summaryrefslogtreecommitdiff
path: root/include/uapi/xen/gntdev.h
blob: 7a7145395c09c8767ef042853b877f4b9a478e04 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
/* SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR MIT) */
/******************************************************************************
 * gntdev.h
 * 
 * Interface to /dev/xen/gntdev.
 * 
 * Copyright (c) 2007, D G Murray
 * Copyright (c) 2018, Oleksandr Andrushchenko, EPAM Systems Inc.
 * 
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License version 2
 * as published by the Free Software Foundation; or, when distributed
 * separately from the Linux kernel or incorporated into other
 * software packages, subject to the following license:
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this source file (the "Software"), to deal in the Software without
 * restriction, including without limitation the rights to use, copy, modify,
 * merge, publish, distribute, sublicense, and/or sell copies of the Software,
 * and to permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 */

#ifndef __LINUX_PUBLIC_GNTDEV_H__
#define __LINUX_PUBLIC_GNTDEV_H__

#include <linux/types.h>

struct ioctl_gntdev_grant_ref {
	/* The domain ID of the grant to be mapped. */
	__u32 domid;
	/* The grant reference of the grant to be mapped. */
	__u32 ref;
};

/*
 * Inserts the grant references into the mapping table of an instance
 * of gntdev. N.B. This does not perform the mapping, which is deferred
 * until mmap() is called with @index as the offset. @index should be
 * considered opaque to userspace, with one exception: if no grant
 * references have ever been inserted into the mapping table of this
 * instance, @index will be set to 0. This is necessary to use gntdev
 * with userspace APIs that expect a file descriptor that can be
 * mmap()'d at offset 0, such as Wayland. If @count is set to 0, this
 * ioctl will fail.
 */
#define IOCTL_GNTDEV_MAP_GRANT_REF \
_IOC(_IOC_NONE, 'G', 0, sizeof(struct ioctl_gntdev_map_grant_ref))
struct ioctl_gntdev_map_grant_ref {
	/* IN parameters */
	/* The number of grants to be mapped. */
	__u32 count;
	__u32 pad;
	/* OUT parameters */
	/* The offset to be used on a subsequent call to mmap(). */
	__u64 index;
	/* Variable IN parameter. */
	/* Array of grant references, of size @count. */
	struct ioctl_gntdev_grant_ref refs[1];
};

/*
 * Removes the grant references from the mapping table of an instance of
 * gntdev. N.B. munmap() must be called on the relevant virtual address(es)
 * before this ioctl is called, or an error will result.
 */
#define IOCTL_GNTDEV_UNMAP_GRANT_REF \
_IOC(_IOC_NONE, 'G', 1, sizeof(struct ioctl_gntdev_unmap_grant_ref))
struct ioctl_gntdev_unmap_grant_ref {
	/* IN parameters */
	/* The offset was returned by the corresponding map operation. */
	__u64 index;
	/* The number of pages to be unmapped. */
	__u32 count;
	__u32 pad;
};

/*
 * Returns the offset in the driver's address space that corresponds
 * to @vaddr. This can be used to perform a munmap(), followed by an
 * UNMAP_GRANT_REF ioctl, where no state about the offset is retained by
 * the caller. The number of pages that were allocated at the same time as
 * @vaddr is returned in @count.
 *
 * N.B. Where more than one page has been mapped into a contiguous range, the
 *      supplied @vaddr must correspond to the start of the range; otherwise
 *      an error will result. It is only possible to munmap() the entire
 *      contiguously-allocated range at once, and not any subrange thereof.
 */
#define IOCTL_GNTDEV_GET_OFFSET_FOR_VADDR \
_IOC(_IOC_NONE, 'G', 2, sizeof(struct ioctl_gntdev_get_offset_for_vaddr))
struct ioctl_gntdev_get_offset_for_vaddr {
	/* IN parameters */
	/* The virtual address of the first mapped page in a range. */
	__u64 vaddr;
	/* OUT parameters */
	/* The offset that was used in the initial mmap() operation. */
	__u64 offset;
	/* The number of pages mapped in the VM area that begins at @vaddr. */
	__u32 count;
	__u32 pad;
};

