Re: [PATCH v4 02/13] iommu/arm-smmu-v3: Add smmu_s1_cfg to smmu_master

[Michael Shavit]

Sorry for the delay; I'm trying to refactor these patches now.

> I think the master should have a pointer to the iommu_domain that owns
> the STE or if NULL the master should assign its internal CD table to
> the STE.
Just to clarify, does the nested domain patch series require writing
CDs into the user-space's CD table using arm_smmu_write_ctx_desc()? Or
is there any other requirement for writing a CD into a domain-owned CD
table from arm_smmu_write_ctx_desc?


Writing a CD entry to the CD table involves some dependencies on the
master(s) that the table is attached to:

1. The CD entries STALL bit value in arm_smmu_write_ctx_desc depends
on the master (e.g. if STALL_FORCE is set on the smmu device). This
could potentially be encoded in arm_smmu_ctx_desc_cfg, at which point
that CD table is only attachable to masters with the same
stall_enabled value.
2. arm_smmu_write_ctx_desc must sync the CD for the attached master(s)
in the middle of writing CD entry.

This is all easier to handle in arm_smmu_write_ctx_desc if the table
is always owned by the master.