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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#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/pgtable.h>
68#include <asm/sync_bitops.h>
69
70/* External tools reserve first few grant table entries. */
71#define NR_RESERVED_ENTRIES 8
72#define GNTTAB_LIST_END 0xffffffff
73
74static grant_ref_t **gnttab_list;
75static unsigned int nr_grant_frames;
76static int gnttab_free_count;
77static grant_ref_t gnttab_free_head;
78static DEFINE_SPINLOCK(gnttab_list_lock);
79struct grant_frames xen_auto_xlat_grant_frames;
80static unsigned int xen_gnttab_version;
81module_param_named(version, xen_gnttab_version, uint, 0);
82
83static union {
84 struct grant_entry_v1 *v1;
85 union grant_entry_v2 *v2;
86 void *addr;
87} gnttab_shared;
88
89/*This is a structure of function pointers for grant table*/
90struct gnttab_ops {
91 /*
92 * Version of the grant interface.
93 */
94 unsigned int version;
95 /*
96 * Grant refs per grant frame.
97 */
98 unsigned int grefs_per_grant_frame;
99 /*
100 * Mapping a list of frames for storing grant entries. Frames parameter
101 * is used to store grant table address when grant table being setup,
102 * nr_gframes is the number of frames to map grant table. Returning
103 * GNTST_okay means success and negative value means failure.
104 */
105 int (*map_frames)(xen_pfn_t *frames, unsigned int nr_gframes);
106 /*
107 * Release a list of frames which are mapped in map_frames for grant
108 * entry status.
109 */
110 void (*unmap_frames)(void);
111 /*
112 * Introducing a valid entry into the grant table, granting the frame of
113 * this grant entry to domain for accessing or transfering. Ref
114 * parameter is reference of this introduced grant entry, domid is id of
115 * granted domain, frame is the page frame to be granted, and flags is
116 * status of the grant entry to be updated.
117 */
118 void (*update_entry)(grant_ref_t ref, domid_t domid,
119 unsigned long frame, unsigned flags);
120 /*
121 * Stop granting a grant entry to domain for accessing. Ref parameter is
122 * reference of a grant entry whose grant access will be stopped,
123 * readonly is not in use in this function. If the grant entry is
124 * currently mapped for reading or writing, just return failure(==0)
125 * directly and don't tear down the grant access. Otherwise, stop grant
126 * access for this entry and return success(==1).
127 */
128 int (*end_foreign_access_ref)(grant_ref_t ref, int readonly);
129 /*
130 * Stop granting a grant entry to domain for transfer. Ref parameter is
131 * reference of a grant entry whose grant transfer will be stopped. If
132 * tranfer has not started, just reclaim the grant entry and return
133 * failure(==0). Otherwise, wait for the transfer to complete and then
134 * return the frame.
135 */
136 unsigned long (*end_foreign_transfer_ref)(grant_ref_t ref);
137 /*
138 * Query the status of a grant entry. Ref parameter is reference of
139 * queried grant entry, return value is the status of queried entry.
140 * Detailed status(writing/reading) can be gotten from the return value
141 * by bit operations.
142 */
143 int (*query_foreign_access)(grant_ref_t ref);
144};
145
146struct unmap_refs_callback_data {
147 struct completion completion;
148 int result;
149};
150
151static const struct gnttab_ops *gnttab_interface;
152
153/* This reflects status of grant entries, so act as a global value. */
154static grant_status_t *grstatus;
155
156static struct gnttab_free_callback *gnttab_free_callback_list;
157
158static int gnttab_expand(unsigned int req_entries);
159
160#define RPP (PAGE_SIZE / sizeof(grant_ref_t))
161#define SPP (PAGE_SIZE / sizeof(grant_status_t))
162
163static inline grant_ref_t *__gnttab_entry(grant_ref_t entry)
164{
165 return &gnttab_list[(entry) / RPP][(entry) % RPP];
166}
167/* This can be used as an l-value */
168#define gnttab_entry(entry) (*__gnttab_entry(entry))
169
170static int get_free_entries(unsigned count)
171{
172 unsigned long flags;
173 int ref, rc = 0;
174 grant_ref_t head;
175
176 spin_lock_irqsave(&gnttab_list_lock, flags);
177
178 if ((gnttab_free_count < count) &&
179 ((rc = gnttab_expand(count - gnttab_free_count)) < 0)) {
180 spin_unlock_irqrestore(&gnttab_list_lock, flags);
181 return rc;
182 }
183
184 ref = head = gnttab_free_head;
185 gnttab_free_count -= count;
186 while (count-- > 1)
187 head = gnttab_entry(head);
188 gnttab_free_head = gnttab_entry(head);
189 gnttab_entry(head) = GNTTAB_LIST_END;
190
191 spin_unlock_irqrestore(&gnttab_list_lock, flags);
192
193 return ref;
194}
195
196static void do_free_callbacks(void)
197{
198 struct gnttab_free_callback *callback, *next;
199
200 callback = gnttab_free_callback_list;
201 gnttab_free_callback_list = NULL;
202
203 while (callback != NULL) {
204 next = callback->next;
205 if (gnttab_free_count >= callback->count) {
206 callback->next = NULL;
207 callback->fn(callback->arg);
208 } else {
209 callback->next = gnttab_free_callback_list;
210 gnttab_free_callback_list = callback;
211 }
212 callback = next;
213 }
214}
215
216static inline void check_free_callbacks(void)
217{
218 if (unlikely(gnttab_free_callback_list))
219 do_free_callbacks();
220}
221
222static void put_free_entry(grant_ref_t ref)
223{
224 unsigned long flags;
225 spin_lock_irqsave(&gnttab_list_lock, flags);
226 gnttab_entry(ref) = gnttab_free_head;
227 gnttab_free_head = ref;
228 gnttab_free_count++;
229 check_free_callbacks();
230 spin_unlock_irqrestore(&gnttab_list_lock, flags);
231}
232
233/*
234 * Following applies to gnttab_update_entry_v1 and gnttab_update_entry_v2.
235 * Introducing a valid entry into the grant table:
236 * 1. Write ent->domid.
237 * 2. Write ent->frame:
238 * GTF_permit_access: Frame to which access is permitted.
239 * GTF_accept_transfer: Pseudo-phys frame slot being filled by new
240 * frame, or zero if none.
241 * 3. Write memory barrier (WMB).
242 * 4. Write ent->flags, inc. valid type.
243 */
244static void gnttab_update_entry_v1(grant_ref_t ref, domid_t domid,
245 unsigned long frame, unsigned flags)
246{
247 gnttab_shared.v1[ref].domid = domid;
248 gnttab_shared.v1[ref].frame = frame;
249 wmb();
250 gnttab_shared.v1[ref].flags = flags;
251}
252
253static void gnttab_update_entry_v2(grant_ref_t ref, domid_t domid,
254 unsigned long frame, unsigned int flags)
255{
256 gnttab_shared.v2[ref].hdr.domid = domid;
257 gnttab_shared.v2[ref].full_page.frame = frame;
258 wmb(); /* Hypervisor concurrent accesses. */
259 gnttab_shared.v2[ref].hdr.flags = GTF_permit_access | flags;
260}
261
262/*
263 * Public grant-issuing interface functions
264 */
265void gnttab_grant_foreign_access_ref(grant_ref_t ref, domid_t domid,
266 unsigned long frame, int readonly)
267{
268 gnttab_interface->update_entry(ref, domid, frame,
269 GTF_permit_access | (readonly ? GTF_readonly : 0));
270}
271EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access_ref);
272
273int gnttab_grant_foreign_access(domid_t domid, unsigned long frame,
274 int readonly)
275{
276 int ref;
277
278 ref = get_free_entries(1);
279 if (unlikely(ref < 0))
280 return -ENOSPC;
281
282 gnttab_grant_foreign_access_ref(ref, domid, frame, readonly);
283
284 return ref;
285}
286EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access);
287
288static int gnttab_query_foreign_access_v1(grant_ref_t ref)
289{
290 return gnttab_shared.v1[ref].flags & (GTF_reading|GTF_writing);
291}
292
293static int gnttab_query_foreign_access_v2(grant_ref_t ref)
294{
295 return grstatus[ref] & (GTF_reading|GTF_writing);
296}
297
298int gnttab_query_foreign_access(grant_ref_t ref)
299{
300 return gnttab_interface->query_foreign_access(ref);
301}
302EXPORT_SYMBOL_GPL(gnttab_query_foreign_access);
303
304static int gnttab_end_foreign_access_ref_v1(grant_ref_t ref, int readonly)
305{
306 u16 flags, nflags;
307 u16 *pflags;
308
309 pflags = &gnttab_shared.v1[ref].flags;
310 nflags = *pflags;
311 do {
312 flags = nflags;
313 if (flags & (GTF_reading|GTF_writing))
314 return 0;
315 } while ((nflags = sync_cmpxchg(pflags, flags, 0)) != flags);
316
317 return 1;
318}
319
320static int gnttab_end_foreign_access_ref_v2(grant_ref_t ref, int readonly)
321{
322 gnttab_shared.v2[ref].hdr.flags = 0;
323 mb(); /* Concurrent access by hypervisor. */
324 if (grstatus[ref] & (GTF_reading|GTF_writing)) {
325 return 0;
326 } else {
327 /*
328 * The read of grstatus needs to have acquire semantics.
329 * On x86, reads already have that, and we just need to
330 * protect against compiler reorderings.
331 * On other architectures we may need a full barrier.
