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1/* SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR MIT) */2/******************************************************************************3 * gntdev.h4 * 5 * Interface to /dev/xen/gntdev.6 * 7 * Copyright (c) 2007, D G Murray8 * Copyright (c) 2018, Oleksandr Andrushchenko, EPAM Systems Inc.9 * 10 * This program is free software; you can redistribute it and/or11 * modify it under the terms of the GNU General Public License version 212 * as published by the Free Software Foundation; or, when distributed13 * separately from the Linux kernel or incorporated into other14 * software packages, subject to the following license:15 * 16 * Permission is hereby granted, free of charge, to any person obtaining a copy17 * of this source file (the "Software"), to deal in the Software without18 * 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 to21 * the following conditions:22 * 23 * The above copyright notice and this permission notice shall be included in24 * all copies or substantial portions of the Software.25 * 26 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR27 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,28 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE29 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER30 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING31 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS32 * IN THE SOFTWARE.33 */34 35#ifndef __LINUX_PUBLIC_GNTDEV_H__36#define __LINUX_PUBLIC_GNTDEV_H__37 38#include <linux/types.h>39 40struct 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 instance49 * of gntdev. N.B. This does not perform the mapping, which is deferred50 * until mmap() is called with @index as the offset. @index should be51 * considered opaque to userspace, with one exception: if no grant52 * references have ever been inserted into the mapping table of this53 * instance, @index will be set to 0. This is necessary to use gntdev54 * with userspace APIs that expect a file descriptor that can be55 * mmap()'d at offset 0, such as Wayland. If @count is set to 0, this56 * ioctl will fail.57 */58#define IOCTL_GNTDEV_MAP_GRANT_REF \59_IOC(_IOC_NONE, 'G', 0, sizeof(struct ioctl_gntdev_map_grant_ref))60struct 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 of75 * 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))80struct 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 corresponds91 * to @vaddr. This can be used to perform a munmap(), followed by an92 * UNMAP_GRANT_REF ioctl, where no state about the offset is retained by93 * the caller. The number of pages that were allocated at the same time as94 * @vaddr is returned in @count.95 *96 * N.B. Where more than one page has been mapped into a contiguous range, the97 * supplied @vaddr must correspond to the start of the range; otherwise98 * an error will result. It is only possible to munmap() the entire99 * 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))103struct 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 gntdev117 * 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))123struct 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 do131 * cleanup if this side crashes. Required to implement cross-domain robust132 * mutexes or close notification on communication channels.133 *134 * Each mapped page only supports one notification; multiple calls referring to135 * the same page overwrite the previous notification. You must clear the136 * notification prior to the IOCTL_GNTALLOC_DEALLOC_GREF if you do not want it137 * to occur.138 */139#define IOCTL_GNTDEV_SET_UNMAP_NOTIFY \140_IOC(_IOC_NONE, 'G', 7, sizeof(struct ioctl_gntdev_unmap_notify))141struct ioctl_gntdev_unmap_notify {142 /* IN parameters */143 /* Offset in the file descriptor for a byte within the page (same as144 * used in mmap). If using UNMAP_NOTIFY_CLEAR_BYTE, this is the byte to145 * be cleared. Otherwise, it can be any byte in the page whose146 * 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 155struct 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 copy174 * to/from one grant reference.175 *176 * Each segment is similar to struct gnttab_copy in the hypervisor ABI177 * except the local buffer is specified using a virtual address178 * (instead of a GFN and offset).179 *180 * The local buffer may cross a Xen page boundary -- the driver will181 * split segments into multiple ops if required.182 *183 * Returns 0 if all segments have been processed and @status in each184 * segment is valid. Note that one or more segments may have failed185 * (status != GNTST_okay).186 *187 * If the driver had to split a segment into two or more ops, @status188 * includes the status of the first failed op for that segment (or189 * 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 and194 * 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))200struct 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 0x1207/* Send an interrupt on the indicated event channel */208#define UNMAP_NOTIFY_SEND_EVENT 0x2209 210/*211 * Flags to be used while requesting memory mapping's backing storage212 * 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 provided227 * by the foreign domain @domid with flags @flags.228 *229 * By default dma-buf is backed by system memory pages, but by providing230 * one of the GNTDEV_DMA_FLAG_XXX flags it can also be created as231 * 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 corresponding235 * dma-buf's file descriptor is returned in @fd.236 *237 * [1] Documentation/driver-api/dma-buf.rst238 */239 240#define IOCTL_GNTDEV_DMABUF_EXP_FROM_REFS \241 _IOC(_IOC_NONE, 'G', 9, \242 sizeof(struct ioctl_gntdev_dmabuf_exp_from_refs))243struct 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 is261 * released. This is only valid for buffers created with262 * IOCTL_GNTDEV_DMABUF_EXP_FROM_REFS.263 *264 * If within @wait_to_ms milliseconds the buffer is not released265 * then -ETIMEDOUT error is returned.266 * If the buffer with the file descriptor @fd does not exist or has already267 * been released, then -ENOENT is returned. For valid file descriptors268 * 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))273struct 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 references281 * 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))286struct 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 descriptor303 * @fd, so it can be released by the owner. This is only valid for buffers304 * 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))309struct ioctl_gntdev_dmabuf_imp_release {310 /* IN parameters */311 __u32 fd;312 __u32 reserved;313};314 315#endif /* __LINUX_PUBLIC_GNTDEV_H__ */316