diff options
Diffstat (limited to 'include/uapi/linux/liveupdate.h')
| -rw-r--r-- | include/uapi/linux/liveupdate.h | 103 |
1 files changed, 103 insertions, 0 deletions
diff --git a/include/uapi/linux/liveupdate.h b/include/uapi/linux/liveupdate.h index 1183cf984b5f..30bc66ee9436 100644 --- a/include/uapi/linux/liveupdate.h +++ b/include/uapi/linux/liveupdate.h @@ -53,6 +53,14 @@ enum { LIVEUPDATE_CMD_RETRIEVE_SESSION = 0x01, }; +/* ioctl commands for session file descriptors */ +enum { + LIVEUPDATE_CMD_SESSION_BASE = 0x40, + LIVEUPDATE_CMD_SESSION_PRESERVE_FD = LIVEUPDATE_CMD_SESSION_BASE, + LIVEUPDATE_CMD_SESSION_RETRIEVE_FD = 0x41, + LIVEUPDATE_CMD_SESSION_FINISH = 0x42, +}; + /** * struct liveupdate_ioctl_create_session - ioctl(LIVEUPDATE_IOCTL_CREATE_SESSION) * @size: Input; sizeof(struct liveupdate_ioctl_create_session) @@ -110,4 +118,99 @@ struct liveupdate_ioctl_retrieve_session { #define LIVEUPDATE_IOCTL_RETRIEVE_SESSION \ _IO(LIVEUPDATE_IOCTL_TYPE, LIVEUPDATE_CMD_RETRIEVE_SESSION) +/* Session specific IOCTLs */ + +/** + * struct liveupdate_session_preserve_fd - ioctl(LIVEUPDATE_SESSION_PRESERVE_FD) + * @size: Input; sizeof(struct liveupdate_session_preserve_fd) + * @fd: Input; The user-space file descriptor to be preserved. + * @token: Input; An opaque, unique token for preserved resource. + * + * Holds parameters for preserving a file descriptor. + * + * User sets the @fd field identifying the file descriptor to preserve + * (e.g., memfd, kvm, iommufd, VFIO). The kernel validates if this FD type + * and its dependencies are supported for preservation. If validation passes, + * the kernel marks the FD internally and *initiates the process* of preparing + * its state for saving. The actual snapshotting of the state typically occurs + * during the subsequent %LIVEUPDATE_IOCTL_PREPARE execution phase, though + * some finalization might occur during freeze. + * On successful validation and initiation, the kernel uses the @token + * field with an opaque identifier representing the resource being preserved. + * This token confirms the FD is targeted for preservation and is required for + * the subsequent %LIVEUPDATE_SESSION_RETRIEVE_FD call after the live update. + * + * Return: 0 on success (validation passed, preservation initiated), negative + * error code on failure (e.g., unsupported FD type, dependency issue, + * validation failed). + */ +struct liveupdate_session_preserve_fd { + __u32 size; + __s32 fd; + __aligned_u64 token; +}; + +#define LIVEUPDATE_SESSION_PRESERVE_FD \ + _IO(LIVEUPDATE_IOCTL_TYPE, LIVEUPDATE_CMD_SESSION_PRESERVE_FD) + +/** + * struct liveupdate_session_retrieve_fd - ioctl(LIVEUPDATE_SESSION_RETRIEVE_FD) + * @size: Input; sizeof(struct liveupdate_session_retrieve_fd) + * @fd: Output; The new file descriptor representing the fully restored + * kernel resource. + * @token: Input; An opaque, token that was used to preserve the resource. + * + * Retrieve a previously preserved file descriptor. + * + * User sets the @token field to the value obtained from a successful + * %LIVEUPDATE_IOCTL_FD_PRESERVE call before the live update. On success, + * the kernel restores the state (saved during the PREPARE/FREEZE phases) + * associated with the token and populates the @fd field with a new file + * descriptor referencing the restored resource in the current (new) kernel. + * This operation must be performed *before* signaling completion via + * %LIVEUPDATE_IOCTL_FINISH. + * + * Return: 0 on success, negative error code on failure (e.g., invalid token). + */ +struct liveupdate_session_retrieve_fd { + __u32 size; + __s32 fd; + __aligned_u64 token; +}; + +#define LIVEUPDATE_SESSION_RETRIEVE_FD \ + _IO(LIVEUPDATE_IOCTL_TYPE, LIVEUPDATE_CMD_SESSION_RETRIEVE_FD) + +/** + * struct liveupdate_session_finish - ioctl(LIVEUPDATE_SESSION_FINISH) + * @size: Input; sizeof(struct liveupdate_session_finish) + * @reserved: Input; Must be zero. Reserved for future use. + * + * Signals the completion of the restoration process for a retrieved session. + * This is the final operation that should be performed on a session file + * descriptor after a live update. + * + * This ioctl must be called once all required file descriptors for the session + * have been successfully retrieved (using %LIVEUPDATE_SESSION_RETRIEVE_FD) and + * are fully restored from the userspace and kernel perspective. + * + * Upon success, the kernel releases its ownership of the preserved resources + * associated with this session. This allows internal resources to be freed, + * typically by decrementing reference counts on the underlying preserved + * objects. + * + * If this operation fails, the resources remain preserved in memory. Userspace + * may attempt to call finish again. The resources will otherwise be reset + * during the next live update cycle. + * + * Return: 0 on success, negative error code on failure. + */ +struct liveupdate_session_finish { + __u32 size; + __u32 reserved; +}; + +#define LIVEUPDATE_SESSION_FINISH \ + _IO(LIVEUPDATE_IOCTL_TYPE, LIVEUPDATE_CMD_SESSION_FINISH) + #endif /* _UAPI_LIVEUPDATE_H */ |