LXR linux/include/uapi/xen/gntalloc.h

   1/******************************************************************************
   2 * gntalloc.h
   3 *
   4 * Interface to /dev/xen/gntalloc.
   5 *
   6 * Author: Daniel De Graaf <dgdegra@tycho.nsa.gov>
   7 *
   8 * This file is in the public domain.
   9 */
  10
  11#ifndef __LINUX_PUBLIC_GNTALLOC_H__
  12#define __LINUX_PUBLIC_GNTALLOC_H__
  13
  14#include <linux/types.h>
  15
  16/*
  17 * Allocates a new page and creates a new grant reference.
  18 */
  19#define IOCTL_GNTALLOC_ALLOC_GREF \
  20_IOC(_IOC_NONE, 'G', 5, sizeof(struct ioctl_gntalloc_alloc_gref))
  21struct ioctl_gntalloc_alloc_gref {
  22        /* IN parameters */
  23        /* The ID of the domain to be given access to the grants. */
  24        __u16 domid;
  25        /* Flags for this mapping */
  26        __u16 flags;
  27        /* Number of pages to map */
  28        __u32 count;
  29        /* OUT parameters */
  30        /* The offset to be used on a subsequent call to mmap(). */
  31        __u64 index;
  32        /* The grant references of the newly created grant, one per page */
  33        /* Variable size, depending on count */
  34        __u32 gref_ids[1];
  35};
  36
  37#define GNTALLOC_FLAG_WRITABLE 1
  38
  39/*
  40 * Deallocates the grant reference, allowing the associated page to be freed if
  41 * no other domains are using it.
  42 */
  43#define IOCTL_GNTALLOC_DEALLOC_GREF \
  44_IOC(_IOC_NONE, 'G', 6, sizeof(struct ioctl_gntalloc_dealloc_gref))
  45struct ioctl_gntalloc_dealloc_gref {
  46        /* IN parameters */
  47        /* The offset returned in the map operation */
  48        __u64 index;
  49        /* Number of references to unmap */
  50        __u32 count;
  51};
  52
  53/*
  54 * Sets up an unmap notification within the page, so that the other side can do
  55 * cleanup if this side crashes. Required to implement cross-domain robust
  56 * mutexes or close notification on communication channels.
  57 *
  58 * Each mapped page only supports one notification; multiple calls referring to
  59 * the same page overwrite the previous notification. You must clear the
  60 * notification prior to the IOCTL_GNTALLOC_DEALLOC_GREF if you do not want it
  61 * to occur.
  62 */
  63#define IOCTL_GNTALLOC_SET_UNMAP_NOTIFY \
  64_IOC(_IOC_NONE, 'G', 7, sizeof(struct ioctl_gntalloc_unmap_notify))
  65struct ioctl_gntalloc_unmap_notify {
  66        /* IN parameters */
  67        /* Offset in the file descriptor for a byte within the page (same as
  68         * used in mmap). If using UNMAP_NOTIFY_CLEAR_BYTE, this is the byte to
  69         * be cleared. Otherwise, it can be any byte in the page whose
  70         * notification we are adjusting.
  71         */
  72        __u64 index;
  73        /* Action(s) to take on unmap */
  74        __u32 action;
  75        /* Event channel to notify */
  76        __u32 event_channel_port;
  77};
  78
  79/* Clear (set to zero) the byte specified by index */
  80#define UNMAP_NOTIFY_CLEAR_BYTE 0x1
  81/* Send an interrupt on the indicated event channel */
  82#define UNMAP_NOTIFY_SEND_EVENT 0x2
  83
  84#endif /* __LINUX_PUBLIC_GNTALLOC_H__ */
  85