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
40#include <asm/page.h>
41
42#include <xen/interface/xen.h>
43#include <xen/interface/grant_table.h>
44
45#include <asm/xen/hypervisor.h>
46
47#include <xen/features.h>
48#include <xen/page.h>
49#include <linux/mm_types.h>
50#include <linux/page-flags.h>
51#include <linux/kernel.h>
52
53#define GNTTAB_RESERVED_XENSTORE 1
54
55/* NR_GRANT_FRAMES must be less than or equal to that configured in Xen */
56#define NR_GRANT_FRAMES 4
57
58struct gnttab_free_callback {
59	struct gnttab_free_callback *next;
60	void (*fn)(void *);
61	void *arg;
62	u16 count;
63};
64
65struct gntab_unmap_queue_data;
66
67typedef void (*gnttab_unmap_refs_done)(int result, struct gntab_unmap_queue_data *data);
68
69struct gntab_unmap_queue_data
70{
71	struct delayed_work	gnttab_work;
72	void *data;
73	gnttab_unmap_refs_done	done;
74	struct gnttab_unmap_grant_ref *unmap_ops;
75	struct gnttab_unmap_grant_ref *kunmap_ops;
76	struct page **pages;
77	unsigned int count;
78	unsigned int age;
79};
80
81int gnttab_init(void);
82int gnttab_suspend(void);
83int gnttab_resume(void);
84
85int gnttab_grant_foreign_access(domid_t domid, unsigned long frame,
86				int readonly);
87
88/*
89 * End access through the given grant reference, iff the grant entry is no
90 * longer in use.  Return 1 if the grant entry was freed, 0 if it is still in
91 * use.
92 */
93int gnttab_end_foreign_access_ref(grant_ref_t ref, int readonly);
94
95/*
96 * Eventually end access through the given grant reference, and once that
97 * access has been ended, free the given page too.  Access will be ended
98 * immediately iff the grant entry is not in use, otherwise it will happen
99 * some time later.  page may be 0, in which case no freeing will occur.
100 */
101void gnttab_end_foreign_access(grant_ref_t ref, int readonly,
102			       unsigned long page);
103
104int gnttab_grant_foreign_transfer(domid_t domid, unsigned long pfn);
105
106unsigned long gnttab_end_foreign_transfer_ref(grant_ref_t ref);
107unsigned long gnttab_end_foreign_transfer(grant_ref_t ref);
108
109int gnttab_query_foreign_access(grant_ref_t ref);
110
111/*
112 * operations on reserved batches of grant references
113 */
114int gnttab_alloc_grant_references(u16 count, grant_ref_t *pprivate_head);
115
116void gnttab_free_grant_reference(grant_ref_t ref);
117
118void gnttab_free_grant_references(grant_ref_t head);
119
120int gnttab_empty_grant_references(const grant_ref_t *pprivate_head);
121
122int gnttab_claim_grant_reference(grant_ref_t *pprivate_head);
123
124void gnttab_release_grant_reference(grant_ref_t *private_head,
125				    grant_ref_t release);
126
127void gnttab_request_free_callback(struct gnttab_free_callback *callback,
128				  void (*fn)(void *), void *arg, u16 count);
129void gnttab_cancel_free_callback(struct gnttab_free_callback *callback);
130
131void gnttab_grant_foreign_access_ref(grant_ref_t ref, domid_t domid,
132				     unsigned long frame, int readonly);
133
134/* Give access to the first 4K of the page */
135static inline void gnttab_page_grant_foreign_access_ref_one(
136	grant_ref_t ref, domid_t domid,
137	struct page *page, int readonly)
138{
139	gnttab_grant_foreign_access_ref(ref, domid, xen_page_to_gfn(page),
140					readonly);
141}
142
143void gnttab_grant_foreign_transfer_ref(grant_ref_t, domid_t domid,
144				       unsigned long pfn);
145
146static inline void
147gnttab_set_map_op(struct gnttab_map_grant_ref *map, phys_addr_t addr,
148		  uint32_t flags, grant_ref_t ref, domid_t domid)
149{
150	if (flags & GNTMAP_contains_pte)
151		map->host_addr = addr;
152	else if (xen_feature(XENFEAT_auto_translated_physmap))
153		map->host_addr = __pa(addr);
154	else
155		map->host_addr = addr;
156
157	map->flags = flags;
158	map->ref = ref;
159	map->dom = domid;
160}
161
162static inline void
163gnttab_set_unmap_op(struct gnttab_unmap_grant_ref *unmap, phys_addr_t addr,
164		    uint32_t flags, grant_handle_t handle)
165{
166	if (flags & GNTMAP_contains_pte)
