/******************************************************************************
* gntalloc.h
*
* Interface to /dev/xen/gntalloc.
*
* Author: Daniel De Graaf <[email protected]>
*
* This file is in the public domain.
*/

#ifndef __LINUX_PUBLIC_GNTALLOC_H__
#define __LINUX_PUBLIC_GNTALLOC_H__

/*
* Allocates a new page and creates a new grant reference.
*/
#define IOCTL_GNTALLOC_ALLOC_GREF \
_IOC(_IOC_NONE, 'G', 5, sizeof(struct ioctl_gntalloc_alloc_gref))
struct ioctl_gntalloc_alloc_gref {
/* IN parameters */
/* The ID of the domain to be given access to the grants. */
uint16_t domid;
/* Flags for this mapping */
uint16_t flags;
/* Number of pages to map */
uint32_t count;
/* OUT parameters */
/* The offset to be used on a subsequent call to mmap(). */
uint64_t index;
/* The grant references of the newly created grant, one per page */
/* Variable size, depending on count */
uint32_t gref_ids[1];
};

#define GNTALLOC_FLAG_WRITABLE 1

/*
* Deallocates the grant reference, allowing the associated page to be freed if
* no other domains are using it.
*/
#define IOCTL_GNTALLOC_DEALLOC_GREF \
_IOC(_IOC_NONE, 'G', 6, sizeof(struct ioctl_gntalloc_dealloc_gref))
struct ioctl_gntalloc_dealloc_gref {
/* IN parameters */
/* The offset returned in the map operation */
uint64_t index;
/* Number of references to unmap */
uint32_t count;
};

/*
* Sets up an unmap notification within the page, so that the other side can do
* cleanup if this side crashes. Required to implement cross-domain robust
* mutexes or close notification on communication channels.
*
* Each mapped page only supports one notification; multiple calls referring to
* the same page overwrite the previous notification. You must clear the
* notification prior to the IOCTL_GNTALLOC_DEALLOC_GREF if you do not want it
* to occur.
*/
#define IOCTL_GNTALLOC_SET_UNMAP_NOTIFY \
_IOC(_IOC_NONE, 'G', 7, sizeof(struct ioctl_gntalloc_unmap_notify))
struct ioctl_gntalloc_unmap_notify {
/* IN parameters */
/* Offset in the file descriptor for a byte within the page (same as
* used in mmap). If using UNMAP_NOTIFY_CLEAR_BYTE, this is the byte to
* be cleared. Otherwise, it can be any byte in the page whose
* notification we are adjusting.
*/
uint64_t index;
/* Action(s) to take on unmap */
uint32_t action;
/* Event channel to notify */
uint32_t event_channel_port;
};

/* Clear (set to zero) the byte specified by index */
#define UNMAP_NOTIFY_CLEAR_BYTE 0x1
/* Send an interrupt on the indicated event channel */
#define UNMAP_NOTIFY_SEND_EVENT 0x2

#endif /* __LINUX_PUBLIC_GNTALLOC_H__ */