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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/slab.h>
38#include <linux/vmalloc.h>
39#include <linux/uaccess.h>
40#include <linux/io.h>
41
42#include <xen/xen.h>
43#include <xen/interface/xen.h>
44#include <xen/page.h>
45#include <xen/grant_table.h>
46#include <xen/interface/memory.h>
47#include <asm/xen/hypercall.h>
48
49#include <asm/pgtable.h>
50#include <asm/sync_bitops.h>
51
52
53/* External tools reserve first few grant table entries. */
54#define NR_RESERVED_ENTRIES 8
55#define GNTTAB_LIST_END 0xffffffff
56#define GREFS_PER_GRANT_FRAME (PAGE_SIZE / sizeof(struct grant_entry))
57
58static grant_ref_t **gnttab_list;
59static unsigned int nr_grant_frames;
60static unsigned int boot_max_nr_grant_frames;
61static int gnttab_free_count;
62static grant_ref_t gnttab_free_head;
63static DEFINE_SPINLOCK(gnttab_list_lock);
64unsigned long xen_hvm_resume_frames;
65EXPORT_SYMBOL_GPL(xen_hvm_resume_frames);
66
67static struct grant_entry *shared;
68
69static struct gnttab_free_callback *gnttab_free_callback_list;
70
71static int gnttab_expand(unsigned int req_entries);
72
73#define RPP (PAGE_SIZE / sizeof(grant_ref_t))
74
75static inline grant_ref_t *__gnttab_entry(grant_ref_t entry)
76{
77 return &gnttab_list[(entry) / RPP][(entry) % RPP];
78}
79/* This can be used as an l-value */
80#define gnttab_entry(entry) (*__gnttab_entry(entry))
81
82static int get_free_entries(unsigned count)
83{
84 unsigned long flags;
85 int ref, rc = 0;
86 grant_ref_t head;
87
88 spin_lock_irqsave(&gnttab_list_lock, flags);
89
90 if ((gnttab_free_count < count) &&
91 ((rc = gnttab_expand(count - gnttab_free_count)) < 0)) {
92 spin_unlock_irqrestore(&gnttab_list_lock, flags);
93 return rc;
94 }
95
96 ref = head = gnttab_free_head;
97 gnttab_free_count -= count;
98 while (count-- > 1)
99 head = gnttab_entry(head);
100 gnttab_free_head = gnttab_entry(head);
101 gnttab_entry(head) = GNTTAB_LIST_END;
102
103 spin_unlock_irqrestore(&gnttab_list_lock, flags);
104
105 return ref;
106}
107
108static void do_free_callbacks(void)
109{
110 struct gnttab_free_callback *callback, *next;
111
112 callback = gnttab_free_callback_list;
113 gnttab_free_callback_list = NULL;
114
115 while (callback != NULL) {
116 next = callback->next;
117 if (gnttab_free_count >= callback->count) {
118 callback->next = NULL;
119 callback->fn(callback->arg);
120 } else {
121 callback->next = gnttab_free_callback_list;
122 gnttab_free_callback_list = callback;
123 }
124 callback = next;
125 }
126}
127
128static inline void check_free_callbacks(void)
129{
130 if (unlikely(gnttab_free_callback_list))
131 do_free_callbacks();
132}
133
134static void put_free_entry(grant_ref_t ref)
135{
136 unsigned long flags;
137 spin_lock_irqsave(&gnttab_list_lock, flags);
138 gnttab_entry(ref) = gnttab_free_head;
139 gnttab_free_head = ref;
140 gnttab_free_count++;
141 check_free_callbacks();
142 spin_unlock_irqrestore(&gnttab_list_lock, flags);
143}
144
145static void update_grant_entry(grant_ref_t ref, domid_t domid,
146 unsigned long frame, unsigned flags)
147{
148 /*
149 * Introducing a valid entry into the grant table:
150 * 1. Write ent->domid.
151 * 2. Write ent->frame:
152 * GTF_permit_access: Frame to which access is permitted.
153 * GTF_accept_transfer: Pseudo-phys frame slot being filled by new
154 * frame, or zero if none.
155 * 3. Write memory barrier (WMB).
156 * 4. Write ent->flags, inc. valid type.
157 */
158 shared[ref].frame = frame;
159 shared[ref].domid = domid;
160 wmb();
161 shared[ref].flags = flags;
162}
163
164/*
165 * Public grant-issuing interface functions
166 */
167void gnttab_grant_foreign_access_ref(grant_ref_t ref, domid_t domid,
168 unsigned long frame, int readonly)
169{
170 update_grant_entry(ref, domid, frame,
171 GTF_permit_access | (readonly ? GTF_readonly : 0));
172}
173EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access_ref);
174
175int gnttab_grant_foreign_access(domid_t domid, unsigned long frame,
176 int readonly)
177{
178 int ref;
179
180 ref = get_free_entries(1);
181 if (unlikely(ref < 0))
182 return -ENOSPC;
183
184 gnttab_grant_foreign_access_ref(ref, domid, frame, readonly);
185
186 return ref;
187}
188EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access);
189
190int gnttab_query_foreign_access(grant_ref_t ref)
191{
192 u16 nflags;
193
194 nflags = shared[ref].flags;
195
196 return (nflags & (GTF_reading|GTF_writing));
197}
198EXPORT_SYMBOL_GPL(gnttab_query_foreign_access);
199
200int gnttab_end_foreign_access_ref(grant_ref_t ref, int readonly)
201{
202 u16 flags, nflags;
203
204 nflags = shared[ref].flags;
205 do {
206 flags = nflags;
207 if (flags & (GTF_reading|GTF_writing)) {
208 printk(KERN_ALERT "WARNING: g.e. still in use!\n");
209 return 0;
210 }
211 } while ((nflags = sync_cmpxchg(&shared[ref].flags, flags, 0)) != flags);
212
213 return 1;
214}
215EXPORT_SYMBOL_GPL(gnttab_end_foreign_access_ref);
216
217void gnttab_end_foreign_access(grant_ref_t ref, int readonly,
218 unsigned long page)
219{
220 if (gnttab_end_foreign_access_ref(ref, readonly)) {
221 put_free_entry(ref);
222 if (page != 0)
223 free_page(page);
224 } else {
225 /* XXX This needs to be fixed so that the ref and page are
226 placed on a list to be freed up later. */
227 printk(KERN_WARNING
228 "WARNING: leaking g.e. and page still in use!\n");
229 }
230}
231EXPORT_SYMBOL_GPL(gnttab_end_foreign_access);
232
233int gnttab_grant_foreign_transfer(domid_t domid, unsigned long pfn)
234{
235 int ref;
236
237 ref = get_free_entries(1);
238 if (unlikely(ref < 0))
239 return -ENOSPC;
240 gnttab_grant_foreign_transfer_ref(ref, domid, pfn);
241
242 return ref;
243}
244EXPORT_SYMBOL_GPL(gnttab_grant_foreign_transfer);
245
246void gnttab_grant_foreign_transfer_ref(grant_ref_t ref, domid_t domid,
247 unsigned long pfn)
248{
249 update_grant_entry(ref, domid, pfn, GTF_accept_transfer);
250}
251EXPORT_SYMBOL_GPL(gnttab_grant_foreign_transfer_ref);
252
253unsigned long gnttab_end_foreign_transfer_ref(grant_ref_t ref)
254{
255 unsigned long frame;
256 u16 flags;
257
258 /*
259 * If a transfer is not even yet started, try to reclaim the grant
260 * reference and return failure (== 0).