332 */
333#ifdef CONFIG_X86
334 barrier();
335#else
336 mb();
337#endif
338 }
339
340 return 1;
341}
342
343static inline int _gnttab_end_foreign_access_ref(grant_ref_t ref, int readonly)
344{
345 return gnttab_interface->end_foreign_access_ref(ref, readonly);
346}
347
348int gnttab_end_foreign_access_ref(grant_ref_t ref, int readonly)
349{
350 if (_gnttab_end_foreign_access_ref(ref, readonly))
351 return 1;
352 pr_warn("WARNING: g.e. %#x still in use!\n", ref);
353 return 0;
354}
355EXPORT_SYMBOL_GPL(gnttab_end_foreign_access_ref);
356
357struct deferred_entry {
358 struct list_head list;
359 grant_ref_t ref;
360 bool ro;
361 uint16_t warn_delay;
362 struct page *page;
363};
364static LIST_HEAD(deferred_list);
365static void gnttab_handle_deferred(struct timer_list *);
366static DEFINE_TIMER(deferred_timer, gnttab_handle_deferred);
367
368static void gnttab_handle_deferred(struct timer_list *unused)
369{
370 unsigned int nr = 10;
371 struct deferred_entry *first = NULL;
372 unsigned long flags;
373
374 spin_lock_irqsave(&gnttab_list_lock, flags);
375 while (nr--) {
376 struct deferred_entry *entry
377 = list_first_entry(&deferred_list,
378 struct deferred_entry, list);
379
380 if (entry == first)
381 break;
382 list_del(&entry->list);
383 spin_unlock_irqrestore(&gnttab_list_lock, flags);
384 if (_gnttab_end_foreign_access_ref(entry->ref, entry->ro)) {
385 put_free_entry(entry->ref);
386 if (entry->page) {
387 pr_debug("freeing g.e. %#x (pfn %#lx)\n",
388 entry->ref, page_to_pfn(entry->page));
389 put_page(entry->page);
390 } else
391 pr_info("freeing g.e. %#x\n", entry->ref);
392 kfree(entry);
393 entry = NULL;
394 } else {
395 if (!--entry->warn_delay)
396 pr_info("g.e. %#x still pending\n", entry->ref);
397 if (!first)
398 first = entry;
399 }
400 spin_lock_irqsave(&gnttab_list_lock, flags);
401 if (entry)
402 list_add_tail(&entry->list, &deferred_list);
403 else if (list_empty(&deferred_list))
404 break;
405 }
406 if (!list_empty(&deferred_list) && !timer_pending(&deferred_timer)) {
407 deferred_timer.expires = jiffies + HZ;
408 add_timer(&deferred_timer);
409 }
410 spin_unlock_irqrestore(&gnttab_list_lock, flags);
411}
412
413static void gnttab_add_deferred(grant_ref_t ref, bool readonly,
414 struct page *page)
415{
416 struct deferred_entry *entry = kmalloc(sizeof(*entry), GFP_ATOMIC);
417 const char *what = KERN_WARNING "leaking";
418
419 if (entry) {
420 unsigned long flags;
421
422 entry->ref = ref;
423 entry->ro = readonly;
424 entry->page = page;
425 entry->warn_delay = 60;
426 spin_lock_irqsave(&gnttab_list_lock, flags);
427 list_add_tail(&entry->list, &deferred_list);
428 if (!timer_pending(&deferred_timer)) {
429 deferred_timer.expires = jiffies + HZ;
430 add_timer(&deferred_timer);
431 }
432 spin_unlock_irqrestore(&gnttab_list_lock, flags);
433 what = KERN_DEBUG "deferring";
434 }
435 printk("%s g.e. %#x (pfn %#lx)\n",
436 what, ref, page ? page_to_pfn(page) : -1);
437}
438
439void gnttab_end_foreign_access(grant_ref_t ref, int readonly,
440 unsigned long page)
441{
442 if (gnttab_end_foreign_access_ref(ref, readonly)) {
443 put_free_entry(ref);
444 if (page != 0)
445 put_page(virt_to_page(page));
446 } else
447 gnttab_add_deferred(ref, readonly,
448 page ? virt_to_page(page) : NULL);
449}
450EXPORT_SYMBOL_GPL(gnttab_end_foreign_access);
451
452int gnttab_grant_foreign_transfer(domid_t domid, unsigned long pfn)
453{
454 int ref;
455
456 ref = get_free_entries(1);
457 if (unlikely(ref < 0))
458 return -ENOSPC;
459 gnttab_grant_foreign_transfer_ref(ref, domid, pfn);
460
461 return ref;
462}
463EXPORT_SYMBOL_GPL(gnttab_grant_foreign_transfer);
464
465void gnttab_grant_foreign_transfer_ref(grant_ref_t ref, domid_t domid,
466 unsigned long pfn)
467{
468 gnttab_interface->update_entry(ref, domid, pfn, GTF_accept_transfer);
469}
470EXPORT_SYMBOL_GPL(gnttab_grant_foreign_transfer_ref);
471
472static unsigned long gnttab_end_foreign_transfer_ref_v1(grant_ref_t ref)
473{
474 unsigned long frame;
475 u16 flags;
476 u16 *pflags;
477
478 pflags = &gnttab_shared.v1[ref].flags;
479
480 /*
481 * If a transfer is not even yet started, try to reclaim the grant
482 * reference and return failure (== 0).
483 */
484 while (!((flags = *pflags) & GTF_transfer_committed)) {
485 if (sync_cmpxchg(pflags, flags, 0) == flags)
486 return 0;
487 cpu_relax();
488 }
489
490 /* If a transfer is in progress then wait until it is completed. */
491 while (!(flags & GTF_transfer_completed)) {
492 flags = *pflags;
493 cpu_relax();
494 }
495
496 rmb(); /* Read the frame number /after/ reading completion status. */
497 frame = gnttab_shared.v1[ref].frame;
498 BUG_ON(frame == 0);
499
500 return frame;
501}
502
503static unsigned long gnttab_end_foreign_transfer_ref_v2(grant_ref_t ref)
504{
505 unsigned long frame;
506 u16 flags;
507 u16 *pflags;
508
509 pflags = &gnttab_shared.v2[ref].hdr.flags;
510
511 /*
512 * If a transfer is not even yet started, try to reclaim the grant
513 * reference and return failure (== 0).
514 */
515 while (!((flags = *pflags) & GTF_transfer_committed)) {
516 if (sync_cmpxchg(pflags, flags, 0) == flags)
517 return 0;
518 cpu_relax();
519 }
520
521 /* If a transfer is in progress then wait until it is completed. */
522 while (!(flags & GTF_transfer_completed)) {
523 flags = *pflags;
524 cpu_relax();
525 }
526
527 rmb(); /* Read the frame number /after/ reading completion status. */
528 frame = gnttab_shared.v2[ref].full_page.frame;
529 BUG_ON(frame == 0);
530
531 return frame;
532}
533
534unsigned long gnttab_end_foreign_transfer_ref(grant_ref_t ref)
535{
536 return gnttab_interface->end_foreign_transfer_ref(ref);
537}
538EXPORT_SYMBOL_GPL(gnttab_end_foreign_transfer_ref);
539
540unsigned long gnttab_end_foreign_transfer(grant_ref_t ref)
541{
542 unsigned long frame = gnttab_end_foreign_transfer_ref(ref);
543 put_free_entry(ref);
544 return frame;
545}
546EXPORT_SYMBOL_GPL(gnttab_end_foreign_transfer);
547
548void gnttab_free_grant_reference(grant_ref_t ref)
549{
550 put_free_entry(ref);
551}
552EXPORT_SYMBOL_GPL(gnttab_free_grant_reference);
553
554void gnttab_free_grant_references(grant_ref_t head)
555{
556 grant_ref_t ref;
557 unsigned long flags;
558 int count = 1;
559 if (head == GNTTAB_LIST_END)
560 return;
561 spin_lock_irqsave(&gnttab_list_lock, flags);
562 ref = head;
563 while (gnttab_entry(ref) != GNTTAB_LIST_END) {
564 ref = gnttab_entry(ref);
565 count++;
566 }
567 gnttab_entry(ref) = gnttab_free_head;
568 gnttab_free_head = head;
569 gnttab_free_count += count;
570 check_free_callbacks();
571 spin_unlock_irqrestore(&gnttab_list_lock, flags);
572}
573EXPORT_SYMBOL_GPL(gnttab_free_grant_references);
574
575int gnttab_alloc_grant_references(u16 count, grant_ref_t *head)
576{
577 int h = get_free_entries(count);
578
579 if (h < 0)
580 return -ENOSPC;
581
582 *head = h;
583
584 return 0;
585}
586EXPORT_SYMBOL_GPL(gnttab_alloc_grant_references);
587
588int gnttab_empty_grant_references(const grant_ref_t *private_head)
589{
590 return (*private_head == GNTTAB_LIST_END);
591}
592EXPORT_SYMBOL_GPL(gnttab_empty_grant_references);
593
594int gnttab_claim_grant_reference(grant_ref_t *private_head)
595{
596 grant_ref_t g = *private_head;
597 if (unlikely(g == GNTTAB_LIST_END))
598 return -ENOSPC;
599 *private_head = gnttab_entry(g);
600 return g;
601}
602EXPORT_SYMBOL_GPL(gnttab_claim_grant_reference);
603
604void gnttab_release_grant_reference(grant_ref_t *private_head,
605 grant_ref_t release)
606{
607 gnttab_entry(release) = *private_head;
608 *private_head = release;
609}
610EXPORT_SYMBOL_GPL(gnttab_release_grant_reference);
611
612void gnttab_request_free_callback(struct gnttab_free_callback *callback,
613 void (*fn)(void *), void *arg, u16 count)
614{
615 unsigned long flags;
616 struct gnttab_free_callback *cb;
617
618 spin_lock_irqsave(&gnttab_list_lock, flags);
