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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#define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt
35
36#include <linux/memblock.h>
37#include <linux/sched.h>
38#include <linux/mm.h>
39#include <linux/slab.h>
40#include <linux/vmalloc.h>
41#include <linux/uaccess.h>
42#include <linux/io.h>
43#include <linux/delay.h>
44#include <linux/hardirq.h>
45#include <linux/workqueue.h>
46#include <linux/ratelimit.h>
47#include <linux/moduleparam.h>
48#ifdef CONFIG_XEN_GRANT_DMA_ALLOC
49#include <linux/dma-mapping.h>
50#endif
51
52#include <xen/xen.h>
53#include <xen/interface/xen.h>
54#include <xen/page.h>
55#include <xen/grant_table.h>
56#include <xen/interface/memory.h>
57#include <xen/hvc-console.h>
58#include <xen/swiotlb-xen.h>
59#include <xen/balloon.h>
60#ifdef CONFIG_X86
61#include <asm/xen/cpuid.h>
62#endif
63#include <xen/mem-reservation.h>
64#include <asm/xen/hypercall.h>
65#include <asm/xen/interface.h>
66
67#include <asm/sync_bitops.h>
68
69/* External tools reserve first few grant table entries. */
70#define NR_RESERVED_ENTRIES 8
71#define GNTTAB_LIST_END 0xffffffff
72
73static grant_ref_t **gnttab_list;
74static unsigned int nr_grant_frames;
75static int gnttab_free_count;
76static grant_ref_t gnttab_free_head;
77static DEFINE_SPINLOCK(gnttab_list_lock);
78struct grant_frames xen_auto_xlat_grant_frames;
79static unsigned int xen_gnttab_version;
80module_param_named(version, xen_gnttab_version, uint, 0);
81
82static union {
83 struct grant_entry_v1 *v1;
84 union grant_entry_v2 *v2;
85 void *addr;
86} gnttab_shared;
87
88/*This is a structure of function pointers for grant table*/
89struct gnttab_ops {
90 /*
91 * Version of the grant interface.
92 */
93 unsigned int version;
94 /*
95 * Grant refs per grant frame.
96 */
97 unsigned int grefs_per_grant_frame;
98 /*
99 * Mapping a list of frames for storing grant entries. Frames parameter
100 * is used to store grant table address when grant table being setup,
101 * nr_gframes is the number of frames to map grant table. Returning
102 * GNTST_okay means success and negative value means failure.
103 */
104 int (*map_frames)(xen_pfn_t *frames, unsigned int nr_gframes);
105 /*
106 * Release a list of frames which are mapped in map_frames for grant
107 * entry status.
108 */
109 void (*unmap_frames)(void);
110 /*
111 * Introducing a valid entry into the grant table, granting the frame of
112 * this grant entry to domain for accessing or transfering. Ref
113 * parameter is reference of this introduced grant entry, domid is id of
114 * granted domain, frame is the page frame to be granted, and flags is
115 * status of the grant entry to be updated.
116 */
117 void (*update_entry)(grant_ref_t ref, domid_t domid,
118 unsigned long frame, unsigned flags);
119 /*
120 * Stop granting a grant entry to domain for accessing. Ref parameter is
121 * reference of a grant entry whose grant access will be stopped,
122 * readonly is not in use in this function. If the grant entry is
123 * currently mapped for reading or writing, just return failure(==0)
124 * directly and don't tear down the grant access. Otherwise, stop grant
125 * access for this entry and return success(==1).
126 */
127 int (*end_foreign_access_ref)(grant_ref_t ref, int readonly);
128 /*
129 * Stop granting a grant entry to domain for transfer. Ref parameter is
130 * reference of a grant entry whose grant transfer will be stopped. If
131 * tranfer has not started, just reclaim the grant entry and return
132 * failure(==0). Otherwise, wait for the transfer to complete and then
133 * return the frame.
134 */
135 unsigned long (*end_foreign_transfer_ref)(grant_ref_t ref);
136 /*
137 * Query the status of a grant entry. Ref parameter is reference of
138 * queried grant entry, return value is the status of queried entry.
139 * Detailed status(writing/reading) can be gotten from the return value
140 * by bit operations.
141 */
142 int (*query_foreign_access)(grant_ref_t ref);
143};
144
145struct unmap_refs_callback_data {
146 struct completion completion;
147 int result;
148};
149
150static const struct gnttab_ops *gnttab_interface;
151
152/* This reflects status of grant entries, so act as a global value. */
153static grant_status_t *grstatus;
154
155static struct gnttab_free_callback *gnttab_free_callback_list;
156
157static int gnttab_expand(unsigned int req_entries);
158
159#define RPP (PAGE_SIZE / sizeof(grant_ref_t))
160#define SPP (PAGE_SIZE / sizeof(grant_status_t))
161
162static inline grant_ref_t *__gnttab_entry(grant_ref_t entry)
163{
164 return &gnttab_list[(entry) / RPP][(entry) % RPP];
165}
166/* This can be used as an l-value */
167#define gnttab_entry(entry) (*__gnttab_entry(entry))
168
169static int get_free_entries(unsigned count)
170{
171 unsigned long flags;
172 int ref, rc = 0;
173 grant_ref_t head;
174
175 spin_lock_irqsave(&gnttab_list_lock, flags);
176
177 if ((gnttab_free_count < count) &&
178 ((rc = gnttab_expand(count - gnttab_free_count)) < 0)) {
179 spin_unlock_irqrestore(&gnttab_list_lock, flags);
180 return rc;
181 }
182
183 ref = head = gnttab_free_head;
184 gnttab_free_count -= count;
185 while (count-- > 1)
186 head = gnttab_entry(head);
187 gnttab_free_head = gnttab_entry(head);
188 gnttab_entry(head) = GNTTAB_LIST_END;
189
190 spin_unlock_irqrestore(&gnttab_list_lock, flags);
191
192 return ref;
193}
194
195static void do_free_callbacks(void)
196{
197 struct gnttab_free_callback *callback, *next;
198
199 callback = gnttab_free_callback_list;
200 gnttab_free_callback_list = NULL;
201
202 while (callback != NULL) {
203 next = callback->next;
204 if (gnttab_free_count >= callback->count) {
205 callback->next = NULL;
206 callback->fn(callback->arg);
207 } else {
208 callback->next = gnttab_free_callback_list;
209 gnttab_free_callback_list = callback;
210 }
211 callback = next;
212 }
213}
214
215static inline void check_free_callbacks(void)
216{
217 if (unlikely(gnttab_free_callback_list))
218 do_free_callbacks();
219}
220
221static void put_free_entry(grant_ref_t ref)
222{
223 unsigned long flags;
224 spin_lock_irqsave(&gnttab_list_lock, flags);
225 gnttab_entry(ref) = gnttab_free_head;
226 gnttab_free_head = ref;
227 gnttab_free_count++;
228 check_free_callbacks();
229 spin_unlock_irqrestore(&gnttab_list_lock, flags);
230}
231
232/*
233 * Following applies to gnttab_update_entry_v1 and gnttab_update_entry_v2.
