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xenio_gntdev.h revision 1.2 
      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 #include <sys/ioccom.h>
     37 
     38 struct ioctl_gntdev_grant_ref {
     39 	/* The domain ID of the grant to be mapped. */
     40 	uint32_t domid;
     41 	/* The grant reference of the grant to be mapped. */
     42 	uint32_t ref;
     43 };
     44 
     45 /*
     46  * Inserts the grant references into the mapping table of an instance
     47  * of gntdev. N.B. This does not perform the mapping, which is deferred
     48  * until mmap() is called with @index as the offset.
     49  */
     50 #define IOCTL_GNTDEV_MAP_GRANT_REF				\
     51 	_IOWR('G', 0, sizeof(struct ioctl_gntdev_map_grant_ref))
     52 struct ioctl_gntdev_map_grant_ref {
     53 	/* IN parameters */
     54 	/* The number of grants to be mapped. */
     55 	uint32_t count;
     56 	uint32_t pad;
     57 	/* OUT parameters */
     58 	/* The offset to be used on a subsequent call to mmap(). */
     59 	uint64_t index;
     60 	/* Variable IN parameter. */
     61 	/* Array of grant references, of size @count. */
     62 	struct ioctl_gntdev_grant_ref refs[1];
     63 };
     64 
     65 /*
     66  * Removes the grant references from the mapping table of an instance of
     67  * of gntdev. N.B. munmap() must be called on the relevant virtual address(es)
     68  * before this ioctl is called, or an error will result.
     69  */
     70 #define IOCTL_GNTDEV_UNMAP_GRANT_REF				\
     71 	_IOW('G', 1, sizeof(struct ioctl_gntdev_unmap_grant_ref))
     72 struct ioctl_gntdev_unmap_grant_ref {
     73 	/* IN parameters */
     74 	/* The offset was returned by the corresponding map operation. */
     75 	uint64_t index;
     76 	/* The number of pages to be unmapped. */
     77 	uint32_t count;
     78 	uint32_t pad;
     79 };
     80 
     81 /*
     82  * Returns the offset in the driver's address space that corresponds
     83  * to @vaddr. This can be used to perform a munmap(), followed by an
     84  * UNMAP_GRANT_REF ioctl, where no state about the offset is retained by
     85  * the caller. The number of pages that were allocated at the same time as
     86  * @vaddr is returned in @count.
     87  *
     88  * N.B. Where more than one page has been mapped into a contiguous range, the
     89  *      supplied @vaddr must correspond to the start of the range; otherwise
     90  *      an error will result. It is only possible to munmap() the entire
     91  *      contiguously-allocated range at once, and not any subrange thereof.
     92  */
     93 #define IOCTL_GNTDEV_GET_OFFSET_FOR_VADDR			\
     94 	_IOWR('G', 2, sizeof(struct ioctl_gntdev_get_offset_for_vaddr))
     95 struct ioctl_gntdev_get_offset_for_vaddr {
     96 	/* IN parameters */
     97 	/* The virtual address of the first mapped page in a range. */
     98 	uint64_t vaddr;
     99 	/* OUT parameters */
    100 	/* The offset that was used in the initial mmap() operation. */
    101 	uint64_t offset;
    102 	/* The number of pages mapped in the VM area that begins at @vaddr. */
    103 	uint32_t count;
    104 	uint32_t pad;
    105 };
    106 
    107 /*
    108  * Sets the maximum number of grants that may mapped at once by this gntdev
    109  * instance.
    110  *
    111  * N.B. This must be called before any other ioctl is performed on the device.
    112  */
    113 #define IOCTL_GNTDEV_SET_MAX_GRANTS \
    114 	_IOW('G', 3, sizeof(struct ioctl_gntdev_set_max_grants))
    115 struct ioctl_gntdev_set_max_grants {
    116 	/* IN parameter */
    117 	/* The maximum number of grants that may be mapped at once. */
    118 	uint32_t count;
    119 };
    120 
    121 #endif /* __XEN_GNTDEV_H__ */
    122