261 */
262 while (!((flags = shared[ref].flags) & GTF_transfer_committed)) {
263 if (sync_cmpxchg(&shared[ref].flags, flags, 0) == flags)
264 return 0;
265 cpu_relax();
266 }
267
268 /* If a transfer is in progress then wait until it is completed. */
269 while (!(flags & GTF_transfer_completed)) {
270 flags = shared[ref].flags;
271 cpu_relax();
272 }
273
274 rmb(); /* Read the frame number /after/ reading completion status. */
275 frame = shared[ref].frame;
276 BUG_ON(frame == 0);
277
278 return frame;
279}
280EXPORT_SYMBOL_GPL(gnttab_end_foreign_transfer_ref);
281
282unsigned long gnttab_end_foreign_transfer(grant_ref_t ref)
283{
284 unsigned long frame = gnttab_end_foreign_transfer_ref(ref);
285 put_free_entry(ref);
286 return frame;
287}
288EXPORT_SYMBOL_GPL(gnttab_end_foreign_transfer);
289
290void gnttab_free_grant_reference(grant_ref_t ref)
291{
292 put_free_entry(ref);
293}
294EXPORT_SYMBOL_GPL(gnttab_free_grant_reference);
295
296void gnttab_free_grant_references(grant_ref_t head)
297{
298 grant_ref_t ref;
299 unsigned long flags;
300 int count = 1;
301 if (head == GNTTAB_LIST_END)
302 return;
303 spin_lock_irqsave(&gnttab_list_lock, flags);
304 ref = head;
305 while (gnttab_entry(ref) != GNTTAB_LIST_END) {
306 ref = gnttab_entry(ref);
307 count++;
308 }
309 gnttab_entry(ref) = gnttab_free_head;
310 gnttab_free_head = head;
311 gnttab_free_count += count;
312 check_free_callbacks();
313 spin_unlock_irqrestore(&gnttab_list_lock, flags);
314}
315EXPORT_SYMBOL_GPL(gnttab_free_grant_references);
316
317int gnttab_alloc_grant_references(u16 count, grant_ref_t *head)
318{
319 int h = get_free_entries(count);
320
321 if (h < 0)
322 return -ENOSPC;
323
324 *head = h;
325
326 return 0;
327}
328EXPORT_SYMBOL_GPL(gnttab_alloc_grant_references);
329
330int gnttab_empty_grant_references(const grant_ref_t *private_head)
331{
332 return (*private_head == GNTTAB_LIST_END);
333}
334EXPORT_SYMBOL_GPL(gnttab_empty_grant_references);
335
336int gnttab_claim_grant_reference(grant_ref_t *private_head)
337{
338 grant_ref_t g = *private_head;
339 if (unlikely(g == GNTTAB_LIST_END))
340 return -ENOSPC;
341 *private_head = gnttab_entry(g);
342 return g;
343}
344EXPORT_SYMBOL_GPL(gnttab_claim_grant_reference);
345
346void gnttab_release_grant_reference(grant_ref_t *private_head,
347 grant_ref_t release)
348{
349 gnttab_entry(release) = *private_head;
350 *private_head = release;
351}
352EXPORT_SYMBOL_GPL(gnttab_release_grant_reference);
353
354void gnttab_request_free_callback(struct gnttab_free_callback *callback,
355 void (*fn)(void *), void *arg, u16 count)
356{
357 unsigned long flags;
358 spin_lock_irqsave(&gnttab_list_lock, flags);
359 if (callback->next)
360 goto out;
361 callback->fn = fn;
362 callback->arg = arg;
363 callback->count = count;
364 callback->next = gnttab_free_callback_list;
365 gnttab_free_callback_list = callback;
366 check_free_callbacks();
367out:
368 spin_unlock_irqrestore(&gnttab_list_lock, flags);
369}
370EXPORT_SYMBOL_GPL(gnttab_request_free_callback);
371
372void gnttab_cancel_free_callback(struct gnttab_free_callback *callback)
373{
374 struct gnttab_free_callback **pcb;
375 unsigned long flags;
376
377 spin_lock_irqsave(&gnttab_list_lock, flags);
378 for (pcb = &gnttab_free_callback_list; *pcb; pcb = &(*pcb)->next) {
379 if (*pcb == callback) {
380 *pcb = callback->next;
381 break;
382 }
383 }
384 spin_unlock_irqrestore(&gnttab_list_lock, flags);
385}
386EXPORT_SYMBOL_GPL(gnttab_cancel_free_callback);
387
388static int grow_gnttab_list(unsigned int more_frames)
389{
390 unsigned int new_nr_grant_frames, extra_entries, i;
391 unsigned int nr_glist_frames, new_nr_glist_frames;
392
393 new_nr_grant_frames = nr_grant_frames + more_frames;
394 extra_entries = more_frames * GREFS_PER_GRANT_FRAME;
395
396 nr_glist_frames = (nr_grant_frames * GREFS_PER_GRANT_FRAME + RPP - 1) / RPP;
397 new_nr_glist_frames =
398 (new_nr_grant_frames * GREFS_PER_GRANT_FRAME + RPP - 1) / RPP;
399 for (i = nr_glist_frames; i < new_nr_glist_frames; i++) {
400 gnttab_list[i] = (grant_ref_t *)__get_free_page(GFP_ATOMIC);
401 if (!gnttab_list[i])
402 goto grow_nomem;
403 }
404
405
406 for (i = GREFS_PER_GRANT_FRAME * nr_grant_frames;
407 i < GREFS_PER_GRANT_FRAME * new_nr_grant_frames - 1; i++)
408 gnttab_entry(i) = i + 1;
409
410 gnttab_entry(i) = gnttab_free_head;
411 gnttab_free_head = GREFS_PER_GRANT_FRAME * nr_grant_frames;
412 gnttab_free_count += extra_entries;
413
414 nr_grant_frames = new_nr_grant_frames;
415
416 check_free_callbacks();
417
418 return 0;
419
420grow_nomem:
421 for ( ; i >= nr_glist_frames; i--)
422 free_page((unsigned long) gnttab_list[i]);
423 return -ENOMEM;
424}
425
426static unsigned int __max_nr_grant_frames(void)
427{
428 struct gnttab_query_size query;
429 int rc;
430
431 query.dom = DOMID_SELF;
432
433 rc = HYPERVISOR_grant_table_op(GNTTABOP_query_size, &query, 1);
434 if ((rc < 0) || (query.status != GNTST_okay))
435 return 4; /* Legacy max supported number of frames */
436
437 return query.max_nr_frames;
438}
439
440unsigned int gnttab_max_grant_frames(void)
441{
442 unsigned int xen_max = __max_nr_grant_frames();
443
444 if (xen_max > boot_max_nr_grant_frames)
445 return boot_max_nr_grant_frames;
446 return xen_max;
447}
448EXPORT_SYMBOL_GPL(gnttab_max_grant_frames);
449
450int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
451 struct page **pages, unsigned int count)
452{
453 int i, ret;
454 pte_t *pte;
455 unsigned long mfn;
456
457 ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, map_ops, count);
458 if (ret)
459 return ret;
460
461 if (xen_feature(XENFEAT_auto_translated_physmap))
462 return ret;
463
464 for (i = 0; i < count; i++) {
465 /* Do not add to override if the map failed. */
466 if (map_ops[i].status)
467 continue;
468
469 if (map_ops[i].flags & GNTMAP_contains_pte) {
470 pte = (pte_t *) (mfn_to_virt(PFN_DOWN(map_ops[i].host_addr)) +
471 (map_ops[i].host_addr & ~PAGE_MASK));
472 mfn = pte_mfn(*pte);
473 } else {
474 /* If you really wanted to do this:
475 * mfn = PFN_DOWN(map_ops[i].dev_bus_addr);
476 *
477 * The reason we do not implement it is b/c on the
478 * unmap path (gnttab_unmap_refs) we have no means of
479 * checking whether the page is !GNTMAP_contains_pte.
480 *
481 * That is without some extra data-structure to carry
482 * the struct page, bool clear_pte, and list_head next
483 * tuples and deal with allocation/delallocation, etc.
484 *
485 * The users of this API set the GNTMAP_contains_pte
486 * flag so lets just return not supported until it
487 * becomes neccessary to implement.
