[PATCH RFC v4 2/4] iommu/arm-smmu-v3: Support shared SIDs in insert/remove_master

Nicolin Chen nicolinc at nvidia.com
Fri Oct 2 09:56:30 PDT 2026


On Fri, Oct 02, 2026 at 06:27:58PM +0800, Peng Fan wrote:
> Ah. So I need a patch list saying:
> 1. iommu/arm-smmu-v3: Allocate streams individually. Change master->streams
>    from an embedded array of struct arm_smmu_stream to an array of pointers,
>    with each stream individually allocated, to prepare for shared-SID support
>    where multiple masters will point to the same stream object
> 2. iommu/arm-smmu-v3: Support shared SIDs in insert/remove_master
> 3. iommu/arm-smmu-v3: Group aliasing devices into the same IOMMU group
> 4. iommu/arm-smmu-v3: Wire up shared-SID STE ordering and feature gating

That looks right to me.

Please also check Sashiko findings:
https://sashiko.dev/#/patchset/20261001-smmu-shared-sid-ver3-v4-0-06b34fb2e691%40nxp.com

Some of them should be gone once you fix the out-of-sync issue.
But findings like lockings would still remain.

Nicolin



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