234 * Introducing a valid entry into the grant table:
235 * 1. Write ent->domid.
236 * 2. Write ent->frame:
237 * GTF_permit_access: Frame to which access is permitted.
238 * GTF_accept_transfer: Pseudo-phys frame slot being filled by new
239 * frame, or zero if none.
240 * 3. Write memory barrier (WMB).
241 * 4. Write ent->flags, inc. valid type.
242 */
243static void gnttab_update_entry_v1(grant_ref_t ref, domid_t domid,
244 unsigned long frame, unsigned flags)
245{
246 gnttab_shared.v1[ref].domid = domid;
247 gnttab_shared.v1[ref].frame = frame;
248 wmb();
249 gnttab_shared.v1[ref].flags = flags;
250}
251
252static void gnttab_update_entry_v2(grant_ref_t ref, domid_t domid,
253 unsigned long frame, unsigned int flags)
254{
255 gnttab_shared.v2[ref].hdr.domid = domid;
256 gnttab_shared.v2[ref].full_page.frame = frame;
257 wmb(); /* Hypervisor concurrent accesses. */
258 gnttab_shared.v2[ref].hdr.flags = GTF_permit_access | flags;
259}
260
261/*
262 * Public grant-issuing interface functions
263 */
264void gnttab_grant_foreign_access_ref(grant_ref_t ref, domid_t domid,
265 unsigned long frame, int readonly)
266{
267 gnttab_interface->update_entry(ref, domid, frame,
268 GTF_permit_access | (readonly ? GTF_readonly : 0));
269}
270EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access_ref);
271
272int gnttab_grant_foreign_access(domid_t domid, unsigned long frame,
273 int readonly)
274{
275 int ref;
276
277 ref = get_free_entries(1);
278 if (unlikely(ref < 0))
279 return -ENOSPC;
280
281 gnttab_grant_foreign_access_ref(ref, domid, frame, readonly);
282
283 return ref;
284}
285EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access);
286
287static int gnttab_query_foreign_access_v1(grant_ref_t ref)
288{
289 return gnttab_shared.v1[ref].flags & (GTF_reading|GTF_writing);
290}
291
292static int gnttab_query_foreign_access_v2(grant_ref_t ref)
293{
294 return grstatus[ref] & (GTF_reading|GTF_writing);
295}
296
297int gnttab_query_foreign_access(grant_ref_t ref)
298{
299 return gnttab_interface->query_foreign_access(ref);
300}
301EXPORT_SYMBOL_GPL(gnttab_query_foreign_access);
302
303static int gnttab_end_foreign_access_ref_v1(grant_ref_t ref, int readonly)
304{
305 u16 flags, nflags;
306 u16 *pflags;
307
308 pflags = &gnttab_shared.v1[ref].flags;
309 nflags = *pflags;
310 do {
311 flags = nflags;
312 if (flags & (GTF_reading|GTF_writing))
313 return 0;
314 } while ((nflags = sync_cmpxchg(pflags, flags, 0)) != flags);
315
316 return 1;
317}
318
319static int gnttab_end_foreign_access_ref_v2(grant_ref_t ref, int readonly)
320{
321 gnttab_shared.v2[ref].hdr.flags = 0;
322 mb(); /* Concurrent access by hypervisor. */
323 if (grstatus[ref] & (GTF_reading|GTF_writing)) {
324 return 0;
325 } else {
326 /*
327 * The read of grstatus needs to have acquire semantics.
328 * On x86, reads already have that, and we just need to
329 * protect against compiler reorderings.
330 * On other architectures we may need a full barrier.
331 */
332#ifdef CONFIG_X86
333 barrier();
334#else
335 mb();
336#endif
337 }
338
339 return 1;
340}
341
342static inline int _gnttab_end_foreign_access_ref(grant_ref_t ref, int readonly)
343{
344 return gnttab_interface->end_foreign_access_ref(ref, readonly);
345}
346
347int gnttab_end_foreign_access_ref(grant_ref_t ref, int readonly)
348{
349 if (_gnttab_end_foreign_access_ref(ref, readonly))
350 return 1;
351 pr_warn("WARNING: g.e. %#x still in use!\n", ref);
352 return 0;
353}
354EXPORT_SYMBOL_GPL(gnttab_end_foreign_access_ref);
355
356struct deferred_entry {
357 struct list_head list;
358 grant_ref_t ref;
359 bool ro;
360 uint16_t warn_delay;
361 struct page *page;
362};
363static LIST_HEAD(deferred_list);
364static void gnttab_handle_deferred(struct timer_list *);
365static DEFINE_TIMER(deferred_timer, gnttab_handle_deferred);
366
367static void gnttab_handle_deferred(struct timer_list *unused)
368{
369 unsigned int nr = 10;
370 struct deferred_entry *first = NULL;
371 unsigned long flags;
372
373 spin_lock_irqsave(&gnttab_list_lock, flags);
374 while (nr--) {
375 struct deferred_entry *entry
376 = list_first_entry(&deferred_list,
377 struct deferred_entry, list);
378
379 if (entry == first)
380 break;
381 list_del(&entry->list);
382 spin_unlock_irqrestore(&gnttab_list_lock, flags);
383 if (_gnttab_end_foreign_access_ref(entry->ref, entry->ro)) {
384 put_free_entry(entry->ref);
385 if (entry->page) {
386 pr_debug("freeing g.e. %#x (pfn %#lx)\n",
387 entry->ref, page_to_pfn(entry->page));
388 put_page(entry->page);
389 } else
390 pr_info("freeing g.e. %#x\n", entry->ref);
391 kfree(entry);
392 entry = NULL;
393 } else {
394 if (!--entry->warn_delay)
395 pr_info("g.e. %#x still pending\n", entry->ref);
396 if (!first)
397 first = entry;
398 }
399 spin_lock_irqsave(&gnttab_list_lock, flags);
400 if (entry)
401 list_add_tail(&entry->list, &deferred_list);
402 else if (list_empty(&deferred_list))
403 break;
404 }
405 if (!list_empty(&deferred_list) && !timer_pending(&deferred_timer)) {
406 deferred_timer.expires = jiffies + HZ;
407 add_timer(&deferred_timer);
408 }
409 spin_unlock_irqrestore(&gnttab_list_lock, flags);
410}
411
412static void gnttab_add_deferred(grant_ref_t ref, bool readonly,
413 struct page *page)
414{
415 struct deferred_entry *entry = kmalloc(sizeof(*entry), GFP_ATOMIC);
416 const char *what = KERN_WARNING "leaking";
417
418 if (entry) {
419 unsigned long flags;
420
421 entry->ref = ref;
422 entry->ro = readonly;
423 entry->page = page;
424 entry->warn_delay = 60;
425 spin_lock_irqsave(&gnttab_list_lock, flags);
426 list_add_tail(&entry->list, &deferred_list);
427 if (!timer_pending(&deferred_timer)) {
428 deferred_timer.expires = jiffies + HZ;
429 add_timer(&deferred_timer);
430 }
431 spin_unlock_irqrestore(&gnttab_list_lock, flags);
432 what = KERN_DEBUG "deferring";
433 }
434 printk("%s g.e. %#x (pfn %#lx)\n",
435 what, ref, page ? page_to_pfn(page) : -1);
436}
437
438void gnttab_end_foreign_access(grant_ref_t ref, int readonly,
439 unsigned long page)
440{
441 if (gnttab_end_foreign_access_ref(ref, readonly)) {
442 put_free_entry(ref);
443 if (page != 0)
444 put_page(virt_to_page(page));
445 } else
446 gnttab_add_deferred(ref, readonly,
447 page ? virt_to_page(page) : NULL);
448}
449EXPORT_SYMBOL_GPL(gnttab_end_foreign_access);
450
451int gnttab_grant_foreign_transfer(domid_t domid, unsigned long pfn)
452{
453 int ref;
454
455 ref = get_free_entries(1);
456 if (unlikely(ref < 0))
457 return -ENOSPC;
458 gnttab_grant_foreign_transfer_ref(ref, domid, pfn);
459
460 return ref;
461}
462EXPORT_SYMBOL_GPL(gnttab_grant_foreign_transfer);
463
464void gnttab_grant_foreign_transfer_ref(grant_ref_t ref, domid_t domid,
465 unsigned long pfn)
466{
467 gnttab_interface->update_entry(ref, domid, pfn, GTF_accept_transfer);
468}
469EXPORT_SYMBOL_GPL(gnttab_grant_foreign_transfer_ref);
470
471static unsigned long gnttab_end_foreign_transfer_ref_v1(grant_ref_t ref)
472{
473 unsigned long frame;
474 u16 flags;
475 u16 *pflags;
476
477 pflags = &gnttab_shared.v1[ref].flags;
478
479 /*
480 * If a transfer is not even yet started, try to reclaim the grant
481 * reference and return failure (== 0).