488 */
489 return -EOPNOTSUPP;
490 }
491 ret = m2p_add_override(mfn, pages[i],
492 map_ops[i].flags & GNTMAP_contains_pte);
493 if (ret)
494 return ret;
495 }
496
497 return ret;
498}
499EXPORT_SYMBOL_GPL(gnttab_map_refs);
500
501int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
502 struct page **pages, unsigned int count)
503{
504 int i, ret;
505
506 ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap_ops, count);
507 if (ret)
508 return ret;
509
510 if (xen_feature(XENFEAT_auto_translated_physmap))
511 return ret;
512
513 for (i = 0; i < count; i++) {
514 ret = m2p_remove_override(pages[i], true /* clear the PTE */);
515 if (ret)
516 return ret;
517 }
518
519 return ret;
520}
521EXPORT_SYMBOL_GPL(gnttab_unmap_refs);
522
523static int gnttab_map(unsigned int start_idx, unsigned int end_idx)
524{
525 struct gnttab_setup_table setup;
526 unsigned long *frames;
527 unsigned int nr_gframes = end_idx + 1;
528 int rc;
529
530 if (xen_hvm_domain()) {
531 struct xen_add_to_physmap xatp;
532 unsigned int i = end_idx;
533 rc = 0;
534 /*
535 * Loop backwards, so that the first hypercall has the largest
536 * index, ensuring that the table will grow only once.
537 */
538 do {
539 xatp.domid = DOMID_SELF;
540 xatp.idx = i;
541 xatp.space = XENMAPSPACE_grant_table;
542 xatp.gpfn = (xen_hvm_resume_frames >> PAGE_SHIFT) + i;
543 rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp);
544 if (rc != 0) {
545 printk(KERN_WARNING
546 "grant table add_to_physmap failed, err=%d\n", rc);
547 break;
548 }
549 } while (i-- > start_idx);
550
551 return rc;
552 }
553
554 frames = kmalloc(nr_gframes * sizeof(unsigned long), GFP_ATOMIC);
555 if (!frames)
556 return -ENOMEM;
557
558 setup.dom = DOMID_SELF;
559 setup.nr_frames = nr_gframes;
560 set_xen_guest_handle(setup.frame_list, frames);
561
562 rc = HYPERVISOR_grant_table_op(GNTTABOP_setup_table, &setup, 1);
563 if (rc == -ENOSYS) {
564 kfree(frames);
565 return -ENOSYS;
566 }
567
568 BUG_ON(rc || setup.status);
569
570 rc = arch_gnttab_map_shared(frames, nr_gframes, gnttab_max_grant_frames(),
571 &shared);
572 BUG_ON(rc);
573
574 kfree(frames);
575
576 return 0;
577}
578
579int gnttab_resume(void)
580{
581 unsigned int max_nr_gframes;
582
583 max_nr_gframes = gnttab_max_grant_frames();
584 if (max_nr_gframes < nr_grant_frames)
585 return -ENOSYS;
586
587 if (xen_pv_domain())
588 return gnttab_map(0, nr_grant_frames - 1);
589
590 if (!shared) {
591 shared = ioremap(xen_hvm_resume_frames, PAGE_SIZE * max_nr_gframes);
592 if (shared == NULL) {
593 printk(KERN_WARNING
594 "Failed to ioremap gnttab share frames!");
595 return -ENOMEM;
596 }
597 }
598
599 gnttab_map(0, nr_grant_frames - 1);
600
601 return 0;
602}
603
604int gnttab_suspend(void)
605{
606 arch_gnttab_unmap_shared(shared, nr_grant_frames);
607 return 0;
608}
609
610static int gnttab_expand(unsigned int req_entries)
611{
612 int rc;
613 unsigned int cur, extra;
614
615 cur = nr_grant_frames;
616 extra = ((req_entries + (GREFS_PER_GRANT_FRAME-1)) /
617 GREFS_PER_GRANT_FRAME);
618 if (cur + extra > gnttab_max_grant_frames())
619 return -ENOSPC;
620
621 rc = gnttab_map(cur, cur + extra - 1);
622 if (rc == 0)
623 rc = grow_gnttab_list(extra);
624
625 return rc;
626}
627
628int gnttab_init(void)
629{
630 int i;
631 unsigned int max_nr_glist_frames, nr_glist_frames;
632 unsigned int nr_init_grefs;
633
634 nr_grant_frames = 1;
635 boot_max_nr_grant_frames = __max_nr_grant_frames();
636
637 /* Determine the maximum number of frames required for the
638 * grant reference free list on the current hypervisor.
639 */
640 max_nr_glist_frames = (boot_max_nr_grant_frames *
641 GREFS_PER_GRANT_FRAME / RPP);
642
643 gnttab_list = kmalloc(max_nr_glist_frames * sizeof(grant_ref_t *),
644 GFP_KERNEL);
645 if (gnttab_list == NULL)
646 return -ENOMEM;
647
648 nr_glist_frames = (nr_grant_frames * GREFS_PER_GRANT_FRAME + RPP - 1) / RPP;
649 for (i = 0; i < nr_glist_frames; i++) {
650 gnttab_list[i] = (grant_ref_t *)__get_free_page(GFP_KERNEL);
651 if (gnttab_list[i] == NULL)
652 goto ini_nomem;
653 }
654
655 if (gnttab_resume() < 0)
656 return -ENODEV;
657
658 nr_init_grefs = nr_grant_frames * GREFS_PER_GRANT_FRAME;
659
660 for (i = NR_RESERVED_ENTRIES; i < nr_init_grefs - 1; i++)
661 gnttab_entry(i) = i + 1;
662
663 gnttab_entry(nr_init_grefs - 1) = GNTTAB_LIST_END;
664 gnttab_free_count = nr_init_grefs - NR_RESERVED_ENTRIES;
665 gnttab_free_head = NR_RESERVED_ENTRIES;
666
667 printk("Grant table initialized\n");
668 return 0;
669
670 ini_nomem:
671 for (i--; i >= 0; i--)
672 free_page((unsigned long)gnttab_list[i]);
673 kfree(gnttab_list);
674 return -ENOMEM;
675}
676EXPORT_SYMBOL_GPL(gnttab_init);
677
678static int __devinit __gnttab_init(void)
679{
680 /* Delay grant-table initialization in the PV on HVM case */
681 if (xen_hvm_domain())
682 return 0;
683
684 if (!xen_pv_domain())
685 return -ENODEV;
686
687 return gnttab_init();
688}
689
690core_initcall(__gnttab_init);
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/slab.h>
38#include <linux/vmalloc.h>
39#include <linux/uaccess.h>
40#include <linux/io.h>
41#include <linux/hardirq.h>
42
43#include <xen/xen.h>
44#include <xen/interface/xen.h>
45#include <xen/page.h>
46#include <xen/grant_table.h>
47#include <xen/interface/memory.h>
48#include <xen/hvc-console.h>
49#include <asm/xen/hypercall.h>
50
51#include <asm/pgtable.h>
52#include <asm/sync_bitops.h>
53
54/* External tools reserve first few grant table entries. */
55#define NR_RESERVED_ENTRIES 8
56#define GNTTAB_LIST_END 0xffffffff
57#define GREFS_PER_GRANT_FRAME \
58(grant_table_version == 1 ? \
59(PAGE_SIZE / sizeof(struct grant_entry_v1)) : \
60(PAGE_SIZE / sizeof(union grant_entry_v2)))
61
62static grant_ref_t **gnttab_list;
63static unsigned int nr_grant_frames;
64static unsigned int boot_max_nr_grant_frames;
65static int gnttab_free_count;
66static grant_ref_t gnttab_free_head;
67static DEFINE_SPINLOCK(gnttab_list_lock);
68unsigned long xen_hvm_resume_frames;
69EXPORT_SYMBOL_GPL(xen_hvm_resume_frames);
70
71static union {
72 struct grant_entry_v1 *v1;
73 union grant_entry_v2 *v2;
74 void *addr;
75} gnttab_shared;
76
77/*This is a structure of function pointers for grant table*/
78struct gnttab_ops {
79 /*
80 * Mapping a list of frames for storing grant entries. Frames parameter
81 * is used to store grant table address when grant table being setup,
82 * nr_gframes is the number of frames to map grant table. Returning
83 * GNTST_okay means success and negative value means failure.
