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 #define GNTTAB_RESERVED_XENSTORE 1
61
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
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
88 int gnttab_init(void);
89 int gnttab_suspend(void);
90 int gnttab_resume(void);
91
92 int gnttab_grant_foreign_access(domid_t domid, unsigned long frame,
93 int readonly);
94
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 * Note that the granted page might still be accessed (read or write) by the
108 * other side after gnttab_end_foreign_access() returns, so even if page was
109 * specified as 0 it is not allowed to just reuse the page for other
110 * purposes immediately. gnttab_end_foreign_access() will take an additional
111 * reference to the granted page in this case, which is dropped only after
112 * the grant is no longer in use.
113 * This requires that multi page allocations for areas subject to
114 * gnttab_end_foreign_access() are done via alloc_pages_exact() (and freeing
115 * via free_pages_exact()) in order to avoid high order pages.
116 */
117 void gnttab_end_foreign_access(grant_ref_t ref, int readonly,
118 unsigned long page);
119
120 /*
121 * End access through the given grant reference, iff the grant entry is
122 * no longer in use. In case of success ending foreign access, the
123 * grant reference is deallocated.
124 * Return 1 if the grant entry was freed, 0 if it is still in use.
125 */
126 int gnttab_try_end_foreign_access(grant_ref_t ref);
127
128 int gnttab_grant_foreign_transfer(domid_t domid, unsigned long pfn);
129
130 unsigned long gnttab_end_foreign_transfer_ref(grant_ref_t ref);
131 unsigned long gnttab_end_foreign_transfer(grant_ref_t ref);
132
133 /*
134 * operations on reserved batches of grant references
135 */
136 int gnttab_alloc_grant_references(u16 count, grant_ref_t *pprivate_head);
137
138 void gnttab_free_grant_reference(grant_ref_t ref);
139
140 void gnttab_free_grant_references(grant_ref_t head);
141
142 int gnttab_empty_grant_references(const grant_ref_t *pprivate_head);
143
144 int gnttab_claim_grant_reference(grant_ref_t *pprivate_head);
145
146 void gnttab_release_grant_reference(grant_ref_t *private_head,
147 grant_ref_t release);
148
149 void gnttab_request_free_callback(struct gnttab_free_callback *callback,
150 void (*fn)(void *), void *arg, u16 count);
151 void gnttab_cancel_free_callback(struct gnttab_free_callback *callback);
152
153 void gnttab_grant_foreign_access_ref(grant_ref_t ref, domid_t domid,
154 unsigned long frame, int readonly);
155
156 /* Give access to the first 4K of the page */
gnttab_page_grant_foreign_access_ref_one(grant_ref_t ref,domid_t domid,struct page * page,int readonly)157 static inline void gnttab_page_grant_foreign_access_ref_one(
158 grant_ref_t ref, domid_t domid,
159 struct page *page, int readonly)
160 {
161 gnttab_grant_foreign_access_ref(ref, domid, xen_page_to_gfn(page),
162 readonly);
163 }
164
165 void gnttab_grant_foreign_transfer_ref(grant_ref_t, domid_t domid,
166 unsigned long pfn);
167
168 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)169 gnttab_set_map_op(struct gnttab_map_grant_ref *map, phys_addr_t addr,
170 uint32_t flags, grant_ref_t ref, domid_t domid)
171 {
172 if (flags & GNTMAP_contains_pte)
173 map->host_addr = addr;
174 else if (xen_feature(XENFEAT_auto_translated_physmap))
175 map->host_addr = __pa(addr);
176 else
177 map->host_addr = addr;
178
179 map->flags = flags;
180 map->ref = ref;
181 map->dom = domid;
182 map->status = 1; /* arbitrary positive value */
183 }
184
185 static inline void
gnttab_set_unmap_op(struct gnttab_unmap_grant_ref * unmap,phys_addr_t addr,uint32_t flags,grant_handle_t handle)186 gnttab_set_unmap_op(struct gnttab_unmap_grant_ref *unmap, phys_addr_t addr,
187 uint32_t flags, grant_handle_t handle)
188 {
189 if (flags & GNTMAP_contains_pte)
190 unmap->host_addr = addr;
191 else if (xen_feature(XENFEAT_auto_translated_physmap))
192 unmap->host_addr = __pa(addr);
193 else
194 unmap->host_addr = addr;
195
196 unmap->handle = handle;
197 unmap->dev_bus_addr = 0;
198 }
199
200 int arch_gnttab_init(unsigned long nr_shared, unsigned long nr_status);
201 int arch_gnttab_map_shared(xen_pfn_t *frames, unsigned long nr_gframes,
202 unsigned long max_nr_gframes,
203 void **__shared);
204 int arch_gnttab_map_status(uint64_t *frames, unsigned long nr_gframes,
205 unsigned long max_nr_gframes,
206 grant_status_t **__shared);
207 void arch_gnttab_unmap(void *shared, unsigned long nr_gframes);
208
209 struct grant_frames {
210 xen_pfn_t *pfn;
211 unsigned int count;
212 void *vaddr;
213 };
214 extern struct grant_frames xen_auto_xlat_grant_frames;
215 unsigned int gnttab_max_grant_frames(void);