/*
 * Sets the maximum number of grants that may mapped at once by this gntdev
 * instance.
 *
 * N.B. This must be called before any other ioctl is performed on the device.
 */
#define IOCTL_GNTDEV_SET_MAX_GRANTS \
_IOC(_IOC_NONE, 'G', 3, sizeof(struct ioctl_gntdev_set_max_grants))
struct ioctl_gntdev_set_max_grants {
	/* IN parameter */
	/* The maximum number of grants that may be mapped at once. */
	__u32 count;
};

/*
 * Sets up an unmap notification within the page, so that the other side can do
 * cleanup if this side crashes. Required to implement cross-domain robust
 * mutexes or close notification on communication channels.
 *
 * Each mapped page only supports one notification; multiple calls referring to
 * the same page overwrite the previous notification. You must clear the
 * notification prior to the IOCTL_GNTALLOC_DEALLOC_GREF if you do not want it
 * to occur.
 */
#define IOCTL_GNTDEV_SET_UNMAP_NOTIFY \
_IOC(_IOC_NONE, 'G', 7, sizeof(struct ioctl_gntdev_unmap_notify))
struct ioctl_gntdev_unmap_notify {
	/* IN parameters */
	/* Offset in the file descriptor for a byte within the page (same as
	 * used in mmap). If using UNMAP_NOTIFY_CLEAR_BYTE, this is the byte to
	 * be cleared. Otherwise, it can be any byte in the page whose
	 * notification we are adjusting.
	 */
	__u64 index;
	/* Action(s) to take on unmap */
	__u32 action;
	/* Event channel to notify */
	__u32 event_channel_port;
};

struct gntdev_grant_copy_segment {
	union {
		void __user *virt;
		struct {
			grant_ref_t ref;
			__u16 offset;
			domid_t domid;
		} foreign;
	} source, dest;
	__u16 len;

	__u16 flags;  /* GNTCOPY_* */
	__s16 status; /* GNTST_* */
};

/*
 * Copy between grant references and local buffers.
 *
 * The copy is split into @count @segments, each of which can copy
 * to/from one grant reference.
 *
 * Each segment is similar to struct gnttab_copy in the hypervisor ABI
 * except the local buffer is specified using a virtual address
 * (instead of a GFN and offset).
 *
 * The local buffer may cross a Xen page boundary -- the driver will
 * split segments into multiple ops if required.
 *
 * Returns 0 if all segments have been processed and @status in each
 * segment is valid.  Note that one or more segments may have failed
 * (status != GNTST_okay).
 *
 * If the driver had to split a segment into two or more ops, @status
 * includes the status of the first failed op for that segment (or
 * GNTST_okay if all ops were successful).
 *
 * If -1 is returned, the status of all segments is undefined.
 *
 * EINVAL: A segment has local buffers for both source and
 *         destination.
 * EINVAL: A segment crosses the boundary of a foreign page.
 * EFAULT: A segment's local buffer is not accessible.
 */
#define IOCTL_GNTDEV_GRANT_COPY \
	_IOC(_IOC_NONE, 'G', 8, sizeof(struct ioctl_gntdev_grant_copy))
struct ioctl_gntdev_grant_copy {
	unsigned int count;
	struct gntdev_grant_copy_segment __user *segments;
};

/* Clear (set to zero) the byte specified by index */
#define UNMAP_NOTIFY_CLEAR_BYTE 0x1
/* Send an interrupt on the indicated event channel */
#define UNMAP_NOTIFY_SEND_EVENT 0x2

/*
 * Flags to be used while requesting memory mapping's backing storage
 * to be allocated with DMA API.
 */

/*
 * The buffer is backed with memory allocated with dma_alloc_wc.
 */
#define GNTDEV_DMA_FLAG_WC		(1 << 0)