84 */
85 int (*map_frames)(unsigned long *frames, unsigned int nr_gframes);
86 /*
87 * Release a list of frames which are mapped in map_frames for grant
88 * entry status.
89 */
90 void (*unmap_frames)(void);
91 /*
92 * Introducing a valid entry into the grant table, granting the frame of
93 * this grant entry to domain for accessing or transfering. Ref
94 * parameter is reference of this introduced grant entry, domid is id of
95 * granted domain, frame is the page frame to be granted, and flags is
96 * status of the grant entry to be updated.
97 */
98 void (*update_entry)(grant_ref_t ref, domid_t domid,
99 unsigned long frame, unsigned flags);
100 /*
101 * Stop granting a grant entry to domain for accessing. Ref parameter is
102 * reference of a grant entry whose grant access will be stopped,
103 * readonly is not in use in this function. If the grant entry is
104 * currently mapped for reading or writing, just return failure(==0)
105 * directly and don't tear down the grant access. Otherwise, stop grant
106 * access for this entry and return success(==1).
107 */
108 int (*end_foreign_access_ref)(grant_ref_t ref, int readonly);
109 /*
110 * Stop granting a grant entry to domain for transfer. Ref parameter is
111 * reference of a grant entry whose grant transfer will be stopped. If
112 * tranfer has not started, just reclaim the grant entry and return
113 * failure(==0). Otherwise, wait for the transfer to complete and then
114 * return the frame.
115 */
116 unsigned long (*end_foreign_transfer_ref)(grant_ref_t ref);
117 /*
118 * Query the status of a grant entry. Ref parameter is reference of
119 * queried grant entry, return value is the status of queried entry.
120 * Detailed status(writing/reading) can be gotten from the return value
121 * by bit operations.
122 */
123 int (*query_foreign_access)(grant_ref_t ref);
124 /*
125 * Grant a domain to access a range of bytes within the page referred by
126 * an available grant entry. Ref parameter is reference of a grant entry
127 * which will be sub-page accessed, domid is id of grantee domain, frame
128 * is frame address of subpage grant, flags is grant type and flag
129 * information, page_off is offset of the range of bytes, and length is
130 * length of bytes to be accessed.
131 */
132 void (*update_subpage_entry)(grant_ref_t ref, domid_t domid,
133 unsigned long frame, int flags,
134 unsigned page_off, unsigned length);
135 /*
136 * Redirect an available grant entry on domain A to another grant
137 * reference of domain B, then allow domain C to use grant reference
138 * of domain B transitively. Ref parameter is an available grant entry
139 * reference on domain A, domid is id of domain C which accesses grant
140 * entry transitively, flags is grant type and flag information,
141 * trans_domid is id of domain B whose grant entry is finally accessed
142 * transitively, trans_gref is grant entry transitive reference of
143 * domain B.
144 */
145 void (*update_trans_entry)(grant_ref_t ref, domid_t domid, int flags,
146 domid_t trans_domid, grant_ref_t trans_gref);
147};
148
149static struct gnttab_ops *gnttab_interface;
150
151/*This reflects status of grant entries, so act as a global value*/
152static grant_status_t *grstatus;
153
154static int grant_table_version;
155
156static struct gnttab_free_callback *gnttab_free_callback_list;
157
158static int gnttab_expand(unsigned int req_entries);
159
160#define RPP (PAGE_SIZE / sizeof(grant_ref_t))
161#define SPP (PAGE_SIZE / sizeof(grant_status_t))
162
163static inline grant_ref_t *__gnttab_entry(grant_ref_t entry)
164{
165 return &gnttab_list[(entry) / RPP][(entry) % RPP];
166}
167/* This can be used as an l-value */
168#define gnttab_entry(entry) (*__gnttab_entry(entry))
169
170static int get_free_entries(unsigned count)
171{
172 unsigned long flags;
173 int ref, rc = 0;
174 grant_ref_t head;
175
176 spin_lock_irqsave(&gnttab_list_lock, flags);
177
178 if ((gnttab_free_count < count) &&
179 ((rc = gnttab_expand(count - gnttab_free_count)) < 0)) {
180 spin_unlock_irqrestore(&gnttab_list_lock, flags);
181 return rc;
182 }
183
184 ref = head = gnttab_free_head;
185 gnttab_free_count -= count;
186 while (count-- > 1)
187 head = gnttab_entry(head);
188 gnttab_free_head = gnttab_entry(head);
189 gnttab_entry(head) = GNTTAB_LIST_END;
190
191 spin_unlock_irqrestore(&gnttab_list_lock, flags);
192
193 return ref;
194}
195
196static void do_free_callbacks(void)
197{
198 struct gnttab_free_callback *callback, *next;
199
200 callback = gnttab_free_callback_list;
201 gnttab_free_callback_list = NULL;
202
203 while (callback != NULL) {
204 next = callback->next;
205 if (gnttab_free_count >= callback->count) {
206 callback->next = NULL;
207 callback->fn(callback->arg);
208 } else {
209 callback->next = gnttab_free_callback_list;
210 gnttab_free_callback_list = callback;
211 }
212 callback = next;
213 }
214}
215
216static inline void check_free_callbacks(void)
217{
218 if (unlikely(gnttab_free_callback_list))
219 do_free_callbacks();
220}
221
222static void put_free_entry(grant_ref_t ref)
223{
224 unsigned long flags;
225 spin_lock_irqsave(&gnttab_list_lock, flags);
226 gnttab_entry(ref) = gnttab_free_head;
227 gnttab_free_head = ref;
228 gnttab_free_count++;
229 check_free_callbacks();
230 spin_unlock_irqrestore(&gnttab_list_lock, flags);
231}
232
233/*
234 * Following applies to gnttab_update_entry_v1 and gnttab_update_entry_v2.
235 * Introducing a valid entry into the grant table:
236 * 1. Write ent->domid.
237 * 2. Write ent->frame:
238 * GTF_permit_access: Frame to which access is permitted.
239 * GTF_accept_transfer: Pseudo-phys frame slot being filled by new
240 * frame, or zero if none.
241 * 3. Write memory barrier (WMB).
242 * 4. Write ent->flags, inc. valid type.
