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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/bootmem.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
49#include <xen/xen.h>
50#include <xen/interface/xen.h>
51#include <xen/page.h>
52#include <xen/grant_table.h>
53#include <xen/interface/memory.h>
54#include <xen/hvc-console.h>
55#include <xen/swiotlb-xen.h>
56#include <xen/balloon.h>
57#ifdef CONFIG_X86
58#include <asm/xen/cpuid.h>
59#endif
60#include <asm/xen/hypercall.h>
61#include <asm/xen/interface.h>
62
63#include <asm/pgtable.h>
64#include <asm/sync_bitops.h>
65
66/* External tools reserve first few grant table entries. */
67#define NR_RESERVED_ENTRIES 8
68#define GNTTAB_LIST_END 0xffffffff
69
70static grant_ref_t **gnttab_list;
71static unsigned int nr_grant_frames;
72static int gnttab_free_count;
73static grant_ref_t gnttab_free_head;
74static DEFINE_SPINLOCK(gnttab_list_lock);
75struct grant_frames xen_auto_xlat_grant_frames;
76static unsigned int xen_gnttab_version;
77module_param_named(version, xen_gnttab_version, uint, 0);
78
79static union {
80 struct grant_entry_v1 *v1;
81 union grant_entry_v2 *v2;
82 void *addr;
83} gnttab_shared;
84
85/*This is a structure of function pointers for grant table*/
86struct gnttab_ops {
87 /*
88 * Version of the grant interface.
89 */
90 unsigned int version;
91 /*
92 * Grant refs per grant frame.
93 */
94 unsigned int grefs_per_grant_frame;
95 /*
96 * Mapping a list of frames for storing grant entries. Frames parameter
97 * is used to store grant table address when grant table being setup,
98 * nr_gframes is the number of frames to map grant table. Returning
99 * GNTST_okay means success and negative value means failure.
100 */
101 int (*map_frames)(xen_pfn_t *frames, unsigned int nr_gframes);
102 /*
103 * Release a list of frames which are mapped in map_frames for grant
104 * entry status.
105 */
106 void (*unmap_frames)(void);
107 /*
108 * Introducing a valid entry into the grant table, granting the frame of
109 * this grant entry to domain for accessing or transfering. Ref
110 * parameter is reference of this introduced grant entry, domid is id of
111 * granted domain, frame is the page frame to be granted, and flags is
112 * status of the grant entry to be updated.
113 */
114 void (*update_entry)(grant_ref_t ref, domid_t domid,
115 unsigned long frame, unsigned flags);
116 /*
117 * Stop granting a grant entry to domain for accessing. Ref parameter is
118 * reference of a grant entry whose grant access will be stopped,
119 * readonly is not in use in this function. If the grant entry is
120 * currently mapped for reading or writing, just return failure(==0)
121 * directly and don't tear down the grant access. Otherwise, stop grant
122 * access for this entry and return success(==1).
123 */
124 int (*end_foreign_access_ref)(grant_ref_t ref, int readonly);
125 /*
126 * Stop granting a grant entry to domain for transfer. Ref parameter is
127 * reference of a grant entry whose grant transfer will be stopped. If
128 * tranfer has not started, just reclaim the grant entry and return
129 * failure(==0). Otherwise, wait for the transfer to complete and then
130 * return the frame.
131 */
132 unsigned long (*end_foreign_transfer_ref)(grant_ref_t ref);
133 /*
134 * Query the status of a grant entry. Ref parameter is reference of
135 * queried grant entry, return value is the status of queried entry.
136 * Detailed status(writing/reading) can be gotten from the return value
137 * by bit operations.
138 */
139 int (*query_foreign_access)(grant_ref_t ref);
140};
141
142struct unmap_refs_callback_data {
143 struct completion completion;
144 int result;
145};
146
147static const struct gnttab_ops *gnttab_interface;
148
149/* This reflects status of grant entries, so act as a global value. */
150static grant_status_t *grstatus;
151
152static struct gnttab_free_callback *gnttab_free_callback_list;
153
154static int gnttab_expand(unsigned int req_entries);
155
156#define RPP (PAGE_SIZE / sizeof(grant_ref_t))
157#define SPP (PAGE_SIZE / sizeof(grant_status_t))
158
159static inline grant_ref_t *__gnttab_entry(grant_ref_t entry)
160{
161 return &gnttab_list[(entry) / RPP][(entry) % RPP];
162}
163/* This can be used as an l-value */
164#define gnttab_entry(entry) (*__gnttab_entry(entry))
165
166static int get_free_entries(unsigned count)
167{
168 unsigned long flags;
169 int ref, rc = 0;
170 grant_ref_t head;
171
172 spin_lock_irqsave(&gnttab_list_lock, flags);
173
174 if ((gnttab_free_count < count) &&
175 ((rc = gnttab_expand(count - gnttab_free_count)) < 0)) {
176 spin_unlock_irqrestore(&gnttab_list_lock, flags);
177 return rc;
178 }
179
180 ref = head = gnttab_free_head;
181 gnttab_free_count -= count;
182 while (count-- > 1)
183 head = gnttab_entry(head);
184 gnttab_free_head = gnttab_entry(head);
185 gnttab_entry(head) = GNTTAB_LIST_END;
186
187 spin_unlock_irqrestore(&gnttab_list_lock, flags);
188
189 return ref;
190}
191
192static void do_free_callbacks(void)
193{
194 struct gnttab_free_callback *callback, *next;
195
196 callback = gnttab_free_callback_list;
197 gnttab_free_callback_list = NULL;
198
199 while (callback != NULL) {
200 next = callback->next;
201 if (gnttab_free_count >= callback->count) {
202 callback->next = NULL;
203 callback->fn(callback->arg);
204 } else {
205 callback->next = gnttab_free_callback_list;
206 gnttab_free_callback_list = callback;
207 }
208 callback = next;
209 }
210}
211
212static inline void check_free_callbacks(void)
213{
214 if (unlikely(gnttab_free_callback_list))
215 do_free_callbacks();
216}
217
218static void put_free_entry(grant_ref_t ref)
219{
220 unsigned long flags;
221 spin_lock_irqsave(&gnttab_list_lock, flags);
222 gnttab_entry(ref) = gnttab_free_head;
223 gnttab_free_head = ref;
224 gnttab_free_count++;
225 check_free_callbacks();
226 spin_unlock_irqrestore(&gnttab_list_lock, flags);
227}
228
229/*
230 * Following applies to gnttab_update_entry_v1 and gnttab_update_entry_v2.
