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__ */