243 */
244static void gnttab_update_entry_v1(grant_ref_t ref, domid_t domid,
245 unsigned long frame, unsigned flags)
246{
247 gnttab_shared.v1[ref].domid = domid;
248 gnttab_shared.v1[ref].frame = frame;
249 wmb();
250 gnttab_shared.v1[ref].flags = flags;
251}
252
253static void gnttab_update_entry_v2(grant_ref_t ref, domid_t domid,
254 unsigned long frame, unsigned flags)
255{
256 gnttab_shared.v2[ref].hdr.domid = domid;
257 gnttab_shared.v2[ref].full_page.frame = frame;
258 wmb();
259 gnttab_shared.v2[ref].hdr.flags = GTF_permit_access | flags;
260}
261
262/*
263 * Public grant-issuing interface functions
264 */
265void gnttab_grant_foreign_access_ref(grant_ref_t ref, domid_t domid,
266 unsigned long frame, int readonly)
267{
268 gnttab_interface->update_entry(ref, domid, frame,
269 GTF_permit_access | (readonly ? GTF_readonly : 0));
270}
271EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access_ref);
272
273int gnttab_grant_foreign_access(domid_t domid, unsigned long frame,
274 int readonly)
275{
276 int ref;
277
278 ref = get_free_entries(1);
279 if (unlikely(ref < 0))
280 return -ENOSPC;
281
282 gnttab_grant_foreign_access_ref(ref, domid, frame, readonly);
283
284 return ref;
285}
286EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access);
287
288void gnttab_update_subpage_entry_v2(grant_ref_t ref, domid_t domid,
289 unsigned long frame, int flags,
290 unsigned page_off,
291 unsigned length)
292{
293 gnttab_shared.v2[ref].sub_page.frame = frame;
294 gnttab_shared.v2[ref].sub_page.page_off = page_off;
295 gnttab_shared.v2[ref].sub_page.length = length;
296 gnttab_shared.v2[ref].hdr.domid = domid;
297 wmb();
298 gnttab_shared.v2[ref].hdr.flags =
299 GTF_permit_access | GTF_sub_page | flags;
300}
301
302int gnttab_grant_foreign_access_subpage_ref(grant_ref_t ref, domid_t domid,
303 unsigned long frame, int flags,
304 unsigned page_off,
305 unsigned length)
306{
307 if (flags & (GTF_accept_transfer | GTF_reading |
308 GTF_writing | GTF_transitive))
309 return -EPERM;
310
311 if (gnttab_interface->update_subpage_entry == NULL)
312 return -ENOSYS;
313
314 gnttab_interface->update_subpage_entry(ref, domid, frame, flags,
315 page_off, length);
316
317 return 0;
318}
319EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access_subpage_ref);
320
321int gnttab_grant_foreign_access_subpage(domid_t domid, unsigned long frame,
322 int flags, unsigned page_off,
323 unsigned length)
324{
325 int ref, rc;
326
327 ref = get_free_entries(1);
328 if (unlikely(ref < 0))
329 return -ENOSPC;
330
331 rc = gnttab_grant_foreign_access_subpage_ref(ref, domid, frame, flags,
332 page_off, length);
333 if (rc < 0) {
334 put_free_entry(ref);
335 return rc;
336 }
337
338 return ref;
339}
340EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access_subpage);
341
342bool gnttab_subpage_grants_available(void)
343{
344 return gnttab_interface->update_subpage_entry != NULL;
345}
346EXPORT_SYMBOL_GPL(gnttab_subpage_grants_available);
347
348void gnttab_update_trans_entry_v2(grant_ref_t ref, domid_t domid,
349 int flags, domid_t trans_domid,
350 grant_ref_t trans_gref)
351{
352 gnttab_shared.v2[ref].transitive.trans_domid = trans_domid;
353 gnttab_shared.v2[ref].transitive.gref = trans_gref;
354 gnttab_shared.v2[ref].hdr.domid = domid;
355 wmb();
356 gnttab_shared.v2[ref].hdr.flags =
357 GTF_permit_access | GTF_transitive | flags;
358}
359
360int gnttab_grant_foreign_access_trans_ref(grant_ref_t ref, domid_t domid,
361 int flags, domid_t trans_domid,
362 grant_ref_t trans_gref)
363{
364 if (flags & (GTF_accept_transfer | GTF_reading |
365 GTF_writing | GTF_sub_page))
366 return -EPERM;
367
368 if (gnttab_interface->update_trans_entry == NULL)
369 return -ENOSYS;
370
371 gnttab_interface->update_trans_entry(ref, domid, flags, trans_domid,
372 trans_gref);
373
374 return 0;
375}
376EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access_trans_ref);
377
378int gnttab_grant_foreign_access_trans(domid_t domid, int flags,
379 domid_t trans_domid,
380 grant_ref_t trans_gref)
381{
382 int ref, rc;
383
384 ref = get_free_entries(1);
385 if (unlikely(ref < 0))
386 return -ENOSPC;
387
388 rc = gnttab_grant_foreign_access_trans_ref(ref, domid, flags,
389 trans_domid, trans_gref);
390 if (rc < 0) {
391 put_free_entry(ref);
392 return rc;
393 }
394
395 return ref;
396}
397EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access_trans);
398
399bool gnttab_trans_grants_available(void)
400{
401 return gnttab_interface->update_trans_entry != NULL;
402}
403EXPORT_SYMBOL_GPL(gnttab_trans_grants_available);
404
405static int gnttab_query_foreign_access_v1(grant_ref_t ref)
406{
407 return gnttab_shared.v1[ref].flags & (GTF_reading|GTF_writing);
408}
409
410static int gnttab_query_foreign_access_v2(grant_ref_t ref)
411{
412 return grstatus[ref] & (GTF_reading|GTF_writing);
413}
414
415int gnttab_query_foreign_access(grant_ref_t ref)
416{
417 return gnttab_interface->query_foreign_access(ref);
418}
419EXPORT_SYMBOL_GPL(gnttab_query_foreign_access);
420
421static int gnttab_end_foreign_access_ref_v1(grant_ref_t ref, int readonly)
422{
423 u16 flags, nflags;
424 u16 *pflags;
425
426 pflags = &gnttab_shared.v1[ref].flags;
427 nflags = *pflags;
428 do {
429 flags = nflags;
430 if (flags & (GTF_reading|GTF_writing))
431 return 0;
432 } while ((nflags = sync_cmpxchg(pflags, flags, 0)) != flags);
433
434 return 1;
435}
436
437static int gnttab_end_foreign_access_ref_v2(grant_ref_t ref, int readonly)
438{
439 gnttab_shared.v2[ref].hdr.flags = 0;
440 mb();
441 if (grstatus[ref] & (GTF_reading|GTF_writing)) {
442 return 0;
443 } else {
444 /* The read of grstatus needs to have acquire
445 semantics. On x86, reads already have
446 that, and we just need to protect against
447 compiler reorderings. On other
448 architectures we may need a full
449 barrier. */
450#ifdef CONFIG_X86
451 barrier();
452#else
453 mb();
454#endif
455 }
456
457 return 1;
458}
459
460static inline int _gnttab_end_foreign_access_ref(grant_ref_t ref, int readonly)
461{
462 return gnttab_interface->end_foreign_access_ref(ref, readonly);
463}
464
465int gnttab_end_foreign_access_ref(grant_ref_t ref, int readonly)
466{
467 if (_gnttab_end_foreign_access_ref(ref, readonly))
468 return 1;
469 pr_warn("WARNING: g.e. %#x still in use!\n", ref);
470 return 0;
471}
472EXPORT_SYMBOL_GPL(gnttab_end_foreign_access_ref);
473
474struct deferred_entry {
475 struct list_head list;
476 grant_ref_t ref;
477 bool ro;
478 uint16_t warn_delay;
479 struct page *page;
480};
481static LIST_HEAD(deferred_list);
482static void gnttab_handle_deferred(unsigned long);
483static DEFINE_TIMER(deferred_timer, gnttab_handle_deferred, 0, 0);
484
485static void gnttab_handle_deferred(unsigned long unused)
486{
487 unsigned int nr = 10;
488 struct deferred_entry *first = NULL;