231 * Introducing a valid entry into the grant table:
232 * 1. Write ent->domid.
233 * 2. Write ent->frame:
234 * GTF_permit_access: Frame to which access is permitted.
235 * GTF_accept_transfer: Pseudo-phys frame slot being filled by new
236 * frame, or zero if none.
237 * 3. Write memory barrier (WMB).
238 * 4. Write ent->flags, inc. valid type.
239 */
240static void gnttab_update_entry_v1(grant_ref_t ref, domid_t domid,
241 unsigned long frame, unsigned flags)
242{
243 gnttab_shared.v1[ref].domid = domid;
244 gnttab_shared.v1[ref].frame = frame;
245 wmb();
246 gnttab_shared.v1[ref].flags = flags;
247}
248
249static void gnttab_update_entry_v2(grant_ref_t ref, domid_t domid,
250 unsigned long frame, unsigned int flags)
251{
252 gnttab_shared.v2[ref].hdr.domid = domid;
253 gnttab_shared.v2[ref].full_page.frame = frame;
254 wmb(); /* Hypervisor concurrent accesses. */
255 gnttab_shared.v2[ref].hdr.flags = GTF_permit_access | flags;
256}
257
258/*
259 * Public grant-issuing interface functions
260 */
261void gnttab_grant_foreign_access_ref(grant_ref_t ref, domid_t domid,
262 unsigned long frame, int readonly)
263{
264 gnttab_interface->update_entry(ref, domid, frame,
265 GTF_permit_access | (readonly ? GTF_readonly : 0));
266}
267EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access_ref);
268
269int gnttab_grant_foreign_access(domid_t domid, unsigned long frame,
270 int readonly)
271{
272 int ref;
273
274 ref = get_free_entries(1);
275 if (unlikely(ref < 0))
276 return -ENOSPC;
277
278 gnttab_grant_foreign_access_ref(ref, domid, frame, readonly);
279
280 return ref;
281}
282EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access);
283
284static int gnttab_query_foreign_access_v1(grant_ref_t ref)
285{
286 return gnttab_shared.v1[ref].flags & (GTF_reading|GTF_writing);
287}
288
289static int gnttab_query_foreign_access_v2(grant_ref_t ref)
290{
291 return grstatus[ref] & (GTF_reading|GTF_writing);
292}
293
294int gnttab_query_foreign_access(grant_ref_t ref)
295{
296 return gnttab_interface->query_foreign_access(ref);
297}
298EXPORT_SYMBOL_GPL(gnttab_query_foreign_access);
299
300static int gnttab_end_foreign_access_ref_v1(grant_ref_t ref, int readonly)
301{
302 u16 flags, nflags;
303 u16 *pflags;
304
305 pflags = &gnttab_shared.v1[ref].flags;
306 nflags = *pflags;
307 do {
308 flags = nflags;
309 if (flags & (GTF_reading|GTF_writing))
310 return 0;
311 } while ((nflags = sync_cmpxchg(pflags, flags, 0)) != flags);
312
313 return 1;
314}
315
316static int gnttab_end_foreign_access_ref_v2(grant_ref_t ref, int readonly)
317{
318 gnttab_shared.v2[ref].hdr.flags = 0;
319 mb(); /* Concurrent access by hypervisor. */
320 if (grstatus[ref] & (GTF_reading|GTF_writing)) {
321 return 0;
322 } else {
323 /*
324 * The read of grstatus needs to have acquire semantics.
325 * On x86, reads already have that, and we just need to
326 * protect against compiler reorderings.
327 * On other architectures we may need a full barrier.
328 */
329#ifdef CONFIG_X86
330 barrier();
331#else
332 mb();
333#endif
334 }
335
336 return 1;
337}
338
339static inline int _gnttab_end_foreign_access_ref(grant_ref_t ref, int readonly)
340{
341 return gnttab_interface->end_foreign_access_ref(ref, readonly);
342}
343
344int gnttab_end_foreign_access_ref(grant_ref_t ref, int readonly)
345{
346 if (_gnttab_end_foreign_access_ref(ref, readonly))
347 return 1;
348 pr_warn("WARNING: g.e. %#x still in use!\n", ref);
349 return 0;
350}
351EXPORT_SYMBOL_GPL(gnttab_end_foreign_access_ref);
352
353struct deferred_entry {
354 struct list_head list;
355 grant_ref_t ref;
356 bool ro;
357 uint16_t warn_delay;
358 struct page *page;
359};
360static LIST_HEAD(deferred_list);
361static void gnttab_handle_deferred(struct timer_list *);
362static DEFINE_TIMER(deferred_timer, gnttab_handle_deferred);
363
364static void gnttab_handle_deferred(struct timer_list *unused)
365{
366 unsigned int nr = 10;
367 struct deferred_entry *first = NULL;
368 unsigned long flags;
