[PATCH v2 00/19] Update SMMUv3 to the modern iommu API (part 1/3)

[Nicolin Chen]

On Mon, Nov 13, 2023 at 01:53:07PM -0400, Jason Gunthorpe wrote:
 
> Overall this takes the approach of turning the STE/CD programming upside
> down where the CD/STE value is computed right at a driver callback
> function and then pushed down into programming logic. The programming
> logic hides the details of the required CD/STE tear-less update. This
> makes the CD/STE functions independent of the arm_smmu_domain which makes
> it fairly straightforward to untangle all the different call chains, and
> add news ones.
> 
> Further, this frees the arm_smmu_domain related logic from keeping track
> of what state the STE/CD is currently in so it can carefully sequence the
> correct update. There are many new update pairs that are subtly introduced
> as the work progresses.
> 
> The locking to support BTM via arm_smmu_asid_lock is a bit subtle right
> now and patches throughout this work adjust and tighten this so that it is
> clearer and doesn't get broken.
> 
> Once the lower STE layers no longer need to touch arm_smmu_domain we can
> isolate struct arm_smmu_domain to be only used for PAGING domains, audit
> all the to_smmu_domain() calls to be only in PAGING domain ops, and
> introduce the normal global static BLOCKED/IDENTITY domains using the new
> STE infrastructure. Part 2 will ultimately migrate SVA over to use
> arm_smmu_domain as well.
> 
> All parts are on github:
> 
>  https://github.com/jgunthorpe/linux/commits/smmuv3_newapi

Ran sanity with part-1 alone, covering S1 Translate and SVA cases.

And ran more functional tests with part-2 and part-3 (nested) in
the repo above, covering host-level S1 Translate, S1DSS_BYPASS +
SVA, and guest VM (stage-2 alone, and stage-1+2 with S1DSS_SSID0
and S1DSS_BYPASS). These should test quite a list of combinations
against the STE updating algorithm.

Tested-by: Nicolin Chen <nicolinc at nvidia.com>