gntalloc.h (2678B) - Raw
1 /****************************************************************************** 2 * gntalloc.h 3 * 4 * Interface to /dev/xen/gntalloc. 5 * 6 * Author: Daniel De Graaf <dgdegra@tycho.nsa.gov> 7 * 8 * This file is in the public domain. 9 */ 10 11 #ifndef __LINUX_PUBLIC_GNTALLOC_H__ 12 #define __LINUX_PUBLIC_GNTALLOC_H__ 13 14 #include <linux/types.h> 15 16 /* 17 * Allocates a new page and creates a new grant reference. 18 */ 19 #define IOCTL_GNTALLOC_ALLOC_GREF \ 20 _IOC(_IOC_NONE, 'G', 5, sizeof(struct ioctl_gntalloc_alloc_gref)) 21 struct ioctl_gntalloc_alloc_gref { 22 /* IN parameters */ 23 /* The ID of the domain to be given access to the grants. */ 24 __u16 domid; 25 /* Flags for this mapping */ 26 __u16 flags; 27 /* Number of pages to map */ 28 __u32 count; 29 /* OUT parameters */ 30 /* The offset to be used on a subsequent call to mmap(). */ 31 __u64 index; 32 /* The grant references of the newly created grant, one per page */ 33 /* Variable size, depending on count */ 34 union { 35 __u32 gref_ids[1]; 36 __DECLARE_FLEX_ARRAY(__u32, gref_ids_flex); 37 }; 38 }; 39 40 #define GNTALLOC_FLAG_WRITABLE 1 41 42 /* 43 * Deallocates the grant reference, allowing the associated page to be freed if 44 * no other domains are using it. 45 */ 46 #define IOCTL_GNTALLOC_DEALLOC_GREF \ 47 _IOC(_IOC_NONE, 'G', 6, sizeof(struct ioctl_gntalloc_dealloc_gref)) 48 struct ioctl_gntalloc_dealloc_gref { 49 /* IN parameters */ 50 /* The offset returned in the map operation */ 51 __u64 index; 52 /* Number of references to unmap */ 53 __u32 count; 54 }; 55 56 /* 57 * Sets up an unmap notification within the page, so that the other side can do 58 * cleanup if this side crashes. Required to implement cross-domain robust 59 * mutexes or close notification on communication channels. 60 * 61 * Each mapped page only supports one notification; multiple calls referring to 62 * the same page overwrite the previous notification. You must clear the 63 * notification prior to the IOCTL_GNTALLOC_DEALLOC_GREF if you do not want it 64 * to occur. 65 */ 66 #define IOCTL_GNTALLOC_SET_UNMAP_NOTIFY \ 67 _IOC(_IOC_NONE, 'G', 7, sizeof(struct ioctl_gntalloc_unmap_notify)) 68 struct ioctl_gntalloc_unmap_notify { 69 /* IN parameters */ 70 /* Offset in the file descriptor for a byte within the page (same as 71 * used in mmap). If using UNMAP_NOTIFY_CLEAR_BYTE, this is the byte to 72 * be cleared. Otherwise, it can be any byte in the page whose 73 * notification we are adjusting. 74 */ 75 __u64 index; 76 /* Action(s) to take on unmap */ 77 __u32 action; 78 /* Event channel to notify */ 79 __u32 event_channel_port; 80 }; 81 82 /* Clear (set to zero) the byte specified by index */ 83 #define UNMAP_NOTIFY_CLEAR_BYTE 0x1 84 /* Send an interrupt on the indicated event channel */ 85 #define UNMAP_NOTIFY_SEND_EVENT 0x2 86 87 #endif /* __LINUX_PUBLIC_GNTALLOC_H__ */