369
370 spin_lock_irqsave(&gnttab_list_lock, flags);
371 while (nr--) {
372 struct deferred_entry *entry
373 = list_first_entry(&deferred_list,
374 struct deferred_entry, list);
375
376 if (entry == first)
377 break;
378 list_del(&entry->list);
379 spin_unlock_irqrestore(&gnttab_list_lock, flags);
380 if (_gnttab_end_foreign_access_ref(entry->ref, entry->ro)) {
381 put_free_entry(entry->ref);
382 if (entry->page) {
383 pr_debug("freeing g.e. %#x (pfn %#lx)\n",
384 entry->ref, page_to_pfn(entry->page));
385 put_page(entry->page);
386 } else
387 pr_info("freeing g.e. %#x\n", entry->ref);
388 kfree(entry);
389 entry = NULL;
390 } else {
391 if (!--entry->warn_delay)
392 pr_info("g.e. %#x still pending\n", entry->ref);
393 if (!first)
394 first = entry;
395 }
396 spin_lock_irqsave(&gnttab_list_lock, flags);
397 if (entry)
398 list_add_tail(&entry->list, &deferred_list);
399 else if (list_empty(&deferred_list))
400 break;
401 }
402 if (!list_empty(&deferred_list) && !timer_pending(&deferred_timer)) {
403 deferred_timer.expires = jiffies + HZ;
404 add_timer(&deferred_timer);
405 }
406 spin_unlock_irqrestore(&gnttab_list_lock, flags);
407}
408
409static void gnttab_add_deferred(grant_ref_t ref, bool readonly,
410 struct page *page)
411{
412 struct deferred_entry *entry = kmalloc(sizeof(*entry), GFP_ATOMIC);
413 const char *what = KERN_WARNING "leaking";
414
415 if (entry) {
416 unsigned long flags;
417
418 entry->ref = ref;
419 entry->ro = readonly;
420 entry->page = page;
421 entry->warn_delay = 60;
422 spin_lock_irqsave(&gnttab_list_lock, flags);
423 list_add_tail(&entry->list, &deferred_list);
424 if (!timer_pending(&deferred_timer)) {
425 deferred_timer.expires = jiffies + HZ;
426 add_timer(&deferred_timer);
427 }
428 spin_unlock_irqrestore(&gnttab_list_lock, flags);
429 what = KERN_DEBUG "deferring";
430 }
431 printk("%s g.e. %#x (pfn %#lx)\n",
432 what, ref, page ? page_to_pfn(page) : -1);
433}
434
435void gnttab_end_foreign_access(grant_ref_t ref, int readonly,
436 unsigned long page)
437{
438 if (gnttab_end_foreign_access_ref(ref, readonly)) {
439 put_free_entry(ref);
440 if (page != 0)
441 put_page(virt_to_page(page));
442 } else
443 gnttab_add_deferred(ref, readonly,
444 page ? virt_to_page(page) : NULL);
445}
446EXPORT_SYMBOL_GPL(gnttab_end_foreign_access);
447
448int gnttab_grant_foreign_transfer(domid_t domid, unsigned long pfn)
449{
450 int ref;
451
452 ref = get_free_entries(1);
453 if (unlikely(ref < 0))
454 return -ENOSPC;
455 gnttab_grant_foreign_transfer_ref(ref, domid, pfn);
456
457 return ref;
458}
459EXPORT_SYMBOL_GPL(gnttab_grant_foreign_transfer);
460
461void gnttab_grant_foreign_transfer_ref(grant_ref_t ref, domid_t domid,
462 unsigned long pfn)
463{
464 gnttab_interface->update_entry(ref, domid, pfn, GTF_accept_transfer);
465}
466EXPORT_SYMBOL_GPL(gnttab_grant_foreign_transfer_ref);
467
468static unsigned long gnttab_end_foreign_transfer_ref_v1(grant_ref_t ref)
469{
470 unsigned long frame;
471 u16 flags;
472 u16 *pflags;
473
474 pflags = &gnttab_shared.v1[ref].flags;
475
476 /*
477 * If a transfer is not even yet started, try to reclaim the grant
478 * reference and return failure (== 0).
479 */
480 while (!((flags = *pflags) & GTF_transfer_committed)) {
481 if (sync_cmpxchg(pflags, flags, 0) == flags)
482 return 0;
483 cpu_relax();
484 }
485
486 /* If a transfer is in progress then wait until it is completed. */
487 while (!(flags & GTF_transfer_completed)) {
488 flags = *pflags;
489 cpu_relax();
490 }
491
492 rmb(); /* Read the frame number /after/ reading completion status. */
493 frame = gnttab_shared.v1[ref].frame;
494 BUG_ON(frame == 0);
495
496 return frame;
497}
498
499static unsigned long gnttab_end_foreign_transfer_ref_v2(grant_ref_t ref)
500{
501 unsigned long frame;
502 u16 flags;
503 u16 *pflags;
504
505 pflags = &gnttab_shared.v2[ref].hdr.flags;
506
507 /*
508 * If a transfer is not even yet started, try to reclaim the grant
509 * reference and return failure (== 0).
