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authorBreno Leitao <leitao@debian.org>2026-08-05 07:52:36 -0700
committerTejun Heo <tj@kernel.org>2026-08-10 11:47:20 -1000
commita5bde5d8fde8a8cb28e59a672d5ddc5b9c1e7656 (patch)
tree39f5b258386e1127d253d293194e9a2991bf3c34 /Documentation/ABI/testing/debugfs-amd-iommu
downloadlinux-stable-a5bde5d8fde8a8cb28e59a672d5ddc5b9c1e7656.tar.gz
linux-stable-a5bde5d8fde8a8cb28e59a672d5ddc5b9c1e7656.zip
workqueue: skip the node_nr_active update for non-unbound workqueuesgrafted
apply_wqattrs_commit() updates node_nr_active->max unconditionally. wq->node_nr_active[] is only allocated for unbound workqueues, so guard the call before per-cpu workqueues start using this path. No functional change: only unbound workqueues reach apply_wqattrs_*() today. Signed-off-by: Breno Leitao <leitao@debian.org> Signed-off-by: Tejun Heo <tj@kernel.org>
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+What: /sys/kernel/debug/iommu/amd/iommu<x>/mmio
+Date: January 2025
+Contact: Dheeraj Kumar Srivastava <dheerajkumar.srivastava@amd.com>
+Description:
+ This file provides read/write access for user input. Users specify the
+ MMIO register offset for iommu<x>, and the file outputs the corresponding
+ MMIO register value of iommu<x>
+
+ Example::
+
+ $ echo "0x18" > /sys/kernel/debug/iommu/amd/iommu00/mmio
+ $ cat /sys/kernel/debug/iommu/amd/iommu00/mmio
+
+ Output::
+
+ Offset:0x18 Value:0x000c22000003f48d
+
+What: /sys/kernel/debug/iommu/amd/iommu<x>/capability
+Date: January 2025
+Contact: Dheeraj Kumar Srivastava <dheerajkumar.srivastava@amd.com>
+Description:
+ This file provides read/write access for user input. Users specify the
+ capability register offset for iommu<x>, and the file outputs the
+ corresponding capability register value of iommu<x>.
+
+ Example::
+
+ $ echo "0x10" > /sys/kernel/debug/iommu/amd/iommu00/capability
+ $ cat /sys/kernel/debug/iommu/amd/iommu00/capability
+
+ Output::
+
+ Offset:0x10 Value:0x00203040
+
+What: /sys/kernel/debug/iommu/amd/iommu<x>/cmdbuf
+Date: January 2025
+Contact: Dheeraj Kumar Srivastava <dheerajkumar.srivastava@amd.com>
+Description:
+ This file is a read-only output file containing iommu<x> command
+ buffer entries.
+
+ Examples::
+
+ $ cat /sys/kernel/debug/iommu/amd/iommu<x>/cmdbuf
+
+ Output::
+
+ CMD Buffer Head Offset:339 Tail Offset:339
+ 0: 00835001 10000001 00003c00 00000000
+ 1: 00000000 30000005 fffff003 7fffffff
+ 2: 00835001 10000001 00003c01 00000000
+ 3: 00000000 30000005 fffff003 7fffffff
+ 4: 00835001 10000001 00003c02 00000000
+ 5: 00000000 30000005 fffff003 7fffffff
+ 6: 00835001 10000001 00003c03 00000000
+ 7: 00000000 30000005 fffff003 7fffffff
+ 8: 00835001 10000001 00003c04 00000000
+ 9: 00000000 30000005 fffff003 7fffffff
+ 10: 00835001 10000001 00003c05 00000000
+ 11: 00000000 30000005 fffff003 7fffffff
+ [...]
+
+What: /sys/kernel/debug/iommu/amd/devid
+Date: January 2025
+Contact: Dheeraj Kumar Srivastava <dheerajkumar.srivastava@amd.com>
+Description:
+ This file provides read/write access for user input. Users specify the
+ device ID, which can be used to dump IOMMU data structures such as the
+ interrupt remapping table and device table.
+
+ Example:
+
+ 1.
+ ::
+
+ $ echo 0000:01:00.0 > /sys/kernel/debug/iommu/amd/devid
+ $ cat /sys/kernel/debug/iommu/amd/devid
+
+ Output::
+
+ 0000:01:00.0
+
+ 2.
+ ::
+
+ $ echo 01:00.0 > /sys/kernel/debug/iommu/amd/devid
+ $ cat /sys/kernel/debug/iommu/amd/devid
+
+ Output::
+
+ 0000:01:00.0
+
+What: /sys/kernel/debug/iommu/amd/devtbl
+Date: January 2025
+Contact: Dheeraj Kumar Srivastava <dheerajkumar.srivastava@amd.com>
+Description:
+ This file is a read-only output file containing the device table entry
+ for the device ID provided in /sys/kernel/debug/iommu/amd/devid.
+
+ Example::
+
+ $ cat /sys/kernel/debug/iommu/amd/devtbl
+
+ Output::
+
+ DeviceId QWORD[3] QWORD[2] QWORD[1] QWORD[0] iommu
+ 0000:01:00.0 0000000000000000 20000001373b8013 0000000000000038 6000000114d7b603 iommu3
+
+What: /sys/kernel/debug/iommu/amd/irqtbl
+Date: January 2025
+Contact: Dheeraj Kumar Srivastava <dheerajkumar.srivastava@amd.com>
+Description:
+ This file is a read-only output file containing valid IRT table entries
+ for the device ID provided in /sys/kernel/debug/iommu/amd/devid.
+
+ Example::
+
+ $ cat /sys/kernel/debug/iommu/amd/irqtbl
+
+ Output::
+
+ DeviceId 0000:01:00.0
+ IRT[0000] 0000000000000020 0000000000000241
+ IRT[0001] 0000000000000020 0000000000000841
+ IRT[0002] 0000000000000020 0000000000002041
+ IRT[0003] 0000000000000020 0000000000008041
+ IRT[0004] 0000000000000020 0000000000020041
+ IRT[0005] 0000000000000020 0000000000080041
+ IRT[0006] 0000000000000020 0000000000200041
+ IRT[0007] 0000000000000020 0000000000800041
+ [...]