482 */
483 while (!((flags = *pflags) & GTF_transfer_committed)) {
484 if (sync_cmpxchg(pflags, flags, 0) == flags)
485 return 0;
486 cpu_relax();
487 }
488
489 /* If a transfer is in progress then wait until it is completed. */
490 while (!(flags & GTF_transfer_completed)) {
491 flags = *pflags;
492 cpu_relax();
493 }
494
495 rmb(); /* Read the frame number /after/ reading completion status. */
496 frame = gnttab_shared.v1[ref].frame;
497 BUG_ON(frame == 0);
498
499 return frame;
500}
501
502static unsigned long gnttab_end_foreign_transfer_ref_v2(grant_ref_t ref)
503{
504 unsigned long frame;
505 u16 flags;
506 u16 *pflags;
507
508 pflags = &gnttab_shared.v2[ref].hdr.flags;
509
510 /*
511 * If a transfer is not even yet started, try to reclaim the grant
512 * reference and return failure (== 0).
513 */
514 while (!((flags = *pflags) & GTF_transfer_committed)) {
515 if (sync_cmpxchg(pflags, flags, 0) == flags)
516 return 0;
517 cpu_relax();
518 }
519
520 /* If a transfer is in progress then wait until it is completed. */
521 while (!(flags & GTF_transfer_completed)) {
522 flags = *pflags;
523 cpu_relax();
524 }
525
526 rmb(); /* Read the frame number /after/ reading completion status. */
527 frame = gnttab_shared.v2[ref].full_page.frame;
528 BUG_ON(frame == 0);
529
530 return frame;
531}
532
533unsigned long gnttab_end_foreign_transfer_ref(grant_ref_t ref)
534{
535 return gnttab_interface->end_foreign_transfer_ref(ref);
536}
537EXPORT_SYMBOL_GPL(gnttab_end_foreign_transfer_ref);
538
539unsigned long gnttab_end_foreign_transfer(grant_ref_t ref)
540{
541 unsigned long frame = gnttab_end_foreign_transfer_ref(ref);
542 put_free_entry(ref);
543 return frame;
544}
545EXPORT_SYMBOL_GPL(gnttab_end_foreign_transfer);
546
547void gnttab_free_grant_reference(grant_ref_t ref)
548{
549 put_free_entry(ref);
550}
551EXPORT_SYMBOL_GPL(gnttab_free_grant_reference);
552
553void gnttab_free_grant_references(grant_ref_t head)
554{
555 grant_ref_t ref;
556 unsigned long flags;
557 int count = 1;
558 if (head == GNTTAB_LIST_END)
559 return;
560 spin_lock_irqsave(&gnttab_list_lock, flags);
561 ref = head;
562 while (gnttab_entry(ref) != GNTTAB_LIST_END) {
563 ref = gnttab_entry(ref);
564 count++;
565 }
566 gnttab_entry(ref) = gnttab_free_head;
567 gnttab_free_head = head;
568 gnttab_free_count += count;
569 check_free_callbacks();
570 spin_unlock_irqrestore(&gnttab_list_lock, flags);
571}
572EXPORT_SYMBOL_GPL(gnttab_free_grant_references);
573
574int gnttab_alloc_grant_references(u16 count, grant_ref_t *head)
575{
576 int h = get_free_entries(count);
577
578 if (h < 0)
579 return -ENOSPC;
580
581 *head = h;
582
583 return 0;
584}
585EXPORT_SYMBOL_GPL(gnttab_alloc_grant_references);
586
587int gnttab_empty_grant_references(const grant_ref_t *private_head)
588{
589 return (*private_head == GNTTAB_LIST_END);
590}
591EXPORT_SYMBOL_GPL(gnttab_empty_grant_references);
592
593int gnttab_claim_grant_reference(grant_ref_t *private_head)
594{
595 grant_ref_t g = *private_head;
596 if (unlikely(g == GNTTAB_LIST_END))
597 return -ENOSPC;
598 *private_head = gnttab_entry(g);
599 return g;
600}
601EXPORT_SYMBOL_GPL(gnttab_claim_grant_reference);
602
603void gnttab_release_grant_reference(grant_ref_t *private_head,
604 grant_ref_t release)
605{
606 gnttab_entry(release) = *private_head;
607 *private_head = release;
608}
609EXPORT_SYMBOL_GPL(gnttab_release_grant_reference);
610
611void gnttab_request_free_callback(struct gnttab_free_callback *callback,
612 void (*fn)(void *), void *arg, u16 count)
613{
614 unsigned long flags;
615 struct gnttab_free_callback *cb;
616
617 spin_lock_irqsave(&gnttab_list_lock, flags);
618
619 /* Check if the callback is already on the list */
620 cb = gnttab_free_callback_list;
621 while (cb) {
622 if (cb == callback)
623 goto out;
624 cb = cb->next;
625 }
626
627 callback->fn = fn;
628 callback->arg = arg;
629 callback->count = count;
630 callback->next = gnttab_free_callback_list;
631 gnttab_free_callback_list = callback;
632 check_free_callbacks();
633out:
634 spin_unlock_irqrestore(&gnttab_list_lock, flags);
635}
636EXPORT_SYMBOL_GPL(gnttab_request_free_callback);
637
638void gnttab_cancel_free_callback(struct gnttab_free_callback *callback)
639{
640 struct gnttab_free_callback **pcb;
641 unsigned long flags;
642
643 spin_lock_irqsave(&gnttab_list_lock, flags);
644 for (pcb = &gnttab_free_callback_list; *pcb; pcb = &(*pcb)->next) {
645 if (*pcb == callback) {
646 *pcb = callback->next;
647 break;
648 }
649 }
650 spin_unlock_irqrestore(&gnttab_list_lock, flags);
651}
652EXPORT_SYMBOL_GPL(gnttab_cancel_free_callback);
653
654static unsigned int gnttab_frames(unsigned int frames, unsigned int align)
655{
656 return (frames * gnttab_interface->grefs_per_grant_frame + align - 1) /
657 align;
658}
659
660static int grow_gnttab_list(unsigned int more_frames)
661{
