gntdev.h (11021B) - Raw
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 *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 *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__ */