From: Qinxin Xia <xiaqinxin@huawei•com>
To: <robin.murphy@arm•com>, <nicolinc@nvidia•com>, <will@kernel•org>,
<jpb@kernel•org>
Cc: <linux-arm-kernel@lists•infradead.org>, <iommu@lists•linux.dev>,
<xiaqinxin@huawei•com>, <wangzhou1@hisilicon•com>,
<prime.zeng@hisilicon•com>, <fanghao11@huawei•com>,
<jonathan.cameron@huawei•com>, <wuyifan50@huawei•com>,
<linuxarm@huawei•com>
Subject: [RFC PATCH v2 0/5] Add debugfs support for ARM SMMUv3
Date: Sat, 28 Mar 2026 18:09:48 +0800 [thread overview]
Message-ID: <20260328100953.3441915-1-xiaqinxin@huawei.com> (raw)
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 V1:
Address the comments from Nicolin:
1.Fixed the incorrect comments and replaced 'kzalloc' with 'kzalloc_obj'
2.'stream_table_create/stream_table_remove' is called in probe_device/release_device
3.Reused some functions in the driver
Address the comments from Robin:
1.Remove unnecessary CR0*EN extra strings
2.Remove the limit on ssid
Address the comments from Robin and Nicolin:
1.The directory structure has been changed
2.Added lock protection for the ste_show and cd_show
Others:
1.'arm_smmu_debugfs_remove' is added to remove the corresponding debugfs when SMMU device is removed
2.'arm_smmu_debugfs_remove_stream_table' is added to remove the corresponding stream_dir when device is removed
3.Use scoped_guard for locks that include return
4.Added 'open' and 'release' operations to prevent the device from being released during dump
5.Merged 'stream_table_create' and 'ste_show' into one patch
6.Some other clean code
- Link: https://lore.kernel.org/all/20260313104351.3502293-1-xiaqinxin@huawei.com/
Qinxin Xia (5):
iommu/arm-smmu-v3: Add basic debugfs framework
iommu/arm-smmu-v3: Add register display to debugfs
iommu/arm-smmu-v3: Add Stream Table Entry display to debugfs
iommu/arm-smmu-v3: Add device symlink in stream table debugfs
iommu/arm-smmu-v3: Add Context Descriptor display to debugfs
drivers/iommu/Kconfig | 11 +
drivers/iommu/arm/arm-smmu-v3/Makefile | 1 +
.../arm/arm-smmu-v3/arm-smmu-v3-debugfs.c | 571 ++++++++++++++++++
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 33 +-
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 32 +
5 files changed, 646 insertions(+), 2 deletions(-)
create mode 100644 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-debugfs.c
--
2.33.0
next reply other threads:[~2026-03-28 10:10 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-28 10:09 Qinxin Xia [this message]
2026-03-28 10:09 ` [RFC PATCH v2 1/5] iommu/arm-smmu-v3: Add basic debugfs framework Qinxin Xia
2026-03-28 10:09 ` [RFC PATCH v2 2/5] iommu/arm-smmu-v3: Add register display to debugfs Qinxin Xia
2026-03-28 10:09 ` [RFC PATCH v2 3/5] iommu/arm-smmu-v3: Add Stream Table Entry " Qinxin Xia
2026-03-28 10:09 ` [RFC PATCH v2 4/5] iommu/arm-smmu-v3: Add device symlink in stream table debugfs Qinxin Xia
2026-03-28 10:09 ` [RFC PATCH v2 5/5] iommu/arm-smmu-v3: Add Context Descriptor display to debugfs Qinxin Xia
2026-03-28 10:14 ` [RFC PATCH v2 0/5] Add debugfs support for ARM SMMUv3 Qinxin Xia
-- strict thread matches above, loose matches on Subject: below --
2026-03-28 10:17 Qinxin Xia
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