662 unsigned int new_nr_grant_frames, extra_entries, i;
663 unsigned int nr_glist_frames, new_nr_glist_frames;
664 unsigned int grefs_per_frame;
665
666 grefs_per_frame = gnttab_interface->grefs_per_grant_frame;
667
668 new_nr_grant_frames = nr_grant_frames + more_frames;
669 extra_entries = more_frames * grefs_per_frame;
670
671 nr_glist_frames = gnttab_frames(nr_grant_frames, RPP);
672 new_nr_glist_frames = gnttab_frames(new_nr_grant_frames, RPP);
673 for (i = nr_glist_frames; i < new_nr_glist_frames; i++) {
674 gnttab_list[i] = (grant_ref_t *)__get_free_page(GFP_ATOMIC);
675 if (!gnttab_list[i])
676 goto grow_nomem;
677 }
678
679
680 for (i = grefs_per_frame * nr_grant_frames;
681 i < grefs_per_frame * new_nr_grant_frames - 1; i++)
682 gnttab_entry(i) = i + 1;
683
684 gnttab_entry(i) = gnttab_free_head;
685 gnttab_free_head = grefs_per_frame * nr_grant_frames;
686 gnttab_free_count += extra_entries;
687
688 nr_grant_frames = new_nr_grant_frames;
689
690 check_free_callbacks();
691
692 return 0;
693
694grow_nomem:
695 while (i-- > nr_glist_frames)
696 free_page((unsigned long) gnttab_list[i]);
697 return -ENOMEM;
698}
699
700static unsigned int __max_nr_grant_frames(void)
701{
702 struct gnttab_query_size query;
703 int rc;
704
705 query.dom = DOMID_SELF;
706
707 rc = HYPERVISOR_grant_table_op(GNTTABOP_query_size, &query, 1);
708 if ((rc < 0) || (query.status != GNTST_okay))
709 return 4; /* Legacy max supported number of frames */
710
711 return query.max_nr_frames;
712}
713
714unsigned int gnttab_max_grant_frames(void)
715{
716 unsigned int xen_max = __max_nr_grant_frames();
717 static unsigned int boot_max_nr_grant_frames;
718
719 /* First time, initialize it properly. */
720 if (!boot_max_nr_grant_frames)
721 boot_max_nr_grant_frames = __max_nr_grant_frames();
722
723 if (xen_max > boot_max_nr_grant_frames)
724 return boot_max_nr_grant_frames;
725 return xen_max;
726}
727EXPORT_SYMBOL_GPL(gnttab_max_grant_frames);
728
729int gnttab_setup_auto_xlat_frames(phys_addr_t addr)
730{
731 xen_pfn_t *pfn;
732 unsigned int max_nr_gframes = __max_nr_grant_frames();
733 unsigned int i;
734 void *vaddr;
735
736 if (xen_auto_xlat_grant_frames.count)
737 return -EINVAL;
738
739 vaddr = xen_remap(addr, XEN_PAGE_SIZE * max_nr_gframes);
740 if (vaddr == NULL) {
741 pr_warn("Failed to ioremap gnttab share frames (addr=%pa)!\n",
742 &addr);
743 return -ENOMEM;
744 }
745 pfn = kcalloc(max_nr_gframes, sizeof(pfn[0]), GFP_KERNEL);
746 if (!pfn) {
747 xen_unmap(vaddr);
748 return -ENOMEM;
749 }
750 for (i = 0; i < max_nr_gframes; i++)
751 pfn[i] = XEN_PFN_DOWN(addr) + i;
752
753 xen_auto_xlat_grant_frames.vaddr = vaddr;
754 xen_auto_xlat_grant_frames.pfn = pfn;
755 xen_auto_xlat_grant_frames.count = max_nr_gframes;
756
757 return 0;
758}
759EXPORT_SYMBOL_GPL(gnttab_setup_auto_xlat_frames);
760
761void gnttab_free_auto_xlat_frames(void)
762{
763 if (!xen_auto_xlat_grant_frames.count)
764 return;
765 kfree(xen_auto_xlat_grant_frames.pfn);
766 xen_unmap(xen_auto_xlat_grant_frames.vaddr);
767
768 xen_auto_xlat_grant_frames.pfn = NULL;
769 xen_auto_xlat_grant_frames.count = 0;
770 xen_auto_xlat_grant_frames.vaddr = NULL;
771}
772EXPORT_SYMBOL_GPL(gnttab_free_auto_xlat_frames);
773
774int gnttab_pages_set_private(int nr_pages, struct page **pages)
775{
776 int i;
777
778 for (i = 0; i < nr_pages; i++) {
779#if BITS_PER_LONG < 64
780 struct xen_page_foreign *foreign;
781
782 foreign = kzalloc(sizeof(*foreign), GFP_KERNEL);
783 if (!foreign)
784 return -ENOMEM;
785
786 set_page_private(pages[i], (unsigned long)foreign);
787#endif
788 SetPagePrivate(pages[i]);
789 }
790
791 return 0;
792}
793EXPORT_SYMBOL_GPL(gnttab_pages_set_private);
794
795/**
796 * gnttab_alloc_pages - alloc pages suitable for grant mapping into
797 * @nr_pages: number of pages to alloc
798 * @pages: returns the pages
799 */
800int gnttab_alloc_pages(int nr_pages, struct page **pages)
801{
802 int ret;
803
804 ret = xen_alloc_unpopulated_pages(nr_pages, pages);
805 if (ret < 0)
806 return ret;
807
808 ret = gnttab_pages_set_private(nr_pages, pages);
809 if (ret < 0)
810 gnttab_free_pages(nr_pages, pages);
811
812 return ret;
813}
814EXPORT_SYMBOL_GPL(gnttab_alloc_pages);
815
816#ifdef CONFIG_XEN_UNPOPULATED_ALLOC
817static inline void cache_init(struct gnttab_page_cache *cache)
818{
819 cache->pages = NULL;
820}
821
822static inline bool cache_empty(struct gnttab_page_cache *cache)
823{
824 return !cache->pages;
825}
826
827static inline struct page *cache_deq(struct gnttab_page_cache *cache)
828{
829 struct page *page;
830
831 page = cache->pages;
832 cache->pages = page->zone_device_data;
833
834 return page;
835}
836
837static inline void cache_enq(struct gnttab_page_cache *cache, struct page *page)
838{
839 page->zone_device_data = cache->pages;
840 cache->pages = page;
841}
842#else
843static inline void cache_init(struct gnttab_page_cache *cache)
