From 27600805e62f800bacf990354632eae4e487d34c Mon Sep 17 00:00:00 2001 From: Yazen Ghannam Date: Thu, 3 Sep 2026 10:43:25 -0500 Subject: x86/amd_node: Fix PCI device reference counting in amd_smn_init() The local "root" pointer is a temporary variable used during the device search. Therefore, refcount related to the search iterators should be cleaned up after the search is complete. Use the __free() cleanup macro to ensure the refcount is decremented when the temporary pointer goes out of scope. Additionally, increment the refcount when caching a root pointer. This ensures the in-use refcount is separate from the temporary search refcounting. Finally, drop the redundant "root = NULL" before the second search loop. The pci_get_class() iterator always decrements the refcount of its "from" argument, so the first loop can only fall through with "root" already NULL. Fixes: 0a4b61d9c2e4 ("x86/amd_node: Fix AMD root device caching") Closes: https://sashiko.dev/#/patchset/20260806160159.230453-1-jason.andryuk%40amd.com Reported-by: Sashiko Assisted-by: LLM Signed-off-by: Yazen Ghannam Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Mario Limonciello (AMD) Cc: Link: https://patch.msgid.link/20260903154325.74343-1-yazen.ghannam@amd.com --- Documentation/ABI/testing/debugfs-amd-iommu | 131 ++++++++++++++++++++++++++++ 1 file changed, 131 insertions(+) create mode 100644 Documentation/ABI/testing/debugfs-amd-iommu (limited to 'Documentation/ABI/testing/debugfs-amd-iommu') diff --git a/Documentation/ABI/testing/debugfs-amd-iommu b/Documentation/ABI/testing/debugfs-amd-iommu new file mode 100644 index 000000000..5621a66aa --- /dev/null +++ b/Documentation/ABI/testing/debugfs-amd-iommu @@ -0,0 +1,131 @@ +What: /sys/kernel/debug/iommu/amd/iommu/mmio +Date: January 2025 +Contact: Dheeraj Kumar Srivastava +Description: + This file provides read/write access for user input. Users specify the + MMIO register offset for iommu, and the file outputs the corresponding + MMIO register value of iommu + + 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/capability +Date: January 2025 +Contact: Dheeraj Kumar Srivastava +Description: + This file provides read/write access for user input. Users specify the + capability register offset for iommu, and the file outputs the + corresponding capability register value of iommu. + + 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/cmdbuf +Date: January 2025 +Contact: Dheeraj Kumar Srivastava +Description: + This file is a read-only output file containing iommu command + buffer entries. + + Examples:: + + $ cat /sys/kernel/debug/iommu/amd/iommu/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 +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 +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 +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 + [...] -- cgit v1.3.1