1 /* SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR MIT) */
2 /******************************************************************************
3 * gntdev.h
4 *
5 * Interface to /dev/xen/gntdev.
6 *
7 * Copyright (c) 2007, D G Murray
8 * Copyright (c) 2018, Oleksandr Andrushchenko, EPAM Systems Inc.
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License version 2
12 * as published by the Free Software Foundation; or, when distributed
13 * separately from the Linux kernel or incorporated into other
14 * software packages, subject to the following license:
15 *
16 * Permission is hereby granted, free of charge, to any person obtaining a copy
17 * of this source file (the "Software"), to deal in the Software without
18 * restriction, including without limitation the rights to use, copy, modify,
19 * merge, publish, distribute, sublicense, and/or sell copies of the Software,
20 * and to permit persons to whom the Software is furnished to do so, subject to
21 * the following conditions:
22 *
23 * The above copyright notice and this permission notice shall be included in
24 * all copies or substantial portions of the Software.
25 *
26 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
27 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
28 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
29 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
30 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
31 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
32 * IN THE SOFTWARE.
33 */
34
35 #ifndef __LINUX_PUBLIC_GNTDEV_H__
36 #define __LINUX_PUBLIC_GNTDEV_H__
37
38 #include <linux/types.h>
39
40 struct ioctl_gntdev_grant_ref {
41 /* The domain ID of the grant to be mapped. */
42 __u32 domid;
43 /* The grant reference of the grant to be mapped. */
44 __u32 ref;
45 };
46
47 /*
48 * Inserts the grant references into the mapping table of an instance
49 * of gntdev. N.B. This does not perform the mapping, which is deferred
50 * until mmap() is called with @index as the offset. @index should be
51 * considered opaque to userspace, with one exception: if no grant
52 * references have ever been inserted into the mapping table of this
53 * instance, @index will be set to 0. This is necessary to use gntdev
54 * with userspace APIs that expect a file descriptor that can be
55 * mmap()'d at offset 0, such as Wayland. If @count is set to 0, this
56 * ioctl will fail.
57 */
58 #define IOCTL_GNTDEV_MAP_GRANT_REF \
59 _IOC(_IOC_NONE, 'G', 0, sizeof(struct ioctl_gntdev_map_grant_ref))
60 struct ioctl_gntdev_map_grant_ref {
61 /* IN parameters */
62 /* The number of grants to be mapped. */
63 __u32 count;
64 __u32 pad;
65 /* OUT parameters */
66 /* The offset to be used on a subsequent call to mmap(). */
67 __u64 index;
68 /* Variable IN parameter. */
69 /* Array of grant references, of size @count. */
70 struct ioctl_gntdev_grant_ref refs[1];
71 };
72
73 /*
74 * Removes the grant references from the mapping table of an instance of
75 * gntdev. N.B. munmap() must be called on the relevant virtual address(es)
76 * before this ioctl is called, or an error will result.
77 */
78 #define IOCTL_GNTDEV_UNMAP_GRANT_REF \
79 _IOC(_IOC_NONE, 'G', 1, sizeof(struct ioctl_gntdev_unmap_grant_ref))
80 struct ioctl_gntdev_unmap_grant_ref {
81 /* IN parameters */
82 /* The offset was returned by the corresponding map operation. */
83 __u64 index;
84 /* The number of pages to be unmapped. */
85 __u32 count;
86 __u32 pad;
87 };
88
89 /*
90 * Returns the offset in the driver's address space that corresponds
91 * to @vaddr. This can be used to perform a munmap(), followed by an
92 * UNMAP_GRANT_REF ioctl, where no state about the offset is retained by
93 * the caller. The number of pages that were allocated at the same time as
94 * @vaddr is returned in @count.
95 *
96 * N.B. Where more than one page has been mapped into a contiguous range, the
97 * supplied @vaddr must correspond to the start of the range; otherwise
98 * an error will result. It is only possible to munmap() the entire
99 * contiguously-allocated range at once, and not any subrange thereof.
