include/uapi/xen/gntdev.h

   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__ */