167		unmap->host_addr = addr;
168	else if (xen_feature(XENFEAT_auto_translated_physmap))
169		unmap->host_addr = __pa(addr);
170	else
171		unmap->host_addr = addr;
172
173	unmap->handle = handle;
174	unmap->dev_bus_addr = 0;
175}
176
177int arch_gnttab_init(unsigned long nr_shared);
178int arch_gnttab_map_shared(xen_pfn_t *frames, unsigned long nr_gframes,
179			   unsigned long max_nr_gframes,
180			   void **__shared);
181void arch_gnttab_unmap(void *shared, unsigned long nr_gframes);
182
183struct grant_frames {
184	xen_pfn_t *pfn;
185	unsigned int count;
186	void *vaddr;
187};
188extern struct grant_frames xen_auto_xlat_grant_frames;
189unsigned int gnttab_max_grant_frames(void);
190int gnttab_setup_auto_xlat_frames(phys_addr_t addr);
191void gnttab_free_auto_xlat_frames(void);
192
193#define gnttab_map_vaddr(map) ((void *)(map.host_virt_addr))
194
195int gnttab_alloc_pages(int nr_pages, struct page **pages);
196void gnttab_free_pages(int nr_pages, struct page **pages);
197
198int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
199		    struct gnttab_map_grant_ref *kmap_ops,
200		    struct page **pages, unsigned int count);
201int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
202		      struct gnttab_unmap_grant_ref *kunmap_ops,
203		      struct page **pages, unsigned int count);
204void gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item);
205int gnttab_unmap_refs_sync(struct gntab_unmap_queue_data *item);
206
207
208/* Perform a batch of grant map/copy operations. Retry every batch slot
209 * for which the hypervisor returns GNTST_eagain. This is typically due
210 * to paged out target frames.
211 *
212 * Will retry for 1, 2, ... 255 ms, i.e. 256 times during 32 seconds.
213 *
214 * Return value in each iand every status field of the batch guaranteed
215 * to not be GNTST_eagain.
216 */
217void gnttab_batch_map(struct gnttab_map_grant_ref *batch, unsigned count);
218void gnttab_batch_copy(struct gnttab_copy *batch, unsigned count);
219
220
221struct xen_page_foreign {
222	domid_t domid;
223	grant_ref_t gref;
224};
225
226static inline struct xen_page_foreign *xen_page_foreign(struct page *page)
227{
228	if (!PageForeign(page))
229		return NULL;
230#if BITS_PER_LONG < 64
231	return (struct xen_page_foreign *)page->private;
232#else
233	BUILD_BUG_ON(sizeof(struct xen_page_foreign) > BITS_PER_LONG);
234	return (struct xen_page_foreign *)&page->private;
235#endif
236}
237
238/* Split Linux page in chunk of the size of the grant and call fn
239 *
240 * Parameters of fn:
241 *	gfn: guest frame number
242 *	offset: offset in the grant
243 *	len: length of the data in the grant.
244 *	data: internal information
245 */
246typedef void (*xen_grant_fn_t)(unsigned long gfn, unsigned int offset,
247			       unsigned int len, void *data);
248
249void gnttab_foreach_grant_in_range(struct page *page,
250				   unsigned int offset,
251				   unsigned int len,
252				   xen_grant_fn_t fn,
253				   void *data);
254
255/* Helper to get to call fn only on the first "grant chunk" */
256static inline void gnttab_for_one_grant(struct page *page, unsigned int offset,
257					unsigned len, xen_grant_fn_t fn,
258					void *data)
259{
260	/* The first request is limited to the size of one grant */
261	len = min_t(unsigned int, XEN_PAGE_SIZE - (offset & ~XEN_PAGE_MASK),
262		    len);
263
264	gnttab_foreach_grant_in_range(page, offset, len, fn, data);
265}
266
267/* Get @nr_grefs grants from an array of page and call fn for each grant */
268void gnttab_foreach_grant(struct page **pages,
269			  unsigned int nr_grefs,
270			  xen_grant_fn_t fn,
271			  void *data);
272
273/* Get the number of grant in a specified region
274 *
275 * start: Offset from the beginning of the first page
276 * len: total length of data (can cross multiple page)
277 */
278static inline unsigned int gnttab_count_grant(unsigned int start,
279					      unsigned int len)
280{
281	return XEN_PFN_UP(xen_offset_in_page(start) + len);
282}
283
284#endif /* __ASM_GNTTAB_H__ */
285