100 */
101 #define IOCTL_GNTDEV_GET_OFFSET_FOR_VADDR \
102 _IOC(_IOC_NONE, 'G', 2, sizeof(struct ioctl_gntdev_get_offset_for_vaddr))
103 struct ioctl_gntdev_get_offset_for_vaddr {
104 /* IN parameters */
105 /* The virtual address of the first mapped page in a range. */
106 __u64 vaddr;
107 /* OUT parameters */
108 /* The offset that was used in the initial mmap() operation. */
109 __u64 offset;
110 /* The number of pages mapped in the VM area that begins at @vaddr. */
111 __u32 count;
112 __u32 pad;
113 };
114
115 /*
116 * Sets the maximum number of grants that may mapped at once by this gntdev
117 * instance.
118 *
119 * N.B. This must be called before any other ioctl is performed on the device.
120 */
121 #define IOCTL_GNTDEV_SET_MAX_GRANTS \
122 _IOC(_IOC_NONE, 'G', 3, sizeof(struct ioctl_gntdev_set_max_grants))
123 struct ioctl_gntdev_set_max_grants {
124 /* IN parameter */
125 /* The maximum number of grants that may be mapped at once. */
126 __u32 count;
127 };
128
129 /*
130 * Sets up an unmap notification within the page, so that the other side can do
131 * cleanup if this side crashes. Required to implement cross-domain robust
132 * mutexes or close notification on communication channels.
133 *
134 * Each mapped page only supports one notification; multiple calls referring to
135 * the same page overwrite the previous notification. You must clear the
136 * notification prior to the IOCTL_GNTALLOC_DEALLOC_GREF if you do not want it
137 * to occur.
138 */
139 #define IOCTL_GNTDEV_SET_UNMAP_NOTIFY \
140 _IOC(_IOC_NONE, 'G', 7, sizeof(struct ioctl_gntdev_unmap_notify))
141 struct ioctl_gntdev_unmap_notify {
142 /* IN parameters */
143 /* Offset in the file descriptor for a byte within the page (same as
144 * used in mmap). If using UNMAP_NOTIFY_CLEAR_BYTE, this is the byte to
145 * be cleared. Otherwise, it can be any byte in the page whose
146 * notification we are adjusting.
147 */
148 __u64 index;
149 /* Action(s) to take on unmap */
150 __u32 action;
151 /* Event channel to notify */
152 __u32 event_channel_port;
153 };
154
155 struct gntdev_grant_copy_segment {
156 union {
157 void __user *virt;
158 struct {
159 grant_ref_t ref;
160 __u16 offset;
161 domid_t domid;
162 } foreign;
163 } source, dest;
164 __u16 len;
165
166 __u16 flags; /* GNTCOPY_* */
167 __s16 status; /* GNTST_* */
168 };
169
170 /*
171 * Copy between grant references and local buffers.
172 *
173 * The copy is split into @count @segments, each of which can copy
174 * to/from one grant reference.
175 *
176 * Each segment is similar to struct gnttab_copy in the hypervisor ABI
177 * except the local buffer is specified using a virtual address
178 * (instead of a GFN and offset).
179 *
180 * The local buffer may cross a Xen page boundary -- the driver will
181 * split segments into multiple ops if required.
182 *
183 * Returns 0 if all segments have been processed and @status in each
184 * segment is valid. Note that one or more segments may have failed
185 * (status != GNTST_okay).
186 *
187 * If the driver had to split a segment into two or more ops, @status
188 * includes the status of the first failed op for that segment (or
189 * GNTST_okay if all ops were successful).
190 *
191 * If -1 is returned, the status of all segments is undefined.
192 *
193 * EINVAL: A segment has local buffers for both source and
194 * destination.
195 * EINVAL: A segment crosses the boundary of a foreign page.
196 * EFAULT: A segment's local buffer is not accessible.
197 */
198 #define IOCTL_GNTDEV_GRANT_COPY \
199 _IOC(_IOC_NONE, 'G', 8, sizeof(struct ioctl_gntdev_grant_copy))
200 struct ioctl_gntdev_grant_copy {
201 unsigned int count;
202 struct gntdev_grant_copy_segment __user *segments;
203 };
204
205 /* Clear (set to zero) the byte specified by index */
206 #define UNMAP_NOTIFY_CLEAR_BYTE 0x1
207 /* Send an interrupt on the indicated event channel */
208 #define UNMAP_NOTIFY_SEND_EVENT 0x2
209
210 /*
211 * Flags to be used while requesting memory mapping's backing storage
212 * to be allocated with DMA API.
213 */
214
215 /*
216 * The buffer is backed with memory allocated with dma_alloc_wc.