844{
845 INIT_LIST_HEAD(&cache->pages);
846}
847
848static inline bool cache_empty(struct gnttab_page_cache *cache)
849{
850 return list_empty(&cache->pages);
851}
852
853static inline struct page *cache_deq(struct gnttab_page_cache *cache)
854{
855 struct page *page;
856
857 page = list_first_entry(&cache->pages, struct page, lru);
858 list_del(&page->lru);
859
860 return page;
861}
862
863static inline void cache_enq(struct gnttab_page_cache *cache, struct page *page)
864{
865 list_add(&page->lru, &cache->pages);
866}
867#endif
868
869void gnttab_page_cache_init(struct gnttab_page_cache *cache)
870{
871 spin_lock_init(&cache->lock);
872 cache_init(cache);
873 cache->num_pages = 0;
874}
875EXPORT_SYMBOL_GPL(gnttab_page_cache_init);
876
877int gnttab_page_cache_get(struct gnttab_page_cache *cache, struct page **page)
878{
879 unsigned long flags;
880
881 spin_lock_irqsave(&cache->lock, flags);
882
883 if (cache_empty(cache)) {
884 spin_unlock_irqrestore(&cache->lock, flags);
885 return gnttab_alloc_pages(1, page);
886 }
887
888 page[0] = cache_deq(cache);
889 cache->num_pages--;
890
891 spin_unlock_irqrestore(&cache->lock, flags);
892
893 return 0;
894}
895EXPORT_SYMBOL_GPL(gnttab_page_cache_get);
896
897void gnttab_page_cache_put(struct gnttab_page_cache *cache, struct page **page,
898 unsigned int num)
899{
900 unsigned long flags;
901 unsigned int i;
902
903 spin_lock_irqsave(&cache->lock, flags);
904
905 for (i = 0; i < num; i++)
906 cache_enq(cache, page[i]);
907 cache->num_pages += num;
908
909 spin_unlock_irqrestore(&cache->lock, flags);
910}
911EXPORT_SYMBOL_GPL(gnttab_page_cache_put);
912
913void gnttab_page_cache_shrink(struct gnttab_page_cache *cache, unsigned int num)
914{
915 struct page *page[10];
916 unsigned int i = 0;
917 unsigned long flags;
918
919 spin_lock_irqsave(&cache->lock, flags);
920
921 while (cache->num_pages > num) {
922 page[i] = cache_deq(cache);
923 cache->num_pages--;
924 if (++i == ARRAY_SIZE(page)) {
925 spin_unlock_irqrestore(&cache->lock, flags);
926 gnttab_free_pages(i, page);
927 i = 0;
928 spin_lock_irqsave(&cache->lock, flags);
929 }
930 }
931
932 spin_unlock_irqrestore(&cache->lock, flags);
933
934 if (i != 0)
935 gnttab_free_pages(i, page);
936}
937EXPORT_SYMBOL_GPL(gnttab_page_cache_shrink);
938
939void gnttab_pages_clear_private(int nr_pages, struct page **pages)
940{
941 int i;
942
943 for (i = 0; i < nr_pages; i++) {
944 if (PagePrivate(pages[i])) {
945#if BITS_PER_LONG < 64
946 kfree((void *)page_private(pages[i]));
947#endif
948 ClearPagePrivate(pages[i]);
949 }
950 }
951}
952EXPORT_SYMBOL_GPL(gnttab_pages_clear_private);
953
954/**
955 * gnttab_free_pages - free pages allocated by gnttab_alloc_pages()
956 * @nr_pages; number of pages to free
957 * @pages: the pages
958 */
959void gnttab_free_pages(int nr_pages, struct page **pages)
960{
961 gnttab_pages_clear_private(nr_pages, pages);
962 xen_free_unpopulated_pages(nr_pages, pages);
963}
964EXPORT_SYMBOL_GPL(gnttab_free_pages);
965
966#ifdef CONFIG_XEN_GRANT_DMA_ALLOC
967/**
968 * gnttab_dma_alloc_pages - alloc DMAable pages suitable for grant mapping into
969 * @args: arguments to the function
970 */
971int gnttab_dma_alloc_pages(struct gnttab_dma_alloc_args *args)
972{
973 unsigned long pfn, start_pfn;
974 size_t size;
975 int i, ret;
976
977 size = args->nr_pages << PAGE_SHIFT;
978 if (args->coherent)
979 args->vaddr = dma_alloc_coherent(args->dev, size,
980 &args->dev_bus_addr,
981 GFP_KERNEL | __GFP_NOWARN);
982 else
983 args->vaddr = dma_alloc_wc(args->dev, size,
984 &args->dev_bus_addr,
985 GFP_KERNEL | __GFP_NOWARN);
986 if (!args->vaddr) {
987 pr_debug("Failed to allocate DMA buffer of size %zu\n", size);
988 return -ENOMEM;
989 }
990
991 start_pfn = __phys_to_pfn(args->dev_bus_addr);
992 for (pfn = start_pfn, i = 0; pfn < start_pfn + args->nr_pages;
993 pfn++, i++) {
994 struct page *page = pfn_to_page(pfn);
995
996 args->pages[i] = page;
997 args->frames[i] = xen_page_to_gfn(page);
998 xenmem_reservation_scrub_page(page);
999 }
1000
1001 xenmem_reservation_va_mapping_reset(args->nr_pages, args->pages);
1002
1003 ret = xenmem_reservation_decrease(args->nr_pages, args->frames);
1004 if (ret != args->nr_pages) {
1005 pr_debug("Failed to decrease reservation for DMA buffer\n");
1006 ret = -EFAULT;
1007 goto fail;
1008 }
1009
1010 ret = gnttab_pages_set_private(args->nr_pages, args->pages);
1011 if (ret < 0)
1012 goto fail;
1013
1014 return 0;
1015
1016fail:
1017 gnttab_dma_free_pages(args);
1018 return ret;
1019}
1020EXPORT_SYMBOL_GPL(gnttab_dma_alloc_pages);
1021
1022/**
1023 * gnttab_dma_free_pages - free DMAable pages
1024 * @args: arguments to the function
1025 */
1026int gnttab_dma_free_pages(struct gnttab_dma_alloc_args *args)
1027{
1028 size_t size;
1029 int i, ret;
1030
1031 gnttab_pages_clear_private(args->nr_pages, args->pages);
1032
