diff options
Diffstat (limited to 'drivers')
-rw-r--r-- | drivers/Makefile | 2 | ||||
-rw-r--r-- | drivers/xen/Makefile | 1 | ||||
-rw-r--r-- | drivers/xen/grant-table.c | 582 |
3 files changed, 585 insertions, 0 deletions
diff --git a/drivers/Makefile b/drivers/Makefile index 503d82569449..6d9d7fab77f5 100644 --- a/drivers/Makefile +++ b/drivers/Makefile | |||
@@ -15,6 +15,8 @@ obj-$(CONFIG_ACPI) += acpi/ | |||
15 | obj-$(CONFIG_PNP) += pnp/ | 15 | obj-$(CONFIG_PNP) += pnp/ |
16 | obj-$(CONFIG_ARM_AMBA) += amba/ | 16 | obj-$(CONFIG_ARM_AMBA) += amba/ |
17 | 17 | ||
18 | obj-$(CONFIG_XEN) += xen/ | ||
19 | |||
18 | # char/ comes before serial/ etc so that the VT console is the boot-time | 20 | # char/ comes before serial/ etc so that the VT console is the boot-time |
19 | # default. | 21 | # default. |
20 | obj-y += char/ | 22 | obj-y += char/ |
diff --git a/drivers/xen/Makefile b/drivers/xen/Makefile new file mode 100644 index 000000000000..eb42b521eef9 --- /dev/null +++ b/drivers/xen/Makefile | |||
@@ -0,0 +1 @@ | |||
obj-y += grant-table.o | |||
diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c new file mode 100644 index 000000000000..ea94dbabf9a9 --- /dev/null +++ b/drivers/xen/grant-table.c | |||
@@ -0,0 +1,582 @@ | |||
1 | /****************************************************************************** | ||
2 | * grant_table.c | ||
3 | * | ||
4 | * Granting foreign access to our memory reservation. | ||
5 | * | ||
6 | * Copyright (c) 2005-2006, Christopher Clark | ||
7 | * Copyright (c) 2004-2005, K A Fraser | ||
8 | * | ||
9 | * This program is free software; you can redistribute it and/or | ||
10 | * modify it under the terms of the GNU General Public License version 2 | ||
11 | * as published by the Free Software Foundation; or, when distributed | ||
12 | * separately from the Linux kernel or incorporated into other | ||
13 | * software packages, subject to the following license: | ||
14 | * | ||
15 | * Permission is hereby granted, free of charge, to any person obtaining a copy | ||
16 | * of this source file (the "Software"), to deal in the Software without | ||
17 | * restriction, including without limitation the rights to use, copy, modify, | ||
18 | * merge, publish, distribute, sublicense, and/or sell copies of the Software, | ||
19 | * and to permit persons to whom the Software is furnished to do so, subject to | ||
20 | * the following conditions: | ||
21 | * | ||
22 | * The above copyright notice and this permission notice shall be included in | ||
23 | * all copies or substantial portions of the Software. | ||
24 | * | ||
25 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | ||
26 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | ||
27 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE | ||
28 | * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | ||
29 | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING | ||
30 | * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS | ||
31 | * IN THE SOFTWARE. | ||
32 | */ | ||
33 | |||
34 | #include <linux/module.h> | ||
