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 /* 15 * Allocates a new page and creates a new grant reference. 16 */ 17 #define IOCTL_GNTALLOC_ALLOC_GREF \ 18 _IOC(_IOC_NONE, 'G', 5, sizeof(struct ioctl_gntalloc_alloc_gref)) 19 struct ioctl_gntalloc_alloc_gref { 20 /* IN parameters */ 21 /* The ID of the domain to be given access to the grants. */ 22 uint16_t domid; 23 /* Flags for this mapping */ 24 uint16_t flags; 25 /* Number of pages to map */ 26 uint32_t count; 27 /* OUT parameters */ 28 /* The offset to be used on a subsequent call to mmap(). */ 29 uint64_t index; 30 /* The grant references of the newly created grant, one per page */ 31 /* Variable size, depending on count */ 32 uint32_t gref_ids[1]; 33 }; 34 35 #define GNTALLOC_FLAG_WRITABLE 1 36 37 /* 38 * Deallocates the grant reference, allowing the associated page to be freed if 39 * no other domains are using it. 40 */ 41 #define IOCTL_GNTALLOC_DEALLOC_GREF \ 42 _IOC(_IOC_NONE, 'G', 6, sizeof(struct ioctl_gntalloc_dealloc_gref)) 43 struct ioctl_gntalloc_dealloc_gref { 44 /* IN parameters */ 45 /* The offset returned in the map operation */ 46 uint64_t index; 47 /* Number of references to unmap */ 48 uint32_t count; 49 }; 50 51 /* 52 * Sets up an unmap notification within the page, so that the other side can do 53 * cleanup if this side crashes. Required to implement cross-domain robust 54 * mutexes or close notification on communication channels. 55 * 56 * Each mapped page only supports one notification; multiple calls referring to 57 * the same page overwrite the previous notification. You must clear the 58 * notification prior to the IOCTL_GNTALLOC_DEALLOC_GREF if you do not want it 59 * to occur. 60 */ 61 #define IOCTL_GNTALLOC_SET_UNMAP_NOTIFY \ 62 _IOC(_IOC_NONE, 'G', 7, sizeof(struct ioctl_gntalloc_unmap_notify)) 63 struct ioctl_gntalloc_unmap_notify { 64 /* IN parameters */ 65 /* Offset in the file descriptor for a byte within the page (same as 66 * used in mmap). If using UNMAP_NOTIFY_CLEAR_BYTE, this is the byte to 67 * be cleared. Otherwise, it can be any byte in the page whose 68 * notification we are adjusting. 69 */ 70 uint64_t index; 71 /* Action(s) to take on unmap */ 72 uint32_t action; 73 /* Event channel to notify */ 74 uint32_t event_channel_port; 75 }; 76 77 /* Clear (set to zero) the byte specified by index */ 78 #define UNMAP_NOTIFY_CLEAR_BYTE 0x1 79 /* Send an interrupt on the indicated event channel */ 80 #define UNMAP_NOTIFY_SEND_EVENT 0x2 81 82 #endif /* __LINUX_PUBLIC_GNTALLOC_H__ */ 83