Re: XSAVE/XRSTOR crash resurgence in 4.3

[Ben Guthro <ben.guthro@gmail.com>]

On Jul 5, 2013, at 6:30 AM, Jan Beulich <JBeulich@suse.com> wrote:

>>>> On 04.07.13 at 20:19, Mark Roddy <mark.roddy@citrix.com> wrote:
>> -----Original Message-----
>> From: Ben Guthro [mailto:ben.guthro@gmail.com]
>>
>> Happy to test a debug patch, as well.
>
> Here you go. The logging is done using thresholds (so you wouldn't
> get your log flooded), but of course this has the risk of not seeing
> anything useful in case the problem happens not on every run
> through these functions. Also the patch instruments on the xsave/
> xrstor paths, not the fxsave/fxrstor ones, so is assumed to be used
> on an xsave-capable and -enabled system. Ideally - if reproducible
> this way - you'd use a single-vCPU guest (easing later log analysis).
>
> Jan
>
> <x86-FPU-selector-loss.patch>

Thanks.

Since I am not in the office today, nor near a machine that I can
access this, I asked someone else to apply and check in this patch, in
the hope that we could get some useful debug info from the weekend
test run.

However, when he went to test booting a VM with this patch, the host
machine rebooted - presumably a Xen crash.

I'll have a closer look on Mon.