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

[Michael Shavit]

On Fri, Jul 14, 2023 at 9:14 AM Nicolin Chen <nicolinc@xxxxxxxxxx> wrote:
> @Michael,
> Would it be possible for you to update a v5, following Jason's
> suggestion overall? And I think we can have a smaller refactor
> series first without set_dev_pasid, to have a common codeline
> sooner for us to add new features, such as set_dev_pasid, the
> use case of IDENTITY default substream, and the nesting series.
> I will help testing with some pasid/non-pasid use cases too.

Want to make sure I fully understand these last few messages first. At
a high level, we want:
1. arm_smmu_master is allowed to own a CD table, but not an
STE-precursor (s1_cfg/s2_cfg). The s1_cfg is practically already that,
and we can probably get there with minimal changes.
2. arm_smmu_master shouldn't point to the currently active CD table
(which may or may not be the one it owns) or STE-precursor as a
shortcut. All code should figure it out by looking at the master's
currently attached domain (functionality could be provided by helper).
3. arm_smmu_domain shouldn't pre-generate any STE-precursors. The
STE/CD for a domain should either be computed right when it is
written, or computed ahead of time and stored as a copy in the
smmu-domain.
Is that right?