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))
19struct 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))
43struct 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))
63struct 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