1 /****************************************************************************** 2 * gntalloc.h 3 * 4 * Interface to /dev/xen/gntalloc. 5 * 6 * Author: Daniel De Graaf <dgdegra (at) 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 __u32 gref_ids[1]; 35 }; 36 37 #define GNTALLOC_FLAG_WRITABLE 1 38 39 /* 40 * Deallocates the grant reference, allowing the associated page to be freed if 41 * no other domains are using it. 42 */ 43 #define IOCTL_GNTALLOC_DEALLOC_GREF \ 44 _IOC(_IOC_NONE, 'G', 6, sizeof(struct ioctl_gntalloc_dealloc_gref)) 45 struct ioctl_gntalloc_dealloc_gref { 46 /* IN parameters */ 47 /* The offset returned in the map operation */ 48 __u64 index; 49 /* Number of references to unmap */ 50 __u32 count; 51 }; 52 53 /* 54 * Sets up an unmap notification within the page, so that the other side can do 55 * cleanup if this side crashes. Required to implement cross-domain robust 56 * mutexes or close notification on communication channels. 57 * 58 * Each mapped page only supports one notification; multiple calls referring to 59 * the same page overwrite the previous notification. You must clear the 60 * notification prior to the IOCTL_GNTALLOC_DEALLOC_GREF if you do not want it 61 * to occur. 62 */ 63 #define IOCTL_GNTALLOC_SET_UNMAP_NOTIFY \ 64 _IOC(_IOC_NONE, 'G', 7, sizeof(struct ioctl_gntalloc_unmap_notify)) 65 struct ioctl_gntalloc_unmap_notify { 66 /* IN parameters */ 67 /* Offset in the file descriptor for a byte within the page (same as 68 * used in mmap). If using UNMAP_NOTIFY_CLEAR_BYTE, this is the byte to 69 * be cleared. Otherwise, it can be any byte in the page whose 70 * notification we are adjusting. 71 */ 72 __u64 index; 73 /* Action(s) to take on unmap */ 74 __u32 action; 75 /* Event channel to notify */ 76 __u32 event_channel_port; 77 }; 78 79 /* Clear (set to zero) the byte specified by index */ 80 #define UNMAP_NOTIFY_CLEAR_BYTE 0x1 81 /* Send an interrupt on the indicated event channel */ 82 #define UNMAP_NOTIFY_SEND_EVENT 0x2 83 84 #endif /* __LINUX_PUBLIC_GNTALLOC_H__ */ 85