510 */
511 while (!((flags = *pflags) & GTF_transfer_committed)) {
512 if (sync_cmpxchg(pflags, flags, 0) == flags)
513 return 0;
514 cpu_relax();
515 }
516
517 /* If a transfer is in progress then wait until it is completed. */
518 while (!(flags & GTF_transfer_completed)) {
519 flags = *pflags;
520 cpu_relax();
521 }
522
523 rmb(); /* Read the frame number /after/ reading completion status. */
524 frame = gnttab_shared.v2[ref].full_page.frame;
525 BUG_ON(frame == 0);
526
527 return frame;
528}
529
530unsigned long gnttab_end_foreign_transfer_ref(grant_ref_t ref)
531{
532 return gnttab_interface->end_foreign_transfer_ref(ref);
533}
534EXPORT_SYMBOL_GPL(gnttab_end_foreign_transfer_ref);
535
536unsigned long gnttab_end_foreign_transfer(grant_ref_t ref)
537{
538 unsigned long frame = gnttab_end_foreign_transfer_ref(ref);
539 put_free_entry(ref);
540 return frame;
541}
542EXPORT_SYMBOL_GPL(gnttab_end_foreign_transfer);
543
544void gnttab_free_grant_reference(grant_ref_t ref)
545{
546 put_free_entry(ref);
547}
548EXPORT_SYMBOL_GPL(gnttab_free_grant_reference);
549
550void gnttab_free_grant_references(grant_ref_t head)
551{
552 grant_ref_t ref;
553 unsigned long flags;
554 int count = 1;
555 if (head == GNTTAB_LIST_END)
556 return;
557 spin_lock_irqsave(&gnttab_list_lock, flags);
558 ref = head;
559 while (gnttab_entry(ref) != GNTTAB_LIST_END) {
560 ref = gnttab_entry(ref);
561 count++;
562 }
563 gnttab_entry(ref) = gnttab_free_head;
564 gnttab_free_head = head;
565 gnttab_free_count += count;
566 check_free_callbacks();
567 spin_unlock_irqrestore(&gnttab_list_lock, flags);
568}
569EXPORT_SYMBOL_GPL(gnttab_free_grant_references);
570
571int gnttab_alloc_grant_references(u16 count, grant_ref_t *head)
572{
573 int h = get_free_entries(count);
574
575 if (h < 0)
576 return -ENOSPC;
577
578 *head = h;
579
580 return 0;
581}
582EXPORT_SYMBOL_GPL(gnttab_alloc_grant_references);
583
584int gnttab_empty_grant_references(const grant_ref_t *private_head)
585{
586 return (*private_head == GNTTAB_LIST_END);
587}
588EXPORT_SYMBOL_GPL(gnttab_empty_grant_references);
589
590int gnttab_claim_grant_reference(grant_ref_t *private_head)
591{
592 grant_ref_t g = *private_head;
593 if (unlikely(g == GNTTAB_LIST_END))
594 return -ENOSPC;
595 *private_head = gnttab_entry(g);
596 return g;
597}
598EXPORT_SYMBOL_GPL(gnttab_claim_grant_reference);
599
600void gnttab_release_grant_reference(grant_ref_t *private_head,
601 grant_ref_t release)
602{
603 gnttab_entry(release) = *private_head;
604 *private_head = release;
605}
606EXPORT_SYMBOL_GPL(gnttab_release_grant_reference);
607
608void gnttab_request_free_callback(struct gnttab_free_callback *callback,
609 void (*fn)(void *), void *arg, u16 count)
610{
611 unsigned long flags;
612 struct gnttab_free_callback *cb;
613
614 spin_lock_irqsave(&gnttab_list_lock, flags);
615
616 /* Check if the callback is already on the list */
617 cb = gnttab_free_callback_list;
618 while (cb) {
619 if (cb == callback)
620 goto out;
621 cb = cb->next;
622 }
623
624 callback->fn = fn;
625 callback->arg = arg;
626 callback->count = count;
627 callback->next = gnttab_free_callback_list;
628 gnttab_free_callback_list = callback;
629 check_free_callbacks();
630out:
631 spin_unlock_irqrestore(&gnttab_list_lock, flags);
632}
633EXPORT_SYMBOL_GPL(gnttab_request_free_callback);
634
635void gnttab_cancel_free_callback(struct gnttab_free_callback *callback)
636{
637 struct gnttab_free_callback **pcb;
638 unsigned long flags;
639
640 spin_lock_irqsave(&gnttab_list_lock, flags);
641 for (pcb = &gnttab_free_callback_list; *pcb; pcb = &(*pcb)->next) {
642 if (*pcb == callback) {
643 *pcb = callback->next;
644 break;
645 }
646 }
647 spin_unlock_irqrestore(&gnttab_list_lock, flags);
648}
649EXPORT_SYMBOL_GPL(gnttab_cancel_free_callback);
650
651static unsigned int gnttab_frames(unsigned int frames, unsigned int align)
652{
653 return (frames * gnttab_interface->grefs_per_grant_frame + align - 1) /
654 align;
655}
656
657static int grow_gnttab_list(unsigned int more_frames)
658{
659 unsigned int new_nr_grant_frames, extra_entries, i;
660 unsigned int nr_glist_frames, new_nr_glist_frames;
661 unsigned int grefs_per_frame;
662
663 BUG_ON(gnttab_interface == NULL);
664 grefs_per_frame = gnttab_interface->grefs_per_grant_frame;
665
666 new_nr_grant_frames = nr_grant_frames + more_frames;
667 extra_entries = more_frames * grefs_per_frame;
668
669 nr_glist_frames = gnttab_frames(nr_grant_frames, RPP);
670 new_nr_glist_frames = gnttab_frames(new_nr_grant_frames, RPP);
671 for (i = nr_glist_frames; i < new_nr_glist_frames; i++) {
672 gnttab_list[i] = (grant_ref_t *)__get_free_page(GFP_ATOMIC);
673 if (!gnttab_list[i])
674 goto grow_nomem;
675 }
676
677
678 for (i = grefs_per_frame * nr_grant_frames;
679 i < grefs_per_frame * new_nr_grant_frames - 1; i++)
680 gnttab_entry(i) = i + 1;
681
682 gnttab_entry(i) = gnttab_free_head;
683 gnttab_free_head = grefs_per_frame * nr_grant_frames;
684 gnttab_free_count += extra_entries;
685
686 nr_grant_frames = new_nr_grant_frames;
687