619
620 /* Check if the callback is already on the list */
621 cb = gnttab_free_callback_list;
622 while (cb) {
623 if (cb == callback)
624 goto out;
625 cb = cb->next;
626 }
627
628 callback->fn = fn;
629 callback->arg = arg;
630 callback->count = count;
631 callback->next = gnttab_free_callback_list;
632 gnttab_free_callback_list = callback;
633 check_free_callbacks();
634out:
635 spin_unlock_irqrestore(&gnttab_list_lock, flags);
636}
637EXPORT_SYMBOL_GPL(gnttab_request_free_callback);
638
639void gnttab_cancel_free_callback(struct gnttab_free_callback *callback)
640{
641 struct gnttab_free_callback **pcb;
642 unsigned long flags;
643
644 spin_lock_irqsave(&gnttab_list_lock, flags);
645 for (pcb = &gnttab_free_callback_list; *pcb; pcb = &(*pcb)->next) {
646 if (*pcb == callback) {
647 *pcb = callback->next;
648 break;
649 }
650 }
651 spin_unlock_irqrestore(&gnttab_list_lock, flags);
652}
653EXPORT_SYMBOL_GPL(gnttab_cancel_free_callback);
654
655static unsigned int gnttab_frames(unsigned int frames, unsigned int align)
656{
657 return (frames * gnttab_interface->grefs_per_grant_frame + align - 1) /
658 align;
659}
660
661static int grow_gnttab_list(unsigned int more_frames)
662{
663 unsigned int new_nr_grant_frames, extra_entries, i;
664 unsigned int nr_glist_frames, new_nr_glist_frames;
665 unsigned int grefs_per_frame;
666
667 BUG_ON(gnttab_interface == NULL);
668 grefs_per_frame = gnttab_interface->grefs_per_grant_frame;
669
670 new_nr_grant_frames = nr_grant_frames + more_frames;
671 extra_entries = more_frames * grefs_per_frame;
672
673 nr_glist_frames = gnttab_frames(nr_grant_frames, RPP);
674 new_nr_glist_frames = gnttab_frames(new_nr_grant_frames, RPP);
675 for (i = nr_glist_frames; i < new_nr_glist_frames; i++) {
676 gnttab_list[i] = (grant_ref_t *)__get_free_page(GFP_ATOMIC);
677 if (!gnttab_list[i])
678 goto grow_nomem;
679 }
680
681
682 for (i = grefs_per_frame * nr_grant_frames;
683 i < grefs_per_frame * new_nr_grant_frames - 1; i++)
684 gnttab_entry(i) = i + 1;
685
686 gnttab_entry(i) = gnttab_free_head;
687 gnttab_free_head = grefs_per_frame * nr_grant_frames;
688 gnttab_free_count += extra_entries;
689
690 nr_grant_frames = new_nr_grant_frames;
691
692 check_free_callbacks();
693
694 return 0;
695
696grow_nomem:
697 while (i-- > nr_glist_frames)
698 free_page((unsigned long) gnttab_list[i]);
699 return -ENOMEM;
700}
701
702static unsigned int __max_nr_grant_frames(void)
703{
704 struct gnttab_query_size query;
705 int rc;
706
707 query.dom = DOMID_SELF;
708
709 rc = HYPERVISOR_grant_table_op(GNTTABOP_query_size, &query, 1);
710 if ((rc < 0) || (query.status != GNTST_okay))
711 return 4; /* Legacy max supported number of frames */
712
713 return query.max_nr_frames;
714}
715
716unsigned int gnttab_max_grant_frames(void)
717{
718 unsigned int xen_max = __max_nr_grant_frames();
719 static unsigned int boot_max_nr_grant_frames;
720
721 /* First time, initialize it properly. */
722 if (!boot_max_nr_grant_frames)
723 boot_max_nr_grant_frames = __max_nr_grant_frames();
724
725 if (xen_max > boot_max_nr_grant_frames)
726 return boot_max_nr_grant_frames;
727 return xen_max;
728}
729EXPORT_SYMBOL_GPL(gnttab_max_grant_frames);
730
731int gnttab_setup_auto_xlat_frames(phys_addr_t addr)
732{
733 xen_pfn_t *pfn;
734 unsigned int max_nr_gframes = __max_nr_grant_frames();
735 unsigned int i;
736 void *vaddr;
737
738 if (xen_auto_xlat_grant_frames.count)
739 return -EINVAL;
740
741 vaddr = xen_remap(addr, XEN_PAGE_SIZE * max_nr_gframes);
742 if (vaddr == NULL) {
743 pr_warn("Failed to ioremap gnttab share frames (addr=%pa)!\n",
744 &addr);
745 return -ENOMEM;
746 }
747 pfn = kcalloc(max_nr_gframes, sizeof(pfn[0]), GFP_KERNEL);
748 if (!pfn) {
749 xen_unmap(vaddr);
750 return -ENOMEM;
751 }
752 for (i = 0; i < max_nr_gframes; i++)
753 pfn[i] = XEN_PFN_DOWN(addr) + i;
754
755 xen_auto_xlat_grant_frames.vaddr = vaddr;
756 xen_auto_xlat_grant_frames.pfn = pfn;
757 xen_auto_xlat_grant_frames.count = max_nr_gframes;
758
759 return 0;
760}
761EXPORT_SYMBOL_GPL(gnttab_setup_auto_xlat_frames);
762
763void gnttab_free_auto_xlat_frames(void)
764{
765 if (!xen_auto_xlat_grant_frames.count)
766 return;
767 kfree(xen_auto_xlat_grant_frames.pfn);
768 xen_unmap(xen_auto_xlat_grant_frames.vaddr);
769
770 xen_auto_xlat_grant_frames.pfn = NULL;
771 xen_auto_xlat_grant_frames.count = 0;
772 xen_auto_xlat_grant_frames.vaddr = NULL;
773}
774EXPORT_SYMBOL_GPL(gnttab_free_auto_xlat_frames);
775
776int gnttab_pages_set_private(int nr_pages, struct page **pages)
777{
778 int i;
779
780 for (i = 0; i < nr_pages; i++) {
781#if BITS_PER_LONG < 64
782 struct xen_page_foreign *foreign;
783
784 foreign = kzalloc(sizeof(*foreign), GFP_KERNEL);
785 if (!foreign)
786 return -ENOMEM;
787
788 set_page_private(pages[i], (unsigned long)foreign);
789#endif
790 SetPagePrivate(pages[i]);
791 }
792
793 return 0;
794}
795EXPORT_SYMBOL_GPL(gnttab_pages_set_private);
796
797/**
798 * gnttab_alloc_pages - alloc pages suitable for grant mapping into
799 * @nr_pages: number of pages to alloc
800 * @pages: returns the pages
801 */
802int gnttab_alloc_pages(int nr_pages, struct page **pages)
803{
804 int ret;
805
806 ret = alloc_xenballooned_pages(nr_pages, pages);
807 if (ret < 0)
808 return ret;
809
810 ret = gnttab_pages_set_private(nr_pages, pages);
811 if (ret < 0)
812 gnttab_free_pages(nr_pages, pages);
813
814 return ret;
815}
816EXPORT_SYMBOL_GPL(gnttab_alloc_pages);
817
818void gnttab_pages_clear_private(int nr_pages, struct page **pages)
819{
820 int i;
821
822 for (i = 0; i < nr_pages; i++) {
823 if (PagePrivate(pages[i])) {
824#if BITS_PER_LONG < 64
825 kfree((void *)page_private(pages[i]));
826#endif
827 ClearPagePrivate(pages[i]);
828 }
829 }
830}
831EXPORT_SYMBOL_GPL(gnttab_pages_clear_private);
832
833/**
834 * gnttab_free_pages - free pages allocated by gnttab_alloc_pages()
835 * @nr_pages; number of pages to free
836 * @pages: the pages
837 */
838void gnttab_free_pages(int nr_pages, struct page **pages)
839{
840 gnttab_pages_clear_private(nr_pages, pages);
841 free_xenballooned_pages(nr_pages, pages);
842}
843EXPORT_SYMBOL_GPL(gnttab_free_pages);
844
845#ifdef CONFIG_XEN_GRANT_DMA_ALLOC
846/**
847 * gnttab_dma_alloc_pages - alloc DMAable pages suitable for grant mapping into
848 * @args: arguments to the function
849 */
850int gnttab_dma_alloc_pages(struct gnttab_dma_alloc_args *args)
851{
852 unsigned long pfn, start_pfn;
853 size_t size;
854 int i, ret;
855
856 size = args->nr_pages << PAGE_SHIFT;
857 if (args->coherent)
858 args->vaddr = dma_alloc_coherent(args->dev, size,
859 &args->dev_bus_addr,
860 GFP_KERNEL | __GFP_NOWARN);
861 else
862 args->vaddr = dma_alloc_wc(args->dev, size,
863 &args->dev_bus_addr,
864 GFP_KERNEL | __GFP_NOWARN);
865 if (!args->vaddr) {
866 pr_debug("Failed to allocate DMA buffer of size %zu\n", size);
867 return -ENOMEM;
868 }
869
870 start_pfn = __phys_to_pfn(args->dev_bus_addr);
871 for (pfn = start_pfn, i = 0; pfn < start_pfn + args->nr_pages;
872 pfn++, i++) {
873 struct page *page = pfn_to_page(pfn);
874
875 args->pages[i] = page;
876 args->frames[i] = xen_page_to_gfn(page);
877 xenmem_reservation_scrub_page(page);
878 }
879
880 xenmem_reservation_va_mapping_reset(args->nr_pages, args->pages);
881
882 ret = xenmem_reservation_decrease(args->nr_pages, args->frames);
883 if (ret != args->nr_pages) {
884 pr_debug("Failed to decrease reservation for DMA buffer\n");
885 ret = -EFAULT;
886 goto fail;
887 }
888
889 ret = gnttab_pages_set_private(args->nr_pages, args->pages);
890 if (ret < 0)
891 goto fail;
892
893 return 0;
894
895fail:
896 gnttab_dma_free_pages(args);
897 return ret;
898}
899EXPORT_SYMBOL_GPL(gnttab_dma_alloc_pages);
900
901/**
902 * gnttab_dma_free_pages - free DMAable pages
903 * @args: arguments to the function
904 */
