[linux-block.git] / include / xen / grant_table.h

/******************************************************************************
 * grant_table.h
 *
 * Two sets of functionality:
 * 1. Granting foreign access to our memory reservation.
 * 2. Accessing others' memory reservations via grant references.
 * (i.e., mechanisms for both sender and recipient of grant references)
 *
 * Copyright (c) 2004-2005, K A Fraser
 * Copyright (c) 2005, Christopher Clark
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License version 2
 * as published by the Free Software Foundation; or, when distributed
 * separately from the Linux kernel or incorporated into other
 * software packages, subject to the following license:
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this source file (the "Software"), to deal in the Software without
 * restriction, including without limitation the rights to use, copy, modify,
 * merge, publish, distribute, sublicense, and/or sell copies of the Software,
 * and to permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 */

#ifndef __ASM_GNTTAB_H__
#define __ASM_GNTTAB_H__

#include <asm/page.h>

#include <xen/interface/xen.h>
#include <xen/interface/grant_table.h>

#include <asm/xen/hypervisor.h>

#include <xen/features.h>
#include <xen/page.h>
#include <linux/mm_types.h>
#include <linux/page-flags.h>
#include <linux/kernel.h>

/*
 * Technically there's no reliably invalid grant reference or grant handle,
 * so pick the value that is the most unlikely one to be observed valid.
 */
#define INVALID_GRANT_REF          ((grant_ref_t)-1)
#define INVALID_GRANT_HANDLE       ((grant_handle_t)-1)

#define GNTTAB_RESERVED_XENSTORE 1

/* NR_GRANT_FRAMES must be less than or equal to that configured in Xen */
#define NR_GRANT_FRAMES 4

struct gnttab_free_callback {
	struct gnttab_free_callback *next;
	void (*fn)(void *);
	void *arg;
	u16 count;
};

struct gntab_unmap_queue_data;

typedef void (*gnttab_unmap_refs_done)(int result, struct gntab_unmap_queue_data *data);

struct gntab_unmap_queue_data
{
	struct delayed_work	gnttab_work;
	void *data;
	gnttab_unmap_refs_done	done;
	struct gnttab_unmap_grant_ref *unmap_ops;
	struct gnttab_unmap_grant_ref *kunmap_ops;
	struct page **pages;
	unsigned int count;
	unsigned int age;
};

int gnttab_init(void);
int gnttab_suspend(void);
int gnttab_resume(void);

int gnttab_grant_foreign_access(domid_t domid, unsigned long frame,
				int readonly);

/*
 * End access through the given grant reference, iff the grant entry is no
 * longer in use.  Return 1 if the grant entry was freed, 0 if it is still in
 * use.
 */
int gnttab_end_foreign_access_ref(grant_ref_t ref, int readonly);

/*
 * Eventually end access through the given grant reference, and once that
 * access has been ended, free the given page too.  Access will be ended
 * immediately iff the grant entry is not in use, otherwise it will happen
 * some time later.  page may be 0, in which case no freeing will occur.
 */
void gnttab_end_foreign_access(grant_ref_t ref, int readonly,
			       unsigned long page);

int gnttab_grant_foreign_transfer(domid_t domid, unsigned long pfn);

unsigned long gnttab_end_foreign_transfer_ref(grant_ref_t ref);
unsigned long gnttab_end_foreign_transfer(grant_ref_t ref);

int gnttab_query_foreign_access(grant_ref_t ref);

/*
 * operations on reserved batches of grant references
 */
int gnttab_alloc_grant_references(u16 count, grant_ref_t *pprivate_head);

void gnttab_free_grant_reference(grant_ref_t ref);

void gnttab_free_grant_references(grant_ref_t head);

int gnttab_empty_grant_references(const grant_ref_t *pprivate_head);

int gnttab_claim_grant_reference(grant_ref_t *pprivate_head);

void gnttab_release_grant_reference(grant_ref_t *private_head,
				    grant_ref_t release);

void gnttab_request_free_callback(struct gnttab_free_callback *callback,
				  void (*fn)(void *), void *arg, u16 count);
void gnttab_cancel_free_callback(struct gnttab_free_callback *callback);

void gnttab_grant_foreign_access_ref(grant_ref_t ref, domid_t domid,
				     unsigned long frame, int readonly);

