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__ */
88
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