Re: S3 crash with VTD Queue Invalidation enabled

[Ben Guthro <ben@guthro.net>]

On Wed, Jun 5, 2013 at 4:27 PM, Ben Guthro <ben@guthro.net> wrote:
> On Wed, Jun 5, 2013 at 11:38 AM, Jan Beulich <JBeulich@suse.com> wrote:
>>>>> On 05.06.13 at 17:25, Ben Guthro <ben@guthro.net> wrote:
>>> On Wed, Jun 5, 2013 at 11:14 AM, Jan Beulich <JBeulich@suse.com> wrote:
>>>> Depending on whether ATS is in use, more than one invalidation
>>>> can be done in the processing here - could you therefore check
>>>> whether there's any sign of ATS use ("iommu=verbose" should
>>>> make you see respective messages), and if so see whether
>>>> disabling it ("ats=off") makes a difference?
>>>
>>> ATS does not appear to be running:
>>>
>>> (XEN) [VT-D]dmar.c:737: Host address width 36
>>> (XEN) [VT-D]dmar.c:751: found ACPI_DMAR_DRHD:
>>> (XEN) [VT-D]dmar.c:412:   dmaru->address = fed90000
>>> (XEN) [VT-D]iommu.c:1197: drhd->address = fed90000 iommu->reg = ffff82c3ffd57000
>>> (XEN) [VT-D]iommu.c:1199: cap = c0000020e60262 ecap = f0101a
>>> (XEN) [VT-D]dmar.c:338:  endpoint: 0000:00:02.0
>>> (XEN) [VT-D]dmar.c:751: found ACPI_DMAR_DRHD:
>>> (XEN) [VT-D]dmar.c:412:   dmaru->address = fed91000
>>> (XEN) [VT-D]iommu.c:1197: drhd->address = fed91000 iommu->reg = ffff82c3ffd56000
>>> (XEN) [VT-D]iommu.c:1199: cap = c9008020660262 ecap = f0105a
>>> (XEN) [VT-D]dmar.c:354:  IOAPIC: 0000:f0:1f.0
>>> (XEN) [VT-D]dmar.c:332:  MSI HPET: 0000:00:0f.0
>>> (XEN) [VT-D]dmar.c:332:  MSI HPET: 0000:00:0f.1
>>> (XEN) [VT-D]dmar.c:332:  MSI HPET: 0000:00:0f.2
>>> (XEN) [VT-D]dmar.c:332:  MSI HPET: 0000:00:0f.3
>>> (XEN) [VT-D]dmar.c:332:  MSI HPET: 0000:00:0f.4
>>> (XEN) [VT-D]dmar.c:332:  MSI HPET: 0000:00:0f.5
>>> (XEN) [VT-D]dmar.c:332:  MSI HPET: 0000:00:0f.6
>>> (XEN) [VT-D]dmar.c:332:  MSI HPET: 0000:00:0f.7
>>> (XEN) [VT-D]dmar.c:426:   flags: INCLUDE_ALL
>>> (XEN) [VT-D]dmar.c:756: found ACPI_DMAR_RMRR:
>>> (XEN) [VT-D]dmar.c:338:  endpoint: 0000:00:1d.0
>>> (XEN) [VT-D]dmar.c:338:  endpoint: 0000:00:1a.0
>>> (XEN) [VT-D]dmar.c:625:   RMRR region: base_addr ba8d5000 end_address
>>> ba8ebfff
>>> (XEN) [VT-D]dmar.c:756: found ACPI_DMAR_RMRR:
>>> (XEN) [VT-D]dmar.c:338:  endpoint: 0000:00:02.0
>>> (XEN) [VT-D]dmar.c:625:   RMRR region: base_addr bb800000 end_address
>>> bf9fffff
>>>
>>> I would expect a line with "found ACPI_DMAR_ATSR" to be printed, if it
>>> was found.
>>
>> Right. So one less variable.
>
> Some more info.
> Ross Philipson provided me with a handy utility to dump a bunch more
> info about the DMAR tables, and with some more trace, this appears to
> be tied to the IGD.
>
> Early in the boot process, I see queue_invalidate_wait() called for
> DRHD unit 0, and 1
> (unit 0 is wired up to the IGD, unit 1 is everything else)
>
> Up until i915 does the following, I see that unit being flushed with
> queue_invalidate_wait() :
>
> [    0.704537] ENERGY_PERF_BIAS: Set to 'normal', was 'performance'
> [    0.704537] ENERGY_PERF_BIAS: View and update with x86_energy_p
> (XEN) XXX queue_invalidate_wait:282 CPU0 DRHD0 ret=0
> (XEN) XXX queue_invalidate_wait:282 CPU0 DRHD0 ret=0
> [    1.983028] [drm] GMBUS [i915 gmbus dpb] timed out, falling back to
> bit banging on pin 5
> [    2.253551] fbcon: inteldrmfb (fb0) is primary device
> [    3.111838] Console: switching to colour frame buffer device 170x48
> [    3.171631] i915 0000:00:02.0: fb0: inteldrmfb frame buffer device
> [    3.171634] i915 0000:00:02.0: registered panic notifier
> [    3.173339] acpi device:00: registered as cooling_device1
> [    3.173401] ACPI: Video Device [VID] (multi-head: yes  rom: no  post: no)
> [    3.173962] input: Video Bus as
> /devices/LNXSYSTM:00/LNXSYBUS:00/PNP0A08:00/LNXVIDEO:00/input/input4
> [    3.174232] [drm] Initialized i915 1.6.0 20080730 for 0000:00:02.0 on minor 0
> [    3.174258] ahci 0000:00:1f.2: version 3.0
> [    3.174270] xen: registering gsi 19 triggering 0 polarity 1
> [    3.174274] Already setup the GSI :19
>
>
> After that - the unit never seems to be flushed.
>
> ...until we enter into the S3 hypercall, which loops over all DRHD
> units, and explicitly flushes all of them via iommu_flush_all()
>
> It is at that point that it hangs up when talking to the device that
> the IGD is plumbed up to.
>
>
> Does this point to something in the i915 driver doing something that
> is incompatible with Xen?

I actually separated it from the S3 hypercall, adding a new debug key
'F' - to just call iommu_flush_all()
I can crash it on demand with this.

Booting with "i915.modeset=0 single" (to prevent both KMS, and Xorg) -
it does not occur.
So, that pretty much narrows it down to the IGD, in my mind.