35 | #include <linux/sched.h> | ||
36 | #include <linux/mm.h> | ||
37 | #include <linux/vmalloc.h> | ||
38 | #include <linux/uaccess.h> | ||
39 | |||
40 | #include <xen/interface/xen.h> | ||
41 | #include <xen/page.h> | ||
42 | #include <xen/grant_table.h> | ||
43 | |||
44 | #include <asm/pgtable.h> | ||
45 | #include <asm/sync_bitops.h> | ||
46 | |||
47 | |||
48 | /* External tools reserve first few grant table entries. */ | ||
49 | #define NR_RESERVED_ENTRIES 8 | ||
50 | #define GNTTAB_LIST_END 0xffffffff | ||
51 | #define GREFS_PER_GRANT_FRAME (PAGE_SIZE / sizeof(struct grant_entry)) | ||
52 | |||
53 | static grant_ref_t **gnttab_list; | ||
54 | static unsigned int nr_grant_frames; | ||
55 | static unsigned int boot_max_nr_grant_frames; | ||
56 | static int gnttab_free_count; | ||
57 | static grant_ref_t gnttab_free_head; | ||
58 | static DEFINE_SPINLOCK(gnttab_list_lock); | ||
59 | |||
60 | static struct grant_entry *shared; | ||
61 | |||
62 | static struct gnttab_free_callback *gnttab_free_callback_list; | ||
63 | |||
64 | static int gnttab_expand(unsigned int req_entries); | ||
65 | |||
66 | #define RPP (PAGE_SIZE / sizeof(grant_ref_t)) | ||
67 | |||
68 | static inline grant_ref_t *__gnttab_entry(grant_ref_t entry) | ||
69 | { | ||
70 | return &gnttab_list[(entry) / RPP][(entry) % RPP]; | ||
71 | } | ||
72 | /* This can be used as an l-value */ | ||
73 | #define gnttab_entry(entry) (*__gnttab_entry(entry)) | ||
74 | |||
75 | static int get_free_entries(unsigned count) | ||
76 | { | ||
77 | unsigned long flags; | ||
78 | int ref, rc; | ||
79 | grant_ref_t head; | ||
80 | |||
81 | spin_lock_irqsave(&gnttab_list_lock, flags); | ||
82 | |||
83 | if ((gnttab_free_count < count) && | ||
84 | ((rc = gnttab_expand(count - gnttab_free_count)) < 0)) { | ||
85 | spin_unlock_irqrestore(&gnttab_list_lock, flags); | ||
86 | return rc; | ||
87 | } | ||
88 | |||
89 | ref = head = gnttab_free_head; | ||
90 | gnttab_free_count -= count; | ||
91 | while (count-- > 1) | ||
92 | head = gnttab_entry(head); | ||
93 | gnttab_free_head = gnttab_entry(head); | ||
94 | gnttab_entry(head) = GNTTAB_LIST_END; | ||
95 | |||
96 | spin_unlock_irqrestore(&gnttab_list_lock, flags); | ||
97 | |||
98 | return ref; | ||
99 | } | ||
100 | |||
101 | static void do_free_callbacks(void) | ||
102 | { | ||
103 | struct gnttab_free_callback *callback, *next; | ||
104 | |||
105 | callback = gnttab_free_callback_list; | ||
106 | gnttab_free_callback_list = NULL; | ||
107 | |||
108 | while (callback != NULL) { | ||
109 | next = callback->next; | ||
110 | if (gnttab_free_count >= callback->count) { | ||
111 | callback->next = NULL; | ||
112 | callback->fn(callback->arg); | ||
113 | } else { | ||
114 | callback->next = gnttab_free_callback_list; | ||
115 | gnttab_free_callback_list = callback; | ||
116 | } | ||
117 | callback = next; | ||
118 | } | ||
119 | } | ||
120 | |||
121 | static inline void check_free_callbacks(void) | ||
122 | { | ||
123 | if (unlikely(gnttab_free_callback_list)) | ||
124 | do_free_callbacks(); | ||
125 | } | ||
126 | |||
127 | static void put_free_entry(grant_ref_t ref) | ||