688 check_free_callbacks();
689
690 return 0;
691
692grow_nomem:
693 while (i-- > nr_glist_frames)
694 free_page((unsigned long) gnttab_list[i]);
695 return -ENOMEM;
696}
697
698static unsigned int __max_nr_grant_frames(void)
699{
700 struct gnttab_query_size query;
701 int rc;
702
703 query.dom = DOMID_SELF;
704
705 rc = HYPERVISOR_grant_table_op(GNTTABOP_query_size, &query, 1);
706 if ((rc < 0) || (query.status != GNTST_okay))
707 return 4; /* Legacy max supported number of frames */
708
709 return query.max_nr_frames;
710}
711
712unsigned int gnttab_max_grant_frames(void)
713{
714 unsigned int xen_max = __max_nr_grant_frames();
715 static unsigned int boot_max_nr_grant_frames;
716
717 /* First time, initialize it properly. */
718 if (!boot_max_nr_grant_frames)
719 boot_max_nr_grant_frames = __max_nr_grant_frames();
720
721 if (xen_max > boot_max_nr_grant_frames)
722 return boot_max_nr_grant_frames;
723 return xen_max;
724}
725EXPORT_SYMBOL_GPL(gnttab_max_grant_frames);
726
727int gnttab_setup_auto_xlat_frames(phys_addr_t addr)
728{
729 xen_pfn_t *pfn;
730 unsigned int max_nr_gframes = __max_nr_grant_frames();
731 unsigned int i;
732 void *vaddr;
733
734 if (xen_auto_xlat_grant_frames.count)
735 return -EINVAL;
736
737 vaddr = xen_remap(addr, XEN_PAGE_SIZE * max_nr_gframes);
738 if (vaddr == NULL) {
739 pr_warn("Failed to ioremap gnttab share frames (addr=%pa)!\n",
740 &addr);
741 return -ENOMEM;
742 }
743 pfn = kcalloc(max_nr_gframes, sizeof(pfn[0]), GFP_KERNEL);
744 if (!pfn) {
745 xen_unmap(vaddr);
746 return -ENOMEM;
747 }
748 for (i = 0; i < max_nr_gframes; i++)
749 pfn[i] = XEN_PFN_DOWN(addr) + i;
750
751 xen_auto_xlat_grant_frames.vaddr = vaddr;
752 xen_auto_xlat_grant_frames.pfn = pfn;
753 xen_auto_xlat_grant_frames.count = max_nr_gframes;
754
755 return 0;
756}
757EXPORT_SYMBOL_GPL(gnttab_setup_auto_xlat_frames);
758
759void gnttab_free_auto_xlat_frames(void)
760{
761 if (!xen_auto_xlat_grant_frames.count)
762 return;
763 kfree(xen_auto_xlat_grant_frames.pfn);
764 xen_unmap(xen_auto_xlat_grant_frames.vaddr);
765
766 xen_auto_xlat_grant_frames.pfn = NULL;
767 xen_auto_xlat_grant_frames.count = 0;
768 xen_auto_xlat_grant_frames.vaddr = NULL;
769}
770EXPORT_SYMBOL_GPL(gnttab_free_auto_xlat_frames);
771
772/**
773 * gnttab_alloc_pages - alloc pages suitable for grant mapping into
774 * @nr_pages: number of pages to alloc
775 * @pages: returns the pages
776 */
777int gnttab_alloc_pages(int nr_pages, struct page **pages)
778{
779 int i;
780 int ret;
781
782 ret = alloc_xenballooned_pages(nr_pages, pages);
783 if (ret < 0)
784 return ret;
785
786 for (i = 0; i < nr_pages; i++) {
787#if BITS_PER_LONG < 64
788 struct xen_page_foreign *foreign;
789
790 foreign = kzalloc(sizeof(*foreign), GFP_KERNEL);
791 if (!foreign) {
792 gnttab_free_pages(nr_pages, pages);
793 return -ENOMEM;
794 }
795 set_page_private(pages[i], (unsigned long)foreign);
796#endif
797 SetPagePrivate(pages[i]);
798 }
799
800 return 0;
801}
802EXPORT_SYMBOL(gnttab_alloc_pages);
803
804/**
805 * gnttab_free_pages - free pages allocated by gnttab_alloc_pages()
806 * @nr_pages; number of pages to free
807 * @pages: the pages
808 */
809void gnttab_free_pages(int nr_pages, struct page **pages)
810{
811 int i;
812
813 for (i = 0; i < nr_pages; i++) {
814 if (PagePrivate(pages[i])) {
815#if BITS_PER_LONG < 64
816 kfree((void *)page_private(pages[i]));
817#endif
818 ClearPagePrivate(pages[i]);
819 }
820 }
821 free_xenballooned_pages(nr_pages, pages);
822}
823EXPORT_SYMBOL(gnttab_free_pages);
824
825/* Handling of paged out grant targets (GNTST_eagain) */
826#define MAX_DELAY 256
827static inline void
828gnttab_retry_eagain_gop(unsigned int cmd, void *gop, int16_t *status,
829 const char *func)
830{
831 unsigned delay = 1;
832
833 do {
834 BUG_ON(HYPERVISOR_grant_table_op(cmd, gop, 1));
835 if (*status == GNTST_eagain)
836 msleep(delay++);
837 } while ((*status == GNTST_eagain) && (delay < MAX_DELAY));
838
839 if (delay >= MAX_DELAY) {
840 pr_err("%s: %s eagain grant\n", func, current->comm);
841 *status = GNTST_bad_page;
842 }
843}
844
845void gnttab_batch_map(struct gnttab_map_grant_ref *batch, unsigned count)
846{
847 struct gnttab_map_grant_ref *op;
848
849 if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, batch, count))
850 BUG();
851 for (op = batch; op < batch + count; op++)
852 if (op->status == GNTST_eagain)
853 gnttab_retry_eagain_gop(GNTTABOP_map_grant_ref, op,
854 &op->status, __func__);
855}
856EXPORT_SYMBOL_GPL(gnttab_batch_map);
857
858void gnttab_batch_copy(struct gnttab_copy *batch, unsigned count)
859{
860 struct gnttab_copy *op;
861
862 if (HYPERVISOR_grant_table_op(GNTTABOP_copy, batch, count))
863 BUG();
864 for (op = batch; op < batch + count; op++)
865 if (op->status == GNTST_eagain)
866 gnttab_retry_eagain_gop(GNTTABOP_copy, op,
867 &op->status, __func__);
868}
869EXPORT_SYMBOL_GPL(gnttab_batch_copy);
870
871void gnttab_foreach_grant_in_range(struct page *page,
872 unsigned int offset,
873 unsigned int len,
874 xen_grant_fn_t fn,
875 void *data)
876{
877 unsigned int goffset;