905int gnttab_dma_free_pages(struct gnttab_dma_alloc_args *args)
906{
907 size_t size;
908 int i, ret;
909
910 gnttab_pages_clear_private(args->nr_pages, args->pages);
911
912 for (i = 0; i < args->nr_pages; i++)
913 args->frames[i] = page_to_xen_pfn(args->pages[i]);
914
915 ret = xenmem_reservation_increase(args->nr_pages, args->frames);
916 if (ret != args->nr_pages) {
917 pr_debug("Failed to increase reservation for DMA buffer\n");
918 ret = -EFAULT;
919 } else {
920 ret = 0;
921 }
922
923 xenmem_reservation_va_mapping_update(args->nr_pages, args->pages,
924 args->frames);
925
926 size = args->nr_pages << PAGE_SHIFT;
927 if (args->coherent)
928 dma_free_coherent(args->dev, size,
929 args->vaddr, args->dev_bus_addr);
930 else
931 dma_free_wc(args->dev, size,
932 args->vaddr, args->dev_bus_addr);
933 return ret;
934}
935EXPORT_SYMBOL_GPL(gnttab_dma_free_pages);
936#endif
937
938/* Handling of paged out grant targets (GNTST_eagain) */
939#define MAX_DELAY 256
940static inline void
941gnttab_retry_eagain_gop(unsigned int cmd, void *gop, int16_t *status,
942 const char *func)
943{
944 unsigned delay = 1;
945
946 do {
947 BUG_ON(HYPERVISOR_grant_table_op(cmd, gop, 1));
948 if (*status == GNTST_eagain)
949 msleep(delay++);
950 } while ((*status == GNTST_eagain) && (delay < MAX_DELAY));
951
952 if (delay >= MAX_DELAY) {
953 pr_err("%s: %s eagain grant\n", func, current->comm);
954 *status = GNTST_bad_page;
955 }
956}
957
958void gnttab_batch_map(struct gnttab_map_grant_ref *batch, unsigned count)
959{
960 struct gnttab_map_grant_ref *op;
961
962 if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, batch, count))
963 BUG();
964 for (op = batch; op < batch + count; op++)
965 if (op->status == GNTST_eagain)
966 gnttab_retry_eagain_gop(GNTTABOP_map_grant_ref, op,
967 &op->status, __func__);
968}
969EXPORT_SYMBOL_GPL(gnttab_batch_map);
970
971void gnttab_batch_copy(struct gnttab_copy *batch, unsigned count)
972{
973 struct gnttab_copy *op;
974
975 if (HYPERVISOR_grant_table_op(GNTTABOP_copy, batch, count))
976 BUG();
977 for (op = batch; op < batch + count; op++)
978 if (op->status == GNTST_eagain)
979 gnttab_retry_eagain_gop(GNTTABOP_copy, op,
980 &op->status, __func__);
981}
982EXPORT_SYMBOL_GPL(gnttab_batch_copy);
983
984void gnttab_foreach_grant_in_range(struct page *page,
985 unsigned int offset,
986 unsigned int len,
987 xen_grant_fn_t fn,
988 void *data)
989{
990 unsigned int goffset;
991 unsigned int glen;
992 unsigned long xen_pfn;
993
994 len = min_t(unsigned int, PAGE_SIZE - offset, len);
995 goffset = xen_offset_in_page(offset);
996
997 xen_pfn = page_to_xen_pfn(page) + XEN_PFN_DOWN(offset);
998
999 while (len) {
1000 glen = min_t(unsigned int, XEN_PAGE_SIZE - goffset, len);
1001 fn(pfn_to_gfn(xen_pfn), goffset, glen, data);
1002
1003 goffset = 0;
1004 xen_pfn++;
1005 len -= glen;
1006 }
1007}
1008EXPORT_SYMBOL_GPL(gnttab_foreach_grant_in_range);
1009
1010void gnttab_foreach_grant(struct page **pages,
1011 unsigned int nr_grefs,
1012 xen_grant_fn_t fn,
1013 void *data)
1014{
1015 unsigned int goffset = 0;
1016 unsigned long xen_pfn = 0;
1017 unsigned int i;
1018
1019 for (i = 0; i < nr_grefs; i++) {
1020 if ((i % XEN_PFN_PER_PAGE) == 0) {
1021 xen_pfn = page_to_xen_pfn(pages[i / XEN_PFN_PER_PAGE]);
1022 goffset = 0;
1023 }
1024
1025 fn(pfn_to_gfn(xen_pfn), goffset, XEN_PAGE_SIZE, data);
1026
1027 goffset += XEN_PAGE_SIZE;
1028 xen_pfn++;
1029 }
1030}
1031
1032int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
1033 struct gnttab_map_grant_ref *kmap_ops,
1034 struct page **pages, unsigned int count)
1035{
1036 int i, ret;
1037
1038 ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, map_ops, count);
1039 if (ret)
1040 return ret;
1041
1042 for (i = 0; i < count; i++) {
1043 switch (map_ops[i].status) {
1044 case GNTST_okay:
1045 {
1046 struct xen_page_foreign *foreign;
1047
1048 SetPageForeign(pages[i]);
1049 foreign = xen_page_foreign(pages[i]);
1050 foreign->domid = map_ops[i].dom;
1051 foreign->gref = map_ops[i].ref;
1052 break;
1053 }
1054
1055 case GNTST_no_device_space:
1056 pr_warn_ratelimited("maptrack limit reached, can't map all guest pages\n");
1057 break;
1058
1059 case GNTST_eagain:
1060 /* Retry eagain maps */
1061 gnttab_retry_eagain_gop(GNTTABOP_map_grant_ref,
1062 map_ops + i,
1063 &map_ops[i].status, __func__);
1064 /* Test status in next loop iteration. */
1065 i--;
1066 break;
1067
1068 default:
1069 break;
1070 }
1071 }
1072
1073 return set_foreign_p2m_mapping(map_ops, kmap_ops, pages, count);
1074}
1075EXPORT_SYMBOL_GPL(gnttab_map_refs);
1076
1077int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
1078 struct gnttab_unmap_grant_ref *kunmap_ops,
1079 struct page **pages, unsigned int count)
1080{
1081 unsigned int i;
1082 int ret;
1083
1084 ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap_ops, count);
1085 if (ret)
1086 return ret;
1087
1088 for (i = 0; i < count; i++)
1089 ClearPageForeign(pages[i]);
1090
1091 return clear_foreign_p2m_mapping(unmap_ops, kunmap_ops, pages, count);
1092}
1093EXPORT_SYMBOL_GPL(gnttab_unmap_refs);
1094
1095#define GNTTAB_UNMAP_REFS_DELAY 5
1096
1097static void __gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item);
1098
1099static void gnttab_unmap_work(struct work_struct *work)
1100{
1101 struct gntab_unmap_queue_data
1102 *unmap_data = container_of(work,
1103 struct gntab_unmap_queue_data,
1104 gnttab_work.work);
1105 if (unmap_data->age != UINT_MAX)
1106 unmap_data->age++;
1107 __gnttab_unmap_refs_async(unmap_data);
1108}
1109
1110static void __gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item)
1111{
1112 int ret;
1113 int pc;
1114
1115 for (pc = 0; pc < item->count; pc++) {
1116 if (page_count(item->pages[pc]) > 1) {
1117 unsigned long delay = GNTTAB_UNMAP_REFS_DELAY * (item->age + 1);
1118 schedule_delayed_work(&item->gnttab_work,
1119 msecs_to_jiffies(delay));
1120 return;
1121 }
1122 }
1123
1124 ret = gnttab_unmap_refs(item->unmap_ops, item->kunmap_ops,
1125 item->pages, item->count);
1126 item->done(ret, item);
1127}
1128
1129void gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item)
1130{
1131 INIT_DELAYED_WORK(&item->gnttab_work, gnttab_unmap_work);
1132 item->age = 0;
1133
1134 __gnttab_unmap_refs_async(item);
1135}
1136EXPORT_SYMBOL_GPL(gnttab_unmap_refs_async);
1137
1138static void unmap_refs_callback(int result,
1139 struct gntab_unmap_queue_data *data)
1140{
1141 struct unmap_refs_callback_data *d = data->data;
1142
1143 d->result = result;
1144 complete(&d->completion);
1145}
1146
1147int gnttab_unmap_refs_sync(struct gntab_unmap_queue_data *item)
1148{
1149 struct unmap_refs_callback_data data;
1150
1151 init_completion(&data.completion);
1152 item->data = &data;
1153 item->done = &unmap_refs_callback;
1154 gnttab_unmap_refs_async(item);
1155 wait_for_completion(&data.completion);
1156
1157 return data.result;
1158}
1159EXPORT_SYMBOL_GPL(gnttab_unmap_refs_sync);
1160
1161static unsigned int nr_status_frames(unsigned int nr_grant_frames)
1162{
1163 BUG_ON(gnttab_interface == NULL);
1164 return gnttab_frames(nr_grant_frames, SPP);
1165}
1166
1167static int gnttab_map_frames_v1(xen_pfn_t *frames, unsigned int nr_gframes)
1168{
1169 int rc;
1170
1171 rc = arch_gnttab_map_shared(frames, nr_gframes,
1172 gnttab_max_grant_frames(),
1173 &gnttab_shared.addr);
1174 BUG_ON(rc);
1175
1176 return 0;
1177}
1178
1179static void gnttab_unmap_frames_v1(void)
1180{
1181 arch_gnttab_unmap(gnttab_shared.addr, nr_grant_frames);
1182}
1183
1184static int gnttab_map_frames_v2(xen_pfn_t *frames, unsigned int nr_gframes)
1185{
1186 uint64_t *sframes;
1187 unsigned int nr_sframes;
1188 struct gnttab_get_status_frames getframes;
1189 int rc;
1190
1191 nr_sframes = nr_status_frames(nr_gframes);
1192
1193 /* No need for kzalloc as it is initialized in following hypercall
1194 * GNTTABOP_get_status_frames.
