Re: S3 crash with VTD Queue Invalidation enabled

[Ben Guthro <ben@guthro.net>]

On Wed, Jun 5, 2013 at 4:24 AM, Jan Beulich <JBeulich@suse.com> wrote:
>>>> On 04.06.13 at 23:09, Ben Guthro <ben@guthro.net> wrote:
>> On Tue, Jun 4, 2013 at 3:49 PM, Ben Guthro <ben@guthro.net> wrote:
>>> On Tue, Jun 4, 2013 at 3:20 PM, Ben Guthro <ben@guthro.net> wrote:
>>>> On Tue, Jun 4, 2013 at 10:01 AM, Jan Beulich <JBeulich@suse.com> wrote:
>>>>>>>> On 04.06.13 at 14:25, Ben Guthro <ben@guthro.net> wrote:
>>>>>> On Tue, Jun 4, 2013 at 4:54 AM, Jan Beulich <JBeulich@suse.com> wrote:
>>>>>>> Is this perhaps having some similarity with
>>>>>>> http://lists.xen.org/archives/html/xen-devel/2013-04/msg00343.html?
>>>>>>> We're clearly running single-CPU only here and there...
>>>>>>
>>>>>> We certainly should be, as we have gone through the
>>>>>> disable_nonboot_cpus() by this point - and I can verify that from the
>>>>>> logs.
>>>>>
>>>>> I'm much more tending towards the connection here, noting that
>>>>> Andrew's original thread didn't really lead anywhere (i.e. we still
>>>>> don't know what the panic he saw was actually caused by).
>>>>>
>>>>
>>>> I'm starting to think you're on to something here.
>>>
>>> hmm - maybe not.
>>> I get the same crash with "maxcpus=1"
>>>
>>>
>>>
>>>> I've put a bunch of trace throughout the functions in qinval.c
>>>>
>>>> It seems that everything is functioning properly, up until we go
>>>> through the disable_nonboot_cpus() path.
>>>> Prior to this, I see the qinval.c functions being executed on all
>>>> cpus, and both drhd units
>>>> Afterward, it gets stuck in queue_invalidate_wait on the first drhd
>>>> unit.. and eventually panics.
>>>>
>>>> I'm not exactly sure what to make of this yet.
>>
>> querying status of the hardware all seems to be working correctly...
>> it just doesn't work with querying the QINVAL_STAT_DONE state, as far
>> as I can tell.
>>
>> Other register state is:
>>
>> (XEN)  VER = 10
>> (XEN)  CAP = c0000020e60262
>> (XEN)  n_fault_reg = 1
>> (XEN)  fault_recording_offset = 200
>> (XEN)  fault_recording_reg_l = 0
>> (XEN)  fault_recording_reg_h = 0
>> (XEN)  ECAP = f0101a
>> (XEN)  GCMD = 0
>> (XEN)  GSTS = c7000000
>> (XEN)  RTADDR = 137a31000
>> (XEN)  CCMD = 800000000000000
>> (XEN)  FSTS = 0
>> (XEN)  FECTL = 0
>> (XEN)  FEDATA = 4128
>> (XEN)  FEADDR = fee0000c
>> (XEN)  FEUADDR = 0
>>
>> (with code lifted from print_iommu_regs() )
>>
>>
>> None of this looks suspicious to my untrained eye - but I'm including
>> it here in case someone else sees something I don't.
>
> Xiantao, you certainly will want to give some advice here. I won't
> be able to look into this more deeply right away.

Thanks Jan. Xiantao - I'd appreciate any insight you may have.

One curious thing I have found, that seems buggy to me, is that
{dis,en}able_qinval() is being called prior to the platform quirks
being executed.
It appears they are being called through iommu_{en,dis}able_x2apic_IR()

However, when I try to put a BUG(), or dump_execution_state in that
code, it would not dump a stack.

I was going to put a platform quirk in, to detect, and disable qinval
on this platform, but it seems that may be too late in the process.