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 /*
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
60 /* NR_GRANT_FRAMES must be less than or equal to that configured in Xen */
61 #define NR_GRANT_FRAMES 4
62
63 struct gnttab_free_callback {
64 struct gnttab_free_callback *next;
65 void (*fn)(void *);
66 void *arg;
67 u16 count;
68 };
69
70 struct gntab_unmap_queue_data;
71
72 typedef void (*gnttab_unmap_refs_done)(int result, struct gntab_unmap_queue_data *data);
73
74 struct gntab_unmap_queue_data
75 {
76 struct delayed_work gnttab_work;
77 void *data;
78 gnttab_unmap_refs_done done;
79 struct gnttab_unmap_grant_ref *unmap_ops;
80 struct gnttab_unmap_grant_ref *kunmap_ops;
81 struct page **pages;
82 unsigned int count;
83 unsigned int age;
84 };
85
86 int gnttab_init(void);
87 int gnttab_suspend(void);
88 int gnttab_resume(void);
89
90 int gnttab_grant_foreign_access(domid_t domid, unsigned long frame,
91 int readonly);
92
93 /*
94 * End access through the given grant reference, iff the grant entry is no
95 * longer in use. Return 1 if the grant entry was freed, 0 if it is still in
96 * use.
97 */
98 int gnttab_end_foreign_access_ref(grant_ref_t ref);
99
100 /*
101 * Eventually end access through the given grant reference, and once that
102 * access has been ended, free the given page too. Access will be ended
103 * immediately iff the grant entry is not in use, otherwise it will happen
104 * some time later. page may be NULL, in which case no freeing will occur.
105 * Note that the granted page might still be accessed (read or write) by the
106 * other side after gnttab_end_foreign_access() returns, so even if page was
107 * specified as NULL it is not allowed to just reuse the page for other
108 * purposes immediately. gnttab_end_foreign_access() will take an additional
109 * reference to the granted page in this case, which is dropped only after
110 * the grant is no longer in use.
111 * This requires that multi page allocations for areas subject to
112 * gnttab_end_foreign_access() are done via alloc_pages_exact() (and freeing
113 * via free_pages_exact()) in order to avoid high order pages.
114 */
115 void gnttab_end_foreign_access(grant_ref_t ref, struct page *page);
116
117 /*
118 * End access through the given grant reference, iff the grant entry is
119 * no longer in use. In case of success ending foreign access, the
120 * grant reference is deallocated.
121 * Return 1 if the grant entry was freed, 0 if it is still in use.
122 */
123 int gnttab_try_end_foreign_access(grant_ref_t ref);
124
125 /*
126 * operations on reserved batches of grant references
127 */
128 int gnttab_alloc_grant_references(u16 count, grant_ref_t *pprivate_head);
129
130 int gnttab_alloc_grant_reference_seq(unsigned int count, grant_ref_t *first);
131
132 void gnttab_free_grant_reference(grant_ref_t ref);
133
134 void gnttab_free_grant_references(grant_ref_t head);
135
136 void gnttab_free_grant_reference_seq(grant_ref_t head, unsigned int count);
137
138 int gnttab_empty_grant_references(const grant_ref_t *pprivate_head);
139
140 int gnttab_claim_grant_reference(grant_ref_t *pprivate_head);
141
142 void gnttab_release_grant_reference(grant_ref_t *private_head,
143 grant_ref_t release);
144
145 void gnttab_request_free_callback(struct gnttab_free_callback *callback,
146 void (*fn)(void *), void *arg, u16 count);
147 void gnttab_cancel_free_callback(struct gnttab_free_callback *callback);
148
149 void gnttab_grant_foreign_access_ref(grant_ref_t ref, domid_t domid,
150 unsigned long frame, int readonly);
151
152 /* Give access to the first 4K of the page */
153 static inline void gnttab_page_grant_foreign_access_ref_one(
154 grant_ref_t ref, domid_t domid,
155 struct page *page, int readonly)
156 {
157 gnttab_grant_foreign_access_ref(ref, domid, xen_page_to_gfn(page),
158 readonly);
159 }
160
161 static inline void
162 gnttab_set_map_op(struct gnttab_map_grant_ref *map, phys_addr_t addr,
163 uint32_t flags, grant_ref_t ref, domid_t domid)
164 {
165 if (flags & GNTMAP_contains_pte)
166 map->host_addr = addr;
167 else if (xen_feature(XENFEAT_auto_translated_physmap))
168 map->host_addr = __pa(addr);
169 else
170 map->host_addr = addr;
171
172 map->flags = flags;
173 map->ref = ref;
174 map->dom = domid;
175 map->status = 1; /* arbitrary positive value */
176 }
177
178 static inline void
179 gnttab_set_unmap_op(struct gnttab_unmap_grant_ref *unmap, phys_addr_t addr,
180 uint32_t flags, grant_handle_t handle)
181 {
182 if (flags & GNTMAP_contains_pte)
183 unmap->host_addr = addr;
184 else if (xen_feature(XENFEAT_auto_translated_physmap))
185 unmap->host_addr = __pa(addr);
186 else
187 unmap->host_addr = addr;
188
189 unmap->handle = handle;
190 unmap->dev_bus_addr = 0;
191 }
192
193 int arch_gnttab_init(unsigned long nr_shared, unsigned long nr_status);
194 int arch_gnttab_map_shared(xen_pfn_t *frames, unsigned long nr_gframes,
195 unsigned long max_nr_gframes,
196 void **__shared);