1195 */
1196 sframes = kmalloc_array(nr_sframes, sizeof(uint64_t), GFP_ATOMIC);
1197 if (!sframes)
1198 return -ENOMEM;
1199
1200 getframes.dom = DOMID_SELF;
1201 getframes.nr_frames = nr_sframes;
1202 set_xen_guest_handle(getframes.frame_list, sframes);
1203
1204 rc = HYPERVISOR_grant_table_op(GNTTABOP_get_status_frames,
1205 &getframes, 1);
1206 if (rc == -ENOSYS) {
1207 kfree(sframes);
1208 return -ENOSYS;
1209 }
1210
1211 BUG_ON(rc || getframes.status);
1212
1213 rc = arch_gnttab_map_status(sframes, nr_sframes,
1214 nr_status_frames(gnttab_max_grant_frames()),
1215 &grstatus);
1216 BUG_ON(rc);
1217 kfree(sframes);
1218
1219 rc = arch_gnttab_map_shared(frames, nr_gframes,
1220 gnttab_max_grant_frames(),
1221 &gnttab_shared.addr);
1222 BUG_ON(rc);
1223
1224 return 0;
1225}
1226
1227static void gnttab_unmap_frames_v2(void)
1228{
1229 arch_gnttab_unmap(gnttab_shared.addr, nr_grant_frames);
1230 arch_gnttab_unmap(grstatus, nr_status_frames(nr_grant_frames));
1231}
1232
1233static int gnttab_map(unsigned int start_idx, unsigned int end_idx)
1234{
1235 struct gnttab_setup_table setup;
1236 xen_pfn_t *frames;
1237 unsigned int nr_gframes = end_idx + 1;
1238 int rc;
1239
1240 if (xen_feature(XENFEAT_auto_translated_physmap)) {
1241 struct xen_add_to_physmap xatp;
1242 unsigned int i = end_idx;
1243 rc = 0;
1244 BUG_ON(xen_auto_xlat_grant_frames.count < nr_gframes);
1245 /*
1246 * Loop backwards, so that the first hypercall has the largest
1247 * index, ensuring that the table will grow only once.
1248 */
1249 do {
1250 xatp.domid = DOMID_SELF;
1251 xatp.idx = i;
1252 xatp.space = XENMAPSPACE_grant_table;
1253 xatp.gpfn = xen_auto_xlat_grant_frames.pfn[i];
1254 rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp);
1255 if (rc != 0) {
1256 pr_warn("grant table add_to_physmap failed, err=%d\n",
1257 rc);
1258 break;
1259 }
1260 } while (i-- > start_idx);
1261
1262 return rc;
1263 }
1264
1265 /* No need for kzalloc as it is initialized in following hypercall
1266 * GNTTABOP_setup_table.
1267 */
1268 frames = kmalloc_array(nr_gframes, sizeof(unsigned long), GFP_ATOMIC);
1269 if (!frames)
1270 return -ENOMEM;
1271
1272 setup.dom = DOMID_SELF;
1273 setup.nr_frames = nr_gframes;
1274 set_xen_guest_handle(setup.frame_list, frames);
1275
1276 rc = HYPERVISOR_grant_table_op(GNTTABOP_setup_table, &setup, 1);
1277 if (rc == -ENOSYS) {
1278 kfree(frames);
1279 return -ENOSYS;
1280 }
1281
1282 BUG_ON(rc || setup.status);
1283
1284 rc = gnttab_interface->map_frames(frames, nr_gframes);
1285
1286 kfree(frames);
1287
1288 return rc;
1289}
1290
1291static const struct gnttab_ops gnttab_v1_ops = {
1292 .version = 1,
1293 .grefs_per_grant_frame = XEN_PAGE_SIZE /
1294 sizeof(struct grant_entry_v1),
1295 .map_frames = gnttab_map_frames_v1,
1296 .unmap_frames = gnttab_unmap_frames_v1,
1297 .update_entry = gnttab_update_entry_v1,
1298 .end_foreign_access_ref = gnttab_end_foreign_access_ref_v1,
1299 .end_foreign_transfer_ref = gnttab_end_foreign_transfer_ref_v1,
1300 .query_foreign_access = gnttab_query_foreign_access_v1,
1301};
1302
1303static const struct gnttab_ops gnttab_v2_ops = {
1304 .version = 2,
1305 .grefs_per_grant_frame = XEN_PAGE_SIZE /
1306 sizeof(union grant_entry_v2),
1307 .map_frames = gnttab_map_frames_v2,
1308 .unmap_frames = gnttab_unmap_frames_v2,
1309 .update_entry = gnttab_update_entry_v2,
1310 .end_foreign_access_ref = gnttab_end_foreign_access_ref_v2,
1311 .end_foreign_transfer_ref = gnttab_end_foreign_transfer_ref_v2,
1312 .query_foreign_access = gnttab_query_foreign_access_v2,
1313};
1314
1315static bool gnttab_need_v2(void)
1316{
1317#ifdef CONFIG_X86
1318 uint32_t base, width;
1319
1320 if (xen_pv_domain()) {
1321 base = xen_cpuid_base();
1322 if (cpuid_eax(base) < 5)
1323 return false; /* Information not available, use V1. */
1324 width = cpuid_ebx(base + 5) &
1325 XEN_CPUID_MACHINE_ADDRESS_WIDTH_MASK;
1326 return width > 32 + PAGE_SHIFT;
1327 }
1328#endif
1329 return !!(max_possible_pfn >> 32);
1330}
1331
1332static void gnttab_request_version(void)
1333{
1334 long rc;
1335 struct gnttab_set_version gsv;
1336
1337 if (gnttab_need_v2())
1338 gsv.version = 2;
1339 else
1340 gsv.version = 1;
1341
1342 /* Boot parameter overrides automatic selection. */
1343 if (xen_gnttab_version >= 1 && xen_gnttab_version <= 2)
1344 gsv.version = xen_gnttab_version;
1345
1346 rc = HYPERVISOR_grant_table_op(GNTTABOP_set_version, &gsv, 1);
1347 if (rc == 0 && gsv.version == 2)
1348 gnttab_interface = &gnttab_v2_ops;
1349 else
1350 gnttab_interface = &gnttab_v1_ops;
1351 pr_info("Grant tables using version %d layout\n",
1352 gnttab_interface->version);
1353}
1354
1355static int gnttab_setup(void)
1356{
1357 unsigned int max_nr_gframes;
1358
1359 max_nr_gframes = gnttab_max_grant_frames();
1360 if (max_nr_gframes < nr_grant_frames)
1361 return -ENOSYS;
1362
1363 if (xen_feature(XENFEAT_auto_translated_physmap) && gnttab_shared.addr == NULL) {
1364 gnttab_shared.addr = xen_auto_xlat_grant_frames.vaddr;
1365 if (gnttab_shared.addr == NULL) {
1366 pr_warn("gnttab share frames is not mapped!\n");
1367 return -ENOMEM;
1368 }
1369 }
1370 return gnttab_map(0, nr_grant_frames - 1);
1371}
1372
1373int gnttab_resume(void)
1374{
1375 gnttab_request_version();
1376 return gnttab_setup();
1377}
1378
1379int gnttab_suspend(void)
1380{
1381 if (!xen_feature(XENFEAT_auto_translated_physmap))
1382 gnttab_interface->unmap_frames();
1383 return 0;
1384}
1385
1386static int gnttab_expand(unsigned int req_entries)
1387{
1388 int rc;
1389 unsigned int cur, extra;
1390
1391 BUG_ON(gnttab_interface == NULL);
1392 cur = nr_grant_frames;
1393 extra = ((req_entries + gnttab_interface->grefs_per_grant_frame - 1) /
1394 gnttab_interface->grefs_per_grant_frame);
1395 if (cur + extra > gnttab_max_grant_frames()) {
1396 pr_warn_ratelimited("xen/grant-table: max_grant_frames reached"
1397 " cur=%u extra=%u limit=%u"
1398 " gnttab_free_count=%u req_entries=%u\n",
1399 cur, extra, gnttab_max_grant_frames(),
1400 gnttab_free_count, req_entries);
1401 return -ENOSPC;
1402 }
1403
1404 rc = gnttab_map(cur, cur + extra - 1);
1405 if (rc == 0)
1406 rc = grow_gnttab_list(extra);
1407
1408 return rc;
1409}
1410
1411int gnttab_init(void)
1412{
1413 int i;
1414 unsigned long max_nr_grant_frames;
1415 unsigned int max_nr_glist_frames, nr_glist_frames;
1416 unsigned int nr_init_grefs;
1417 int ret;
1418
1419 gnttab_request_version();
1420 max_nr_grant_frames = gnttab_max_grant_frames();
1421 nr_grant_frames = 1;
1422
1423 /* Determine the maximum number of frames required for the
1424 * grant reference free list on the current hypervisor.
1425 */
1426 BUG_ON(gnttab_interface == NULL);
1427 max_nr_glist_frames = (max_nr_grant_frames *
1428 gnttab_interface->grefs_per_grant_frame / RPP);
1429
1430 gnttab_list = kmalloc_array(max_nr_glist_frames,
1431 sizeof(grant_ref_t *),
1432 GFP_KERNEL);
1433 if (gnttab_list == NULL)
1434 return -ENOMEM;
1435
1436 nr_glist_frames = gnttab_frames(nr_grant_frames, RPP);
1437 for (i = 0; i < nr_glist_frames; i++) {
1438 gnttab_list[i] = (grant_ref_t *)__get_free_page(GFP_KERNEL);
1439 if (gnttab_list[i] == NULL) {
1440 ret = -ENOMEM;
1441 goto ini_nomem;
1442 }
1443 }
1444
1445 ret = arch_gnttab_init(max_nr_grant_frames,
1446 nr_status_frames(max_nr_grant_frames));
1447 if (ret < 0)
1448 goto ini_nomem;
1449
1450 if (gnttab_setup() < 0) {
1451 ret = -ENODEV;
1452 goto ini_nomem;
1453 }
1454
1455 nr_init_grefs = nr_grant_frames *
1456 gnttab_interface->grefs_per_grant_frame;
1457
1458 for (i = NR_RESERVED_ENTRIES; i < nr_init_grefs - 1; i++)
1459 gnttab_entry(i) = i + 1;
1460
1461 gnttab_entry(nr_init_grefs - 1) = GNTTAB_LIST_END;
1462 gnttab_free_count = nr_init_grefs - NR_RESERVED_ENTRIES;
1463 gnttab_free_head = NR_RESERVED_ENTRIES;
1464
1465 printk("Grant table initialized\n");
1466 return 0;
1467
1468 ini_nomem:
1469 for (i--; i >= 0; i--)
1470 free_page((unsigned long)gnttab_list[i]);
1471 kfree(gnttab_list);
1472 return ret;
1473}
1474EXPORT_SYMBOL_GPL(gnttab_init);
1475
1476static int __gnttab_init(void)
1477{
1478 if (!xen_domain())
1479 return -ENODEV;
1480
1481 /* Delay grant-table initialization in the PV on HVM case */
1482 if (xen_hvm_domain() && !xen_pvh_domain())
1483 return 0;
1484
1485 return gnttab_init();
1486}
1487/* Starts after core_initcall so that xen_pvh_gnttab_setup can be called
1488 * beforehand to initialize xen_auto_xlat_grant_frames. */
1489core_initcall_sync(__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/module.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
46#include <xen/xen.h>
47#include <xen/interface/xen.h>
48#include <xen/page.h>
49#include <xen/grant_table.h>
50#include <xen/interface/memory.h>
51#include <xen/hvc-console.h>
52#include <xen/swiotlb-xen.h>
53#include <asm/xen/hypercall.h>
54#include <asm/xen/interface.h>
55
56#include <asm/pgtable.h>
57#include <asm/sync_bitops.h>
58
59/* External tools reserve first few grant table entries. */
60#define NR_RESERVED_ENTRIES 8
61#define GNTTAB_LIST_END 0xffffffff
62
63static grant_ref_t **gnttab_list;
64static unsigned int nr_grant_frames;
65static int gnttab_free_count;
66static grant_ref_t gnttab_free_head;
67static DEFINE_SPINLOCK(gnttab_list_lock);
68struct grant_frames xen_auto_xlat_grant_frames;
69
70static union {
71 struct grant_entry_v1 *v1;
72 union grant_entry_v2 *v2;
73 void *addr;
74} gnttab_shared;
75
76/*This is a structure of function pointers for grant table*/
77struct gnttab_ops {
78 /*
79 * Mapping a list of frames for storing grant entries. Frames parameter
80 * is used to store grant table address when grant table being setup,
81 * nr_gframes is the number of frames to map grant table. Returning
82 * GNTST_okay means success and negative value means failure.
