[PATCH v4 0/2] Fix handling of S2 stalls

[Mostafa Saleh <smostafa@google.com>]

While debugging something else, I spent hours looking at hexdumps of
STEs, CDs and commands while comparing them against the arch specs,
where I noticed a minor violation in the driver regarding handling of
S2S bit in the STE.

This has been there for ages, so it’s highly unlikely that any HW (if
it exists with such features) running Linux is affected.

I don’t have access to HW with stalls so I just tested normal usage
and (terminated) translation fault events.

Also, add some unit tests for stall enabled masters.

Mostafa Saleh (2):
  iommu/arm-smmu-v3: Match Stall behaviour for S2
  iommu/arm-smmu-v3-test: Test masters with stall enabled

 .../iommu/arm/arm-smmu-v3/arm-smmu-v3-test.c  | 83 ++++++++++++++-----
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c   |  8 +-
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h   |  1 +
 3 files changed, 66 insertions(+), 26 deletions(-)

v4:
- Add S2S bit to get_used for stage-2
- Add unit tests for masters with stall enabled

v3:
- Set S2S for s2 and not s1 domain
- Ignore ats check

v2:
- Fix index of the STE
- Fix conflict with ATS
- Squash the 2 patches and drop enable_nesting

-- 
2.46.0.469.g59c65b2a67-goog