197 int arch_gnttab_map_status(uint64_t *frames, unsigned long nr_gframes,
198 unsigned long max_nr_gframes,
199 grant_status_t **__shared);
200 void arch_gnttab_unmap(void *shared, unsigned long nr_gframes);
201
202 struct grant_frames {
203 xen_pfn_t *pfn;
204 unsigned int count;
205 void *vaddr;
206 };
207 extern struct grant_frames xen_auto_xlat_grant_frames;
208 unsigned int gnttab_max_grant_frames(void);
209 int gnttab_setup_auto_xlat_frames(phys_addr_t addr);
210 void gnttab_free_auto_xlat_frames(void);
211
212 #define gnttab_map_vaddr(map) ((void *)(map.host_virt_addr))
213
214 int gnttab_alloc_pages(int nr_pages, struct page **pages);
215 void gnttab_free_pages(int nr_pages, struct page **pages);
216
217 struct gnttab_page_cache {
218 spinlock_t lock;
219 #ifdef CONFIG_XEN_UNPOPULATED_ALLOC
220 struct page *pages;
221 #else
222 struct list_head pages;
223 #endif
224 unsigned int num_pages;
225 };
226
227 void gnttab_page_cache_init(struct gnttab_page_cache *cache);
228 int gnttab_page_cache_get(struct gnttab_page_cache *cache, struct page **page);
229 void gnttab_page_cache_put(struct gnttab_page_cache *cache, struct page **page,
230 unsigned int num);
231 void gnttab_page_cache_shrink(struct gnttab_page_cache *cache,
232 unsigned int num);
233
234 #ifdef CONFIG_XEN_GRANT_DMA_ALLOC
235 struct gnttab_dma_alloc_args {
236 /* Device for which DMA memory will be/was allocated. */
237 struct device *dev;
238 /* If set then DMA buffer is coherent and write-combine otherwise. */
239 bool coherent;
240
241 int nr_pages;
242 struct page **pages;
243 xen_pfn_t *frames;
244 void *vaddr;
245 dma_addr_t dev_bus_addr;
246 };
247
248 int gnttab_dma_alloc_pages(struct gnttab_dma_alloc_args *args);
249 int gnttab_dma_free_pages(struct gnttab_dma_alloc_args *args);
250 #endif
251
252 int gnttab_pages_set_private(int nr_pages, struct page **pages);
253 void gnttab_pages_clear_private(int nr_pages, struct page **pages);
254
255 int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
256 struct gnttab_map_grant_ref *kmap_ops,
257 struct page **pages, unsigned int count);
258 int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
259 struct gnttab_unmap_grant_ref *kunmap_ops,
260 struct page **pages, unsigned int count);
261 void gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item);
262 int gnttab_unmap_refs_sync(struct gntab_unmap_queue_data *item);
263
264
265 /* Perform a batch of grant map/copy operations. Retry every batch slot
266 * for which the hypervisor returns GNTST_eagain. This is typically due
267 * to paged out target frames.
268 *
269 * Will retry for 1, 2, ... 255 ms, i.e. 256 times during 32 seconds.
270 *
271 * Return value in each iand every status field of the batch guaranteed
272 * to not be GNTST_eagain.
273 */
274 void gnttab_batch_map(struct gnttab_map_grant_ref *batch, unsigned count);
275 void gnttab_batch_copy(struct gnttab_copy *batch, unsigned count);
276
277
278 struct xen_page_foreign {
279 domid_t domid;
280 grant_ref_t gref;
281 };
282
283 static inline struct xen_page_foreign *xen_page_foreign(struct page *page)
284 {
285 if (!PageForeign(page))
286 return NULL;
287 #if BITS_PER_LONG < 64
288 return (struct xen_page_foreign *)page->private;
289 #else
290 BUILD_BUG_ON(sizeof(struct xen_page_foreign) > BITS_PER_LONG);
291 return (struct xen_page_foreign *)&page->private;
292 #endif
293 }
294
295 /* Split Linux page in chunk of the size of the grant and call fn
296 *
297 * Parameters of fn:
298 * gfn: guest frame number
299 * offset: offset in the grant
300 * len: length of the data in the grant.
301 * data: internal information
302 */
303 typedef void (*xen_grant_fn_t)(unsigned long gfn, unsigned int offset,
304 unsigned int len, void *data);
305
306 void gnttab_foreach_grant_in_range(struct page *page,
307 unsigned int offset,
308 unsigned int len,
309 xen_grant_fn_t fn,
310 void *data);
311
312 /* Helper to get to call fn only on the first "grant chunk" */
313 static inline void gnttab_for_one_grant(struct page *page, unsigned int offset,
314 unsigned len, xen_grant_fn_t fn,
315 void *data)
316 {
317 /* The first request is limited to the size of one grant */
318 len = min_t(unsigned int, XEN_PAGE_SIZE - (offset & ~XEN_PAGE_MASK),
319 len);
320
321 gnttab_foreach_grant_in_range(page, offset, len, fn, data);
322 }
323
324 /* Get @nr_grefs grants from an array of page and call fn for each grant */
325 void gnttab_foreach_grant(struct page **pages,
326 unsigned int nr_grefs,
327 xen_grant_fn_t fn,
328 void *data);
329
330 /* Get the number of grant in a specified region
331 *
332 * start: Offset from the beginning of the first page
333 * len: total length of data (can cross multiple page)
334 */
335 static inline unsigned int gnttab_count_grant(unsigned int start,
336 unsigned int len)
337 {
338 return XEN_PFN_UP(xen_offset_in_page(start) + len);
339 }
340
341 #endif /* __ASM_GNTTAB_H__ */
342
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