217 */
218 #define GNTDEV_DMA_FLAG_WC (1 << 0)
219
220 /*
221 * The buffer is backed with memory allocated with dma_alloc_coherent.
222 */
223 #define GNTDEV_DMA_FLAG_COHERENT (1 << 1)
224
225 /*
226 * Create a dma-buf [1] from grant references @refs of count @count provided
227 * by the foreign domain @domid with flags @flags.
228 *
229 * By default dma-buf is backed by system memory pages, but by providing
230 * one of the GNTDEV_DMA_FLAG_XXX flags it can also be created as
231 * a DMA write-combine or coherent buffer, e.g. allocated with dma_alloc_wc/
232 * dma_alloc_coherent.
233 *
234 * Returns 0 if dma-buf was successfully created and the corresponding
235 * dma-buf's file descriptor is returned in @fd.
236 *
237 * [1] Documentation/driver-api/dma-buf.rst
238 */
239
240 #define IOCTL_GNTDEV_DMABUF_EXP_FROM_REFS \
241 _IOC(_IOC_NONE, 'G', 9, \
242 sizeof(struct ioctl_gntdev_dmabuf_exp_from_refs))
243 struct ioctl_gntdev_dmabuf_exp_from_refs {
244 /* IN parameters. */
245 /* Specific options for this dma-buf: see GNTDEV_DMA_FLAG_XXX. */
246 __u32 flags;
247 /* Number of grant references in @refs array. */
248 __u32 count;
249 /* OUT parameters. */
250 /* File descriptor of the dma-buf. */
251 __u32 fd;
252 /* The domain ID of the grant references to be mapped. */
253 __u32 domid;
254 /* Variable IN parameter. */
255 /* Array of grant references of size @count. */
256 __u32 refs[1];
257 };
258
259 /*
260 * This will block until the dma-buf with the file descriptor @fd is
261 * released. This is only valid for buffers created with
262 * IOCTL_GNTDEV_DMABUF_EXP_FROM_REFS.
263 *
264 * If within @wait_to_ms milliseconds the buffer is not released
265 * then -ETIMEDOUT error is returned.
266 * If the buffer with the file descriptor @fd does not exist or has already
267 * been released, then -ENOENT is returned. For valid file descriptors
268 * this must not be treated as error.
269 */
270 #define IOCTL_GNTDEV_DMABUF_EXP_WAIT_RELEASED \
271 _IOC(_IOC_NONE, 'G', 10, \
272 sizeof(struct ioctl_gntdev_dmabuf_exp_wait_released))
273 struct ioctl_gntdev_dmabuf_exp_wait_released {
274 /* IN parameters */
275 __u32 fd;
276 __u32 wait_to_ms;
277 };
278
279 /*
280 * Import a dma-buf with file descriptor @fd and export granted references
281 * to the pages of that dma-buf into array @refs of size @count.
282 */
283 #define IOCTL_GNTDEV_DMABUF_IMP_TO_REFS \
284 _IOC(_IOC_NONE, 'G', 11, \
285 sizeof(struct ioctl_gntdev_dmabuf_imp_to_refs))
286 struct ioctl_gntdev_dmabuf_imp_to_refs {
287 /* IN parameters. */
288 /* File descriptor of the dma-buf. */
289 __u32 fd;
290 /* Number of grant references in @refs array. */
291 __u32 count;
292 /* The domain ID for which references to be granted. */
293 __u32 domid;
294 /* Reserved - must be zero. */
295 __u32 reserved;
296 /* OUT parameters. */
297 /* Array of grant references of size @count. */
298 __u32 refs[1];
299 };
300
301 /*
302 * This will close all references to the imported buffer with file descriptor
303 * @fd, so it can be released by the owner. This is only valid for buffers
304 * created with IOCTL_GNTDEV_DMABUF_IMP_TO_REFS.
305 */
306 #define IOCTL_GNTDEV_DMABUF_IMP_RELEASE \
307 _IOC(_IOC_NONE, 'G', 12, \
308 sizeof(struct ioctl_gntdev_dmabuf_imp_release))
309 struct ioctl_gntdev_dmabuf_imp_release {
310 /* IN parameters */
311 __u32 fd;
312 __u32 reserved;
313 };
314
315 #endif /* __LINUX_PUBLIC_GNTDEV_H__ */
316
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