[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Xen-devel] [Xen-users] Xen 4.7.0 graphics pass through problems (Win10, AMD Radeon)





On 2016-09-14 16:49, Jan Beulich wrote:
On 14.09.16 at 16:04, <miles@xxxxxxxx> wrote:
On 2016-09-14 14:50, Jan Beulich wrote:
On 14.09.16 at 13:34, <george.dunlap@xxxxxxxxxx> wrote:
Can you think of anything that's changed between 4.6 and 4.7 that
would cause the performance problems he's describing when both a video
card and a usb controller are passed through, but not when only the
video card is passed through?
Not really, no. Peter - are there any indications of problems in
one or more of the logs (Xen, xl, qemu)? Did you try running a
debug build of all Xen components?
No, I did not try a debug build. However, the system seems fairly stable
now, only the display driver crashing once, or twice a day. That did
occur with Xen 4.6.3 also, but maybe once a week. Looking at the log
files, I cannot see anything particular that stands out, except for the
domU log.

The domU log file qemu-dm-<Name>.log started to contain the following
lines after upgrading to 4.7:

[00:06.0] xen_pt_bar_read: Error: Should not read BAR through QEMU.
@0x0000000000000004
[00:06.0] xen_pt_bar_write: Error: Should not write BAR through QEMU.
@0x0000000000000000

There are only a couple of lines with write, the rest with read. I don't
know what significance it's got, but there are around 350 lines every day.
Looks wrong in any case, but I have no clue whether it's indicative
of the problem you're having. In any event in the qemu tree in
hw/xen/xen_pt.h there's an "#ifdef XEN_PT_LOGGING_ENABLED"
conditional close to the top. Could you make this "#if 1" instead
(or simply #define XEN_PT_LOGGING_ENABLED in the line above)
and re-build at least qemu? The log of a subsequent guest run
should then be quite a bit more helpful in possibly spotting what's
going wrong to cause those messages.

And then it's of course rather relevant to know what device 00:06.0
actually is (iirc these are guest BDF values), considering that you're
passing through more than one.

Jan


Hi Jan,

I had a look at the guest devices, and Windows says "Standard Enhanced PCI to USB Host Controller". Having a look at the Properties, in the Device status field is the following message:
---
This device cannot start. (Code 10)

{Operation Failed}
The requested operation was unsuccessful.
---

This USB device wasn't there with Xen 4.6.3. Has it got something to do with the new USB passthrough? However, I have tried USB passthrough (xl usbctrl-attach), which doesn't work. But that is possibly another problem.

No problem to recompile Xen with the logging flag, if it would be required.

Best regards,

Peter

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
https://lists.xen.org/xen-devel

 


Rackspace

Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.