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  *
   9  * This program is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU General Public License version 2
  11  * as published by the Free Software Foundation; or, when distributed
  12  * separately from the Linux kernel or incorporated into other
  13  * software packages, subject to the following license:
  14  *
  15  * Permission is hereby granted, free of charge, to any person obtaining a copy
  16  * of this source file (the "Software"), to deal in the Software without
  17  * restriction, including without limitation the rights to use, copy, modify,
  18  * merge, publish, distribute, sublicense, and/or sell copies of the Software,
  19  * and to permit persons to whom the Software is furnished to do so, subject to
  20  * the following conditions:
  21  *
  22  * The above copyright notice and this permission notice shall be included in
  23  * all copies or substantial portions of the Software.
  24  *
  25  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  26  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  27  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  28  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  29  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  30  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  31  * IN THE SOFTWARE.
  32  */
  33
  34 #ifndef __LINUX_PUBLIC_GNTDEV_H__
  35 #define __LINUX_PUBLIC_GNTDEV_H__
  36
  37 #include <linux/types.h>
  38
  39 struct ioctl_gntdev_grant_ref {
  40         /* The domain ID of the grant to be mapped. */
  41         __u32 domid;
  42         /* The grant reference of the grant to be mapped. */
  43         __u32 ref;
  44 };
  45
  46 /*
  47  * Inserts the grant references into the mapping table of an instance
  48  * of gntdev. N.B. This does not perform the mapping, which is deferred
  49  * until mmap() is called with @index as the offset.
  50  */
  51 #define IOCTL_GNTDEV_MAP_GRANT_REF \
  52 _IOC(_IOC_NONE, 'G', 0, sizeof(struct ioctl_gntdev_map_grant_ref))
  53 struct ioctl_gntdev_map_grant_ref {
  54         /* IN parameters */
  55         /* The number of grants to be mapped. */
  56         __u32 count;
  57         __u32 pad;
  58         /* OUT parameters */
  59         /* The offset to be used on a subsequent call to mmap(). */
  60         __u64 index;
  61         /* Variable IN parameter. */
  62         /* Array of grant references, of size @count. */
  63         struct ioctl_gntdev_grant_ref refs[1];
  64 };
  65
  66 /*
  67  * Removes the grant references from the mapping table of an instance of
  68  * of gntdev. N.B. munmap() must be called on the relevant virtual address(es)
  69  * before this ioctl is called, or an error will result.
  70  */
  71 #define IOCTL_GNTDEV_UNMAP_GRANT_REF \
  72 _IOC(_IOC_NONE, 'G', 1, sizeof(struct ioctl_gntdev_unmap_grant_ref))
  73 struct ioctl_gntdev_unmap_grant_ref {
  74         /* IN parameters */
  75         /* The offset was returned by the corresponding map operation. */
  76         __u64 index;
  77         /* The number of pages to be unmapped. */
  78         __u32 count;
  79         __u32 pad;
  80 };
  81
  82 /*
  83  * Returns the offset in the driver's address space that corresponds
  84  * to @vaddr. This can be used to perform a munmap(), followed by an
  85  * UNMAP_GRANT_REF ioctl, where no state about the offset is retained by
  86  * the caller. The number of pages that were allocated at the same time as
  87  * @vaddr is returned in @count.
  88  *
  89  * N.B. Where more than one page has been mapped into a contiguous range, the
  90  *      supplied @vaddr must correspond to the start of the range; otherwise
  91  *      an error will result. It is only possible to munmap() the entire
  92  *      contiguously-allocated range at once, and not any subrange thereof.
  93  */
  94 #define IOCTL_GNTDEV_GET_OFFSET_FOR_VADDR \
  95 _IOC(_IOC_NONE, 'G', 2, sizeof(struct ioctl_gntdev_get_offset_for_vaddr))
  96 struct ioctl_gntdev_get_offset_for_vaddr {
  97         /* IN parameters */
  98         /* The virtual address of the first mapped page in a range. */
  99         __u64 vaddr;
 100         /* OUT parameters */
 101         /* The offset that was used in the initial mmap() operation. */
 102         __u64 offset;
 103         /* The number of pages mapped in the VM area that begins at @vaddr. */
 104         __u32 count;
 105         __u32 pad;
 106 };
 107
 108 /*
 109  * Sets the maximum number of grants that may mapped at once by this gntdev
 110  * instance.