128 | { | ||
129 | unsigned long flags; | ||
130 | spin_lock_irqsave(&gnttab_list_lock, flags); | ||
131 | gnttab_entry(ref) = gnttab_free_head; | ||
132 | gnttab_free_head = ref; | ||
133 | gnttab_free_count++; | ||
134 | check_free_callbacks(); | ||
135 | spin_unlock_irqrestore(&gnttab_list_lock, flags); | ||
136 | } | ||
137 | |||
138 | static void update_grant_entry(grant_ref_t ref, domid_t domid, | ||
139 | unsigned long frame, unsigned flags) | ||
140 | { | ||
141 | /* | ||
142 | * Introducing a valid entry into the grant table: | ||
143 | * 1. Write ent->domid. | ||
144 | * 2. Write ent->frame: | ||
145 | * GTF_permit_access: Frame to which access is permitted. | ||
146 | * GTF_accept_transfer: Pseudo-phys frame slot being filled by new | ||
147 | * frame, or zero if none. | ||
148 | * 3. Write memory barrier (WMB). | ||
149 | * 4. Write ent->flags, inc. valid type. | ||
150 | */ | ||
151 | shared[ref].frame = frame; | ||
152 | shared[ref].domid = domid; | ||
153 | wmb(); | ||
154 | shared[ref].flags = flags; | ||
155 | } | ||
156 | |||
157 | /* | ||
158 | * Public grant-issuing interface functions | ||
159 | */ | ||
160 | void gnttab_grant_foreign_access_ref(grant_ref_t ref, domid_t domid, | ||
161 | unsigned long frame, int readonly) | ||
162 | { | ||
163 | update_grant_entry(ref, domid, frame, | ||
164 | GTF_permit_access | (readonly ? GTF_readonly : 0)); | ||
165 | } | ||
166 | EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access_ref); | ||
167 | |||
168 | int gnttab_grant_foreign_access(domid_t domid, unsigned long frame, | ||
169 | int readonly) | ||
170 | { | ||
171 | int ref; | ||
172 | |||
173 | ref = get_free_entries(1); | ||
174 | if (unlikely(ref < 0)) | ||
175 | return -ENOSPC; | ||
176 | |||
177 | gnttab_grant_foreign_access_ref(ref, domid, frame, readonly); | ||
178 | |||
179 | return ref; | ||
180 | } | ||
181 | EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access); | ||
182 | |||
183 | int gnttab_query_foreign_access(grant_ref_t ref) | ||
184 | { | ||
185 | u16 nflags; | ||
186 | |||
187 | nflags = shared[ref].flags; | ||
188 | |||
189 | return (nflags & (GTF_reading|GTF_writing)); | ||
190 | } | ||
191 | EXPORT_SYMBOL_GPL(gnttab_query_foreign_access); | ||
192 | |||
193 | int gnttab_end_foreign_access_ref(grant_ref_t ref, int readonly) | ||
194 | { | ||
195 | u16 flags, nflags; | ||
196 | |||
197 | nflags = shared[ref].flags; | ||
198 | do { | ||
199 | flags = nflags; | ||
200 | if (flags & (GTF_reading|GTF_writing)) { | ||
201 | printk(KERN_ALERT "WARNING: g.e. still in use!\n"); | ||
202 | return 0; | ||
203 | } | ||
204 | } while ((nflags = sync_cmpxchg(&shared[ref].flags, flags, 0)) != flags); | ||
205 | |||
206 | return 1; | ||
207 | } | ||
208 | EXPORT_SYMBOL_GPL(gnttab_end_foreign_access_ref); | ||
209 | |||
210 | void gnttab_end_foreign_access(grant_ref_t ref, int readonly, | ||
211 | unsigned long page) | ||
212 | { | ||
213 | if (gnttab_end_foreign_access_ref(ref, readonly)) { | ||
214 | put_free_entry(ref); | ||
215 | if (page != 0) | ||
