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))
21struct 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))
48struct 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))
68struct 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__ */