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/****************************************************************************** 
 * gntalloc.h 
 * 
 * Interface to /dev/xen/gntalloc. 
 * 
 * Author: Daniel De Graaf <dgdegra@tycho.nsa.gov> 
 * 
 * This file is in the public domain. 
 */ 
 
#ifndef __LINUX_PUBLIC_GNTALLOC_H__ 
#define __LINUX_PUBLIC_GNTALLOC_H__ 
 
#include <linux/types.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. */ 
	__u16 domid; 
	/* Flags for this mapping */ 
	__u16 flags; 
	/* Number of pages to map */ 
	__u32 count; 
	/* OUT parameters */ 
	/* The offset to be used on a subsequent call to mmap(). */ 
	__u64 index; 
	/* The grant references of the newly created grant, one per page */ 
	/* Variable size, depending on count */ 
	__u32 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 */ 
	__u64 index; 
	/* Number of references to unmap */ 
	__u32 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. 
	 */ 
	__u64 index; 
	/* Action(s) to take on unmap */ 
	__u32 action; 
	/* Event channel to notify */ 
	__u32 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__ */