code.delx.au - pulseaudio/blob - src/modules/xen/gntalloc.h

   1 /*
   2  * This file is copied from the linux kernel headers. It defines the standard
   3  * interface to the xen/gntalloc device.
   4  *
   5  */
   6
   7 /******************************************************************************
   8  * gntalloc.h
   9  *
  10  * Interface to /dev/xen/gntalloc.
  11  *
  12  * Author: Daniel De Graaf <dgdegra@tycho.nsa.gov>
  13  *
  14  * This file is in the public domain.
  15  */
  16
  17 #ifndef __LINUX_PUBLIC_GNTALLOC_H__
  18 #define __LINUX_PUBLIC_GNTALLOC_H__
  19
  20 /*
  21  * Allocates a new page and creates a new grant reference.
  22  */
  23 #define IOCTL_GNTALLOC_ALLOC_GREF \
  24 _IOC(_IOC_NONE, 'G', 5, sizeof(struct ioctl_gntalloc_alloc_gref))
  25 struct ioctl_gntalloc_alloc_gref {
  26         /* IN parameters */
  27         /* The ID of the domain to be given access to the grants. */
  28         uint16_t domid;
  29         /* Flags for this mapping */
  30         uint16_t flags;
  31         /* Number of pages to map */
  32         uint32_t count;
  33         /* OUT parameters */
  34         /* The offset to be used on a subsequent call to mmap(). */
  35         uint64_t index;
  36         /* The grant references of the newly created grant, one per page */
  37         /* Variable size, depending on count */
  38         uint32_t gref_ids[1];
  39 };
  40
  41 #define GNTALLOC_FLAG_WRITABLE 1
  42
  43 /*
  44  * Deallocates the grant reference, allowing the associated page to be freed if
  45  * no other domains are using it.
  46  */
  47 #define IOCTL_GNTALLOC_DEALLOC_GREF \
  48 _IOC(_IOC_NONE, 'G', 6, sizeof(struct ioctl_gntalloc_dealloc_gref))
  49 struct ioctl_gntalloc_dealloc_gref {
  50         /* IN parameters */
  51         /* The offset returned in the map operation */
  52         uint64_t index;
  53         /* Number of references to unmap */
  54         uint32_t count;
  55 };
  56
  57 /*
  58  * Sets up an unmap notification within the page, so that the other side can do
  59  * cleanup if this side crashes. Required to implement cross-domain robust
  60  * mutexes or close notification on communication channels.
  61  *
  62  * Each mapped page only supports one notification; multiple calls referring to
  63  * the same page overwrite the previous notification. You must clear the
  64  * notification prior to the IOCTL_GNTALLOC_DEALLOC_GREF if you do not want it
  65  * to occur.
  66  */
  67 #define IOCTL_GNTALLOC_SET_UNMAP_NOTIFY \
  68 _IOC(_IOC_NONE, 'G', 7, sizeof(struct ioctl_gntalloc_unmap_notify))
  69 struct ioctl_gntalloc_unmap_notify {
  70         /* IN parameters */
  71         /* Offset in the file descriptor for a byte within the page (same as
  72          * used in mmap). If using UNMAP_NOTIFY_CLEAR_BYTE, this is the byte to
  73          * be cleared. Otherwise, it can be any byte in the page whose
  74          * notification we are adjusting.
  75          */
  76         uint64_t index;
  77         /* Action(s) to take on unmap */
  78         uint32_t action;
  79         /* Event channel to notify */
  80         uint32_t event_channel_port;
  81 };
  82
  83 /* Clear (set to zero) the byte specified by index */
  84 #define UNMAP_NOTIFY_CLEAR_BYTE 0x1
  85 /* Send an interrupt on the indicated event channel */
  86 #define UNMAP_NOTIFY_SEND_EVENT 0x2
  87
  88 #endif /* __LINUX_PUBLIC_GNTALLOC_H__ */