LXR linux/include/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/*
  15 * Allocates a new page and creates a new grant reference.
  16 */
  17#define IOCTL_GNTALLOC_ALLOC_GREF \
  18_IOC(_IOC_NONE, 'G', 5, sizeof(struct ioctl_gntalloc_alloc_gref))
  19struct ioctl_gntalloc_alloc_gref {
  20        /* IN parameters */
  21        /* The ID of the domain to be given access to the grants. */
  22        uint16_t domid;
  23        /* Flags for this mapping */
  24        uint16_t flags;
  25        /* Number of pages to map */
  26        uint32_t count;
  27        /* OUT parameters */
  28        /* The offset to be used on a subsequent call to mmap(). */
  29        uint64_t index;
  30        /* The grant references of the newly created grant, one per page */
  31        /* Variable size, depending on count */
  32        uint32_t gref_ids[1];
  33};
  34
  35#define GNTALLOC_FLAG_WRITABLE 1
  36
  37/*
  38 * Deallocates the grant reference, allowing the associated page to be freed if
  39 * no other domains are using it.
  40 */
  41#define IOCTL_GNTALLOC_DEALLOC_GREF \
  42_IOC(_IOC_NONE, 'G', 6, sizeof(struct ioctl_gntalloc_dealloc_gref))
  43struct ioctl_gntalloc_dealloc_gref {
  44        /* IN parameters */
  45        /* The offset returned in the map operation */
  46        uint64_t index;
  47        /* Number of references to unmap */
  48        uint32_t count;
  49};
  50
  51/*
  52 * Sets up an unmap notification within the page, so that the other side can do
  53 * cleanup if this side crashes. Required to implement cross-domain robust
  54 * mutexes or close notification on communication channels.
  55 *
  56 * Each mapped page only supports one notification; multiple calls referring to
  57 * the same page overwrite the previous notification. You must clear the
  58 * notification prior to the IOCTL_GNTALLOC_DEALLOC_GREF if you do not want it
  59 * to occur.
  60 */
  61#define IOCTL_GNTALLOC_SET_UNMAP_NOTIFY \
  62_IOC(_IOC_NONE, 'G', 7, sizeof(struct ioctl_gntalloc_unmap_notify))
  63struct ioctl_gntalloc_unmap_notify {
  64        /* IN parameters */
  65        /* Offset in the file descriptor for a byte within the page (same as
  66         * used in mmap). If using UNMAP_NOTIFY_CLEAR_BYTE, this is the byte to
  67         * be cleared. Otherwise, it can be any byte in the page whose
  68         * notification we are adjusting.
  69         */
  70        uint64_t index;
  71        /* Action(s) to take on unmap */
  72        uint32_t action;
  73        /* Event channel to notify */
  74        uint32_t event_channel_port;
  75};
  76
  77/* Clear (set to zero) the byte specified by index */
  78#define UNMAP_NOTIFY_CLEAR_BYTE 0x1
  79/* Send an interrupt on the indicated event channel */
  80#define UNMAP_NOTIFY_SEND_EVENT 0x2
  81
  82#endif /* __LINUX_PUBLIC_GNTALLOC_H__ */
  83