216 | free_page(page); | ||
217 | } else { | ||
218 | /* XXX This needs to be fixed so that the ref and page are | ||
219 | placed on a list to be freed up later. */ | ||
220 | printk(KERN_WARNING | ||
221 | "WARNING: leaking g.e. and page still in use!\n"); | ||
222 | } | ||
223 | } | ||
224 | EXPORT_SYMBOL_GPL(gnttab_end_foreign_access); | ||
225 | |||
226 | int gnttab_grant_foreign_transfer(domid_t domid, unsigned long pfn) | ||
227 | { | ||
228 | int ref; | ||
229 | |||
230 | ref = get_free_entries(1); | ||
231 | if (unlikely(ref < 0)) | ||
232 | return -ENOSPC; | ||
233 | gnttab_grant_foreign_transfer_ref(ref, domid, pfn); | ||
234 | |||
235 | return ref; | ||
236 | } | ||
237 | EXPORT_SYMBOL_GPL(gnttab_grant_foreign_transfer); | ||
238 | |||
239 | void gnttab_grant_foreign_transfer_ref(grant_ref_t ref, domid_t domid, | ||
240 | unsigned long pfn) | ||
241 | { | ||
242 | update_grant_entry(ref, domid, pfn, GTF_accept_transfer); | ||
243 | } | ||
244 | EXPORT_SYMBOL_GPL(gnttab_grant_foreign_transfer_ref); | ||
245 | |||
246 | unsigned long gnttab_end_foreign_transfer_ref(grant_ref_t ref) | ||
247 | { | ||
248 | unsigned long frame; | ||
249 | u16 flags; | ||
250 | |||
251 | /* | ||
252 | * If a transfer is not even yet started, try to reclaim the grant | ||
253 | * reference and return failure (== 0). | ||
254 | */ | ||
255 | while (!((flags = shared[ref].flags) & GTF_transfer_committed)) { | ||
256 | if (sync_cmpxchg(&shared[ref].flags, flags, 0) == flags) | ||
257 | return 0; | ||
258 | cpu_relax(); | ||
259 | } | ||
260 | |||
261 | /* If a transfer is in progress then wait until it is completed. */ | ||
262 | while (!(flags & GTF_transfer_completed)) { | ||
263 | flags = shared[ref].flags; | ||
264 | cpu_relax(); | ||
265 | } | ||
266 | |||
267 | rmb(); /* Read the frame number /after/ reading completion status. */ | ||
268 | frame = shared[ref].frame; | ||
269 | BUG_ON(frame == 0); | ||
270 | |||
271 | return frame; | ||
272 | } | ||
273 | EXPORT_SYMBOL_GPL(gnttab_end_foreign_transfer_ref); | ||
274 | |||
275 | unsigned long gnttab_end_foreign_transfer(grant_ref_t ref) | ||
276 | { | ||
277 | unsigned long frame = gnttab_end_foreign_transfer_ref(ref); | ||
278 | put_free_entry(ref); | ||
279 | return frame; | ||
280 | } | ||
281 | EXPORT_SYMBOL_GPL(gnttab_end_foreign_transfer); | ||
282 | |||
283 | void gnttab_free_grant_reference(grant_ref_t ref) | ||
284 | { | ||
285 | put_free_entry(ref); | ||
286 | } | ||
287 | EXPORT_SYMBOL_GPL(gnttab_free_grant_reference); | ||
288 | |||
289 | void gnttab_free_grant_references(grant_ref_t head) | ||
290 | { | ||
291 | grant_ref_t ref; | ||
292 | unsigned long flags; | ||
293 | int count = 1; | ||
294 | if (head == GNTTAB_LIST_END) | ||
295 | return; | ||
296 | spin_lock_irqsave(&gnttab_list_lock, flags); | ||
297 | ref = head; | ||
298 | while (gnttab_entry(ref) != GNTTAB_LIST_END) { | ||
299 | ref = gnttab_entry(ref); | ||
300 | count++; | ||
301 | } | ||
302 | gnttab_entry(ref) = gnttab_free_head; | ||
303 | gnttab_free_head = head; | ||
304 | gnttab_free_count += count; | ||
