Re: [Intel-gfx] [PATCH v6 0/2] drm/i915: add guard page to ggtt->error_capture

[Andrzej Hajda <andrzej.hajda@intel.com>]

On 10.03.2023 10:23, Andrzej Hajda wrote:
> This patch tries to diminish plague of DMAR read errors present
> in CI for ADL*, RPL*, DG2 platforms, see for example [1] (grep DMAR).
> CI is usually tolerant for these errors, so the scale of the problem
> is not really visible.
> To show it I have counted lines containing DMAR read errors in dmesgs
> produced by CI for all three versions of the patch, but in contrast to v2
> I have grepped only for lines containing "PTE Read access".
> Below stats for kernel w/o patchset vs patched one.
> v1: 210 vs 0
> v2: 201 vs 0
> v3: 214 vs 0
> Apparently the patchset fixes all common PTE read errors.
> 
> Changelog:
> v2:
>      - modified commit message (I hope the diagnosis is correct),
>      - added bug checks to ensure scratch is initialized on gen3 platforms.
>        CI produces strange stacktrace for it suggesting scratch[0] is NULL,
>        to be removed after resolving the issue with gen3 platforms.
> v3:
>      - removed bug checks, replaced with gen check.
> v4:
>      - change code for scratch page insertion to support all platforms,
>      - add info in commit message there could be more similar issues
> v5:
>      - changed to patchset adding nop_clear_range related code,
>      - re-insert scratch PTEs on resume
> v6:
>      - use scratch_range
> 
> To: Jani Nikula <jani.nikula@linux.intel.com>
> To: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
> To: Rodrigo Vivi <rodrigo.vivi@intel.com>
> To: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
> Cc: intel-gfx@lists.freedesktop.org
> Cc: dri-devel@lists.freedesktop.org
> Cc: linux-kernel@vger.kernel.org
> Cc: Andi Shyti <andi.shyti@linux.intel.com>
> Cc: Chris Wilson <chris.p.wilson@linux.intel.com>
> Cc: Nirmoy Das <nirmoy.das@intel.com>
> 
> Signed-off-by: Andrzej Hajda <andrzej.hajda@intel.com>
> 

Queued to drm-intel-gt-next

Regards
Andrzej

> ---
> - Link to v5: https://lore.kernel.org/r/20230308-guard_error_capture-v5-0-6d1410d13540@intel.com
> 
> ---
> Andrzej Hajda (2):
>        drm/i915/gt: introduce vm->scratch_range callback
>        drm/i915: add guard page to ggtt->error_capture
> 
>   drivers/gpu/drm/i915/gt/intel_ggtt.c      | 43 ++++++++++++++++++++++++++++---
>   drivers/gpu/drm/i915/gt/intel_ggtt_gmch.c |  1 +
>   drivers/gpu/drm/i915/gt/intel_gtt.h       |  2 ++
>   3 files changed, 42 insertions(+), 4 deletions(-)
> ---
> base-commit: 3cd6c251f39c14df9ab711e3eb56e703b359ff54
> change-id: 20230308-guard_error_capture-f3f334eec85f
> 
> Best regards,