/* Give access to the first 4K of the page */
static inline void gnttab_page_grant_foreign_access_ref_one(
	grant_ref_t ref, domid_t domid,
	struct page *page, int readonly)
{
	gnttab_grant_foreign_access_ref(ref, domid, xen_page_to_gfn(page),
					readonly);
}

void gnttab_grant_foreign_transfer_ref(grant_ref_t, domid_t domid,
				       unsigned long pfn);

static inline void
gnttab_set_map_op(struct gnttab_map_grant_ref *map, phys_addr_t addr,
		  uint32_t flags, grant_ref_t ref, domid_t domid)
{
	if (flags & GNTMAP_contains_pte)
		map->host_addr = addr;
	else if (xen_feature(XENFEAT_auto_translated_physmap))
		map->host_addr = __pa(addr);
	else
		map->host_addr = addr;

	map->flags = flags;
	map->ref = ref;
	map->dom = domid;
	map->status = 1; /* arbitrary positive value */
}

static inline void
gnttab_set_unmap_op(struct gnttab_unmap_grant_ref *unmap, phys_addr_t addr,
		    uint32_t flags, grant_handle_t handle)
{
	if (flags & GNTMAP_contains_pte)
		unmap->host_addr = addr;
	else if (xen_feature(XENFEAT_auto_translated_physmap))
		unmap->host_addr = __pa(addr);
	else
		unmap->host_addr = addr;

	unmap->handle = handle;
	unmap->dev_bus_addr = 0;
}

int arch_gnttab_init(unsigned long nr_shared, unsigned long nr_status);
int arch_gnttab_map_shared(xen_pfn_t *frames, unsigned long nr_gframes,
			   unsigned long max_nr_gframes,
			   void **__shared);
int arch_gnttab_map_status(uint64_t *frames, unsigned long nr_gframes,
			   unsigned long max_nr_gframes,
			   grant_status_t **__shared);
void arch_gnttab_unmap(void *shared, unsigned long nr_gframes);

struct grant_frames {
	xen_pfn_t *pfn;
	unsigned int count;
	void *vaddr;
};
extern struct grant_frames xen_auto_xlat_grant_frames;
unsigned int gnttab_max_grant_frames(void);
int gnttab_setup_auto_xlat_frames(phys_addr_t addr);
void gnttab_free_auto_xlat_frames(void);

#define gnttab_map_vaddr(map) ((void *)(map.host_virt_addr))

int gnttab_alloc_pages(int nr_pages, struct page **pages);
void gnttab_free_pages(int nr_pages, struct page **pages);

struct gnttab_page_cache {
	spinlock_t		lock;
#ifdef CONFIG_XEN_UNPOPULATED_ALLOC
	struct page		*pages;
#else
	struct list_head	pages;
#endif
	unsigned int		num_pages;
};

void gnttab_page_cache_init(struct gnttab_page_cache *cache);
int gnttab_page_cache_get(struct gnttab_page_cache *cache, struct page **page);
void gnttab_page_cache_put(struct gnttab_page_cache *cache, struct page **page,
			   unsigned int num);
void gnttab_page_cache_shrink(struct gnttab_page_cache *cache,
			      unsigned int num);

#ifdef CONFIG_XEN_GRANT_DMA_ALLOC
struct gnttab_dma_alloc_args {
	/* Device for which DMA memory will be/was allocated. */
	struct device *dev;
	/* If set then DMA buffer is coherent and write-combine otherwise. */
	bool coherent;

	int nr_pages;
	struct page **pages;
	xen_pfn_t *frames;
	void *vaddr;
	dma_addr_t dev_bus_addr;
};

int gnttab_dma_alloc_pages(struct gnttab_dma_alloc_args *args);
int gnttab_dma_free_pages(struct gnttab_dma_alloc_args *args);
#endif

int gnttab_pages_set_private(int nr_pages, struct page **pages);
void gnttab_pages_clear_private(int nr_pages, struct page **pages);

int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
		    struct gnttab_map_grant_ref *kmap_ops,
		    struct page **pages, unsigned int count);
int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
		      struct gnttab_unmap_grant_ref *kunmap_ops,
		      struct page **pages, unsigned int count);
void gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item);
int gnttab_unmap_refs_sync(struct gntab_unmap_queue_data *item);