305 | check_free_callbacks(); | ||
306 | spin_unlock_irqrestore(&gnttab_list_lock, flags); | ||
307 | } | ||
308 | EXPORT_SYMBOL_GPL(gnttab_free_grant_references); | ||
309 | |||
310 | int gnttab_alloc_grant_references(u16 count, grant_ref_t *head) | ||
311 | { | ||
312 | int h = get_free_entries(count); | ||
313 | |||
314 | if (h < 0) | ||
315 | return -ENOSPC; | ||
316 | |||
317 | *head = h; | ||
318 | |||
319 | return 0; | ||
320 | } | ||
321 | EXPORT_SYMBOL_GPL(gnttab_alloc_grant_references); | ||
322 | |||
323 | int gnttab_empty_grant_references(const grant_ref_t *private_head) | ||
324 | { | ||
325 | return (*private_head == GNTTAB_LIST_END); | ||
326 | } | ||
327 | EXPORT_SYMBOL_GPL(gnttab_empty_grant_references); | ||
328 | |||
329 | int gnttab_claim_grant_reference(grant_ref_t *private_head) | ||
330 | { | ||
331 | grant_ref_t g = *private_head; | ||
332 | if (unlikely(g == GNTTAB_LIST_END)) | ||
333 | return -ENOSPC; | ||
334 | *private_head = gnttab_entry(g); | ||
335 | return g; | ||
336 | } | ||
337 | EXPORT_SYMBOL_GPL(gnttab_claim_grant_reference); | ||
338 | |||
339 | void gnttab_release_grant_reference(grant_ref_t *private_head, | ||
340 | grant_ref_t release) | ||
341 | { | ||
342 | gnttab_entry(release) = *private_head; | ||
343 | *private_head = release; | ||
344 | } | ||
345 | EXPORT_SYMBOL_GPL(gnttab_release_grant_reference); | ||
346 | |||
347 | void gnttab_request_free_callback(struct gnttab_free_callback *callback, | ||
348 | void (*fn)(void *), void *arg, u16 count) | ||
349 | { | ||
350 | unsigned long flags; | ||
351 | spin_lock_irqsave(&gnttab_list_lock, flags); | ||
352 | if (callback->next) | ||
353 | goto out; | ||
354 | callback->fn = fn; | ||
355 | callback->arg = arg; | ||
356 | callback->count = count; | ||
357 | callback->next = gnttab_free_callback_list; | ||
358 | gnttab_free_callback_list = callback; | ||
359 | check_free_callbacks(); | ||
360 | out: | ||
361 | spin_unlock_irqrestore(&gnttab_list_lock, flags); | ||
362 | } | ||
363 | EXPORT_SYMBOL_GPL(gnttab_request_free_callback); | ||
364 | |||
365 | void gnttab_cancel_free_callback(struct gnttab_free_callback *callback) | ||
366 | { | ||
367 | struct gnttab_free_callback **pcb; | ||
368 | unsigned long flags; | ||
369 | |||
370 | spin_lock_irqsave(&gnttab_list_lock, flags); | ||
371 | for (pcb = &gnttab_free_callback_list; *pcb; pcb = &(*pcb)->next) { | ||
372 | if (*pcb == callback) { | ||
373 | *pcb = callback->next; | ||
374 | break; | ||
375 | } | ||
376 | } | ||
377 | spin_unlock_irqrestore(&gnttab_list_lock, flags); | ||
378 | } | ||
379 | EXPORT_SYMBOL_GPL(gnttab_cancel_free_callback); | ||
380 | |||
381 | static int grow_gnttab_list(unsigned int more_frames) | ||
382 | { | ||
383 | unsigned int new_nr_grant_frames, extra_entries, i; | ||
384 | |||
385 | new_nr_grant_frames = nr_grant_frames + more_frames; | ||
386 | extra_entries = more_frames * GREFS_PER_GRANT_FRAME; | ||
387 | |||
388 | for (i = nr_grant_frames; i < new_nr_grant_frames; i++) { | ||
389 | gnttab_list[i] = (grant_ref_t *)__get_free_page(GFP_ATOMIC); | ||