489 unsigned long flags;
490
491 spin_lock_irqsave(&gnttab_list_lock, flags);
492 while (nr--) {
493 struct deferred_entry *entry
494 = list_first_entry(&deferred_list,
495 struct deferred_entry, list);
496
497 if (entry == first)
498 break;
499 list_del(&entry->list);
500 spin_unlock_irqrestore(&gnttab_list_lock, flags);
501 if (_gnttab_end_foreign_access_ref(entry->ref, entry->ro)) {
502 put_free_entry(entry->ref);
503 if (entry->page) {
504 pr_debug("freeing g.e. %#x (pfn %#lx)\n",
505 entry->ref, page_to_pfn(entry->page));
506 __free_page(entry->page);
507 } else
508 pr_info("freeing g.e. %#x\n", entry->ref);
509 kfree(entry);
510 entry = NULL;
511 } else {
512 if (!--entry->warn_delay)
513 pr_info("g.e. %#x still pending\n",
514 entry->ref);
515 if (!first)
516 first = entry;
517 }
518 spin_lock_irqsave(&gnttab_list_lock, flags);
519 if (entry)
520 list_add_tail(&entry->list, &deferred_list);
521 else if (list_empty(&deferred_list))
522 break;
523 }
524 if (!list_empty(&deferred_list) && !timer_pending(&deferred_timer)) {
525 deferred_timer.expires = jiffies + HZ;
526 add_timer(&deferred_timer);
527 }
528 spin_unlock_irqrestore(&gnttab_list_lock, flags);
529}
530
531static void gnttab_add_deferred(grant_ref_t ref, bool readonly,
532 struct page *page)
533{
534 struct deferred_entry *entry = kmalloc(sizeof(*entry), GFP_ATOMIC);
535 const char *what = KERN_WARNING "leaking";
536
537 if (entry) {
538 unsigned long flags;
539
540 entry->ref = ref;
541 entry->ro = readonly;
542 entry->page = page;
543 entry->warn_delay = 60;
544 spin_lock_irqsave(&gnttab_list_lock, flags);
545 list_add_tail(&entry->list, &deferred_list);
546 if (!timer_pending(&deferred_timer)) {
547 deferred_timer.expires = jiffies + HZ;
548 add_timer(&deferred_timer);
549 }
550 spin_unlock_irqrestore(&gnttab_list_lock, flags);
551 what = KERN_DEBUG "deferring";
552 }
553 printk("%s g.e. %#x (pfn %#lx)\n",
554 what, ref, page ? page_to_pfn(page) : -1);
555}
556
557void gnttab_end_foreign_access(grant_ref_t ref, int readonly,
558 unsigned long page)
559{
560 if (gnttab_end_foreign_access_ref(ref, readonly)) {
561 put_free_entry(ref);
562 if (page != 0)
563 free_page(page);
564 } else
565 gnttab_add_deferred(ref, readonly,
566 page ? virt_to_page(page) : NULL);
567}
568EXPORT_SYMBOL_GPL(gnttab_end_foreign_access);
569
570int gnttab_grant_foreign_transfer(domid_t domid, unsigned long pfn)
571{
572 int ref;
573
574 ref = get_free_entries(1);
575 if (unlikely(ref < 0))
576 return -ENOSPC;
577 gnttab_grant_foreign_transfer_ref(ref, domid, pfn);
578
579 return ref;
580}
581EXPORT_SYMBOL_GPL(gnttab_grant_foreign_transfer);
582
583void gnttab_grant_foreign_transfer_ref(grant_ref_t ref, domid_t domid,
584 unsigned long pfn)
585{
586 gnttab_interface->update_entry(ref, domid, pfn, GTF_accept_transfer);
587}
588EXPORT_SYMBOL_GPL(gnttab_grant_foreign_transfer_ref);
589
590static unsigned long gnttab_end_foreign_transfer_ref_v1(grant_ref_t ref)
591{
592 unsigned long frame;
593 u16 flags;
594 u16 *pflags;
595
596 pflags = &gnttab_shared.v1[ref].flags;
597
598 /*
599 * If a transfer is not even yet started, try to reclaim the grant
600 * reference and return failure (== 0).
601 */
602 while (!((flags = *pflags) & GTF_transfer_committed)) {
603 if (sync_cmpxchg(pflags, flags, 0) == flags)
604 return 0;
605 cpu_relax();
606 }
607
608 /* If a transfer is in progress then wait until it is completed. */
609 while (!(flags & GTF_transfer_completed)) {
610 flags = *pflags;
611 cpu_relax();
612 }
613
614 rmb(); /* Read the frame number /after/ reading completion status. */
615 frame = gnttab_shared.v1[ref].frame;
616 BUG_ON(frame == 0);
617
618 return frame;
619}
620
621static unsigned long gnttab_end_foreign_transfer_ref_v2(grant_ref_t ref)
622{
623 unsigned long frame;
624 u16 flags;
625 u16 *pflags;
626
627 pflags = &gnttab_shared.v2[ref].hdr.flags;
628
629 /*
630 * If a transfer is not even yet started, try to reclaim the grant
631 * reference and return failure (== 0).
632 */
633 while (!((flags = *pflags) & GTF_transfer_committed)) {
634 if (sync_cmpxchg(pflags, flags, 0) == flags)
635 return 0;
636 cpu_relax();
637 }
638
639 /* If a transfer is in progress then wait until it is completed. */
640 while (!(flags & GTF_transfer_completed)) {
641 flags = *pflags;
642 cpu_relax();
643 }
644
645 rmb(); /* Read the frame number /after/ reading completion status. */
646 frame = gnttab_shared.v2[ref].full_page.frame;
647 BUG_ON(frame == 0);
648
649 return frame;
650}
651
652unsigned long gnttab_end_foreign_transfer_ref(grant_ref_t ref)
653{
654 return gnttab_interface->end_foreign_transfer_ref(ref);
655}
656EXPORT_SYMBOL_GPL(gnttab_end_foreign_transfer_ref);
657
658unsigned long gnttab_end_foreign_transfer(grant_ref_t ref)
659{
660 unsigned long frame = gnttab_end_foreign_transfer_ref(ref);
661 put_free_entry(ref);
662 return frame;
663}
664EXPORT_SYMBOL_GPL(gnttab_end_foreign_transfer);
665
666void gnttab_free_grant_reference(grant_ref_t ref)
667{
668 put_free_entry(ref);
669}
670EXPORT_SYMBOL_GPL(gnttab_free_grant_reference);
671
672void gnttab_free_grant_references(grant_ref_t head)
673{
674 grant_ref_t ref;
675 unsigned long flags;
676 int count = 1;
677 if (head == GNTTAB_LIST_END)
678 return;
679 spin_lock_irqsave(&gnttab_list_lock, flags);
680 ref = head;
681 while (gnttab_entry(ref) != GNTTAB_LIST_END) {
682 ref = gnttab_entry(ref);
683 count++;
684 }
685 gnttab_entry(ref) = gnttab_free_head;
686 gnttab_free_head = head;
687 gnttab_free_count += count;
688 check_free_callbacks();
689 spin_unlock_irqrestore(&gnttab_list_lock, flags);
690}
691EXPORT_SYMBOL_GPL(gnttab_free_grant_references);
692
693int gnttab_alloc_grant_references(u16 count, grant_ref_t *head)
694{
695 int h = get_free_entries(count);
696
697 if (h < 0)
698 return -ENOSPC;
699
700 *head = h;
701
702 return 0;
703}
704EXPORT_SYMBOL_GPL(gnttab_alloc_grant_references);
705
706int gnttab_empty_grant_references(const grant_ref_t *private_head)
707{
708 return (*private_head == GNTTAB_LIST_END);
709}
710EXPORT_SYMBOL_GPL(gnttab_empty_grant_references);
711
712int gnttab_claim_grant_reference(grant_ref_t *private_head)
713{
714 grant_ref_t g = *private_head;
715 if (unlikely(g == GNTTAB_LIST_END))
716 return -ENOSPC;
717 *private_head = gnttab_entry(g);
718 return g;
719}
720EXPORT_SYMBOL_GPL(gnttab_claim_grant_reference);
721
722void gnttab_release_grant_reference(grant_ref_t *private_head,
723 grant_ref_t release)
724{
725 gnttab_entry(release) = *private_head;
726 *private_head = release;
727}
728EXPORT_SYMBOL_GPL(gnttab_release_grant_reference);
729
730void gnttab_request_free_callback(struct gnttab_free_callback *callback,
731 void (*fn)(void *), void *arg, u16 count)
732{
733 unsigned long flags;
734 spin_lock_irqsave(&gnttab_list_lock, flags);
735 if (callback->next)
