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 __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__ */