390 | if (!gnttab_list[i]) | ||
391 | goto grow_nomem; | ||
392 | } | ||
393 | |||
394 | |||
395 | for (i = GREFS_PER_GRANT_FRAME * nr_grant_frames; | ||
396 | i < GREFS_PER_GRANT_FRAME * new_nr_grant_frames - 1; i++) | ||
397 | gnttab_entry(i) = i + 1; | ||
398 | |||
399 | gnttab_entry(i) = gnttab_free_head; | ||
400 | gnttab_free_head = GREFS_PER_GRANT_FRAME * nr_grant_frames; | ||
401 | gnttab_free_count += extra_entries; | ||
402 | |||
403 | nr_grant_frames = new_nr_grant_frames; | ||
404 | |||
405 | check_free_callbacks(); | ||
406 | |||
407 | return 0; | ||
408 | |||
409 | grow_nomem: | ||
410 | for ( ; i >= nr_grant_frames; i--) | ||
411 | free_page((unsigned long) gnttab_list[i]); | ||
412 | return -ENOMEM; | ||
413 | } | ||
414 | |||
415 | static unsigned int __max_nr_grant_frames(void) | ||
416 | { | ||
417 | struct gnttab_query_size query; | ||
418 | int rc; | ||
419 | |||
420 | query.dom = DOMID_SELF; | ||
421 | |||
422 | rc = HYPERVISOR_grant_table_op(GNTTABOP_query_size, &query, 1); | ||
423 | if ((rc < 0) || (query.status != GNTST_okay)) | ||
424 | return 4; /* Legacy max supported number of frames */ | ||
425 | |||
426 | return query.max_nr_frames; | ||
427 | } | ||
428 | |||
429 | static inline unsigned int max_nr_grant_frames(void) | ||
430 | { | ||
431 | unsigned int xen_max = __max_nr_grant_frames(); | ||
432 | |||
433 | if (xen_max > boot_max_nr_grant_frames) | ||
434 | return boot_max_nr_grant_frames; | ||
435 | return xen_max; | ||
436 | } | ||
437 | |||
438 | static int map_pte_fn(pte_t *pte, struct page *pmd_page, | ||
439 | unsigned long addr, void *data) | ||
440 | { | ||
441 | unsigned long **frames = (unsigned long **)data; | ||
442 | |||
443 | set_pte_at(&init_mm, addr, pte, mfn_pte((*frames)[0], PAGE_KERNEL)); | ||
444 | (*frames)++; | ||
445 | return 0; | ||
446 | } | ||
447 | |||
448 | static int unmap_pte_fn(pte_t *pte, struct page *pmd_page, | ||
449 | unsigned long addr, void *data) | ||
450 | { | ||
451 | |||
452 | set_pte_at(&init_mm, addr, pte, __pte(0)); | ||
453 | return 0; | ||
454 | } | ||
455 | |||
456 | static int gnttab_map(unsigned int start_idx, unsigned int end_idx) | ||
457 | { | ||
458 | struct gnttab_setup_table setup; | ||
459 | unsigned long *frames; | ||
460 | unsigned int nr_gframes = end_idx + 1; | ||
461 | int rc; | ||
462 | |||
463 | frames = kmalloc(nr_gframes * sizeof(unsigned long), GFP_ATOMIC); | ||
464 | if (!frames) | ||
465 | return -ENOMEM; | ||
466 | |||
467 | setup.dom = DOMID_SELF; | ||
468 | setup.nr_frames = nr_gframes; | ||
469 | setup.frame_list = frames; | ||
470 | |||
471 | rc = HYPERVISOR_grant_table_op(GNTTABOP_setup_table, &setup, 1); | ||
472 | if (rc == -ENOSYS) { | ||
473 | kfree(frames); | ||
474 | return -ENOSYS; | ||
475 | } | ||
476 | |||
477 | BUG_ON(rc || setup.status); | ||
478 | |||
479 | if (shared == NULL) { | ||
480 | struct vm_struct *area; | ||
481 | area = alloc_vm_area(PAGE_SIZE * max_nr_grant_frames()); | ||
482 | BUG_ON(area == NULL); | ||
483 | shared = area->addr; | ||
484 | } | ||
485 | rc = apply_to_page_range(&init_mm, (unsigned long)shared, | ||
