iommu/amd: flush IOTLB for specific domains only (v2)

[Tom Lendacky]

On 5/15/2018 7:34 AM, Nath, Arindam wrote:
> 
> 
>> -----Original Message-----
>> From: Joseph Salisbury [mailto:joseph.salisbury at canonical.com]
>> Sent: Tuesday, May 15, 2018 5:40 PM
>> To: Nath, Arindam <Arindam.Nath at amd.com>
>> Cc: iommu at lists.linux-foundation.org; Bridgman, John
>> <John.Bridgman at amd.com>; joro at 8bytes.org; amd-
>> gfx at lists.freedesktop.org; drake at endlessm.com; stein12c at gmail.com;
>> Suthikulpanit, Suravee <Suravee.Suthikulpanit at amd.com>; Deucher,
>> Alexander <Alexander.Deucher at amd.com>; Kuehling, Felix
>> <Felix.Kuehling at amd.com>; linux at endlessm.com; michel at daenzer.net;
>> 1747463 at bugs.launchpad.net; Lendacky, Thomas
>> <Thomas.Lendacky at amd.com>
>> Subject: Re: iommu/amd: flush IOTLB for specific domains only (v2)
>>
>> On 05/15/2018 04:03 AM, Nath, Arindam wrote:
>>> Adding Tom.
>>>
>>> Hi Joe,
>>>
>>> My original patch was never accepted. Tom and Joerg worked on another
>> patch series which was supposed to fix the issue in question in addition to do
>> some code cleanups. I believe their patches are already in the mainline. If I
>> remember correctly, one of the patches disabled PCI ATS for the graphics
>> card which was causing the issue.
>>>
>>> Do you still see the issue with latest mainline kernel?
>>>
>>> BR,
>>> Arindam
>>>
>>> -----Original Message-----
>>> From: Joseph Salisbury [mailto:joseph.salisbury at canonical.com]
>>> Sent: Tuesday, May 15, 2018 1:17 AM
>>> To: Nath, Arindam <Arindam.Nath at amd.com>
>>> Cc: iommu at lists.linux-foundation.org; Bridgman, John
>>> <John.Bridgman at amd.com>; joro at 8bytes.org;
>>> amd-gfx at lists.freedesktop.org; drake at endlessm.com;
>> stein12c at gmail.com;
>>> Suthikulpanit, Suravee <Suravee.Suthikulpanit at amd.com>; Deucher,
>>> Alexander <Alexander.Deucher at amd.com>; Kuehling, Felix
>>> <Felix.Kuehling at amd.com>; linux at endlessm.com; michel at daenzer.net;
>>> 1747463 at bugs.launchpad.net
>>> Subject: iommu/amd: flush IOTLB for specific domains only (v2)
>>>
>>> Hello Arindam,
>>>
>>> There is a bug report[0] that you created a patch[1] for a while back.
>> However, the patch never landed in mainline.  There is a bug reporter in
>> Ubuntu[2] that is affected by this bug and is willing to test the patch.  I
>> attempted to build a test kernel with the patch, but it does not apply to
>> currently mainline cleanly.  Do you still think this patch may resolve this
>> bug?  If so, is there a version of your patch available that will apply to current
>> mainline?
>>>
>>> Thanks,
>>>
>>> Joe
>>>
>>> [0] https://bugs.freedesktop.org/show_bug.cgi?id=101029
>>> [1] https://patchwork.freedesktop.org/patch/157327/
>>> [2] http://pad.lv/1747463
>>>
>> Hi Arindam,
>>
>> Thanks for the feedback.  Yes, the latest mainline kernel was tested, and it is
>> reported the bug still happens in the Ubuntu kernel bug[0]. Is there any
>> specific diagnostic info we can collect that might help?
> 
> Joe, I believe all the information needed is already provided in [2]. Let us wait for inputs from Tom and Joerg.
> 
> I could take a look at the issue locally, but it will take me some really long time since I am occupied with other assignments right now.

I don't see anything in the bug that indicates the latest mainline kernel
was tested.  The patches/fixes in question are part of the 4.13 kernel, I
only see references to 4.10 kernels so I wouldn't expect the issue to be
resolved unless the patches from 4.13 were backported to the Ubuntu 4.10
kernel.

Thanks,
Tom

> 
> BR,
> Arindam
> 
>>
>> Thanks,
>>
>> Joe
>>
>> [0] http://pad.lv/1747463