83 */
84 int (*map_frames)(xen_pfn_t *frames, unsigned int nr_gframes);
85 /*
86 * Release a list of frames which are mapped in map_frames for grant
87 * entry status.
88 */
89 void (*unmap_frames)(void);
90 /*
91 * Introducing a valid entry into the grant table, granting the frame of
92 * this grant entry to domain for accessing or transfering. Ref
93 * parameter is reference of this introduced grant entry, domid is id of
94 * granted domain, frame is the page frame to be granted, and flags is
95 * status of the grant entry to be updated.
96 */
97 void (*update_entry)(grant_ref_t ref, domid_t domid,
98 unsigned long frame, unsigned flags);
99 /*
100 * Stop granting a grant entry to domain for accessing. Ref parameter is
101 * reference of a grant entry whose grant access will be stopped,
102 * readonly is not in use in this function. If the grant entry is
103 * currently mapped for reading or writing, just return failure(==0)
104 * directly and don't tear down the grant access. Otherwise, stop grant
105 * access for this entry and return success(==1).
106 */
107 int (*end_foreign_access_ref)(grant_ref_t ref, int readonly);
108 /*
109 * Stop granting a grant entry to domain for transfer. Ref parameter is
110 * reference of a grant entry whose grant transfer will be stopped. If
111 * tranfer has not started, just reclaim the grant entry and return
112 * failure(==0). Otherwise, wait for the transfer to complete and then
113 * return the frame.
114 */
115 unsigned long (*end_foreign_transfer_ref)(grant_ref_t ref);
116 /*
117 * Query the status of a grant entry. Ref parameter is reference of
118 * queried grant entry, return value is the status of queried entry.
119 * Detailed status(writing/reading) can be gotten from the return value
120 * by bit operations.
121 */
122 int (*query_foreign_access)(grant_ref_t ref);
123 /*
124 * Grant a domain to access a range of bytes within the page referred by
125 * an available grant entry. Ref parameter is reference of a grant entry
126 * which will be sub-page accessed, domid is id of grantee domain, frame
127 * is frame address of subpage grant, flags is grant type and flag
128 * information, page_off is offset of the range of bytes, and length is
129 * length of bytes to be accessed.
130 */
131 void (*update_subpage_entry)(grant_ref_t ref, domid_t domid,
132 unsigned long frame, int flags,
133 unsigned page_off, unsigned length);
134 /*
135 * Redirect an available grant entry on domain A to another grant
136 * reference of domain B, then allow domain C to use grant reference
137 * of domain B transitively. Ref parameter is an available grant entry
138 * reference on domain A, domid is id of domain C which accesses grant
139 * entry transitively, flags is grant type and flag information,
140 * trans_domid is id of domain B whose grant entry is finally accessed
141 * transitively, trans_gref is grant entry transitive reference of
142 * domain B.
143 */
144 void (*update_trans_entry)(grant_ref_t ref, domid_t domid, int flags,
145 domid_t trans_domid, grant_ref_t trans_gref);
146};
147
148static struct gnttab_ops *gnttab_interface;
149
150/*This reflects status of grant entries, so act as a global value*/
151static grant_status_t *grstatus;
152
153static int grant_table_version;
154static int grefs_per_grant_frame;
155
156static struct gnttab_free_callback *gnttab_free_callback_list;
157
158static int gnttab_expand(unsigned int req_entries);
159
160#define RPP (PAGE_SIZE / sizeof(grant_ref_t))
161#define SPP (PAGE_SIZE / sizeof(grant_status_t))
162
163static inline grant_ref_t *__gnttab_entry(grant_ref_t entry)
164{
165 return &gnttab_list[(entry) / RPP][(entry) % RPP];
166}
167/* This can be used as an l-value */
168#define gnttab_entry(entry) (*__gnttab_entry(entry))
169
170static int get_free_entries(unsigned count)
171{
172 unsigned long flags;
173 int ref, rc = 0;
174 grant_ref_t head;
175
176 spin_lock_irqsave(&gnttab_list_lock, flags);
177
178 if ((gnttab_free_count < count) &&
179 ((rc = gnttab_expand(count - gnttab_free_count)) < 0)) {
180 spin_unlock_irqrestore(&gnttab_list_lock, flags);
181 return rc;
182 }
183
184 ref = head = gnttab_free_head;
185 gnttab_free_count -= count;
186 while (count-- > 1)
187 head = gnttab_entry(head);
188 gnttab_free_head = gnttab_entry(head);
189 gnttab_entry(head) = GNTTAB_LIST_END;
190
191 spin_unlock_irqrestore(&gnttab_list_lock, flags);
192
193 return ref;
194}
195
196static void do_free_callbacks(void)
197{
198 struct gnttab_free_callback *callback, *next;
199
200 callback = gnttab_free_callback_list;
201 gnttab_free_callback_list = NULL;
202
203 while (callback != NULL) {
204 next = callback->next;
205 if (gnttab_free_count >= callback->count) {
206 callback->next = NULL;
207 callback->fn(callback->arg);
208 } else {
209 callback->next = gnttab_free_callback_list;
210 gnttab_free_callback_list = callback;
211 }
212 callback = next;
213 }
214}
215
216static inline void check_free_callbacks(void)
217{
218 if (unlikely(gnttab_free_callback_list))
219 do_free_callbacks();
220}
221
222static void put_free_entry(grant_ref_t ref)
223{
224 unsigned long flags;
225 spin_lock_irqsave(&gnttab_list_lock, flags);
226 gnttab_entry(ref) = gnttab_free_head;
227 gnttab_free_head = ref;
228 gnttab_free_count++;
229 check_free_callbacks();
230 spin_unlock_irqrestore(&gnttab_list_lock, flags);
231}
232
233/*
234 * Following applies to gnttab_update_entry_v1 and gnttab_update_entry_v2.
235 * Introducing a valid entry into the grant table:
236 * 1. Write ent->domid.
237 * 2. Write ent->frame:
238 * GTF_permit_access: Frame to which access is permitted.
239 * GTF_accept_transfer: Pseudo-phys frame slot being filled by new
240 * frame, or zero if none.
241 * 3. Write memory barrier (WMB).
242 * 4. Write ent->flags, inc. valid type.