 111  *
 112  * N.B. This must be called before any other ioctl is performed on the device.
 113  */
 114 #define IOCTL_GNTDEV_SET_MAX_GRANTS \
 115 _IOC(_IOC_NONE, 'G', 3, sizeof(struct ioctl_gntdev_set_max_grants))
 116 struct ioctl_gntdev_set_max_grants {
 117         /* IN parameter */
 118         /* The maximum number of grants that may be mapped at once. */
 119         __u32 count;
 120 };
 121
 122 /*
 123  * Sets up an unmap notification within the page, so that the other side can do
 124  * cleanup if this side crashes. Required to implement cross-domain robust
 125  * mutexes or close notification on communication channels.
 126  *
 127  * Each mapped page only supports one notification; multiple calls referring to
 128  * the same page overwrite the previous notification. You must clear the
 129  * notification prior to the IOCTL_GNTALLOC_DEALLOC_GREF if you do not want it
 130  * to occur.
 131  */
 132 #define IOCTL_GNTDEV_SET_UNMAP_NOTIFY \
 133 _IOC(_IOC_NONE, 'G', 7, sizeof(struct ioctl_gntdev_unmap_notify))
 134 struct ioctl_gntdev_unmap_notify {
 135         /* IN parameters */
 136         /* Offset in the file descriptor for a byte within the page (same as
 137          * used in mmap). If using UNMAP_NOTIFY_CLEAR_BYTE, this is the byte to
 138          * be cleared. Otherwise, it can be any byte in the page whose
 139          * notification we are adjusting.
 140          */
 141         __u64 index;
 142         /* Action(s) to take on unmap */
 143         __u32 action;
 144         /* Event channel to notify */
 145         __u32 event_channel_port;
 146 };
 147
 148 struct gntdev_grant_copy_segment {
 149         union {
 150                 void __user *virt;
 151                 struct {
 152                         grant_ref_t ref;
 153                         __u16 offset;
 154                         domid_t domid;
 155                 } foreign;
 156         } source, dest;
 157         __u16 len;
 158
 159         __u16 flags;  /* GNTCOPY_* */
 160         __s16 status; /* GNTST_* */
 161 };
 162
 163 /*
 164  * Copy between grant references and local buffers.
 165  *
 166  * The copy is split into @count @segments, each of which can copy
 167  * to/from one grant reference.
 168  *
 169  * Each segment is similar to struct gnttab_copy in the hypervisor ABI
 170  * except the local buffer is specified using a virtual address
 171  * (instead of a GFN and offset).
 172  *
 173  * The local buffer may cross a Xen page boundary -- the driver will
 174  * split segments into multiple ops if required.
 175  *
 176  * Returns 0 if all segments have been processed and @status in each
 177  * segment is valid.  Note that one or more segments may have failed
 178  * (status != GNTST_okay).
 179  *
 180  * If the driver had to split a segment into two or more ops, @status
 181  * includes the status of the first failed op for that segment (or
 182  * GNTST_okay if all ops were successful).
 183  *
 184  * If -1 is returned, the status of all segments is undefined.
 185  *
 186  * EINVAL: A segment has local buffers for both source and
 187  *         destination.
 188  * EINVAL: A segment crosses the boundary of a foreign page.
 189  * EFAULT: A segment's local buffer is not accessible.
 190  */
 191 #define IOCTL_GNTDEV_GRANT_COPY \
 192         _IOC(_IOC_NONE, 'G', 8, sizeof(struct ioctl_gntdev_grant_copy))
 193 struct ioctl_gntdev_grant_copy {
 194         unsigned int count;
 195         struct gntdev_grant_copy_segment __user *segments;
 196 };
 197
 198 /* Clear (set to zero) the byte specified by index */
 199 #define UNMAP_NOTIFY_CLEAR_BYTE 0x1
 200 /* Send an interrupt on the indicated event channel */
 201 #define UNMAP_NOTIFY_SEND_EVENT 0x2
 202
 203 #endif /* __LINUX_PUBLIC_GNTDEV_H__ */