736 goto out;
737 callback->fn = fn;
738 callback->arg = arg;
739 callback->count = count;
740 callback->next = gnttab_free_callback_list;
741 gnttab_free_callback_list = callback;
742 check_free_callbacks();
743out:
744 spin_unlock_irqrestore(&gnttab_list_lock, flags);
745}
746EXPORT_SYMBOL_GPL(gnttab_request_free_callback);
747
748void gnttab_cancel_free_callback(struct gnttab_free_callback *callback)
749{
750 struct gnttab_free_callback **pcb;
751 unsigned long flags;
752
753 spin_lock_irqsave(&gnttab_list_lock, flags);
754 for (pcb = &gnttab_free_callback_list; *pcb; pcb = &(*pcb)->next) {
755 if (*pcb == callback) {
756 *pcb = callback->next;
757 break;
758 }
759 }
760 spin_unlock_irqrestore(&gnttab_list_lock, flags);
761}
762EXPORT_SYMBOL_GPL(gnttab_cancel_free_callback);
763
764static int grow_gnttab_list(unsigned int more_frames)
765{
766 unsigned int new_nr_grant_frames, extra_entries, i;
767 unsigned int nr_glist_frames, new_nr_glist_frames;
768
769 new_nr_grant_frames = nr_grant_frames + more_frames;
770 extra_entries = more_frames * GREFS_PER_GRANT_FRAME;
771
772 nr_glist_frames = (nr_grant_frames * GREFS_PER_GRANT_FRAME + RPP - 1) / RPP;
773 new_nr_glist_frames =
774 (new_nr_grant_frames * GREFS_PER_GRANT_FRAME + RPP - 1) / RPP;
775 for (i = nr_glist_frames; i < new_nr_glist_frames; i++) {
776 gnttab_list[i] = (grant_ref_t *)__get_free_page(GFP_ATOMIC);
777 if (!gnttab_list[i])
778 goto grow_nomem;
779 }
780
781
782 for (i = GREFS_PER_GRANT_FRAME * nr_grant_frames;
783 i < GREFS_PER_GRANT_FRAME * new_nr_grant_frames - 1; i++)
784 gnttab_entry(i) = i + 1;
785
786 gnttab_entry(i) = gnttab_free_head;
787 gnttab_free_head = GREFS_PER_GRANT_FRAME * nr_grant_frames;
788 gnttab_free_count += extra_entries;
789
790 nr_grant_frames = new_nr_grant_frames;
791
792 check_free_callbacks();
793
794 return 0;
795
796grow_nomem:
797 for ( ; i >= nr_glist_frames; i--)
798 free_page((unsigned long) gnttab_list[i]);
799 return -ENOMEM;
800}
801
802static unsigned int __max_nr_grant_frames(void)
803{
804 struct gnttab_query_size query;
805 int rc;
806
807 query.dom = DOMID_SELF;
808
809 rc = HYPERVISOR_grant_table_op(GNTTABOP_query_size, &query, 1);
810 if ((rc < 0) || (query.status != GNTST_okay))
811 return 4; /* Legacy max supported number of frames */
812
813 return query.max_nr_frames;
814}
815
816unsigned int gnttab_max_grant_frames(void)
817{
818 unsigned int xen_max = __max_nr_grant_frames();
819
820 if (xen_max > boot_max_nr_grant_frames)
821 return boot_max_nr_grant_frames;
822 return xen_max;
823}
824EXPORT_SYMBOL_GPL(gnttab_max_grant_frames);
825
826int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
827 struct gnttab_map_grant_ref *kmap_ops,
828 struct page **pages, unsigned int count)
829{
830 int i, ret;
831 bool lazy = false;
832 pte_t *pte;
833 unsigned long mfn;
834
835 ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, map_ops, count);
836 if (ret)
837 return ret;
838
839 if (xen_feature(XENFEAT_auto_translated_physmap))
840 return ret;
841
842 if (!in_interrupt() && paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE) {
843 arch_enter_lazy_mmu_mode();
844 lazy = true;
845 }
846
847 for (i = 0; i < count; i++) {
848 /* Do not add to override if the map failed. */
849 if (map_ops[i].status)
850 continue;
851
852 if (map_ops[i].flags & GNTMAP_contains_pte) {
853 pte = (pte_t *) (mfn_to_virt(PFN_DOWN(map_ops[i].host_addr)) +
854 (map_ops[i].host_addr & ~PAGE_MASK));
855 mfn = pte_mfn(*pte);
856 } else {
857 mfn = PFN_DOWN(map_ops[i].dev_bus_addr);
858 }
859 ret = m2p_add_override(mfn, pages[i], kmap_ops ?
860 &kmap_ops[i] : NULL);
861 if (ret)
862 return ret;
863 }
864
865 if (lazy)
866 arch_leave_lazy_mmu_mode();
867
868 return ret;
869}
870EXPORT_SYMBOL_GPL(gnttab_map_refs);
871
872int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
873 struct gnttab_map_grant_ref *kmap_ops,
874 struct page **pages, unsigned int count)
875{
876 int i, ret;
877 bool lazy = false;
878
879 ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap_ops, count);
880 if (ret)
881 return ret;
882
883 if (xen_feature(XENFEAT_auto_translated_physmap))
884 return ret;
885
886 if (!in_interrupt() && paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE) {
887 arch_enter_lazy_mmu_mode();
888 lazy = true;
889 }
890
891 for (i = 0; i < count; i++) {
892 ret = m2p_remove_override(pages[i], kmap_ops ?
893 &kmap_ops[i] : NULL);
894 if (ret)
895 return ret;
896 }
897
898 if (lazy)
899 arch_leave_lazy_mmu_mode();
900
901 return ret;
902}
903EXPORT_SYMBOL_GPL(gnttab_unmap_refs);
904
905static unsigned nr_status_frames(unsigned nr_grant_frames)
906{
907 return (nr_grant_frames * GREFS_PER_GRANT_FRAME + SPP - 1) / SPP;
908}
909
910static int gnttab_map_frames_v1(unsigned long *frames, unsigned int nr_gframes)
911{
912 int rc;
913
914 rc = arch_gnttab_map_shared(frames, nr_gframes,
915 gnttab_max_grant_frames(),
916 &gnttab_shared.addr);
917 BUG_ON(rc);
918
919 return 0;
920}
921
922static void gnttab_unmap_frames_v1(void)
923{
924 arch_gnttab_unmap(gnttab_shared.addr, nr_grant_frames);
925}
926
927static int gnttab_map_frames_v2(unsigned long *frames, unsigned int nr_gframes)
928{
929 uint64_t *sframes;
930 unsigned int nr_sframes;
931 struct gnttab_get_status_frames getframes;
932 int rc;
933
934 nr_sframes = nr_status_frames(nr_gframes);
935
936 /* No need for kzalloc as it is initialized in following hypercall
937 * GNTTABOP_get_status_frames.
938 */
939 sframes = kmalloc(nr_sframes * sizeof(uint64_t), GFP_ATOMIC);
940 if (!sframes)
941 return -ENOMEM;
942
943 getframes.dom = DOMID_SELF;
944 getframes.nr_frames = nr_sframes;
945 set_xen_guest_handle(getframes.frame_list, sframes);
946
947 rc = HYPERVISOR_grant_table_op(GNTTABOP_get_status_frames,
948 &getframes, 1);
949 if (rc == -ENOSYS) {
950 kfree(sframes);
951 return -ENOSYS;
952 }
953
954 BUG_ON(rc || getframes.status);
955
956 rc = arch_gnttab_map_status(sframes, nr_sframes,
957 nr_status_frames(gnttab_max_grant_frames()),
958 &grstatus);
959 BUG_ON(rc);
960 kfree(sframes);
961
962 rc = arch_gnttab_map_shared(frames, nr_gframes,
963 gnttab_max_grant_frames(),
964 &gnttab_shared.addr);
965 BUG_ON(rc);
966
967 return 0;
968}
969
970static void gnttab_unmap_frames_v2(void)
971{
972 arch_gnttab_unmap(gnttab_shared.addr, nr_grant_frames);
973 arch_gnttab_unmap(grstatus, nr_status_frames(nr_grant_frames));
974}
975
976static int gnttab_map(unsigned int start_idx, unsigned int end_idx)
977{
978 struct gnttab_setup_table setup;
979 unsigned long *frames;
980 unsigned int nr_gframes = end_idx + 1;
981 int rc;
982
983 if (xen_hvm_domain()) {
984 struct xen_add_to_physmap xatp;
985 unsigned int i = end_idx;
986 rc = 0;
987 /*
988 * Loop backwards, so that the first hypercall has the largest
989 * index, ensuring that the table will grow only once.