/* Perform a batch of grant map/copy operations. Retry every batch slot
 * for which the hypervisor returns GNTST_eagain. This is typically due
 * to paged out target frames.
 *
 * Will retry for 1, 2, ... 255 ms, i.e. 256 times during 32 seconds.
 *
 * Return value in each iand every status field of the batch guaranteed
 * to not be GNTST_eagain.
 */
void gnttab_batch_map(struct gnttab_map_grant_ref *batch, unsigned count);
void gnttab_batch_copy(struct gnttab_copy *batch, unsigned count);


struct xen_page_foreign {
	domid_t domid;
	grant_ref_t gref;
};

static inline struct xen_page_foreign *xen_page_foreign(struct page *page)
{
	if (!PageForeign(page))
		return NULL;
#if BITS_PER_LONG < 64
	return (struct xen_page_foreign *)page->private;
#else
	BUILD_BUG_ON(sizeof(struct xen_page_foreign) > BITS_PER_LONG);
	return (struct xen_page_foreign *)&page->private;
#endif
}

/* Split Linux page in chunk of the size of the grant and call fn
 *
 * Parameters of fn:
 *	gfn: guest frame number
 *	offset: offset in the grant
 *	len: length of the data in the grant.
 *	data: internal information
 */
typedef void (*xen_grant_fn_t)(unsigned long gfn, unsigned int offset,
			       unsigned int len, void *data);

void gnttab_foreach_grant_in_range(struct page *page,
				   unsigned int offset,
				   unsigned int len,
				   xen_grant_fn_t fn,
				   void *data);

/* Helper to get to call fn only on the first "grant chunk" */
static inline void gnttab_for_one_grant(struct page *page, unsigned int offset,
					unsigned len, xen_grant_fn_t fn,
					void *data)
{
	/* The first request is limited to the size of one grant */
	len = min_t(unsigned int, XEN_PAGE_SIZE - (offset & ~XEN_PAGE_MASK),
		    len);

	gnttab_foreach_grant_in_range(page, offset, len, fn, data);
}

/* Get @nr_grefs grants from an array of page and call fn for each grant */
void gnttab_foreach_grant(struct page **pages,
			  unsigned int nr_grefs,
			  xen_grant_fn_t fn,
			  void *data);

/* Get the number of grant in a specified region
 *
 * start: Offset from the beginning of the first page
 * len: total length of data (can cross multiple page)
 */
static inline unsigned int gnttab_count_grant(unsigned int start,
					      unsigned int len)
{
	return XEN_PFN_UP(xen_offset_in_page(start) + len);
}

