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.
51 */
52 #define IOCTL_GNTDEV_MAP_GRANT_REF \
53 _IOC(_IOC_NONE, 'G', 0, sizeof(struct ioctl_gntdev_map_grant_ref))
54 struct ioctl_gntdev_map_grant_ref {
55 /* IN parameters */
56 /* The number of grants to be mapped. */
57 __u32 count;
58 __u32 pad;
59 /* OUT parameters */
60 /* The offset to be used on a subsequent call to mmap(). */
61 __u64 index;
62 /* Variable IN parameter. */
63 /* Array of grant references, of size @count. */
64 struct ioctl_gntdev_grant_ref refs[1];
65 };
66
67 /*
68 * Removes the grant references from the mapping table of an instance of
69 * of gntdev. N.B. munmap() must be called on the relevant virtual address(es)
70 * before this ioctl is called, or an error will result.
71 */
72 #define IOCTL_GNTDEV_UNMAP_GRANT_REF \
73 _IOC(_IOC_NONE, 'G', 1, sizeof(struct ioctl_gntdev_unmap_grant_ref))
74 struct ioctl_gntdev_unmap_grant_ref {
75 /* IN parameters */
76 /* The offset was returned by the corresponding map operation. */
77 __u64 index;
78 /* The number of pages to be unmapped. */
79 __u32 count;
80 __u32 pad;
81 };
82
83 /*
84 * Returns the offset in the driver's address space that corresponds
85 * to @vaddr. This can be used to perform a munmap(), followed by an
86 * UNMAP_GRANT_REF ioctl, where no state about the offset is retained by
87 * the caller. The number of pages that were allocated at the same time as
88 * @vaddr is returned in @count.
89 *
90 * N.B. Where more than one page has been mapped into a contiguous range, the
91 * supplied @vaddr must correspond to the start of the range; otherwise
92 * an error will result. It is only possible to munmap() the entire
93 * contiguously-allocated range at once, and not any subrange thereof.
94 */
95 #define IOCTL_GNTDEV_GET_OFFSET_FOR_VADDR \
96 _IOC(_IOC_NONE, 'G', 2, sizeof(struct ioctl_gntdev_get_offset_for_vaddr))
97 struct ioctl_gntdev_get_offset_for_vaddr {
98 /* IN parameters */
99 /* The virtual address of the first mapped page in a range. */
100 __u64 vaddr;
101 /* OUT parameters */
102 /* The offset that was used in the initial mmap() operation. */
103 __u64 offset;
104 /* The number of pages mapped in the VM area that begins at @vaddr. */
105 __u32 count;
106 __u32 pad;
107 };
108
109 /*
110 * Sets the maximum number of grants that may mapped at once by this gntdev
111 * instance.
112 *
113 * N.B. This must be called before any other ioctl is performed on the device.
114 */
115 #define IOCTL_GNTDEV_SET_MAX_GRANTS \
116 _IOC(_IOC_NONE, 'G', 3, sizeof(struct ioctl_gntdev_set_max_grants))
117 struct ioctl_gntdev_set_max_grants {
118 /* IN parameter */
119 /* The maximum number of grants that may be mapped at once. */
120 __u32 count;
121 };
122
123 /*
124 * Sets up an unmap notification within the page, so that the other side can do
125 * cleanup if this side crashes. Required to implement cross-domain robust
126 * mutexes or close notification on communication channels.
127 *
128 * Each mapped page only supports one notification; multiple calls referring to
129 * the same page overwrite the previous notification. You must clear the
130 * notification prior to the IOCTL_GNTALLOC_DEALLOC_GREF if you do not want it
131 * to occur.
132 */
133 #define IOCTL_GNTDEV_SET_UNMAP_NOTIFY \
134 _IOC(_IOC_NONE, 'G', 7, sizeof(struct ioctl_gntdev_unmap_notify))
135 struct ioctl_gntdev_unmap_notify {
136 /* IN parameters */
137 /* Offset in the file descriptor for a byte within the page (same as
138 * used in mmap). If using UNMAP_NOTIFY_CLEAR_BYTE, this is the byte to
139 * be cleared. Otherwise, it can be any byte in the page whose
140 * notification we are adjusting.
141 */
142 __u64 index;
143 /* Action(s) to take on unmap */
144 __u32 action;
145 /* Event channel to notify */
146 __u32 event_channel_port;
147 };
148
149 struct gntdev_grant_copy_segment {
150 union {
151 void __user *virt;
152 struct {
153 grant_ref_t ref;
154 __u16 offset;
155 domid_t domid;
156 } foreign;
157 } source, dest;
158 __u16 len;
159
160 __u16 flags; /* GNTCOPY_* */
161 __s16 status; /* GNTST_* */
162 };
163
164 /*
165 * Copy between grant references and local buffers.
166 *
167 * The copy is split into @count @segments, each of which can copy
168 * to/from one grant reference.
169 *
170 * Each segment is similar to struct gnttab_copy in the hypervisor ABI
171 * except the local buffer is specified using a virtual address
172 * (instead of a GFN and offset).
173 *
174 * The local buffer may cross a Xen page boundary -- the driver will
175 * split segments into multiple ops if required.
176 *
177 * Returns 0 if all segments have been processed and @status in each
178 * segment is valid. Note that one or more segments may have failed
179 * (status != GNTST_okay).
180 *
181 * If the driver had to split a segment into two or more ops, @status
182 * includes the status of the first failed op for that segment (or
183 * GNTST_okay if all ops were successful).