1033 for (i = 0; i < args->nr_pages; i++)
1034 args->frames[i] = page_to_xen_pfn(args->pages[i]);
1035
1036 ret = xenmem_reservation_increase(args->nr_pages, args->frames);
1037 if (ret != args->nr_pages) {
1038 pr_debug("Failed to increase reservation for DMA buffer\n");
1039 ret = -EFAULT;
1040 } else {
1041 ret = 0;
1042 }
1043
1044 xenmem_reservation_va_mapping_update(args->nr_pages, args->pages,
1045 args->frames);
1046
1047 size = args->nr_pages << PAGE_SHIFT;
1048 if (args->coherent)
1049 dma_free_coherent(args->dev, size,
1050 args->vaddr, args->dev_bus_addr);
1051 else
1052 dma_free_wc(args->dev, size,
1053 args->vaddr, args->dev_bus_addr);
1054 return ret;
1055}
1056EXPORT_SYMBOL_GPL(gnttab_dma_free_pages);
1057#endif
1058
1059/* Handling of paged out grant targets (GNTST_eagain) */
1060#define MAX_DELAY 256
1061static inline void
1062gnttab_retry_eagain_gop(unsigned int cmd, void *gop, int16_t *status,
1063 const char *func)
1064{
1065 unsigned delay = 1;
1066
1067 do {
1068 BUG_ON(HYPERVISOR_grant_table_op(cmd, gop, 1));
1069 if (*status == GNTST_eagain)
1070 msleep(delay++);
1071 } while ((*status == GNTST_eagain) && (delay < MAX_DELAY));
1072
1073 if (delay >= MAX_DELAY) {
1074 pr_err("%s: %s eagain grant\n", func, current->comm);
1075 *status = GNTST_bad_page;
1076 }
1077}
1078
1079void gnttab_batch_map(struct gnttab_map_grant_ref *batch, unsigned count)
1080{
1081 struct gnttab_map_grant_ref *op;
1082
1083 if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, batch, count))
1084 BUG();
1085 for (op = batch; op < batch + count; op++)
1086 if (op->status == GNTST_eagain)
1087 gnttab_retry_eagain_gop(GNTTABOP_map_grant_ref, op,
1088 &op->status, __func__);
1089}
1090EXPORT_SYMBOL_GPL(gnttab_batch_map);
1091
1092void gnttab_batch_copy(struct gnttab_copy *batch, unsigned count)
1093{
1094 struct gnttab_copy *op;
1095
1096 if (HYPERVISOR_grant_table_op(GNTTABOP_copy, batch, count))
1097 BUG();
1098 for (op = batch; op < batch + count; op++)
1099 if (op->status == GNTST_eagain)
1100 gnttab_retry_eagain_gop(GNTTABOP_copy, op,
1101 &op->status, __func__);
1102}
1103EXPORT_SYMBOL_GPL(gnttab_batch_copy);
1104
1105void gnttab_foreach_grant_in_range(struct page *page,
1106 unsigned int offset,
1107 unsigned int len,
1108 xen_grant_fn_t fn,
1109 void *data)
1110{
1111 unsigned int goffset;
1112 unsigned int glen;
1113 unsigned long xen_pfn;
1114
1115 len = min_t(unsigned int, PAGE_SIZE - offset, len);
1116 goffset = xen_offset_in_page(offset);
1117
1118 xen_pfn = page_to_xen_pfn(page) + XEN_PFN_DOWN(offset);
1119
1120 while (len) {
1121 glen = min_t(unsigned int, XEN_PAGE_SIZE - goffset, len);
1122 fn(pfn_to_gfn(xen_pfn), goffset, glen, data);
1123
1124 goffset = 0;
1125 xen_pfn++;
1126 len -= glen;
1127 }
1128}
1129EXPORT_SYMBOL_GPL(gnttab_foreach_grant_in_range);
1130
1131void gnttab_foreach_grant(struct page **pages,
1132 unsigned int nr_grefs,
1133 xen_grant_fn_t fn,
1134 void *data)
1135{
1136 unsigned int goffset = 0;
1137 unsigned long xen_pfn = 0;
1138 unsigned int i;
1139
1140 for (i = 0; i < nr_grefs; i++) {
1141 if ((i % XEN_PFN_PER_PAGE) == 0) {
1142 xen_pfn = page_to_xen_pfn(pages[i / XEN_PFN_PER_PAGE]);
1143 goffset = 0;
1144 }
1145
1146 fn(pfn_to_gfn(xen_pfn), goffset, XEN_PAGE_SIZE, data);
1147
1148 goffset += XEN_PAGE_SIZE;
1149 xen_pfn++;
1150 }
1151}
1152
1153int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
1154 struct gnttab_map_grant_ref *kmap_ops,
1155 struct page **pages, unsigned int count)
1156{
1157 int i, ret;
1158
1159 ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, map_ops, count);
1160 if (ret)
1161 return ret;
1162
1163 for (i = 0; i < count; i++) {
1164 switch (map_ops[i].status) {
1165 case GNTST_okay:
1166 {
1167 struct xen_page_foreign *foreign;
1168
1169 SetPageForeign(pages[i]);
1170 foreign = xen_page_foreign(pages[i]);
1171 foreign->domid = map_ops[i].dom;
1172 foreign->gref = map_ops[i].ref;
1173 break;
1174 }
1175
1176 case GNTST_no_device_space:
1177 pr_warn_ratelimited("maptrack limit reached, can't map all guest pages\n");
1178 break;
1179
1180 case GNTST_eagain:
1181 /* Retry eagain maps */
1182 gnttab_retry_eagain_gop(GNTTABOP_map_grant_ref,
1183 map_ops + i,
1184 &map_ops[i].status, __func__);
1185 /* Test status in next loop iteration. */
1186 i--;
1187 break;
1188
1189 default:
1190 break;
1191 }
1192 }
1193
1194 return set_foreign_p2m_mapping(map_ops, kmap_ops, pages, count);
1195}
1196EXPORT_SYMBOL_GPL(gnttab_map_refs);
1197
1198int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
1199 struct gnttab_unmap_grant_ref *kunmap_ops,
1200 struct page **pages, unsigned int count)
1201{
1202 unsigned int i;
1203 int ret;
1204
1205 ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap_ops, count);
1206 if (ret)
1207 return ret;
1208
1209 for (i = 0; i < count; i++)
1210 ClearPageForeign(pages[i]);
1211
