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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 
36 #include <linux/types.h>
37 
38 struct ioctl_gntdev_grant_ref {
39 	/* The domain ID of the grant to be mapped. */
40 	__u32 domid;
41 	/* The grant reference of the grant to be mapped. */
42 	__u32 ref;
43 };
44 
45 /*
46  * Inserts the grant references into the mapping table of an instance
47  * of gntdev. N.B. This does not perform the mapping, which is deferred
48  * until mmap() is called with @index as the offset.
49  */
50 #define IOCTL_GNTDEV_MAP_GRANT_REF \
51 _IOC(_IOC_NONE, 'G', 0, sizeof(struct ioctl_gntdev_map_grant_ref))
52 struct ioctl_gntdev_map_grant_ref {
53 	/* IN parameters */
54 	/* The number of grants to be mapped. */
55 	__u32 count;
56 	__u32 pad;
57 	/* OUT parameters */
58 	/* The offset to be used on a subsequent call to mmap(). */
59 	__u64 index;
60 	/* Variable IN parameter. */
61 	/* Array of grant references, of size @count. */
62 	struct ioctl_gntdev_grant_ref refs[1];
63 };
64 
65 /*
66  * Removes the grant references from the mapping table of an instance of
67  * of gntdev. N.B. munmap() must be called on the relevant virtual address(es)
68  * before this ioctl is called, or an error will result.
69  */
70 #define IOCTL_GNTDEV_UNMAP_GRANT_REF \
71 _IOC(_IOC_NONE, 'G', 1, sizeof(struct ioctl_gntdev_unmap_grant_ref))
72 struct ioctl_gntdev_unmap_grant_ref {
73 	/* IN parameters */
74 	/* The offset was returned by the corresponding map operation. */
75 	__u64 index;
76 	/* The number of pages to be unmapped. */
77 	__u32 count;
78 	__u32 pad;
79 };
80 
81 /*
82  * Returns the offset in the driver's address space that corresponds
83  * to @vaddr. This can be used to perform a munmap(), followed by an
84  * UNMAP_GRANT_REF ioctl, where no state about the offset is retained by
85  * the caller. The number of pages that were allocated at the same time as
86  * @vaddr is returned in @count.
87  *
88  * N.B. Where more than one page has been mapped into a contiguous range, the
89  *      supplied @vaddr must correspond to the start of the range; otherwise
90  *      an error will result. It is only possible to munmap() the entire
91  *      contiguously-allocated range at once, and not any subrange thereof.
92  */
93 #define IOCTL_GNTDEV_GET_OFFSET_FOR_VADDR \
94 _IOC(_IOC_NONE, 'G', 2, sizeof(struct ioctl_gntdev_get_offset_for_vaddr))
95 struct ioctl_gntdev_get_offset_for_vaddr {
96 	/* IN parameters */
97 	/* The virtual address of the first mapped page in a range. */
98 	__u64 vaddr;
99 	/* OUT parameters */
100 	/* The offset that was used in the initial mmap() operation. */
101 	__u64 offset;
102 	/* The number of pages mapped in the VM area that begins at @vaddr. */
103 	__u32 count;
104 	__u32 pad;
105 };
106 
107 /*
108  * Sets the maximum number of grants that may mapped at once by this gntdev
109  * instance.
110  *
111  * N.B. This must be called before any other ioctl is performed on the device.
112  */
113 #define IOCTL_GNTDEV_SET_MAX_GRANTS \
114 _IOC(_IOC_NONE, 'G', 3, sizeof(struct ioctl_gntdev_set_max_grants))
115 struct ioctl_gntdev_set_max_grants {
116 	/* IN parameter */
117 	/* The maximum number of grants that may be mapped at once. */
118 	__u32 count;
119 };
120 
121 /*
122  * Sets up an unmap notification within the page, so that the other side can do
123  * cleanup if this side crashes. Required to implement cross-domain robust
124  * mutexes or close notification on communication channels.
125  *
126  * Each mapped page only supports one notification; multiple calls referring to
127  * the same page overwrite the previous notification. You must clear the
128  * notification prior to the IOCTL_GNTALLOC_DEALLOC_GREF if you do not want it
129  * to occur.
130  */
131 #define IOCTL_GNTDEV_SET_UNMAP_NOTIFY \
132 _IOC(_IOC_NONE, 'G', 7, sizeof(struct ioctl_gntdev_unmap_notify))
133 struct ioctl_gntdev_unmap_notify {
134 	/* IN parameters */
135 	/* Offset in the file descriptor for a byte within the page (same as
136 	 * used in mmap). If using UNMAP_NOTIFY_CLEAR_BYTE, this is the byte to
137 	 * be cleared. Otherwise, it can be any byte in the page whose
138 	 * notification we are adjusting.
139 	 */
140 	__u64 index;
141 	/* Action(s) to take on unmap */
142 	__u32 action;
143 	/* Event channel to notify */
144 	__u32 event_channel_port;
145 };
146 
147 struct gntdev_grant_copy_segment {
148 	union {
149 		void __user *virt;
150 		struct {
151 			grant_ref_t ref;
152 			__u16 offset;
153 			domid_t domid;
154 		} foreign;
155 	} source, dest;
156 	__u16 len;
157 
158 	__u16 flags;  /* GNTCOPY_* */
159 	__s16 status; /* GNTST_* */
160 };
161 
162 /*
163  * Copy between grant references and local buffers.
164  *
165  * The copy is split into @count @segments, each of which can copy
166  * to/from one grant reference.
167  *
168  * Each segment is similar to struct gnttab_copy in the hypervisor ABI
169  * except the local buffer is specified using a virtual address
170  * (instead of a GFN and offset).
171  *
172  * The local buffer may cross a Xen page boundary -- the driver will
173  * split segments into multiple ops if required.
174  *
175  * Returns 0 if all segments have been processed and @status in each
176  * segment is valid.  Note that one or more segments may have failed
177  * (status != GNTST_okay).
178  *
179  * If the driver had to split a segment into two or more ops, @status
180  * includes the status of the first failed op for that segment (or
181  * GNTST_okay if all ops were successful).
182  *
183  * If -1 is returned, the status of all segments is undefined.
184  *
185  * EINVAL: A segment has local buffers for both source and
186  *         destination.
187  * EINVAL: A segment crosses the boundary of a foreign page.
188  * EFAULT: A segment's local buffer is not accessible.
189  */
190 #define IOCTL_GNTDEV_GRANT_COPY \
191 	_IOC(_IOC_NONE, 'G', 8, sizeof(struct ioctl_gntdev_grant_copy))
192 struct ioctl_gntdev_grant_copy {
193 	unsigned int count;
194 	struct gntdev_grant_copy_segment __user *segments;
195 };
196 
197 /* Clear (set to zero) the byte specified by index */
198 #define UNMAP_NOTIFY_CLEAR_BYTE 0x1
199 /* Send an interrupt on the indicated event channel */
200 #define UNMAP_NOTIFY_SEND_EVENT 0x2
201 
202 #endif /* __LINUX_PUBLIC_GNTDEV_H__ */
203