#endif /* __ASM_GNTTAB_H__ */
Commit	Line	Data
ad9a8612 JF	1	/******************************************************************************
	2	* grant_table.h
	3	*
	4	* Two sets of functionality:
	5	* 1. Granting foreign access to our memory reservation.
	6	* 2. Accessing others' memory reservations via grant references.
	7	* (i.e., mechanisms for both sender and recipient of grant references)
	8	*
	9	* Copyright (c) 2004-2005, K A Fraser
	10	* Copyright (c) 2005, Christopher Clark
	11	*
	12	* This program is free software; you can redistribute it and/or
	13	* modify it under the terms of the GNU General Public License version 2
	14	* as published by the Free Software Foundation; or, when distributed
	15	* separately from the Linux kernel or incorporated into other
	16	* software packages, subject to the following license:
	17	*
	18	* Permission is hereby granted, free of charge, to any person obtaining a copy
	19	* of this source file (the "Software"), to deal in the Software without
	20	* restriction, including without limitation the rights to use, copy, modify,
	21	* merge, publish, distribute, sublicense, and/or sell copies of the Software,
	22	* and to permit persons to whom the Software is furnished to do so, subject to
	23	* the following conditions:
	24	*
	25	* The above copyright notice and this permission notice shall be included in
	26	* all copies or substantial portions of the Software.
	27	*
	28	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	29	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	30	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
	31	* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
	32	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
	33	* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
	34	* IN THE SOFTWARE.
	35	*/
	36
	37	#ifndef __ASM_GNTTAB_H__
	38	#define __ASM_GNTTAB_H__
	39
f0774532 IC	40	#include <asm/page.h>
	41
	42	#include <xen/interface/xen.h>
ad9a8612	43	#include <xen/interface/grant_table.h>
f0774532 IC	44
f0774532 IC	45	#include <asm/xen/hypervisor.h>
ad9a8612	46
f0774532	47	#include <xen/features.h>
008c320a	48	#include <xen/page.h>
8da7633f JH	49	#include <linux/mm_types.h>
8da7633f JH	50	#include <linux/page-flags.h>
008c320a	51	#include <linux/kernel.h>
f0774532	52
bce21a2b JB	53	/*
	54	* Technically there's no reliably invalid grant reference or grant handle,
	55	* so pick the value that is the most unlikely one to be observed valid.
	56	*/
	57	#define INVALID_GRANT_REF ((grant_ref_t)-1)
	58	#define INVALID_GRANT_HANDLE ((grant_handle_t)-1)
	59
d2fb4c51 DDG	60	#define GNTTAB_RESERVED_XENSTORE 1
d2fb4c51 DDG	61
ad9a8612 JF	62	/* NR_GRANT_FRAMES must be less than or equal to that configured in Xen */
	63	#define NR_GRANT_FRAMES 4
	64
	65	struct gnttab_free_callback {
	66	struct gnttab_free_callback *next;
	67	void (fn)(void );
	68	void *arg;
	69	u16 count;
	70	};
	71
3f9f1c67 JH	72	struct gntab_unmap_queue_data;
	73
	74	typedef void (gnttab_unmap_refs_done)(int result, struct gntab_unmap_queue_data data);
	75
	76	struct gntab_unmap_queue_data
	77	{
	78	struct delayed_work gnttab_work;
	79	void *data;
	80	gnttab_unmap_refs_done done;
	81	struct gnttab_unmap_grant_ref *unmap_ops;
	82	struct gnttab_unmap_grant_ref *kunmap_ops;
	83	struct page **pages;
	84	unsigned int count;
	85	unsigned int age;
	86	};
	87
183d03cc	88	int gnttab_init(void);
0e91398f JF	89	int gnttab_suspend(void);
	90	int gnttab_resume(void);
	91
ad9a8612 JF	92	int gnttab_grant_foreign_access(domid_t domid, unsigned long frame,
ad9a8612 JF	93	int readonly);
9438ce9d	94
ad9a8612 JF	95	/*
	96	* End access through the given grant reference, iff the grant entry is no
	97	* longer in use. Return 1 if the grant entry was freed, 0 if it is still in
	98	* use.
	99	*/
	100	int gnttab_end_foreign_access_ref(grant_ref_t ref, int readonly);
	101
	102	/*
	103	* Eventually end access through the given grant reference, and once that
	104	* access has been ended, free the given page too. Access will be ended
	105	* immediately iff the grant entry is not in use, otherwise it will happen
	106	* some time later. page may be 0, in which case no freeing will occur.