1212 return clear_foreign_p2m_mapping(unmap_ops, kunmap_ops, pages, count);
1213}
1214EXPORT_SYMBOL_GPL(gnttab_unmap_refs);
1215
1216#define GNTTAB_UNMAP_REFS_DELAY 5
1217
1218static void __gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item);
1219
1220static void gnttab_unmap_work(struct work_struct *work)
1221{
1222 struct gntab_unmap_queue_data
1223 *unmap_data = container_of(work,
1224 struct gntab_unmap_queue_data,
1225 gnttab_work.work);
1226 if (unmap_data->age != UINT_MAX)
1227 unmap_data->age++;
1228 __gnttab_unmap_refs_async(unmap_data);
1229}
1230
1231static void __gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item)
1232{
1233 int ret;
1234 int pc;
1235
1236 for (pc = 0; pc < item->count; pc++) {
1237 if (page_count(item->pages[pc]) > 1) {
1238 unsigned long delay = GNTTAB_UNMAP_REFS_DELAY * (item->age + 1);
1239 schedule_delayed_work(&item->gnttab_work,
1240 msecs_to_jiffies(delay));
1241 return;
1242 }
1243 }
1244
1245 ret = gnttab_unmap_refs(item->unmap_ops, item->kunmap_ops,
1246 item->pages, item->count);
1247 item->done(ret, item);
1248}
1249
1250void gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item)
1251{
1252 INIT_DELAYED_WORK(&item->gnttab_work, gnttab_unmap_work);
1253 item->age = 0;
1254
1255 __gnttab_unmap_refs_async(item);
1256}
1257EXPORT_SYMBOL_GPL(gnttab_unmap_refs_async);
1258
1259static void unmap_refs_callback(int result,
1260 struct gntab_unmap_queue_data *data)
1261{
1262 struct unmap_refs_callback_data *d = data->data;
1263
1264 d->result = result;
1265 complete(&d->completion);
1266}
1267
1268int gnttab_unmap_refs_sync(struct gntab_unmap_queue_data *item)
1269{
1270 struct unmap_refs_callback_data data;
1271
1272 init_completion(&data.completion);
1273 item->data = &data;
1274 item->done = &unmap_refs_callback;
1275 gnttab_unmap_refs_async(item);
1276 wait_for_completion(&data.completion);
1277
1278 return data.result;
1279}
1280EXPORT_SYMBOL_GPL(gnttab_unmap_refs_sync);
1281
1282static unsigned int nr_status_frames(unsigned int nr_grant_frames)
1283{
1284 return gnttab_frames(nr_grant_frames, SPP);
1285}
1286
1287static int gnttab_map_frames_v1(xen_pfn_t *frames, unsigned int nr_gframes)
1288{
1289 int rc;
1290
1291 rc = arch_gnttab_map_shared(frames, nr_gframes,
1292 gnttab_max_grant_frames(),
1293 &gnttab_shared.addr);
1294 BUG_ON(rc);
1295
1296 return 0;
1297}
1298
1299static void gnttab_unmap_frames_v1(void)
1300{
1301 arch_gnttab_unmap(gnttab_shared.addr, nr_grant_frames);
1302}
1303
1304static int gnttab_map_frames_v2(xen_pfn_t *frames, unsigned int nr_gframes)
1305{
1306 uint64_t *sframes;
1307 unsigned int nr_sframes;
1308 struct gnttab_get_status_frames getframes;
1309 int rc;
1310
1311 nr_sframes = nr_status_frames(nr_gframes);
1312
1313 /* No need for kzalloc as it is initialized in following hypercall
1314 * GNTTABOP_get_status_frames.
1315 */
1316 sframes = kmalloc_array(nr_sframes, sizeof(uint64_t), GFP_ATOMIC);
1317 if (!sframes)
1318 return -ENOMEM;
1319
1320 getframes.dom = DOMID_SELF;
1321 getframes.nr_frames = nr_sframes;
1322 set_xen_guest_handle(getframes.frame_list, sframes);
1323
1324 rc = HYPERVISOR_grant_table_op(GNTTABOP_get_status_frames,
1325 &getframes, 1);
1326 if (rc == -ENOSYS) {
1327 kfree(sframes);
1328 return -ENOSYS;
1329 }
1330
1331 BUG_ON(rc || getframes.status);
1332
1333 rc = arch_gnttab_map_status(sframes, nr_sframes,
1334 nr_status_frames(gnttab_max_grant_frames()),
1335 &grstatus);
1336 BUG_ON(rc);
1337 kfree(sframes);
1338
1339 rc = arch_gnttab_map_shared(frames, nr_gframes,
1340 gnttab_max_grant_frames(),
1341 &gnttab_shared.addr);
1342 BUG_ON(rc);
1343
1344 return 0;
1345}
1346
1347static void gnttab_unmap_frames_v2(void)
1348{
1349 arch_gnttab_unmap(gnttab_shared.addr, nr_grant_frames);
1350 arch_gnttab_unmap(grstatus, nr_status_frames(nr_grant_frames));
1351}
1352
1353static int gnttab_map(unsigned int start_idx, unsigned int end_idx)
1354{
1355 struct gnttab_setup_table setup;
1356 xen_pfn_t *frames;
1357 unsigned int nr_gframes = end_idx + 1;
1358 int rc;
1359
1360 if (xen_feature(XENFEAT_auto_translated_physmap)) {
1361 struct xen_add_to_physmap xatp;
1362 unsigned int i = end_idx;
1363 rc = 0;
1364 BUG_ON(xen_auto_xlat_grant_frames.count < nr_gframes);
1365 /*
1366 * Loop backwards, so that the first hypercall has the largest
1367 * index, ensuring that the table will grow only once.
1368 */
1369 do {
1370 xatp.domid = DOMID_SELF;
1371 xatp.idx = i;
1372 xatp.space = XENMAPSPACE_grant_table;
1373 xatp.gpfn = xen_auto_xlat_grant_frames.pfn[i];
1374 rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp);
1375 if (rc != 0) {
1376 pr_warn("grant table add_to_physmap failed, err=%d\n",
1377 rc);
1378 break;
1379 }
1380 } while (i-- > start_idx);
1381
1382 return rc;
1383 }
1384
1385 /* No need for kzalloc as it is initialized in following hypercall
1386 * GNTTABOP_setup_table.
