linux/include/xen/gntdev.h
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   1/******************************************************************************
   2 * gntdev.h
   3 * 
   4 * Interface to /dev/xen/gntdev.
   5 * 
   6 * Copyright (c) 2007, D G Murray
   7 * 
   8 * This program is free software; you can redistribute it and/or
   9 * modify it under the terms of the GNU General Public License version 2
  10 * as published by the Free Software Foundation; or, when distributed
  11 * separately from the Linux kernel or incorporated into other
  12 * software packages, subject to the following license:
  13 * 
  14 * Permission is hereby granted, free of charge, to any person obtaining a copy
  15 * of this source file (the "Software"), to deal in the Software without
  16 * restriction, including without limitation the rights to use, copy, modify,
  17 * merge, publish, distribute, sublicense, and/or sell copies of the Software,
  18 * and to permit persons to whom the Software is furnished to do so, subject to
  19 * the following conditions:
  20 * 
  21 * The above copyright notice and this permission notice shall be included in
  22 * all copies or substantial portions of the Software.
  23 * 
  24 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  25 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  26 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  27 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  28 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  29 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  30 * IN THE SOFTWARE.
  31 */
  32
  33#ifndef __LINUX_PUBLIC_GNTDEV_H__
  34#define __LINUX_PUBLIC_GNTDEV_H__
  35
  36struct ioctl_gntdev_grant_ref {
  37        /* The domain ID of the grant to be mapped. */
  38        uint32_t domid;
  39        /* The grant reference of the grant to be mapped. */
  40        uint32_t ref;
  41};
  42
  43/*
  44 * Inserts the grant references into the mapping table of an instance
  45 * of gntdev. N.B. This does not perform the mapping, which is deferred
  46 * until mmap() is called with @index as the offset.
  47 */
  48#define IOCTL_GNTDEV_MAP_GRANT_REF \
  49_IOC(_IOC_NONE, 'G', 0, sizeof(struct ioctl_gntdev_map_grant_ref))
  50struct ioctl_gntdev_map_grant_ref {
  51        /* IN parameters */
  52        /* The number of grants to be mapped. */
  53        uint32_t count;
  54        uint32_t pad;
  55        /* OUT parameters */
  56        /* The offset to be used on a subsequent call to mmap(). */
  57        uint64_t index;
  58        /* Variable IN parameter. */
  59        /* Array of grant references, of size @count. */
  60        struct ioctl_gntdev_grant_ref refs[1];
  61};
  62
  63/*
  64 * Removes the grant references from the mapping table of an instance of
  65 * of gntdev. N.B. munmap() must be called on the relevant virtual address(es)
  66 * before this ioctl is called, or an error will result.
  67 */
  68#define IOCTL_GNTDEV_UNMAP_GRANT_REF \
  69_IOC(_IOC_NONE, 'G', 1, sizeof(struct ioctl_gntdev_unmap_grant_ref))
  70struct ioctl_gntdev_unmap_grant_ref {
  71        /* IN parameters */
  72        /* The offset was returned by the corresponding map operation. */
  73        uint64_t index;
  74        /* The number of pages to be unmapped. */
  75        uint32_t count;
  76        uint32_t pad;
  77};
  78
  79/*
  80 * Returns the offset in the driver's address space that corresponds
  81 * to @vaddr. This can be used to perform a munmap(), followed by an
  82 * UNMAP_GRANT_REF ioctl, where no state about the offset is retained by
  83 * the caller. The number of pages that were allocated at the same time as
  84 * @vaddr is returned in @count.
  85 *
  86 * N.B. Where more than one page has been mapped into a contiguous range, the
  87 *      supplied @vaddr must correspond to the start of the range; otherwise
  88 *      an error will result. It is only possible to munmap() the entire
  89 *      contiguously-allocated range at once, and not any subrange thereof.
  90 */
  91#define IOCTL_GNTDEV_GET_OFFSET_FOR_VADDR \
  92_IOC(_IOC_NONE, 'G', 2, sizeof(struct ioctl_gntdev_get_offset_for_vaddr))
  93struct ioctl_gntdev_get_offset_for_vaddr {
  94        /* IN parameters */
  95        /* The virtual address of the first mapped page in a range. */
  96        uint64_t vaddr;
  97        /* OUT parameters */
  98        /* The offset that was used in the initial mmap() operation. */
  99        uint64_t offset;
 100        /* The number of pages mapped in the VM area that begins at @vaddr. */
 101        uint32_t count;
 102        uint32_t pad;
 103};
 104
 105/*
 106 * Sets the maximum number of grants that may mapped at once by this gntdev
 107 * instance.
 108 *
 109 * N.B. This must be called before any other ioctl is performed on the device.
 110 */
 111#define IOCTL_GNTDEV_SET_MAX_GRANTS \
 112_IOC(_IOC_NONE, 'G', 3, sizeof(struct ioctl_gntdev_set_max_grants))
 113struct ioctl_gntdev_set_max_grants {
 114        /* IN parameter */
 115        /* The maximum number of grants that may be mapped at once. */
 116        uint32_t count;
 117};
 118
 119/*
 120 * Sets up an unmap notification within the page, so that the other side can do
 121 * cleanup if this side crashes. Required to implement cross-domain robust
 122 * mutexes or close notification on communication channels.
 123 *
 124 * Each mapped page only supports one notification; multiple calls referring to
 125 * the same page overwrite the previous notification. You must clear the
 126 * notification prior to the IOCTL_GNTALLOC_DEALLOC_GREF if you do not want it
 127 * to occur.
 128 */
 129#define IOCTL_GNTDEV_SET_UNMAP_NOTIFY \
 130_IOC(_IOC_NONE, 'G', 7, sizeof(struct ioctl_gntdev_unmap_notify))
 131struct ioctl_gntdev_unmap_notify {
 132        /* IN parameters */
 133        /* Offset in the file descriptor for a byte within the page (same as
 134         * used in mmap). If using UNMAP_NOTIFY_CLEAR_BYTE, this is the byte to
 135         * be cleared. Otherwise, it can be any byte in the page whose
 136         * notification we are adjusting.
 137         */
 138        uint64_t index;
 139        /* Action(s) to take on unmap */
 140        uint32_t action;
 141        /* Event channel to notify */
 142        uint32_t event_channel_port;
 143};
 144
 145/* Clear (set to zero) the byte specified by index */
 146#define UNMAP_NOTIFY_CLEAR_BYTE 0x1
 147/* Send an interrupt on the indicated event channel */
 148#define UNMAP_NOTIFY_SEND_EVENT 0x2
 149
 150#endif /* __LINUX_PUBLIC_GNTDEV_H__ */
 151
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