	107	*/
	108	void gnttab_end_foreign_access(grant_ref_t ref, int readonly,
	109	unsigned long page);
	110
	111	int gnttab_grant_foreign_transfer(domid_t domid, unsigned long pfn);
	112
	113	unsigned long gnttab_end_foreign_transfer_ref(grant_ref_t ref);
	114	unsigned long gnttab_end_foreign_transfer(grant_ref_t ref);
	115
	116	int gnttab_query_foreign_access(grant_ref_t ref);
	117
	118	/*
	119	* operations on reserved batches of grant references
	120	*/
	121	int gnttab_alloc_grant_references(u16 count, grant_ref_t *pprivate_head);
	122
	123	void gnttab_free_grant_reference(grant_ref_t ref);
	124
	125	void gnttab_free_grant_references(grant_ref_t head);
	126
	127	int gnttab_empty_grant_references(const grant_ref_t *pprivate_head);
	128
	129	int gnttab_claim_grant_reference(grant_ref_t *pprivate_head);
	130
	131	void gnttab_release_grant_reference(grant_ref_t *private_head,
	132	grant_ref_t release);
	133
	134	void gnttab_request_free_callback(struct gnttab_free_callback *callback,
	135	void (fn)(void ), void *arg, u16 count);
	136	void gnttab_cancel_free_callback(struct gnttab_free_callback *callback);
	137
	138	void gnttab_grant_foreign_access_ref(grant_ref_t ref, domid_t domid,
	139	unsigned long frame, int readonly);
	140
3922f32c JG	141	/* Give access to the first 4K of the page */
	142	static inline void gnttab_page_grant_foreign_access_ref_one(
	143	grant_ref_t ref, domid_t domid,
	144	struct page *page, int readonly)
	145	{
	146	gnttab_grant_foreign_access_ref(ref, domid, xen_page_to_gfn(page),
	147	readonly);
	148	}
	149
ad9a8612 JF	150	void gnttab_grant_foreign_transfer_ref(grant_ref_t, domid_t domid,
	151	unsigned long pfn);
	152
f0774532 IC	153	static inline void
	154	gnttab_set_map_op(struct gnttab_map_grant_ref *map, phys_addr_t addr,
	155	uint32_t flags, grant_ref_t ref, domid_t domid)
	156	{
	157	if (flags & GNTMAP_contains_pte)
	158	map->host_addr = addr;
	159	else if (xen_feature(XENFEAT_auto_translated_physmap))
	160	map->host_addr = __pa(addr);
	161	else
	162	map->host_addr = addr;
	163
	164	map->flags = flags;
	165	map->ref = ref;
	166	map->dom = domid;
ebee0eab	167	map->status = 1; /* arbitrary positive value */
f0774532 IC	168	}
	169
	170	static inline void
	171	gnttab_set_unmap_op(struct gnttab_unmap_grant_ref *unmap, phys_addr_t addr,
	172	uint32_t flags, grant_handle_t handle)
	173	{
	174	if (flags & GNTMAP_contains_pte)
	175	unmap->host_addr = addr;
	176	else if (xen_feature(XENFEAT_auto_translated_physmap))
	177	unmap->host_addr = __pa(addr);
	178	else
	179	unmap->host_addr = addr;
	180
	181	unmap->handle = handle;
	182	unmap->dev_bus_addr = 0;
	183	}
	184
b988b8ff	185	int arch_gnttab_init(unsigned long nr_shared, unsigned long nr_status);
ef32f892	186	int arch_gnttab_map_shared(xen_pfn_t *frames, unsigned long nr_gframes,
8d3d2106	187	unsigned long max_nr_gframes,
0f9f5a95	188	void **__shared);
b988b8ff JG	189	int arch_gnttab_map_status(uint64_t *frames, unsigned long nr_gframes,
	190	unsigned long max_nr_gframes,
	191	grant_status_t **__shared);
85ff6acb	192	void arch_gnttab_unmap(void *shared, unsigned long nr_gframes);
8d3d2106	193
efaf30a3 KRW	194	struct grant_frames {
	195	xen_pfn_t *pfn;
	196	unsigned int count;
	197	void *vaddr;
	198	};
	199	extern struct grant_frames xen_auto_xlat_grant_frames;
183d03cc	200	unsigned int gnttab_max_grant_frames(void);
47c54205	201	int gnttab_setup_auto_xlat_frames(phys_addr_t addr);
efaf30a3	202	void gnttab_free_auto_xlat_frames(void);
183d03cc	203
ad9a8612 JF	204	#define gnttab_map_vaddr(map) ((void *)(map.host_virt_addr))
ad9a8612 JF	205
ff4b156f DV	206	int gnttab_alloc_pages(int nr_pages, struct page **pages);
	207	void gnttab_free_pages(int nr_pages, struct page **pages);
	208
ca33479c JG	209	struct gnttab_page_cache {
ca33479c JG	210	spinlock_t lock;
ee32f323 JG	211	#ifdef CONFIG_XEN_UNPOPULATED_ALLOC
	212	struct page *pages;
	213	#else
ca33479c	214	struct list_head pages;
ee32f323	215	#endif
ca33479c JG	216	unsigned int num_pages;
	217	};
	218
	219	void gnttab_page_cache_init(struct gnttab_page_cache *cache);
	220	int gnttab_page_cache_get(struct gnttab_page_cache cache, struct page *page);
