Subject: Re: [PATCH v2 0/9] Remove SMMUv3 struct arm_smmu_cmdq_ent

From: Samiullah Khawaja <[email-masked]>
Date: Sat, 16 May 2026 00:46:26 +0000

On Wed, May 13, 2026 at 08:57:39PM -0300, Jason Gunthorpe wrote:
>[ This is part of the patch pile to move SMMUv3 over to the generic page
>table:
>1) Introduction of new gather items and RISCV usage
>  https://patch.msgid.link/r/[email-masked]
>2) Remove SMMUv3 struct arm_smmu_cmdq_ent
>3) Organize the SMMUv3 invalidation flow so iommupt can use it
>4) Use the generic iommu page table for SMMUv3
>
>The whole branch is here:
>   https://github.com/jgunthorpe/linux/commits/iommu_pt_arm64/
>]
>
>The invalidation logic has this multi-step process where it first
>writes the command into a 32 byte struct arm_smmu_cmdq_ent, then it
>calls a function which converts it into a 16 byte HW struct, and
>sometimes it then edits the HW struct a little bit before passing it
>off to the batch or submission functions.
>
>Instead just generate the HW struct directly by moving the FIELD_PREP
>blocks out of the big case statement and into helper functions. Call the
>right function in all the places that were building arm_smmu_cmdq_ent.
>
>Add a type for the CMDQ entry similar to the STE/CD types that wraps the
>two u64s for clarity and use it everywhere.
>
>This is intended to have no functional change. It makes the following
>patches work better and removes a bunch of LOC. I've run several AI tools
>with instruction to look for functional changes, which did find one subtle
>mistake in PRI response.
>
>The removal of arm_smmu_cmdq_build_cmd() also achieves what Mostafa is
>doing in the pkvm series by making the command formation entirely header
>based with the arm_smmu_make_cmd_*() mini inlines.
>
>This series has no dependencies. Several people have already tested this
>on various ARM systems along with the full iommupt conversion.
>
>v2:
> - Collect tags and add a commit message note about ATS
>v1: https://patch.msgid.link/r/[email-masked]
>
>Jason Gunthorpe (9):
>  iommu/arm-smmu-v3: Add struct arm_smmu_cmd to represent the HW format
>    command
>  iommu/arm-smmu-v3: Use the HW arm_smmu_cmd in cmdq selection functions
>  iommu/arm-smmu-v3: Use the HW arm_smmu_cmd in cmdq submission
>    functions
>  iommu/arm-smmu-v3: Convert arm_smmu_cmdq_batch cmds to struct
>    arm_smmu_cmd
>  iommu/arm-smmu-v3: Remove CMDQ_OP_CFGI_CD_ALL from
>    arm_smmu_cmdq_build_cmd()
>  iommu/arm-smmu-v3: Directly encode simple commands
>  iommu/arm-smmu-v3: Directly encode CMDQ_OP_ATC_INV
>  iommu/arm-smmu-v3: Directly encode CMDQ_OP_SYNC
>  iommu/arm-smmu-v3: Directly encode TLBI commands
>
> .../arm/arm-smmu-v3/arm-smmu-v3-iommufd.c     |  24 +-
> drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c   | 475 +++++++-----------
> drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h   | 248 +++++----
> .../iommu/arm/arm-smmu-v3/tegra241-cmdqv.c    |  16 +-
> 4 files changed, 350 insertions(+), 413 deletions(-)
>
>
>base-commit: d8fa633ffaf43316bc3ee8d7b21366cc92c02002
>-- 
>2.43.0
>
>

Sanity tested on non-coherent rockchip rk3588s with nvme.

Tested-by: Samiullah Khawaja <[email-masked]>