216 int gnttab_setup_auto_xlat_frames(phys_addr_t addr);
217 void gnttab_free_auto_xlat_frames(void);
218
219 #define gnttab_map_vaddr(map) ((void *)(map.host_virt_addr))
220
221 int gnttab_alloc_pages(int nr_pages, struct page **pages);
222 void gnttab_free_pages(int nr_pages, struct page **pages);
223
224 struct gnttab_page_cache {
225 spinlock_t lock;
226 #ifdef CONFIG_XEN_UNPOPULATED_ALLOC
227 struct page *pages;
228 #else
229 struct list_head pages;
230 #endif
231 unsigned int num_pages;
232 };
233
234 void gnttab_page_cache_init(struct gnttab_page_cache *cache);
235 int gnttab_page_cache_get(struct gnttab_page_cache *cache, struct page **page);
236 void gnttab_page_cache_put(struct gnttab_page_cache *cache, struct page **page,
237 unsigned int num);
238 void gnttab_page_cache_shrink(struct gnttab_page_cache *cache,
239 unsigned int num);
240
241 #ifdef CONFIG_XEN_GRANT_DMA_ALLOC
242 struct gnttab_dma_alloc_args {
243 /* Device for which DMA memory will be/was allocated. */
244 struct device *dev;
245 /* If set then DMA buffer is coherent and write-combine otherwise. */
246 bool coherent;
247
248 int nr_pages;
249 struct page **pages;
250 xen_pfn_t *frames;
251 void *vaddr;
252 dma_addr_t dev_bus_addr;
253 };
254
255 int gnttab_dma_alloc_pages(struct gnttab_dma_alloc_args *args);
256 int gnttab_dma_free_pages(struct gnttab_dma_alloc_args *args);
257 #endif
258
259 int gnttab_pages_set_private(int nr_pages, struct page **pages);
260 void gnttab_pages_clear_private(int nr_pages, struct page **pages);
261
262 int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
263 struct gnttab_map_grant_ref *kmap_ops,
264 struct page **pages, unsigned int count);
265 int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
266 struct gnttab_unmap_grant_ref *kunmap_ops,
267 struct page **pages, unsigned int count);
268 void gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item);
269 int gnttab_unmap_refs_sync(struct gntab_unmap_queue_data *item);
270
271
272 /* Perform a batch of grant map/copy operations. Retry every batch slot
273 * for which the hypervisor returns GNTST_eagain. This is typically due
274 * to paged out target frames.
275 *
276 * Will retry for 1, 2, ... 255 ms, i.e. 256 times during 32 seconds.
277 *
278 * Return value in each iand every status field of the batch guaranteed
279 * to not be GNTST_eagain.
280 */
281 void gnttab_batch_map(struct gnttab_map_grant_ref *batch, unsigned count);
282 void gnttab_batch_copy(struct gnttab_copy *batch, unsigned count);
283
284
285 struct xen_page_foreign {
286 domid_t domid;
287 grant_ref_t gref;
288 };
289
xen_page_foreign(struct page * page)290 static inline struct xen_page_foreign *xen_page_foreign(struct page *page)
291 {
292 if (!PageForeign(page))
293 return NULL;
294 #if BITS_PER_LONG < 64
295 return (struct xen_page_foreign *)page->private;
296 #else
297 BUILD_BUG_ON(sizeof(struct xen_page_foreign) > BITS_PER_LONG);
298 return (struct xen_page_foreign *)&page->private;
299 #endif
300 }
301
302 /* Split Linux page in chunk of the size of the grant and call fn
303 *
304 * Parameters of fn:
305 * gfn: guest frame number
306 * offset: offset in the grant
307 * len: length of the data in the grant.
308 * data: internal information
309 */
310 typedef void (*xen_grant_fn_t)(unsigned long gfn, unsigned int offset,
311 unsigned int len, void *data);
312
313 void gnttab_foreach_grant_in_range(struct page *page,
314 unsigned int offset,
315 unsigned int len,
316 xen_grant_fn_t fn,
317 void *data);
318
319 /* Helper to get to call fn only on the first "grant chunk" */
gnttab_for_one_grant(struct page * page,unsigned int offset,unsigned len,xen_grant_fn_t fn,void * data)320 static inline void gnttab_for_one_grant(struct page *page, unsigned int offset,
321 unsigned len, xen_grant_fn_t fn,
322 void *data)
323 {
324 /* The first request is limited to the size of one grant */
325 len = min_t(unsigned int, XEN_PAGE_SIZE - (offset & ~XEN_PAGE_MASK),
326 len);
327
328 gnttab_foreach_grant_in_range(page, offset, len, fn, data);
329 }
330
331 /* Get @nr_grefs grants from an array of page and call fn for each grant */
332 void gnttab_foreach_grant(struct page **pages,
333 unsigned int nr_grefs,
334 xen_grant_fn_t fn,
335 void *data);
336
337 /* Get the number of grant in a specified region
338 *
339 * start: Offset from the beginning of the first page
340 * len: total length of data (can cross multiple page)
341 */
gnttab_count_grant(unsigned int start,unsigned int len)342 static inline unsigned int gnttab_count_grant(unsigned int start,
343 unsigned int len)
344 {
345 return XEN_PFN_UP(xen_offset_in_page(start) + len);
346 }
347
348 #endif /* __ASM_GNTTAB_H__ */
349