878 unsigned int glen;
879 unsigned long xen_pfn;
880
881 len = min_t(unsigned int, PAGE_SIZE - offset, len);
882 goffset = xen_offset_in_page(offset);
883
884 xen_pfn = page_to_xen_pfn(page) + XEN_PFN_DOWN(offset);
885
886 while (len) {
887 glen = min_t(unsigned int, XEN_PAGE_SIZE - goffset, len);
888 fn(pfn_to_gfn(xen_pfn), goffset, glen, data);
889
890 goffset = 0;
891 xen_pfn++;
892 len -= glen;
893 }
894}
895EXPORT_SYMBOL_GPL(gnttab_foreach_grant_in_range);
896
897void gnttab_foreach_grant(struct page **pages,
898 unsigned int nr_grefs,
899 xen_grant_fn_t fn,
900 void *data)
901{
902 unsigned int goffset = 0;
903 unsigned long xen_pfn = 0;
904 unsigned int i;
905
906 for (i = 0; i < nr_grefs; i++) {
907 if ((i % XEN_PFN_PER_PAGE) == 0) {
908 xen_pfn = page_to_xen_pfn(pages[i / XEN_PFN_PER_PAGE]);
909 goffset = 0;
910 }
911
912 fn(pfn_to_gfn(xen_pfn), goffset, XEN_PAGE_SIZE, data);
913
914 goffset += XEN_PAGE_SIZE;
915 xen_pfn++;
916 }
917}
918
919int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
920 struct gnttab_map_grant_ref *kmap_ops,
921 struct page **pages, unsigned int count)
922{
923 int i, ret;
924
925 ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, map_ops, count);
926 if (ret)
927 return ret;
928
929 for (i = 0; i < count; i++) {
930 /* Retry eagain maps */
931 if (map_ops[i].status == GNTST_eagain)
932 gnttab_retry_eagain_gop(GNTTABOP_map_grant_ref, map_ops + i,
933 &map_ops[i].status, __func__);
934
935 if (map_ops[i].status == GNTST_okay) {
936 struct xen_page_foreign *foreign;
937
938 SetPageForeign(pages[i]);
939 foreign = xen_page_foreign(pages[i]);
940 foreign->domid = map_ops[i].dom;
941 foreign->gref = map_ops[i].ref;
942 }
943 }
944
945 return set_foreign_p2m_mapping(map_ops, kmap_ops, pages, count);
946}
947EXPORT_SYMBOL_GPL(gnttab_map_refs);
948
949int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
950 struct gnttab_unmap_grant_ref *kunmap_ops,
951 struct page **pages, unsigned int count)
952{
953 unsigned int i;
954 int ret;
955
956 ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap_ops, count);
957 if (ret)
958 return ret;
959
960 for (i = 0; i < count; i++)
961 ClearPageForeign(pages[i]);
962
963 return clear_foreign_p2m_mapping(unmap_ops, kunmap_ops, pages, count);
964}
965EXPORT_SYMBOL_GPL(gnttab_unmap_refs);
966
967#define GNTTAB_UNMAP_REFS_DELAY 5
968
969static void __gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item);
970
971static void gnttab_unmap_work(struct work_struct *work)
972{
973 struct gntab_unmap_queue_data
974 *unmap_data = container_of(work,
975 struct gntab_unmap_queue_data,
976 gnttab_work.work);
977 if (unmap_data->age != UINT_MAX)
978 unmap_data->age++;
979 __gnttab_unmap_refs_async(unmap_data);
980}
981
982static void __gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item)
983{
984 int ret;
985 int pc;
986
987 for (pc = 0; pc < item->count; pc++) {
988 if (page_count(item->pages[pc]) > 1) {
989 unsigned long delay = GNTTAB_UNMAP_REFS_DELAY * (item->age + 1);
990 schedule_delayed_work(&item->gnttab_work,
991 msecs_to_jiffies(delay));
992 return;
993 }
994 }
995
996 ret = gnttab_unmap_refs(item->unmap_ops, item->kunmap_ops,
997 item->pages, item->count);
998 item->done(ret, item);
999}
1000
1001void gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item)
1002{
1003 INIT_DELAYED_WORK(&item->gnttab_work, gnttab_unmap_work);
1004 item->age = 0;
1005
1006 __gnttab_unmap_refs_async(item);
1007}
1008EXPORT_SYMBOL_GPL(gnttab_unmap_refs_async);
1009
1010static void unmap_refs_callback(int result,
1011 struct gntab_unmap_queue_data *data)
1012{
1013 struct unmap_refs_callback_data *d = data->data;
1014
1015 d->result = result;
1016 complete(&d->completion);
1017}
1018
1019int gnttab_unmap_refs_sync(struct gntab_unmap_queue_data *item)
1020{
1021 struct unmap_refs_callback_data data;
1022
1023 init_completion(&data.completion);
1024 item->data = &data;
1025 item->done = &unmap_refs_callback;
1026 gnttab_unmap_refs_async(item);
1027 wait_for_completion(&data.completion);
1028
1029 return data.result;
1030}
1031EXPORT_SYMBOL_GPL(gnttab_unmap_refs_sync);
1032
1033static unsigned int nr_status_frames(unsigned int nr_grant_frames)
1034{
1035 BUG_ON(gnttab_interface == NULL);
1036 return gnttab_frames(nr_grant_frames, SPP);
1037}
1038
1039static int gnttab_map_frames_v1(xen_pfn_t *frames, unsigned int nr_gframes)
1040{
1041 int rc;
1042
1043 rc = arch_gnttab_map_shared(frames, nr_gframes,
1044 gnttab_max_grant_frames(),
1045 &gnttab_shared.addr);
1046 BUG_ON(rc);
1047
1048 return 0;
1049}
1050
1051static void gnttab_unmap_frames_v1(void)
1052{
1053 arch_gnttab_unmap(gnttab_shared.addr, nr_grant_frames);
1054}
1055
1056static int gnttab_map_frames_v2(xen_pfn_t *frames, unsigned int nr_gframes)
1057{
1058 uint64_t *sframes;
1059 unsigned int nr_sframes;
1060 struct gnttab_get_status_frames getframes;
1061 int rc;
1062
1063 nr_sframes = nr_status_frames(nr_gframes);
1064
1065 /* No need for kzalloc as it is initialized in following hypercall
1066 * GNTTABOP_get_status_frames.
