88 lines · c
1/******************************************************************************2 * gntalloc.h3 *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 union {35 __u32 gref_ids[1];36 __DECLARE_FLEX_ARRAY(__u32, gref_ids_flex);37 };38};39 40#define GNTALLOC_FLAG_WRITABLE 141 42/*43 * Deallocates the grant reference, allowing the associated page to be freed if44 * no other domains are using it.45 */46#define IOCTL_GNTALLOC_DEALLOC_GREF \47_IOC(_IOC_NONE, 'G', 6, sizeof(struct ioctl_gntalloc_dealloc_gref))48struct ioctl_gntalloc_dealloc_gref {49 /* IN parameters */50 /* The offset returned in the map operation */51 __u64 index;52 /* Number of references to unmap */53 __u32 count;54};55 56/*57 * Sets up an unmap notification within the page, so that the other side can do58 * cleanup if this side crashes. Required to implement cross-domain robust59 * mutexes or close notification on communication channels.60 *61 * Each mapped page only supports one notification; multiple calls referring to62 * the same page overwrite the previous notification. You must clear the63 * notification prior to the IOCTL_GNTALLOC_DEALLOC_GREF if you do not want it64 * to occur.65 */66#define IOCTL_GNTALLOC_SET_UNMAP_NOTIFY \67_IOC(_IOC_NONE, 'G', 7, sizeof(struct ioctl_gntalloc_unmap_notify))68struct ioctl_gntalloc_unmap_notify {69 /* IN parameters */70 /* Offset in the file descriptor for a byte within the page (same as71 * used in mmap). If using UNMAP_NOTIFY_CLEAR_BYTE, this is the byte to72 * be cleared. Otherwise, it can be any byte in the page whose73 * notification we are adjusting.74 */75 __u64 index;76 /* Action(s) to take on unmap */77 __u32 action;78 /* Event channel to notify */79 __u32 event_channel_port;80};81 82/* Clear (set to zero) the byte specified by index */83#define UNMAP_NOTIFY_CLEAR_BYTE 0x184/* Send an interrupt on the indicated event channel */85#define UNMAP_NOTIFY_SEND_EVENT 0x286 87#endif /* __LINUX_PUBLIC_GNTALLOC_H__ */88