisdom to put all 7 PCIe slots
behind NF200s, none are directly attached to the Intel NB).
I'm so sorry :P. NF200 has probably caused a lot of xen
tinkerers to
utter a few dozen cuss words a piece.
I can believe that. What is the solution, though?
The thing that drives me really nuts about the issues I'm seeing
(which may or may not be specifically related to the NF200) is
that it
is so intermittent. It works well enough to boot up and work with a
gaming type load for a few minutes. Then something happens that
causes
the VGA card to require a reset, and it all falls apart.
My solution was to buy another motherboard, I had no luck at all
passing the devices behind the NF200, and similar to your situation
all but one PCIe slot on that board was behind that bridge.
Did you not manage to get it working at all? Or was it just
intermittent like in my case? I can typically get about 5 minutes of
gaming out of my ATI card before it all goes wrong.
Ironically, I was thinking about an Asus Sabertooth with an 8-core AMD,
but opted to go for broke and get a couple of 6-core Xeons and an
EVGA SR-2. It turns out, a solution that is 4x more expensive isn't
actually better... :(
I was unable to get it working at all. The NF200 simply threw errors
that 100% prevented me from passing the device. I think it was missing
a number of specific features required for passthrough, and I vaguely
remember running lspci -vvv to verify what was missing. Perhaps not all
NF200's are created equal?
The only logged issue I had with the NF200s was the lack of ACS, which
can be disabled as I mentioned on this thread (at least if you are using
the xm stack). After I disabled that PCI passthrough has been working
OK. It's just VGA passthrough BSOD-ing after some minutes that is
causing me problems.
What about with PCIe devices behind NF200 bridges? I know the
NF200s
don't support PCI ACS, but that is a security feature (which I have
disabled enforcement of to get this far), and AFAIK shouldn't
actually
affect the basic PCI passthrough capability.
Question: how'd you disable ACS? I think it may be causing me
some
issues.
Put:
(pci-passthrough-strict-check no)
(pci-dev-assign-strict-check no)
in /etc/xen/xend-config.sxp
If it was causing you issues, however, I'd expect you to find
errors
in logs pointing at it.
As I understand the xend-config.sxp [1] is for the xm toolstack and
deprecated Xend service.
xm toolstack and xend are what I am using. I have read reports of issues
with VGA passthrough using the xl stack so I didn't even attempt to
use it.
The xm toolstack was deprecated in version 4.1. I read that it had not
been updated in months due to a lack of maintainers.
I heard that xl is still feature-incomplete and experimental, and
problematic with VGA passthrough.
I did try xm back
when I started, the passthrough worked but had the same problems I had
when I began testing xl. I have been using xl since then. My logic was
simply "why become dependent on a tool that is no-longer maintained and
may be removed from the next release?"
I'm not wedded to any particular tool stack, I'm happy to use whatever
works. But since libvirt and virt-manager are still using xm, and since
I have seen recent reports of xl being problematic for VGA passthrough
as well as there being no apparent way to disable ACS requirements with
the xl stack, that rules it out for me completely at the moment.
Does anyone know whether the xm toolstack been modified since 4.1 to
accommodate changes with Xen 4.2? If it has not, it might be worth
considering xl.
Does anyone know how to disable the ACS bridge requirement with the xl
stack?
Perhaps I am confused, or things changed while I wasn't looking, but
for me enabling Xend breaks the xl toolstack. My understanding
is it
was for the xm toolstack only and deprecated with 4.2. Any chance
you can share how you configured it to work? Apparently it is
required to get libvirt working, which I also did not know was
compatible with Xen 4.2.
It is possible I'm the one doing it wrong. I'm on EL6, and using
virt-manager (at least for things it is willing to do), and that
defaults to the xm stack and xend.
For what it's worth, it works for the most part - apart from VGA
passthrough crashing within 5 minutes of gaming.
If you are using xm then it makes sense, as libvirt seems to require
xm/xend to be loaded in order to function.
There are more upgrade notes
<http://wiki.xen.org/wiki/MigrationGuideToXen4.1%2B#Toolstack_upgrade_notes>
about
xend now, so that is new to me. According to the Xen Man Pages the
xend-config.sxp file doesn't have the flags you added; can you link to
resources that mentioned them? I have not seen xl equivalents for your
xend configuration, so I guess xm does have some features xl does not still.
This mentions it, among others:
http://wiki.xen.org/wiki/Xen_PCI_Passthrough
Google for
xen pci-passthrough-strict-check pci-dev-assign-strict-check
and you should find some relevant things easily enough.
Gordan
_______________________________________________
Xen-users mailing list
Xen-users@xxxxxxxxxxxxx
http://lists.xen.org/xen-users
|
