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gntdev.h
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1 /******************************************************************************
2  * gntdev.h
3  *
4  * Interface to /dev/xen/gntdev.
5  *
6  * Copyright (c) 2007, D G Murray
7  *
8  * This program is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU General Public License version 2
10  * as published by the Free Software Foundation; or, when distributed
11  * separately from the Linux kernel or incorporated into other
12  * software packages, subject to the following license:
13  *
14  * Permission is hereby granted, free of charge, to any person obtaining a copy
15  * of this source file (the "Software"), to deal in the Software without
16  * restriction, including without limitation the rights to use, copy, modify,
17  * merge, publish, distribute, sublicense, and/or sell copies of the Software,
18  * and to permit persons to whom the Software is furnished to do so, subject to
19  * the following conditions:
20  *
21  * The above copyright notice and this permission notice shall be included in
22  * all copies or substantial portions of the Software.
23  *
24  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
25  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
26  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
27  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
28  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
29  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
30  * IN THE SOFTWARE.
31  */
32 
33 #ifndef __LINUX_PUBLIC_GNTDEV_H__
34 #define __LINUX_PUBLIC_GNTDEV_H__
35 
37  /* The domain ID of the grant to be mapped. */
39  /* The grant reference of the grant to be mapped. */
41 };
42 
43 /*
44  * Inserts the grant references into the mapping table of an instance
45  * of gntdev. N.B. This does not perform the mapping, which is deferred
46  * until mmap() is called with @index as the offset.
47  */
48 #define IOCTL_GNTDEV_MAP_GRANT_REF \
49 _IOC(_IOC_NONE, 'G', 0, sizeof(struct ioctl_gntdev_map_grant_ref))
51  /* IN parameters */
52  /* The number of grants to be mapped. */
55  /* OUT parameters */
56  /* The offset to be used on a subsequent call to mmap(). */
58  /* Variable IN parameter. */
59  /* Array of grant references, of size @count. */
61 };
62 
63 /*
64  * Removes the grant references from the mapping table of an instance of
65  * of gntdev. N.B. munmap() must be called on the relevant virtual address(es)
66  * before this ioctl is called, or an error will result.
67  */
68 #define IOCTL_GNTDEV_UNMAP_GRANT_REF \
69 _IOC(_IOC_NONE, 'G', 1, sizeof(struct ioctl_gntdev_unmap_grant_ref))
71  /* IN parameters */
72  /* The offset was returned by the corresponding map operation. */
74  /* The number of pages to be unmapped. */
77 };
78 
79 /*
80  * Returns the offset in the driver's address space that corresponds
81  * to @vaddr. This can be used to perform a munmap(), followed by an
82  * UNMAP_GRANT_REF ioctl, where no state about the offset is retained by
83  * the caller. The number of pages that were allocated at the same time as
84  * @vaddr is returned in @count.
85  *
86  * N.B. Where more than one page has been mapped into a contiguous range, the
87  * supplied @vaddr must correspond to the start of the range; otherwise
88  * an error will result. It is only possible to munmap() the entire
89  * contiguously-allocated range at once, and not any subrange thereof.
90  */
91 #define IOCTL_GNTDEV_GET_OFFSET_FOR_VADDR \
92 _IOC(_IOC_NONE, 'G', 2, sizeof(struct ioctl_gntdev_get_offset_for_vaddr))
94  /* IN parameters */
95  /* The virtual address of the first mapped page in a range. */
97  /* OUT parameters */
98  /* The offset that was used in the initial mmap() operation. */
100  /* The number of pages mapped in the VM area that begins at @vaddr. */
103 };
104 
105 /*
106  * Sets the maximum number of grants that may mapped at once by this gntdev
107  * instance.
108  *
109  * N.B. This must be called before any other ioctl is performed on the device.
110  */
111 #define IOCTL_GNTDEV_SET_MAX_GRANTS \
112 _IOC(_IOC_NONE, 'G', 3, sizeof(struct ioctl_gntdev_set_max_grants))
114  /* IN parameter */
115  /* The maximum number of grants that may be mapped at once. */
117 };
118 
119 /*
120  * Sets up an unmap notification within the page, so that the other side can do
121  * cleanup if this side crashes. Required to implement cross-domain robust
122  * mutexes or close notification on communication channels.
123  *
124  * Each mapped page only supports one notification; multiple calls referring to
125  * the same page overwrite the previous notification. You must clear the
126  * notification prior to the IOCTL_GNTALLOC_DEALLOC_GREF if you do not want it
127  * to occur.
128  */
129 #define IOCTL_GNTDEV_SET_UNMAP_NOTIFY \
130 _IOC(_IOC_NONE, 'G', 7, sizeof(struct ioctl_gntdev_unmap_notify))
132  /* IN parameters */
133  /* Offset in the file descriptor for a byte within the page (same as
134  * used in mmap). If using UNMAP_NOTIFY_CLEAR_BYTE, this is the byte to
135  * be cleared. Otherwise, it can be any byte in the page whose
136  * notification we are adjusting.
137  */
139  /* Action(s) to take on unmap */
141  /* Event channel to notify */
143 };
144 
145 /* Clear (set to zero) the byte specified by index */
146 #define UNMAP_NOTIFY_CLEAR_BYTE 0x1
147 /* Send an interrupt on the indicated event channel */
148 #define UNMAP_NOTIFY_SEND_EVENT 0x2
149 
150 #endif /* __LINUX_PUBLIC_GNTDEV_H__ */