diff options
Diffstat (limited to 'include/xen/gntalloc.h')
| -rw-r--r-- | include/xen/gntalloc.h | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/include/xen/gntalloc.h b/include/xen/gntalloc.h index bc3b85e8bff7..76bd58065f4f 100644 --- a/include/xen/gntalloc.h +++ b/include/xen/gntalloc.h @@ -47,4 +47,36 @@ struct ioctl_gntalloc_dealloc_gref { /* Number of references to unmap */ uint32_t 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. + */ + uint64_t index; + /* Action(s) to take on unmap */ + uint32_t action; + /* Event channel to notify */ + uint32_t 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__ */ |