184 *
185 * If -1 is returned, the status of all segments is undefined.
186 *
187 * EINVAL: A segment has local buffers for both source and
188 * destination.
189 * EINVAL: A segment crosses the boundary of a foreign page.
190 * EFAULT: A segment's local buffer is not accessible.
191 */
192 #define IOCTL_GNTDEV_GRANT_COPY \
193 _IOC(_IOC_NONE, 'G', 8, sizeof(struct ioctl_gntdev_grant_copy))
194 struct ioctl_gntdev_grant_copy {
195 unsigned int count;
196 struct gntdev_grant_copy_segment __user *segments;
197 };
198
199 /* Clear (set to zero) the byte specified by index */
200 #define UNMAP_NOTIFY_CLEAR_BYTE 0x1
201 /* Send an interrupt on the indicated event channel */
202 #define UNMAP_NOTIFY_SEND_EVENT 0x2
203
204 /*
205 * Flags to be used while requesting memory mapping's backing storage
206 * to be allocated with DMA API.
207 */
208
209 /*
210 * The buffer is backed with memory allocated with dma_alloc_wc.
211 */
212 #define GNTDEV_DMA_FLAG_WC (1 << 0)
213
214 /*
215 * The buffer is backed with memory allocated with dma_alloc_coherent.
216 */
217 #define GNTDEV_DMA_FLAG_COHERENT (1 << 1)
218
219 /*
220 * Create a dma-buf [1] from grant references @refs of count @count provided
221 * by the foreign domain @domid with flags @flags.
222 *
223 * By default dma-buf is backed by system memory pages, but by providing
224 * one of the GNTDEV_DMA_FLAG_XXX flags it can also be created as
225 * a DMA write-combine or coherent buffer, e.g. allocated with dma_alloc_wc/
226 * dma_alloc_coherent.
227 *
228 * Returns 0 if dma-buf was successfully created and the corresponding
229 * dma-buf's file descriptor is returned in @fd.
230 *
231 * [1] Documentation/driver-api/dma-buf.rst
232 */
233
234 #define IOCTL_GNTDEV_DMABUF_EXP_FROM_REFS \
235 _IOC(_IOC_NONE, 'G', 9, \
236 sizeof(struct ioctl_gntdev_dmabuf_exp_from_refs))
237 struct ioctl_gntdev_dmabuf_exp_from_refs {
238 /* IN parameters. */
239 /* Specific options for this dma-buf: see GNTDEV_DMA_FLAG_XXX. */
240 __u32 flags;
241 /* Number of grant references in @refs array. */
242 __u32 count;
243 /* OUT parameters. */
244 /* File descriptor of the dma-buf. */
245 __u32 fd;
246 /* The domain ID of the grant references to be mapped. */
247 __u32 domid;
248 /* Variable IN parameter. */
249 /* Array of grant references of size @count. */
250 __u32 refs[1];
251 };
252
253 /*
254 * This will block until the dma-buf with the file descriptor @fd is
255 * released. This is only valid for buffers created with
256 * IOCTL_GNTDEV_DMABUF_EXP_FROM_REFS.
257 *
258 * If within @wait_to_ms milliseconds the buffer is not released
259 * then -ETIMEDOUT error is returned.
260 * If the buffer with the file descriptor @fd does not exist or has already
261 * been released, then -ENOENT is returned. For valid file descriptors
262 * this must not be treated as error.
263 */
264 #define IOCTL_GNTDEV_DMABUF_EXP_WAIT_RELEASED \
265 _IOC(_IOC_NONE, 'G', 10, \
266 sizeof(struct ioctl_gntdev_dmabuf_exp_wait_released))
267 struct ioctl_gntdev_dmabuf_exp_wait_released {
268 /* IN parameters */
269 __u32 fd;
270 __u32 wait_to_ms;
271 };
272
273 /*
274 * Import a dma-buf with file descriptor @fd and export granted references
275 * to the pages of that dma-buf into array @refs of size @count.
276 */
277 #define IOCTL_GNTDEV_DMABUF_IMP_TO_REFS \
278 _IOC(_IOC_NONE, 'G', 11, \
279 sizeof(struct ioctl_gntdev_dmabuf_imp_to_refs))
280 struct ioctl_gntdev_dmabuf_imp_to_refs {
281 /* IN parameters. */
282 /* File descriptor of the dma-buf. */
283 __u32 fd;
284 /* Number of grant references in @refs array. */
285 __u32 count;
286 /* The domain ID for which references to be granted. */
287 __u32 domid;
288 /* Reserved - must be zero. */
289 __u32 reserved;
290 /* OUT parameters. */
291 /* Array of grant references of size @count. */
292 __u32 refs[1];
293 };
294
295 /*
296 * This will close all references to the imported buffer with file descriptor
297 * @fd, so it can be released by the owner. This is only valid for buffers
298 * created with IOCTL_GNTDEV_DMABUF_IMP_TO_REFS.
299 */
300 #define IOCTL_GNTDEV_DMABUF_IMP_RELEASE \
301 _IOC(_IOC_NONE, 'G', 12, \
302 sizeof(struct ioctl_gntdev_dmabuf_imp_release))
303 struct ioctl_gntdev_dmabuf_imp_release {
304 /* IN parameters */
305 __u32 fd;
306 __u32 reserved;
307 };
308
309 #endif /* __LINUX_PUBLIC_GNTDEV_H__ */