243 */
244static void gnttab_update_entry_v1(grant_ref_t ref, domid_t domid,
245 unsigned long frame, unsigned flags)
246{
247 gnttab_shared.v1[ref].domid = domid;
248 gnttab_shared.v1[ref].frame = frame;
249 wmb();
250 gnttab_shared.v1[ref].flags = flags;
251}
252
253static void gnttab_update_entry_v2(grant_ref_t ref, domid_t domid,
254 unsigned long frame, unsigned flags)
255{
256 gnttab_shared.v2[ref].hdr.domid = domid;
257 gnttab_shared.v2[ref].full_page.frame = frame;
258 wmb();
259 gnttab_shared.v2[ref].hdr.flags = GTF_permit_access | flags;
260}
261
262/*
263 * Public grant-issuing interface functions
264 */
265void gnttab_grant_foreign_access_ref(grant_ref_t ref, domid_t domid,
266 unsigned long frame, int readonly)
267{
268 gnttab_interface->update_entry(ref, domid, frame,
269 GTF_permit_access | (readonly ? GTF_readonly : 0));
270}
271EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access_ref);
272
273int gnttab_grant_foreign_access(domid_t domid, unsigned long frame,
274 int readonly)
275{
276 int ref;
277
278 ref = get_free_entries(1);
279 if (unlikely(ref < 0))
280 return -ENOSPC;
281
282 gnttab_grant_foreign_access_ref(ref, domid, frame, readonly);
283
284 return ref;
285}
286EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access);
287
288static void gnttab_update_subpage_entry_v2(grant_ref_t ref, domid_t domid,
289 unsigned long frame, int flags,
290 unsigned page_off, unsigned length)
291{
292 gnttab_shared.v2[ref].sub_page.frame = frame;
293 gnttab_shared.v2[ref].sub_page.page_off = page_off;
294 gnttab_shared.v2[ref].sub_page.length = length;
295 gnttab_shared.v2[ref].hdr.domid = domid;
296 wmb();
297 gnttab_shared.v2[ref].hdr.flags =
298 GTF_permit_access | GTF_sub_page | flags;
299}
300
301int gnttab_grant_foreign_access_subpage_ref(grant_ref_t ref, domid_t domid,
302 unsigned long frame, int flags,
303 unsigned page_off,
304 unsigned length)
305{
306 if (flags & (GTF_accept_transfer | GTF_reading |
307 GTF_writing | GTF_transitive))
308 return -EPERM;
309
310 if (gnttab_interface->update_subpage_entry == NULL)
311 return -ENOSYS;
312
313 gnttab_interface->update_subpage_entry(ref, domid, frame, flags,
314 page_off, length);
315
316 return 0;
317}
318EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access_subpage_ref);
319
320int gnttab_grant_foreign_access_subpage(domid_t domid, unsigned long frame,
321 int flags, unsigned page_off,
322 unsigned length)
323{
324 int ref, rc;
325
326 ref = get_free_entries(1);
327 if (unlikely(ref < 0))
328 return -ENOSPC;
329
330 rc = gnttab_grant_foreign_access_subpage_ref(ref, domid, frame, flags,
331 page_off, length);
332 if (rc < 0) {
333 put_free_entry(ref);
334 return rc;
335 }
336
337 return ref;
338}
339EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access_subpage);
340
341bool gnttab_subpage_grants_available(void)
342{
343 return gnttab_interface->update_subpage_entry != NULL;
344}
345EXPORT_SYMBOL_GPL(gnttab_subpage_grants_available);
346
347static void gnttab_update_trans_entry_v2(grant_ref_t ref, domid_t domid,
348 int flags, domid_t trans_domid,
349 grant_ref_t trans_gref)
350{
351 gnttab_shared.v2[ref].transitive.trans_domid = trans_domid;
352 gnttab_shared.v2[ref].transitive.gref = trans_gref;
353 gnttab_shared.v2[ref].hdr.domid = domid;
354 wmb();
355 gnttab_shared.v2[ref].hdr.flags =
356 GTF_permit_access | GTF_transitive | flags;
357}
358
359int gnttab_grant_foreign_access_trans_ref(grant_ref_t ref, domid_t domid,
360 int flags, domid_t trans_domid,
361 grant_ref_t trans_gref)
362{
363 if (flags & (GTF_accept_transfer | GTF_reading |
364 GTF_writing | GTF_sub_page))
365 return -EPERM;
366
367 if (gnttab_interface->update_trans_entry == NULL)
368 return -ENOSYS;
369
370 gnttab_interface->update_trans_entry(ref, domid, flags, trans_domid,
371 trans_gref);
372
373 return 0;
374}
375EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access_trans_ref);
376
377int gnttab_grant_foreign_access_trans(domid_t domid, int flags,
378 domid_t trans_domid,
379 grant_ref_t trans_gref)
380{
381 int ref, rc;
382
383 ref = get_free_entries(1);
384 if (unlikely(ref < 0))
385 return -ENOSPC;
386
387 rc = gnttab_grant_foreign_access_trans_ref(ref, domid, flags,
388 trans_domid, trans_gref);
389 if (rc < 0) {
390 put_free_entry(ref);
391 return rc;
392 }
393
394 return ref;
395}
396EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access_trans);
397
398bool gnttab_trans_grants_available(void)
399{
400 return gnttab_interface->update_trans_entry != NULL;
401}
402EXPORT_SYMBOL_GPL(gnttab_trans_grants_available);
403
404static int gnttab_query_foreign_access_v1(grant_ref_t ref)
405{
406 return gnttab_shared.v1[ref].flags & (GTF_reading|GTF_writing);
407}
408
409static int gnttab_query_foreign_access_v2(grant_ref_t ref)
410{
411 return grstatus[ref] & (GTF_reading|GTF_writing);
412}
413
414int gnttab_query_foreign_access(grant_ref_t ref)
415{
416 return gnttab_interface->query_foreign_access(ref);
417}
418EXPORT_SYMBOL_GPL(gnttab_query_foreign_access);
419
420static int gnttab_end_foreign_access_ref_v1(grant_ref_t ref, int readonly)
421{
422 u16 flags, nflags;
423 u16 *pflags;
424
425 pflags = &gnttab_shared.v1[ref].flags;
426 nflags = *pflags;
427 do {
428 flags = nflags;
429 if (flags & (GTF_reading|GTF_writing))
430 return 0;
431 } while ((nflags = sync_cmpxchg(pflags, flags, 0)) != flags);
432
433 return 1;
434}
435
436static int gnttab_end_foreign_access_ref_v2(grant_ref_t ref, int readonly)
437{
438 gnttab_shared.v2[ref].hdr.flags = 0;
439 mb();
440 if (grstatus[ref] & (GTF_reading|GTF_writing)) {
441 return 0;
442 } else {
443 /* The read of grstatus needs to have acquire
444 semantics. On x86, reads already have
445 that, and we just need to protect against
446 compiler reorderings. On other
447 architectures we may need a full
448 barrier. */
449#ifdef CONFIG_X86
450 barrier();
451#else
452 mb();
453#endif
454 }
455
456 return 1;
457}
458
459static inline int _gnttab_end_foreign_access_ref(grant_ref_t ref, int readonly)
460{
461 return gnttab_interface->end_foreign_access_ref(ref, readonly);
462}
463
464int gnttab_end_foreign_access_ref(grant_ref_t ref, int readonly)
465{
466 if (_gnttab_end_foreign_access_ref(ref, readonly))
467 return 1;
468 pr_warn("WARNING: g.e. %#x still in use!\n", ref);
469 return 0;
470}
471EXPORT_SYMBOL_GPL(gnttab_end_foreign_access_ref);
472
473struct deferred_entry {
474 struct list_head list;
475 grant_ref_t ref;
476 bool ro;
477 uint16_t warn_delay;
478 struct page *page;
479};
480static LIST_HEAD(deferred_list);
481static void gnttab_handle_deferred(unsigned long);
482static DEFINE_TIMER(deferred_timer, gnttab_handle_deferred, 0, 0);
483
484static void gnttab_handle_deferred(unsigned long unused)
485{
486 unsigned int nr = 10;
487 struct deferred_entry *first = NULL;
488 unsigned long flags;
489
490 spin_lock_irqsave(&gnttab_list_lock, flags);
491 while (nr--) {
492 struct deferred_entry *entry
493 = list_first_entry(&deferred_list,
494 struct deferred_entry, list);
495
496 if (entry == first)
497 break;
498 list_del(&entry->list);
499 spin_unlock_irqrestore(&gnttab_list_lock, flags);
500 if (_gnttab_end_foreign_access_ref(entry->ref, entry->ro)) {
501 put_free_entry(entry->ref);
502 if (entry->page) {
503 pr_debug("freeing g.e. %#x (pfn %#lx)\n",
504 entry->ref, page_to_pfn(entry->page));
505 __free_page(entry->page);
506 } else
507 pr_info("freeing g.e. %#x\n", entry->ref);
508 kfree(entry);
509 entry = NULL;
510 } else {
511 if (!--entry->warn_delay)
512 pr_info("g.e. %#x still pending\n", entry->ref);
513 if (!first)
514 first = entry;
515 }
516 spin_lock_irqsave(&gnttab_list_lock, flags);
517 if (entry)
518 list_add_tail(&entry->list, &deferred_list);
519 else if (list_empty(&deferred_list))
520 break;
521 }
522 if (!list_empty(&deferred_list) && !timer_pending(&deferred_timer)) {
523 deferred_timer.expires = jiffies + HZ;
524 add_timer(&deferred_timer);
525 }
526 spin_unlock_irqrestore(&gnttab_list_lock, flags);
527}
528
529static void gnttab_add_deferred(grant_ref_t ref, bool readonly,
530 struct page *page)
531{
532 struct deferred_entry *entry = kmalloc(sizeof(*entry), GFP_ATOMIC);
533 const char *what = KERN_WARNING "leaking";
534
535 if (entry) {
536 unsigned long flags;
537
538 entry->ref = ref;
539 entry->ro = readonly;
540 entry->page = page;
541 entry->warn_delay = 60;
542 spin_lock_irqsave(&gnttab_list_lock, flags);
543 list_add_tail(&entry->list, &deferred_list);
544 if (!timer_pending(&deferred_timer)) {
545 deferred_timer.expires = jiffies + HZ;
546 add_timer(&deferred_timer);
547 }
548 spin_unlock_irqrestore(&gnttab_list_lock, flags);
549 what = KERN_DEBUG "deferring";
550 }
551 printk("%s g.e. %#x (pfn %#lx)\n",
552 what, ref, page ? page_to_pfn(page) : -1);
553}
554
555void gnttab_end_foreign_access(grant_ref_t ref, int readonly,
556 unsigned long page)
557{
558 if (gnttab_end_foreign_access_ref(ref, readonly)) {
559 put_free_entry(ref);
560 if (page != 0)
561 free_page(page);
562 } else
563 gnttab_add_deferred(ref, readonly,
564 page ? virt_to_page(page) : NULL);
565}
566EXPORT_SYMBOL_GPL(gnttab_end_foreign_access);
567
568int gnttab_grant_foreign_transfer(domid_t domid, unsigned long pfn)
569{
570 int ref;
571
572 ref = get_free_entries(1);
573 if (unlikely(ref < 0))
574 return -ENOSPC;
575 gnttab_grant_foreign_transfer_ref(ref, domid, pfn);
576
577 return ref;
578}
579EXPORT_SYMBOL_GPL(gnttab_grant_foreign_transfer);
580
581void gnttab_grant_foreign_transfer_ref(grant_ref_t ref, domid_t domid,
582 unsigned long pfn)
583{
584 gnttab_interface->update_entry(ref, domid, pfn, GTF_accept_transfer);
585}
586EXPORT_SYMBOL_GPL(gnttab_grant_foreign_transfer_ref);
587
588static unsigned long gnttab_end_foreign_transfer_ref_v1(grant_ref_t ref)
589{
590 unsigned long frame;
591 u16 flags;
592 u16 *pflags;
593
594 pflags = &gnttab_shared.v1[ref].flags;
595
596 /*
597 * If a transfer is not even yet started, try to reclaim the grant
598 * reference and return failure (== 0).