1387 */
1388 frames = kmalloc_array(nr_gframes, sizeof(unsigned long), GFP_ATOMIC);
1389 if (!frames)
1390 return -ENOMEM;
1391
1392 setup.dom = DOMID_SELF;
1393 setup.nr_frames = nr_gframes;
1394 set_xen_guest_handle(setup.frame_list, frames);
1395
1396 rc = HYPERVISOR_grant_table_op(GNTTABOP_setup_table, &setup, 1);
1397 if (rc == -ENOSYS) {
1398 kfree(frames);
1399 return -ENOSYS;
1400 }
1401
1402 BUG_ON(rc || setup.status);
1403
1404 rc = gnttab_interface->map_frames(frames, nr_gframes);
1405
1406 kfree(frames);
1407
1408 return rc;
1409}
1410
1411static const struct gnttab_ops gnttab_v1_ops = {
1412 .version = 1,
1413 .grefs_per_grant_frame = XEN_PAGE_SIZE /
1414 sizeof(struct grant_entry_v1),
1415 .map_frames = gnttab_map_frames_v1,
1416 .unmap_frames = gnttab_unmap_frames_v1,
1417 .update_entry = gnttab_update_entry_v1,
1418 .end_foreign_access_ref = gnttab_end_foreign_access_ref_v1,
1419 .end_foreign_transfer_ref = gnttab_end_foreign_transfer_ref_v1,
1420 .query_foreign_access = gnttab_query_foreign_access_v1,
1421};
1422
1423static const struct gnttab_ops gnttab_v2_ops = {
1424 .version = 2,
1425 .grefs_per_grant_frame = XEN_PAGE_SIZE /
1426 sizeof(union grant_entry_v2),
1427 .map_frames = gnttab_map_frames_v2,
1428 .unmap_frames = gnttab_unmap_frames_v2,
1429 .update_entry = gnttab_update_entry_v2,
1430 .end_foreign_access_ref = gnttab_end_foreign_access_ref_v2,
1431 .end_foreign_transfer_ref = gnttab_end_foreign_transfer_ref_v2,
1432 .query_foreign_access = gnttab_query_foreign_access_v2,
1433};
1434
1435static bool gnttab_need_v2(void)
1436{
1437#ifdef CONFIG_X86
1438 uint32_t base, width;
1439
1440 if (xen_pv_domain()) {
1441 base = xen_cpuid_base();
1442 if (cpuid_eax(base) < 5)
1443 return false; /* Information not available, use V1. */
1444 width = cpuid_ebx(base + 5) &
1445 XEN_CPUID_MACHINE_ADDRESS_WIDTH_MASK;
1446 return width > 32 + PAGE_SHIFT;
1447 }
1448#endif
1449 return !!(max_possible_pfn >> 32);
1450}
1451
1452static void gnttab_request_version(void)
1453{
1454 long rc;
1455 struct gnttab_set_version gsv;
1456
1457 if (gnttab_need_v2())
1458 gsv.version = 2;
1459 else
1460 gsv.version = 1;
1461
1462 /* Boot parameter overrides automatic selection. */
1463 if (xen_gnttab_version >= 1 && xen_gnttab_version <= 2)
1464 gsv.version = xen_gnttab_version;
1465
1466 rc = HYPERVISOR_grant_table_op(GNTTABOP_set_version, &gsv, 1);
1467 if (rc == 0 && gsv.version == 2)
1468 gnttab_interface = &gnttab_v2_ops;
1469 else
1470 gnttab_interface = &gnttab_v1_ops;
1471 pr_info("Grant tables using version %d layout\n",
1472 gnttab_interface->version);
1473}
1474
1475static int gnttab_setup(void)
1476{
1477 unsigned int max_nr_gframes;
1478
1479 max_nr_gframes = gnttab_max_grant_frames();
1480 if (max_nr_gframes < nr_grant_frames)
1481 return -ENOSYS;
1482
1483 if (xen_feature(XENFEAT_auto_translated_physmap) && gnttab_shared.addr == NULL) {
1484 gnttab_shared.addr = xen_auto_xlat_grant_frames.vaddr;
1485 if (gnttab_shared.addr == NULL) {
1486 pr_warn("gnttab share frames is not mapped!\n");
1487 return -ENOMEM;
1488 }
1489 }
1490 return gnttab_map(0, nr_grant_frames - 1);
1491}
1492
1493int gnttab_resume(void)
1494{
1495 gnttab_request_version();
1496 return gnttab_setup();
1497}
1498
1499int gnttab_suspend(void)
1500{
1501 if (!xen_feature(XENFEAT_auto_translated_physmap))
1502 gnttab_interface->unmap_frames();
1503 return 0;
1504}
1505
1506static int gnttab_expand(unsigned int req_entries)
1507{
1508 int rc;
1509 unsigned int cur, extra;
1510
1511 cur = nr_grant_frames;
1512 extra = ((req_entries + gnttab_interface->grefs_per_grant_frame - 1) /
1513 gnttab_interface->grefs_per_grant_frame);
1514 if (cur + extra > gnttab_max_grant_frames()) {
1515 pr_warn_ratelimited("xen/grant-table: max_grant_frames reached"
1516 " cur=%u extra=%u limit=%u"
1517 " gnttab_free_count=%u req_entries=%u\n",
1518 cur, extra, gnttab_max_grant_frames(),
1519 gnttab_free_count, req_entries);
1520 return -ENOSPC;
1521 }
1522
1523 rc = gnttab_map(cur, cur + extra - 1);
1524 if (rc == 0)
1525 rc = grow_gnttab_list(extra);
1526
1527 return rc;
1528}
1529
1530int gnttab_init(void)
1531{
1532 int i;
1533 unsigned long max_nr_grant_frames;
1534 unsigned int max_nr_glist_frames, nr_glist_frames;
1535 unsigned int nr_init_grefs;
1536 int ret;
1537
1538 gnttab_request_version();
1539 max_nr_grant_frames = gnttab_max_grant_frames();
1540 nr_grant_frames = 1;
1541
1542 /* Determine the maximum number of frames required for the
1543 * grant reference free list on the current hypervisor.
1544 */
1545 max_nr_glist_frames = (max_nr_grant_frames *
1546 gnttab_interface->grefs_per_grant_frame / RPP);
1547
1548 gnttab_list = kmalloc_array(max_nr_glist_frames,
1549 sizeof(grant_ref_t *),
1550 GFP_KERNEL);
1551 if (gnttab_list == NULL)
1552 return -ENOMEM;
1553
1554 nr_glist_frames = gnttab_frames(nr_grant_frames, RPP);
1555 for (i = 0; i < nr_glist_frames; i++) {
1556 gnttab_list[i] = (grant_ref_t *)__get_free_page(GFP_KERNEL);
1557 if (gnttab_list[i] == NULL) {
1558 ret = -ENOMEM;
1559 goto ini_nomem;
1560 }
1561 }
1562
1563 ret = arch_gnttab_init(max_nr_grant_frames,
1564 nr_status_frames(max_nr_grant_frames));
1565 if (ret < 0)
1566 goto ini_nomem;
1567
1568 if (gnttab_setup() < 0) {
1569 ret = -ENODEV;
1570 goto ini_nomem;
1571 }
1572
1573 nr_init_grefs = nr_grant_frames *
1574 gnttab_interface->grefs_per_grant_frame;
1575
1576 for (i = NR_RESERVED_ENTRIES; i < nr_init_grefs - 1; i++)
1577 gnttab_entry(i) = i + 1;
1578
1579 gnttab_entry(nr_init_grefs - 1) = GNTTAB_LIST_END;
1580 gnttab_free_count = nr_init_grefs - NR_RESERVED_ENTRIES;
1581 gnttab_free_head = NR_RESERVED_ENTRIES;
1582
1583 printk("Grant table initialized\n");
1584 return 0;
1585
1586 ini_nomem:
1587 for (i--; i >= 0; i--)
1588 free_page((unsigned long)gnttab_list[i]);
1589 kfree(gnttab_list);
1590 return ret;
1591}
1592EXPORT_SYMBOL_GPL(gnttab_init);
1593
1594static int __gnttab_init(void)
1595{
1596 if (!xen_domain())
1597 return -ENODEV;
1598
1599 /* Delay grant-table initialization in the PV on HVM case */
1600 if (xen_hvm_domain() && !xen_pvh_domain())
1601 return 0;
1602
1603 return gnttab_init();
1604}
1605/* Starts after core_initcall so that xen_pvh_gnttab_setup can be called
1606 * beforehand to initialize xen_auto_xlat_grant_frames. */
1607core_initcall_sync(__gnttab_init);