Subject: Re: [PATCH 0/5] Add debugfs support for ARM SMMUv3

From: Nicolin Chen <[email-masked]>
Date: Tue, 26 May 2026 17:07:17 -0700

On Wed, May 20, 2026 at 02:37:06PM +0800, Qinxin Xia wrote:
> Add a comprehensive debugfs framework to the ARM SMMUv3 driver,
> providing visibility into internal hardware state for debugging
> and performance analysis. The debugfs entries are organized under
> /sys/kernel/debug/iommu/arm_smmu_v3/, with per-SMMU instance directories
> and per-device stream table entries.
> 
> Each SMMU instance provides:
> - capabilities – static SMMU features and queue sizes.
> - registers – SMMU key registers.
> - stream_table/ – a directory per device with subdirectories per Stream ID.
> 
> Each Stream ID subdirectory contains:
> - ste – the Stream Table Entry in decoded and raw format.
> - cd – all valid Context Descriptors (Stage 1 translation tables) associated with the device.
> - a symlink named with the device's BDF/name pointing to its sysfs directory for easy navigation.
> 
> /sys/kernel/debug/iommu/arm_smmu_v3/smmu0/stream_table/
>     ├── <sid>/
>     │   ├── ste
>     │   ├── cd
>     │   └── <dev_name>
> 
> Changes since RFCv2:
>   Address review comments from Nicolin Chen, kernel test robot, and Sashiko
>   automated review:

This seems to reuse the same message ID as RFCv2's?

So, it ended up with attaching to RFCv2, on my side (mutt).

Sashiko also failed to review against the new patches:
https://sashiko.dev/#/patchset/20260328101706.3448655-1-xiaqinxin%40huawei.com

Nicolin