486 | PAGE_SIZE * nr_gframes, | ||
487 | map_pte_fn, &frames); | ||
488 | BUG_ON(rc); | ||
489 | frames -= nr_gframes; /* adjust after map_pte_fn() */ | ||
490 | |||
491 | kfree(frames); | ||
492 | |||
493 | return 0; | ||
494 | } | ||
495 | |||
496 | static int gnttab_resume(void) | ||
497 | { | ||
498 | if (max_nr_grant_frames() < nr_grant_frames) | ||
499 | return -ENOSYS; | ||
500 | return gnttab_map(0, nr_grant_frames - 1); | ||
501 | } | ||
502 | |||
503 | static int gnttab_suspend(void) | ||
504 | { | ||
505 | apply_to_page_range(&init_mm, (unsigned long)shared, | ||
506 | PAGE_SIZE * nr_grant_frames, | ||
507 | unmap_pte_fn, NULL); | ||
508 | |||
509 | return 0; | ||
510 | } | ||
511 | |||
512 | static int gnttab_expand(unsigned int req_entries) | ||
513 | { | ||
514 | int rc; | ||
515 | unsigned int cur, extra; | ||
516 | |||
517 | cur = nr_grant_frames; | ||
518 | extra = ((req_entries + (GREFS_PER_GRANT_FRAME-1)) / | ||
519 | GREFS_PER_GRANT_FRAME); | ||
520 | if (cur + extra > max_nr_grant_frames()) | ||
521 | return -ENOSPC; | ||
522 | |||
523 | rc = gnttab_map(cur, cur + extra - 1); | ||
524 | if (rc == 0) | ||
525 | rc = grow_gnttab_list(extra); | ||
526 | |||
527 | return rc; | ||
528 | } | ||
529 | |||
530 | static int __devinit gnttab_init(void) | ||
531 | { | ||
532 | int i; | ||
533 | unsigned int max_nr_glist_frames; | ||
534 | unsigned int nr_init_grefs; | ||
535 | |||
536 | if (!is_running_on_xen()) | ||
537 | return -ENODEV; | ||
538 | |||
539 | nr_grant_frames = 1; | ||
540 | boot_max_nr_grant_frames = __max_nr_grant_frames(); | ||
541 | |||
542 | /* Determine the maximum number of frames required for the | ||
543 | * grant reference free list on the current hypervisor. | ||
544 | */ | ||
545 | max_nr_glist_frames = (boot_max_nr_grant_frames * | ||
546 | GREFS_PER_GRANT_FRAME / | ||
547 | (PAGE_SIZE / sizeof(grant_ref_t))); | ||
548 | |||
549 | gnttab_list = kmalloc(max_nr_glist_frames * sizeof(grant_ref_t *), | ||
550 | GFP_KERNEL); | ||
551 | if (gnttab_list == NULL) | ||
552 | return -ENOMEM; | ||
553 | |||
554 | for (i = 0; i < nr_grant_frames; i++) { | ||
555 | gnttab_list[i] = (grant_ref_t *)__get_free_page(GFP_KERNEL); | ||
556 | if (gnttab_list[i] == NULL) | ||
557 | goto ini_nomem; | ||
558 | } | ||
559 | |||
560 | if (gnttab_resume() < 0) | ||
561 | return -ENODEV; | ||
562 | |||
563 | nr_init_grefs = nr_grant_frames * GREFS_PER_GRANT_FRAME; | ||
564 | |||
565 | for (i = NR_RESERVED_ENTRIES; i < nr_init_grefs - 1; i++) | ||
566 | gnttab_entry(i) = i + 1; | ||
567 | |||
568 | gnttab_entry(nr_init_grefs - 1) = GNTTAB_LIST_END; | ||
569 | gnttab_free_count = nr_init_grefs - NR_RESERVED_ENTRIES; | ||
570 | gnttab_free_head = NR_RESERVED_ENTRIES; | ||
571 | |||
572 | printk("Grant table initialized\n"); | ||
573 | return 0; | ||
574 | |||
575 | ini_nomem: | ||
576 | for (i--; i >= 0; i--) | ||
577 | free_page((unsigned long)gnttab_list[i]); | ||
578 | kfree(gnttab_list); | ||
579 | return -ENOMEM; | ||
580 | } | ||
581 | |||
582 | core_initcall(gnttab_init); | ||