/*
 * The buffer is backed with memory allocated with dma_alloc_coherent.
 */
#define GNTDEV_DMA_FLAG_COHERENT	(1 << 1)

/*
 * Create a dma-buf [1] from grant references @refs of count @count provided
 * by the foreign domain @domid with flags @flags.
 *
 * By default dma-buf is backed by system memory pages, but by providing
 * one of the GNTDEV_DMA_FLAG_XXX flags it can also be created as
 * a DMA write-combine or coherent buffer, e.g. allocated with dma_alloc_wc/
 * dma_alloc_coherent.
 *
 * Returns 0 if dma-buf was successfully created and the corresponding
 * dma-buf's file descriptor is returned in @fd.
 *
 * [1] Documentation/driver-api/dma-buf.rst
 */

#define IOCTL_GNTDEV_DMABUF_EXP_FROM_REFS \
	_IOC(_IOC_NONE, 'G', 9, \
	     sizeof(struct ioctl_gntdev_dmabuf_exp_from_refs))
struct ioctl_gntdev_dmabuf_exp_from_refs {
	/* IN parameters. */
	/* Specific options for this dma-buf: see GNTDEV_DMA_FLAG_XXX. */
	__u32 flags;
	/* Number of grant references in @refs array. */
	__u32 count;
	/* OUT parameters. */
	/* File descriptor of the dma-buf. */
	__u32 fd;
	/* The domain ID of the grant references to be mapped. */
	__u32 domid;
	/* Variable IN parameter. */
	/* Array of grant references of size @count. */
	__u32 refs[1];
};

/*
 * This will block until the dma-buf with the file descriptor @fd is
 * released. This is only valid for buffers created with
 * IOCTL_GNTDEV_DMABUF_EXP_FROM_REFS.
 *
 * If within @wait_to_ms milliseconds the buffer is not released
 * then -ETIMEDOUT error is returned.
 * If the buffer with the file descriptor @fd does not exist or has already
 * been released, then -ENOENT is returned. For valid file descriptors
 * this must not be treated as error.
 */
#define IOCTL_GNTDEV_DMABUF_EXP_WAIT_RELEASED \
	_IOC(_IOC_NONE, 'G', 10, \
	     sizeof(struct ioctl_gntdev_dmabuf_exp_wait_released))
struct ioctl_gntdev_dmabuf_exp_wait_released {
	/* IN parameters */
	__u32 fd;
	__u32 wait_to_ms;
};

/*
 * Import a dma-buf with file descriptor @fd and export granted references
 * to the pages of that dma-buf into array @refs of size @count.
 */
#define IOCTL_GNTDEV_DMABUF_IMP_TO_REFS \
	_IOC(_IOC_NONE, 'G', 11, \
	     sizeof(struct ioctl_gntdev_dmabuf_imp_to_refs))
struct ioctl_gntdev_dmabuf_imp_to_refs {
	/* IN parameters. */
	/* File descriptor of the dma-buf. */
	__u32 fd;
	/* Number of grant references in @refs array. */
	__u32 count;
	/* The domain ID for which references to be granted. */
	__u32 domid;
	/* Reserved - must be zero. */
	__u32 reserved;
	/* OUT parameters. */
	/* Array of grant references of size @count. */
	__u32 refs[1];
};

/*
 * This will close all references to the imported buffer with file descriptor
 * @fd, so it can be released by the owner. This is only valid for buffers
 * created with IOCTL_GNTDEV_DMABUF_IMP_TO_REFS.
 */
#define IOCTL_GNTDEV_DMABUF_IMP_RELEASE \
	_IOC(_IOC_NONE, 'G', 12, \
	     sizeof(struct ioctl_gntdev_dmabuf_imp_release))
struct ioctl_gntdev_dmabuf_imp_release {
	/* IN parameters */
	__u32 fd;
	__u32 reserved;
};

#endif /* __LINUX_PUBLIC_GNTDEV_H__ */