1067 */
1068 sframes = kmalloc_array(nr_sframes, sizeof(uint64_t), GFP_ATOMIC);
1069 if (!sframes)
1070 return -ENOMEM;
1071
1072 getframes.dom = DOMID_SELF;
1073 getframes.nr_frames = nr_sframes;
1074 set_xen_guest_handle(getframes.frame_list, sframes);
1075
1076 rc = HYPERVISOR_grant_table_op(GNTTABOP_get_status_frames,
1077 &getframes, 1);
1078 if (rc == -ENOSYS) {
1079 kfree(sframes);
1080 return -ENOSYS;
1081 }
1082
1083 BUG_ON(rc || getframes.status);
1084
1085 rc = arch_gnttab_map_status(sframes, nr_sframes,
1086 nr_status_frames(gnttab_max_grant_frames()),
1087 &grstatus);
1088 BUG_ON(rc);
1089 kfree(sframes);
1090
1091 rc = arch_gnttab_map_shared(frames, nr_gframes,
1092 gnttab_max_grant_frames(),
1093 &gnttab_shared.addr);
1094 BUG_ON(rc);
1095
1096 return 0;
1097}
1098
1099static void gnttab_unmap_frames_v2(void)
1100{
1101 arch_gnttab_unmap(gnttab_shared.addr, nr_grant_frames);
1102 arch_gnttab_unmap(grstatus, nr_status_frames(nr_grant_frames));
1103}
1104
1105static int gnttab_map(unsigned int start_idx, unsigned int end_idx)
1106{
1107 struct gnttab_setup_table setup;
1108 xen_pfn_t *frames;
1109 unsigned int nr_gframes = end_idx + 1;
1110 int rc;
1111
1112 if (xen_feature(XENFEAT_auto_translated_physmap)) {
1113 struct xen_add_to_physmap xatp;
1114 unsigned int i = end_idx;
1115 rc = 0;
1116 BUG_ON(xen_auto_xlat_grant_frames.count < nr_gframes);
1117 /*
1118 * Loop backwards, so that the first hypercall has the largest
1119 * index, ensuring that the table will grow only once.
1120 */
1121 do {
1122 xatp.domid = DOMID_SELF;
1123 xatp.idx = i;
1124 xatp.space = XENMAPSPACE_grant_table;
1125 xatp.gpfn = xen_auto_xlat_grant_frames.pfn[i];
1126 rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp);
1127 if (rc != 0) {
1128 pr_warn("grant table add_to_physmap failed, err=%d\n",
1129 rc);
1130 break;
1131 }
1132 } while (i-- > start_idx);
1133
1134 return rc;
1135 }
1136
1137 /* No need for kzalloc as it is initialized in following hypercall
1138 * GNTTABOP_setup_table.
1139 */
1140 frames = kmalloc(nr_gframes * sizeof(unsigned long), GFP_ATOMIC);
1141 if (!frames)
1142 return -ENOMEM;
1143
1144 setup.dom = DOMID_SELF;
1145 setup.nr_frames = nr_gframes;
1146 set_xen_guest_handle(setup.frame_list, frames);
1147
1148 rc = HYPERVISOR_grant_table_op(GNTTABOP_setup_table, &setup, 1);
1149 if (rc == -ENOSYS) {
1150 kfree(frames);
1151 return -ENOSYS;
1152 }
1153
1154 BUG_ON(rc || setup.status);
1155
1156 rc = gnttab_interface->map_frames(frames, nr_gframes);
1157
1158 kfree(frames);
1159
1160 return rc;
1161}
1162
1163static const struct gnttab_ops gnttab_v1_ops = {
1164 .version = 1,
1165 .grefs_per_grant_frame = XEN_PAGE_SIZE /
1166 sizeof(struct grant_entry_v1),
1167 .map_frames = gnttab_map_frames_v1,
1168 .unmap_frames = gnttab_unmap_frames_v1,
1169 .update_entry = gnttab_update_entry_v1,
1170 .end_foreign_access_ref = gnttab_end_foreign_access_ref_v1,
1171 .end_foreign_transfer_ref = gnttab_end_foreign_transfer_ref_v1,
1172 .query_foreign_access = gnttab_query_foreign_access_v1,
1173};
1174
1175static const struct gnttab_ops gnttab_v2_ops = {
1176 .version = 2,
1177 .grefs_per_grant_frame = XEN_PAGE_SIZE /
1178 sizeof(union grant_entry_v2),
1179 .map_frames = gnttab_map_frames_v2,
1180 .unmap_frames = gnttab_unmap_frames_v2,
1181 .update_entry = gnttab_update_entry_v2,
1182 .end_foreign_access_ref = gnttab_end_foreign_access_ref_v2,
1183 .end_foreign_transfer_ref = gnttab_end_foreign_transfer_ref_v2,
1184 .query_foreign_access = gnttab_query_foreign_access_v2,
1185};
1186
1187static bool gnttab_need_v2(void)
1188{
1189#ifdef CONFIG_X86
1190 uint32_t base, width;
1191
1192 if (xen_pv_domain()) {
1193 base = xen_cpuid_base();
1194 if (cpuid_eax(base) < 5)
1195 return false; /* Information not available, use V1. */
1196 width = cpuid_ebx(base + 5) &
1197 XEN_CPUID_MACHINE_ADDRESS_WIDTH_MASK;
1198 return width > 32 + PAGE_SHIFT;
1199 }
1200#endif
1201 return !!(max_possible_pfn >> 32);
1202}
1203
1204static void gnttab_request_version(void)
1205{
1206 long rc;
1207 struct gnttab_set_version gsv;
1208
1209 if (gnttab_need_v2())
1210 gsv.version = 2;
1211 else
1212 gsv.version = 1;
1213
1214 /* Boot parameter overrides automatic selection. */
