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/sysfs-bus-vfio-mdev | 113 ++++++++++++++++++++++++++ 1 file changed, 113 insertions(+) create mode 100644 Documentation/ABI/testing/sysfs-bus-vfio-mdev (limited to 'Documentation/ABI/testing/sysfs-bus-vfio-mdev') diff --git a/Documentation/ABI/testing/sysfs-bus-vfio-mdev b/Documentation/ABI/testing/sysfs-bus-vfio-mdev new file mode 100644 index 000000000..59fc80426 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-bus-vfio-mdev @@ -0,0 +1,113 @@ +What: /sys/...//mdev_supported_types/ +Date: October 2016 +Contact: Kirti Wankhede +Description: + This directory contains list of directories of currently + supported mediated device types and their details for + . Supported type attributes are defined by the + vendor driver who registers with Mediated device framework. + Each supported type is a directory whose name is created + by adding the device driver string as a prefix to the + string provided by the vendor driver. + +What: /sys/...//mdev_supported_types// +Date: October 2016 +Contact: Kirti Wankhede +Description: + This directory gives details of supported type, like name, + description, available_instances, device_api etc. + 'device_api' and 'available_instances' are mandatory + attributes to be provided by vendor driver. 'name', + 'description' and other vendor driver specific attributes + are optional. + +What: /sys/.../mdev_supported_types//create +Date: October 2016 +Contact: Kirti Wankhede +Description: + Writing UUID to this file will create mediated device of + type for parent device . This is a + write-only file. + For example:: + + # echo "83b8f4f2-509f-382f-3c1e-e6bfe0fa1001" > \ + /sys/devices/foo/mdev_supported_types/foo-1/create + +What: /sys/.../mdev_supported_types//devices/ +Date: October 2016 +Contact: Kirti Wankhede +Description: + This directory contains symbolic links pointing to mdev + devices sysfs entries which are created of this . + +What: /sys/.../mdev_supported_types//available_instances +Date: October 2016 +Contact: Kirti Wankhede +Description: + Reading this attribute will show the number of mediated + devices of type that can be created. This is a + readonly file. +Users: + Userspace applications interested in creating mediated + device of that type. Userspace application should check + the number of available instances could be created before + creating mediated device of this type. + +What: /sys/.../mdev_supported_types//device_api +Date: October 2016 +Contact: Kirti Wankhede +Description: + Reading this attribute will show VFIO device API supported + by this type. For example, "vfio-pci" for a PCI device, + "vfio-platform" for platform device. + +What: /sys/.../mdev_supported_types//name +Date: October 2016 +Contact: Kirti Wankhede +Description: + Reading this attribute will show human readable name of the + mediated device that will get created of type . + This is optional attribute. For example: "Grid M60-0Q" +Users: + Userspace applications interested in knowing the name of + a particular that can help in understanding the + type of mediated device. + +What: /sys/.../mdev_supported_types//description +Date: October 2016 +Contact: Kirti Wankhede +Description: + Reading this attribute will show description of the type of + mediated device that will get created of type . + This is optional attribute. For example: + "2 heads, 512M FB, 2560x1600 maximum resolution" +Users: + Userspace applications interested in knowing the details of + a particular that can help in understanding the + features provided by that type of mediated device. + +What: /sys/.../// +Date: October 2016 +Contact: Kirti Wankhede +Description: + This directory represents device directory of mediated + device. It contains all the attributes related to mediated + device. + +What: /sys/...///mdev_type +Date: October 2016 +Contact: Kirti Wankhede +Description: + This is symbolic link pointing to supported type, + directory of which this mediated device is created. + +What: /sys/...///remove +Date: October 2016 +Contact: Kirti Wankhede +Description: + Writing '1' to this file destroys the mediated device. The + vendor driver can fail the remove() callback if that device + is active and the vendor driver doesn't support hot unplug. + Example:: + + # echo 1 > /sys/bus/mdev/devices//remove -- cgit v1.3.1