	221	void gnttab_page_cache_put(struct gnttab_page_cache cache, struct page *page,
	222	unsigned int num);
	223	void gnttab_page_cache_shrink(struct gnttab_page_cache *cache,
	224	unsigned int num);
	225
9bdc7304 OA	226	#ifdef CONFIG_XEN_GRANT_DMA_ALLOC
	227	struct gnttab_dma_alloc_args {
	228	/* Device for which DMA memory will be/was allocated. */
	229	struct device *dev;
	230	/* If set then DMA buffer is coherent and write-combine otherwise. */
	231	bool coherent;
	232
	233	int nr_pages;
	234	struct page **pages;
	235	xen_pfn_t *frames;
	236	void *vaddr;
	237	dma_addr_t dev_bus_addr;
	238	};
	239
	240	int gnttab_dma_alloc_pages(struct gnttab_dma_alloc_args *args);
	241	int gnttab_dma_free_pages(struct gnttab_dma_alloc_args *args);
	242	#endif
	243
8c3799ee OA	244	int gnttab_pages_set_private(int nr_pages, struct page **pages);
	245	void gnttab_pages_clear_private(int nr_pages, struct page **pages);
	246
289b777e	247	int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
e85fc980	248	struct gnttab_map_grant_ref *kmap_ops,
289b777e SS	249	struct page **pages, unsigned int count);
289b777e SS	250	int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
853d0289	251	struct gnttab_unmap_grant_ref *kunmap_ops,
2fc136ee	252	struct page **pages, unsigned int count);
3f9f1c67	253	void gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item);
b44166cd	254	int gnttab_unmap_refs_sync(struct gntab_unmap_queue_data *item);
3f9f1c67	255
289b777e	256
c571898f ALC	257	/* Perform a batch of grant map/copy operations. Retry every batch slot
	258	* for which the hypervisor returns GNTST_eagain. This is typically due
	259	* to paged out target frames.
	260	*
	261	* Will retry for 1, 2, ... 255 ms, i.e. 256 times during 32 seconds.
	262	*
	263	* Return value in each iand every status field of the batch guaranteed
	264	* to not be GNTST_eagain.
	265	*/
	266	void gnttab_batch_map(struct gnttab_map_grant_ref *batch, unsigned count);
	267	void gnttab_batch_copy(struct gnttab_copy *batch, unsigned count);
	268
8da7633f JH	269
	270	struct xen_page_foreign {
	271	domid_t domid;
	272	grant_ref_t gref;
	273	};
	274
	275	static inline struct xen_page_foreign xen_page_foreign(struct page page)
	276	{
	277	if (!PageForeign(page))
	278	return NULL;
	279	#if BITS_PER_LONG < 64
	280	return (struct xen_page_foreign *)page->private;
	281	#else
	282	BUILD_BUG_ON(sizeof(struct xen_page_foreign) > BITS_PER_LONG);
	283	return (struct xen_page_foreign *)&page->private;
	284	#endif
	285	}
	286
008c320a JG	287	/* Split Linux page in chunk of the size of the grant and call fn
	288	*
	289	* Parameters of fn:
	290	* gfn: guest frame number
	291	* offset: offset in the grant
	292	* len: length of the data in the grant.
	293	* data: internal information
	294	*/
	295	typedef void (*xen_grant_fn_t)(unsigned long gfn, unsigned int offset,
	296	unsigned int len, void *data);
	297
	298	void gnttab_foreach_grant_in_range(struct page *page,
	299	unsigned int offset,
	300	unsigned int len,
	301	xen_grant_fn_t fn,
	302	void *data);
	303
	304	/* Helper to get to call fn only on the first "grant chunk" */
	305	static inline void gnttab_for_one_grant(struct page *page, unsigned int offset,
	306	unsigned len, xen_grant_fn_t fn,
	307	void *data)
	308	{
	309	/* The first request is limited to the size of one grant */
	310	len = min_t(unsigned int, XEN_PAGE_SIZE - (offset & ~XEN_PAGE_MASK),
	311	len);
	312
	313	gnttab_foreach_grant_in_range(page, offset, len, fn, data);
	314	}
	315
f73314b2 JG	316	/* Get @nr_grefs grants from an array of page and call fn for each grant */
	317	void gnttab_foreach_grant(struct page **pages,
	318	unsigned int nr_grefs,
	319	xen_grant_fn_t fn,
	320	void *data);
	321
008c320a JG	322	/* Get the number of grant in a specified region
	323	*
	324	* start: Offset from the beginning of the first page
	325	* len: total length of data (can cross multiple page)
	326	*/
	327	static inline unsigned int gnttab_count_grant(unsigned int start,
	328	unsigned int len)
	329	{
	330	return XEN_PFN_UP(xen_offset_in_page(start) + len);
	331	}
	332
ad9a8612	333	#endif /* __ASM_GNTTAB_H__ */