Re: [xen-unstable bisection] complete test-amd64-amd64-xl-xsm

[Andrew Cooper <andrew.cooper3@citrix.com>]

On 15/06/15 10:30, Jan Beulich wrote:
>>>> On 14.06.15 at 22:54, <osstest@xenbits.xen.org> wrote:
>> branch xen-unstable
>> xen branch xen-unstable
>> job test-amd64-amd64-xl-xsm
>> test xen-boot
>>
>> Tree: linux git://xenbits.xen.org/linux-pvops.git
>> Tree: linuxfirmware git://xenbits.xen.org/osstest/linux-firmware.git
>> Tree: qemu git://xenbits.xen.org/staging/qemu-xen-unstable.git
>> Tree: qemuu git://xenbits.xen.org/staging/qemu-upstream-unstable.git
>> Tree: xen git://xenbits.xen.org/xen.git
>>
>> *** Found and reproduced problem changeset ***
>>
>>   Bug is in tree:  xen git://xenbits.xen.org/xen.git
>>   Bug introduced:  73cb5d43a8f48930e4594ef7b15b974487651ffe
>>   Bug not present: 284ffb4f9b0d5c3a33c4c5bd87645d0cc342ca96
>>
>>
>>   commit 73cb5d43a8f48930e4594ef7b15b974487651ffe
>>   Author: Jan Beulich <jbeulich@suse.com>
>>   Date:   Thu Jun 11 11:53:20 2015 +0200
>>   
>>       x86/MSI-X: use qword MMIO access for address writes
>>       
>>       Now that we support it for our guests, let's do so ourselves too.
>>       
>>       Signed-off-by: Jan Beulich <jbeulich@suse.com>
>>       Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
> The only thing I can see us doing here is revert. Three machine
> pairs are affected, yet each exhibits the problem in different ways:
> - elbling[01] see tg3 transmit timeouts
> - merlot[01] see SERR NMIs
> - godello[01] appear to suffer from silent reboots
> Other than assuming that the NICs of these systems (all using the
> tg3 driver) don't properly support what the standard mandates I
> have no explanation so far. Maybe once I run the code on a few
> more systems here I can find one also showing such bad behavior.

I can't explain this either.  Best to revert for now.

~Andrew