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 --- include/uapi/xen/gntalloc.h | 87 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 87 insertions(+) create mode 100644 include/uapi/xen/gntalloc.h (limited to 'include/uapi/xen/gntalloc.h') diff --git a/include/uapi/xen/gntalloc.h b/include/uapi/xen/gntalloc.h new file mode 100644 index 000000000..310928267 --- /dev/null +++ b/include/uapi/xen/gntalloc.h @@ -0,0 +1,87 @@ +/****************************************************************************** + * gntalloc.h + * + * Interface to /dev/xen/gntalloc. + * + * Author: Daniel De Graaf + * + * This file is in the public domain. + */ + +#ifndef __LINUX_PUBLIC_GNTALLOC_H__ +#define __LINUX_PUBLIC_GNTALLOC_H__ + +#include + +/* + * Allocates a new page and creates a new grant reference. + */ +#define IOCTL_GNTALLOC_ALLOC_GREF \ +_IOC(_IOC_NONE, 'G', 5, sizeof(struct ioctl_gntalloc_alloc_gref)) +struct ioctl_gntalloc_alloc_gref { + /* IN parameters */ + /* The ID of the domain to be given access to the grants. */ + __u16 domid; + /* Flags for this mapping */ + __u16 flags; + /* Number of pages to map */ + __u32 count; + /* OUT parameters */ + /* The offset to be used on a subsequent call to mmap(). */ + __u64 index; + /* The grant references of the newly created grant, one per page */ + /* Variable size, depending on count */ + union { + __u32 gref_ids[1]; + __DECLARE_FLEX_ARRAY(__u32, gref_ids_flex); + }; +}; + +#define GNTALLOC_FLAG_WRITABLE 1 + +/* + * Deallocates the grant reference, allowing the associated page to be freed if + * no other domains are using it. + */ +#define IOCTL_GNTALLOC_DEALLOC_GREF \ +_IOC(_IOC_NONE, 'G', 6, sizeof(struct ioctl_gntalloc_dealloc_gref)) +struct ioctl_gntalloc_dealloc_gref { + /* IN parameters */ + /* The offset returned in the map operation */ + __u64 index; + /* Number of references to unmap */ + __u32 count; +}; + +/* + * Sets up an unmap notification within the page, so that the other side can do + * cleanup if this side crashes. Required to implement cross-domain robust + * mutexes or close notification on communication channels. + * + * Each mapped page only supports one notification; multiple calls referring to + * the same page overwrite the previous notification. You must clear the + * notification prior to the IOCTL_GNTALLOC_DEALLOC_GREF if you do not want it + * to occur. + */ +#define IOCTL_GNTALLOC_SET_UNMAP_NOTIFY \ +_IOC(_IOC_NONE, 'G', 7, sizeof(struct ioctl_gntalloc_unmap_notify)) +struct ioctl_gntalloc_unmap_notify { + /* IN parameters */ + /* Offset in the file descriptor for a byte within the page (same as + * used in mmap). If using UNMAP_NOTIFY_CLEAR_BYTE, this is the byte to + * be cleared. Otherwise, it can be any byte in the page whose + * notification we are adjusting. + */ + __u64 index; + /* Action(s) to take on unmap */ + __u32 action; + /* Event channel to notify */ + __u32 event_channel_port; +}; + +/* Clear (set to zero) the byte specified by index */ +#define UNMAP_NOTIFY_CLEAR_BYTE 0x1 +/* Send an interrupt on the indicated event channel */ +#define UNMAP_NOTIFY_SEND_EVENT 0x2 + +#endif /* __LINUX_PUBLIC_GNTALLOC_H__ */ -- cgit v1.3.1