1215 if (xen_gnttab_version >= 1 && xen_gnttab_version <= 2)
1216 gsv.version = xen_gnttab_version;
1217
1218 rc = HYPERVISOR_grant_table_op(GNTTABOP_set_version, &gsv, 1);
1219 if (rc == 0 && gsv.version == 2)
1220 gnttab_interface = &gnttab_v2_ops;
1221 else
1222 gnttab_interface = &gnttab_v1_ops;
1223 pr_info("Grant tables using version %d layout\n",
1224 gnttab_interface->version);
1225}
1226
1227static int gnttab_setup(void)
1228{
1229 unsigned int max_nr_gframes;
1230
1231 max_nr_gframes = gnttab_max_grant_frames();
1232 if (max_nr_gframes < nr_grant_frames)
1233 return -ENOSYS;
1234
1235 if (xen_feature(XENFEAT_auto_translated_physmap) && gnttab_shared.addr == NULL) {
1236 gnttab_shared.addr = xen_auto_xlat_grant_frames.vaddr;
1237 if (gnttab_shared.addr == NULL) {
1238 pr_warn("gnttab share frames (addr=0x%08lx) is not mapped!\n",
1239 (unsigned long)xen_auto_xlat_grant_frames.vaddr);
1240 return -ENOMEM;
1241 }
1242 }
1243 return gnttab_map(0, nr_grant_frames - 1);
1244}
1245
1246int gnttab_resume(void)
1247{
1248 gnttab_request_version();
1249 return gnttab_setup();
1250}
1251
1252int gnttab_suspend(void)
1253{
1254 if (!xen_feature(XENFEAT_auto_translated_physmap))
1255 gnttab_interface->unmap_frames();
1256 return 0;
1257}
1258
1259static int gnttab_expand(unsigned int req_entries)
1260{
1261 int rc;
1262 unsigned int cur, extra;
1263
1264 BUG_ON(gnttab_interface == NULL);
1265 cur = nr_grant_frames;
1266 extra = ((req_entries + gnttab_interface->grefs_per_grant_frame - 1) /
1267 gnttab_interface->grefs_per_grant_frame);
1268 if (cur + extra > gnttab_max_grant_frames()) {
1269 pr_warn_ratelimited("xen/grant-table: max_grant_frames reached"
1270 " cur=%u extra=%u limit=%u"
1271 " gnttab_free_count=%u req_entries=%u\n",
1272 cur, extra, gnttab_max_grant_frames(),
1273 gnttab_free_count, req_entries);
1274 return -ENOSPC;
1275 }
1276
1277 rc = gnttab_map(cur, cur + extra - 1);
1278 if (rc == 0)
1279 rc = grow_gnttab_list(extra);
1280
1281 return rc;
1282}
1283
1284int gnttab_init(void)
1285{
1286 int i;
1287 unsigned long max_nr_grant_frames;
1288 unsigned int max_nr_glist_frames, nr_glist_frames;
1289 unsigned int nr_init_grefs;
1290 int ret;
1291
1292 gnttab_request_version();
1293 max_nr_grant_frames = gnttab_max_grant_frames();
1294 nr_grant_frames = 1;
1295
1296 /* Determine the maximum number of frames required for the
1297 * grant reference free list on the current hypervisor.
1298 */
1299 BUG_ON(gnttab_interface == NULL);
1300 max_nr_glist_frames = (max_nr_grant_frames *
1301 gnttab_interface->grefs_per_grant_frame / RPP);
1302
1303 gnttab_list = kmalloc(max_nr_glist_frames * sizeof(grant_ref_t *),
1304 GFP_KERNEL);
1305 if (gnttab_list == NULL)
1306 return -ENOMEM;
1307
1308 nr_glist_frames = gnttab_frames(nr_grant_frames, RPP);
1309 for (i = 0; i < nr_glist_frames; i++) {
1310 gnttab_list[i] = (grant_ref_t *)__get_free_page(GFP_KERNEL);
1311 if (gnttab_list[i] == NULL) {
1312 ret = -ENOMEM;
1313 goto ini_nomem;
1314 }
1315 }
1316
1317 ret = arch_gnttab_init(max_nr_grant_frames,
1318 nr_status_frames(max_nr_grant_frames));
1319 if (ret < 0)
1320 goto ini_nomem;
1321
1322 if (gnttab_setup() < 0) {
1323 ret = -ENODEV;
1324 goto ini_nomem;
1325 }
1326
1327 nr_init_grefs = nr_grant_frames *
1328 gnttab_interface->grefs_per_grant_frame;
1329
1330 for (i = NR_RESERVED_ENTRIES; i < nr_init_grefs - 1; i++)
1331 gnttab_entry(i) = i + 1;
1332
1333 gnttab_entry(nr_init_grefs - 1) = GNTTAB_LIST_END;
1334 gnttab_free_count = nr_init_grefs - NR_RESERVED_ENTRIES;
1335 gnttab_free_head = NR_RESERVED_ENTRIES;
1336
1337 printk("Grant table initialized\n");
1338 return 0;
1339
1340 ini_nomem:
1341 for (i--; i >= 0; i--)
1342 free_page((unsigned long)gnttab_list[i]);
1343 kfree(gnttab_list);
1344 return ret;
1345}
1346EXPORT_SYMBOL_GPL(gnttab_init);
1347
1348static int __gnttab_init(void)
1349{
1350 if (!xen_domain())
1351 return -ENODEV;
1352
1353 /* Delay grant-table initialization in the PV on HVM case */
1354 if (xen_hvm_domain() && !xen_pvh_domain())
1355 return 0;
1356
1357 return gnttab_init();
1358}
1359/* Starts after core_initcall so that xen_pvh_gnttab_setup can be called
1360 * beforehand to initialize xen_auto_xlat_grant_frames. */
1361core_initcall_sync(__gnttab_init);