990 */
991 do {
992 xatp.domid = DOMID_SELF;
993 xatp.idx = i;
994 xatp.space = XENMAPSPACE_grant_table;
995 xatp.gpfn = (xen_hvm_resume_frames >> PAGE_SHIFT) + i;
996 rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp);
997 if (rc != 0) {
998 printk(KERN_WARNING
999 "grant table add_to_physmap failed, err=%d\n", rc);
1000 break;
1001 }
1002 } while (i-- > start_idx);
1003
1004 return rc;
1005 }
1006
1007 /* No need for kzalloc as it is initialized in following hypercall
1008 * GNTTABOP_setup_table.
1009 */
1010 frames = kmalloc(nr_gframes * sizeof(unsigned long), GFP_ATOMIC);
1011 if (!frames)
1012 return -ENOMEM;
1013
1014 setup.dom = DOMID_SELF;
1015 setup.nr_frames = nr_gframes;
1016 set_xen_guest_handle(setup.frame_list, frames);
1017
1018 rc = HYPERVISOR_grant_table_op(GNTTABOP_setup_table, &setup, 1);
1019 if (rc == -ENOSYS) {
1020 kfree(frames);
1021 return -ENOSYS;
1022 }
1023
1024 BUG_ON(rc || setup.status);
1025
1026 rc = gnttab_interface->map_frames(frames, nr_gframes);
1027
1028 kfree(frames);
1029
1030 return rc;
1031}
1032
1033static struct gnttab_ops gnttab_v1_ops = {
1034 .map_frames = gnttab_map_frames_v1,
1035 .unmap_frames = gnttab_unmap_frames_v1,
1036 .update_entry = gnttab_update_entry_v1,
1037 .end_foreign_access_ref = gnttab_end_foreign_access_ref_v1,
1038 .end_foreign_transfer_ref = gnttab_end_foreign_transfer_ref_v1,
1039 .query_foreign_access = gnttab_query_foreign_access_v1,
1040};
1041
1042static struct gnttab_ops gnttab_v2_ops = {
1043 .map_frames = gnttab_map_frames_v2,
1044 .unmap_frames = gnttab_unmap_frames_v2,
1045 .update_entry = gnttab_update_entry_v2,
1046 .end_foreign_access_ref = gnttab_end_foreign_access_ref_v2,
1047 .end_foreign_transfer_ref = gnttab_end_foreign_transfer_ref_v2,
1048 .query_foreign_access = gnttab_query_foreign_access_v2,
1049 .update_subpage_entry = gnttab_update_subpage_entry_v2,
1050 .update_trans_entry = gnttab_update_trans_entry_v2,
1051};
1052
1053static void gnttab_request_version(void)
1054{
1055 int rc;
1056 struct gnttab_set_version gsv;
1057
1058 if (xen_hvm_domain())
1059 gsv.version = 1;
1060 else
1061 gsv.version = 2;
1062 rc = HYPERVISOR_grant_table_op(GNTTABOP_set_version, &gsv, 1);
1063 if (rc == 0 && gsv.version == 2) {
1064 grant_table_version = 2;
1065 gnttab_interface = &gnttab_v2_ops;
1066 } else if (grant_table_version == 2) {
1067 /*
1068 * If we've already used version 2 features,
1069 * but then suddenly discover that they're not
1070 * available (e.g. migrating to an older
1071 * version of Xen), almost unbounded badness
1072 * can happen.
1073 */
1074 panic("we need grant tables version 2, but only version 1 is available");
1075 } else {
1076 grant_table_version = 1;
1077 gnttab_interface = &gnttab_v1_ops;
1078 }
1079 printk(KERN_INFO "Grant tables using version %d layout.\n",
1080 grant_table_version);
1081}
1082
1083int gnttab_resume(void)
1084{
1085 unsigned int max_nr_gframes;
1086
1087 gnttab_request_version();
1088 max_nr_gframes = gnttab_max_grant_frames();
1089 if (max_nr_gframes < nr_grant_frames)
1090 return -ENOSYS;
1091
1092 if (xen_pv_domain())
1093 return gnttab_map(0, nr_grant_frames - 1);
1094
1095 if (gnttab_shared.addr == NULL) {
1096 gnttab_shared.addr = ioremap(xen_hvm_resume_frames,
1097 PAGE_SIZE * max_nr_gframes);
1098 if (gnttab_shared.addr == NULL) {
1099 printk(KERN_WARNING
1100 "Failed to ioremap gnttab share frames!");
1101 return -ENOMEM;
1102 }
1103 }
1104
1105 gnttab_map(0, nr_grant_frames - 1);
1106
1107 return 0;
1108}
1109
1110int gnttab_suspend(void)
1111{
1112 gnttab_interface->unmap_frames();
1113 return 0;
1114}
1115
1116static int gnttab_expand(unsigned int req_entries)
1117{
1118 int rc;
1119 unsigned int cur, extra;
1120
1121 cur = nr_grant_frames;
1122 extra = ((req_entries + (GREFS_PER_GRANT_FRAME-1)) /
1123 GREFS_PER_GRANT_FRAME);
1124 if (cur + extra > gnttab_max_grant_frames())
1125 return -ENOSPC;
1126
1127 rc = gnttab_map(cur, cur + extra - 1);
1128 if (rc == 0)
1129 rc = grow_gnttab_list(extra);
1130
1131 return rc;
1132}
1133
1134int gnttab_init(void)
1135{
1136 int i;
1137 unsigned int max_nr_glist_frames, nr_glist_frames;
1138 unsigned int nr_init_grefs;
1139 int ret;
1140
1141 nr_grant_frames = 1;
1142 boot_max_nr_grant_frames = __max_nr_grant_frames();
1143
1144 /* Determine the maximum number of frames required for the
1145 * grant reference free list on the current hypervisor.
1146 */
1147 max_nr_glist_frames = (boot_max_nr_grant_frames *
1148 GREFS_PER_GRANT_FRAME / RPP);
1149
1150 gnttab_list = kmalloc(max_nr_glist_frames * sizeof(grant_ref_t *),
1151 GFP_KERNEL);
1152 if (gnttab_list == NULL)
1153 return -ENOMEM;
1154
1155 nr_glist_frames = (nr_grant_frames * GREFS_PER_GRANT_FRAME + RPP - 1) / RPP;
1156 for (i = 0; i < nr_glist_frames; i++) {
1157 gnttab_list[i] = (grant_ref_t *)__get_free_page(GFP_KERNEL);
1158 if (gnttab_list[i] == NULL) {
1159 ret = -ENOMEM;
1160 goto ini_nomem;
1161 }
1162 }
1163
1164 if (gnttab_resume() < 0) {
1165 ret = -ENODEV;
1166 goto ini_nomem;
1167 }
1168
1169 nr_init_grefs = nr_grant_frames * GREFS_PER_GRANT_FRAME;
1170
1171 for (i = NR_RESERVED_ENTRIES; i < nr_init_grefs - 1; i++)
1172 gnttab_entry(i) = i + 1;
1173
1174 gnttab_entry(nr_init_grefs - 1) = GNTTAB_LIST_END;
1175 gnttab_free_count = nr_init_grefs - NR_RESERVED_ENTRIES;
1176 gnttab_free_head = NR_RESERVED_ENTRIES;
1177
1178 printk("Grant table initialized\n");
1179 return 0;
1180
1181 ini_nomem:
1182 for (i--; i >= 0; i--)
1183 free_page((unsigned long)gnttab_list[i]);
1184 kfree(gnttab_list);
1185 return ret;
1186}
1187EXPORT_SYMBOL_GPL(gnttab_init);
1188
1189static int __devinit __gnttab_init(void)
1190{
1191 /* Delay grant-table initialization in the PV on HVM case */
1192 if (xen_hvm_domain())
1193 return 0;
1194
1195 if (!xen_pv_domain())
1196 return -ENODEV;
1197
1198 return gnttab_init();
1199}
1200
1201core_initcall(__gnttab_init);