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xenio_gntdev.h revision 1.1 
      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 __XEN_GNTDEV_H__
     34 #define __XEN_GNTDEV_H__
     35 
     36 struct 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 	_IOWR('G', 0, sizeof(struct ioctl_gntdev_map_grant_ref))
     50 struct 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 	_IOW('G', 1, sizeof(struct ioctl_gntdev_unmap_grant_ref))
     70 struct 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 	_IOWR('G', 2, sizeof(struct ioctl_gntdev_get_offset_for_vaddr))
     93 struct 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 	_IOW('G', 3, sizeof(struct ioctl_gntdev_set_max_grants))
    113 struct 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 #endif /* __XEN_GNTDEV_H__ */
    120