599 */
600 while (!((flags = *pflags) & GTF_transfer_committed)) {
601 if (sync_cmpxchg(pflags, flags, 0) == flags)
602 return 0;
603 cpu_relax();
604 }
605
606 /* If a transfer is in progress then wait until it is completed. */
607 while (!(flags & GTF_transfer_completed)) {
608 flags = *pflags;
609 cpu_relax();
610 }
611
612 rmb(); /* Read the frame number /after/ reading completion status. */
613 frame = gnttab_shared.v1[ref].frame;
614 BUG_ON(frame == 0);
615
616 return frame;
617}
618
619static unsigned long gnttab_end_foreign_transfer_ref_v2(grant_ref_t ref)
620{
621 unsigned long frame;
622 u16 flags;
623 u16 *pflags;
624
625 pflags = &gnttab_shared.v2[ref].hdr.flags;
626
627 /*
628 * If a transfer is not even yet started, try to reclaim the grant
629 * reference and return failure (== 0).
630 */
631 while (!((flags = *pflags) & GTF_transfer_committed)) {
632 if (sync_cmpxchg(pflags, flags, 0) == flags)
633 return 0;
634 cpu_relax();
635 }
636
637 /* If a transfer is in progress then wait until it is completed. */
638 while (!(flags & GTF_transfer_completed)) {
639 flags = *pflags;
640 cpu_relax();
641 }
642
643 rmb(); /* Read the frame number /after/ reading completion status. */
644 frame = gnttab_shared.v2[ref].full_page.frame;
645 BUG_ON(frame == 0);
646
647 return frame;
648}
649
650unsigned long gnttab_end_foreign_transfer_ref(grant_ref_t ref)
651{
652 return gnttab_interface->end_foreign_transfer_ref(ref);
653}
654EXPORT_SYMBOL_GPL(gnttab_end_foreign_transfer_ref);
655
656unsigned long gnttab_end_foreign_transfer(grant_ref_t ref)
657{
658 unsigned long frame = gnttab_end_foreign_transfer_ref(ref);
659 put_free_entry(ref);
660 return frame;
661}
662EXPORT_SYMBOL_GPL(gnttab_end_foreign_transfer);
663
664void gnttab_free_grant_reference(grant_ref_t ref)
665{
666 put_free_entry(ref);
667}
668EXPORT_SYMBOL_GPL(gnttab_free_grant_reference);
669
670void gnttab_free_grant_references(grant_ref_t head)
671{
672 grant_ref_t ref;
673 unsigned long flags;
674 int count = 1;
675 if (head == GNTTAB_LIST_END)
676 return;
677 spin_lock_irqsave(&gnttab_list_lock, flags);
678 ref = head;
679 while (gnttab_entry(ref) != GNTTAB_LIST_END) {
680 ref = gnttab_entry(ref);
681 count++;
682 }
683 gnttab_entry(ref) = gnttab_free_head;
684 gnttab_free_head = head;
685 gnttab_free_count += count;
686 check_free_callbacks();
687 spin_unlock_irqrestore(&gnttab_list_lock, flags);
688}
689EXPORT_SYMBOL_GPL(gnttab_free_grant_references);
690
691int gnttab_alloc_grant_references(u16 count, grant_ref_t *head)
692{
693 int h = get_free_entries(count);
694
695 if (h < 0)
696 return -ENOSPC;
697
698 *head = h;
699
700 return 0;
701}
702EXPORT_SYMBOL_GPL(gnttab_alloc_grant_references);
703
704int gnttab_empty_grant_references(const grant_ref_t *private_head)
705{
706 return (*private_head == GNTTAB_LIST_END);
707}
708EXPORT_SYMBOL_GPL(gnttab_empty_grant_references);
709
710int gnttab_claim_grant_reference(grant_ref_t *private_head)
711{
712 grant_ref_t g = *private_head;
713 if (unlikely(g == GNTTAB_LIST_END))
714 return -ENOSPC;
715 *private_head = gnttab_entry(g);
716 return g;
717}
718EXPORT_SYMBOL_GPL(gnttab_claim_grant_reference);
719
720void gnttab_release_grant_reference(grant_ref_t *private_head,
721 grant_ref_t release)
722{
723 gnttab_entry(release) = *private_head;
724 *private_head = release;
725}
726EXPORT_SYMBOL_GPL(gnttab_release_grant_reference);
727
728void gnttab_request_free_callback(struct gnttab_free_callback *callback,
729 void (*fn)(void *), void *arg, u16 count)
730{
731 unsigned long flags;
732 struct gnttab_free_callback *cb;
733
734 spin_lock_irqsave(&gnttab_list_lock, flags);
735
736 /* Check if the callback is already on the list */
737 cb = gnttab_free_callback_list;
738 while (cb) {
739 if (cb == callback)
740 goto out;
741 cb = cb->next;
742 }
743
744 callback->fn = fn;
745 callback->arg = arg;
746 callback->count = count;
747 callback->next = gnttab_free_callback_list;
748 gnttab_free_callback_list = callback;
749 check_free_callbacks();
750out:
751 spin_unlock_irqrestore(&gnttab_list_lock, flags);
752}
753EXPORT_SYMBOL_GPL(gnttab_request_free_callback);
754
755void gnttab_cancel_free_callback(struct gnttab_free_callback *callback)
756{
757 struct gnttab_free_callback **pcb;
758 unsigned long flags;
759
760 spin_lock_irqsave(&gnttab_list_lock, flags);
761 for (pcb = &gnttab_free_callback_list; *pcb; pcb = &(*pcb)->next) {
762 if (*pcb == callback) {
763 *pcb = callback->next;
764 break;
765 }
766 }
767 spin_unlock_irqrestore(&gnttab_list_lock, flags);
768}
769EXPORT_SYMBOL_GPL(gnttab_cancel_free_callback);
770
771static int grow_gnttab_list(unsigned int more_frames)
772{
773 unsigned int new_nr_grant_frames, extra_entries, i;
774 unsigned int nr_glist_frames, new_nr_glist_frames;
775
776 BUG_ON(grefs_per_grant_frame == 0);
777
778 new_nr_grant_frames = nr_grant_frames + more_frames;
779 extra_entries = more_frames * grefs_per_grant_frame;
780
781 nr_glist_frames = (nr_grant_frames * grefs_per_grant_frame + RPP - 1) / RPP;
782 new_nr_glist_frames =
783 (new_nr_grant_frames * grefs_per_grant_frame + RPP - 1) / RPP;
784 for (i = nr_glist_frames; i < new_nr_glist_frames; i++) {
785 gnttab_list[i] = (grant_ref_t *)__get_free_page(GFP_ATOMIC);
786 if (!gnttab_list[i])
787 goto grow_nomem;
788 }
789
790
791 for (i = grefs_per_grant_frame * nr_grant_frames;
792 i < grefs_per_grant_frame * new_nr_grant_frames - 1; i++)
793 gnttab_entry(i) = i + 1;
794
795 gnttab_entry(i) = gnttab_free_head;
796 gnttab_free_head = grefs_per_grant_frame * nr_grant_frames;
797 gnttab_free_count += extra_entries;
798
799 nr_grant_frames = new_nr_grant_frames;
800
801 check_free_callbacks();
802
803 return 0;
804
805grow_nomem:
806 for ( ; i >= nr_glist_frames; i--)
807 free_page((unsigned long) gnttab_list[i]);
808 return -ENOMEM;
809}
810
811static unsigned int __max_nr_grant_frames(void)
812{
813 struct gnttab_query_size query;
814 int rc;
815
816 query.dom = DOMID_SELF;
817
818 rc = HYPERVISOR_grant_table_op(GNTTABOP_query_size, &query, 1);
819 if ((rc < 0) || (query.status != GNTST_okay))
820 return 4; /* Legacy max supported number of frames */
821
822 return query.max_nr_frames;
823}
824
825unsigned int gnttab_max_grant_frames(void)
826{
827 unsigned int xen_max = __max_nr_grant_frames();
828 static unsigned int boot_max_nr_grant_frames;
829
830 /* First time, initialize it properly. */
831 if (!boot_max_nr_grant_frames)
832 boot_max_nr_grant_frames = __max_nr_grant_frames();
833
834 if (xen_max > boot_max_nr_grant_frames)
835 return boot_max_nr_grant_frames;
836 return xen_max;
837}
838EXPORT_SYMBOL_GPL(gnttab_max_grant_frames);
839
840int gnttab_setup_auto_xlat_frames(phys_addr_t addr)
841{
842 xen_pfn_t *pfn;
843 unsigned int max_nr_gframes = __max_nr_grant_frames();
844 unsigned int i;
845 void *vaddr;
846
847 if (xen_auto_xlat_grant_frames.count)
848 return -EINVAL;
849
850 vaddr = xen_remap(addr, PAGE_SIZE * max_nr_gframes);
851 if (vaddr == NULL) {
852 pr_warn("Failed to ioremap gnttab share frames (addr=%pa)!\n",
853 &addr);
854 return -ENOMEM;
855 }
856 pfn = kcalloc(max_nr_gframes, sizeof(pfn[0]), GFP_KERNEL);
857 if (!pfn) {
858 xen_unmap(vaddr);
859 return -ENOMEM;
860 }
861 for (i = 0; i < max_nr_gframes; i++)
862 pfn[i] = PFN_DOWN(addr) + i;
863
864 xen_auto_xlat_grant_frames.vaddr = vaddr;
865 xen_auto_xlat_grant_frames.pfn = pfn;
866 xen_auto_xlat_grant_frames.count = max_nr_gframes;
867
868 return 0;
869}
870EXPORT_SYMBOL_GPL(gnttab_setup_auto_xlat_frames);
871
872void gnttab_free_auto_xlat_frames(void)
873{
874 if (!xen_auto_xlat_grant_frames.count)
875 return;
876 kfree(xen_auto_xlat_grant_frames.pfn);
877 xen_unmap(xen_auto_xlat_grant_frames.vaddr);
878
879 xen_auto_xlat_grant_frames.pfn = NULL;
880 xen_auto_xlat_grant_frames.count = 0;
881 xen_auto_xlat_grant_frames.vaddr = NULL;
882}
883EXPORT_SYMBOL_GPL(gnttab_free_auto_xlat_frames);
884
885/* Handling of paged out grant targets (GNTST_eagain) */
886#define MAX_DELAY 256
887static inline void
888gnttab_retry_eagain_gop(unsigned int cmd, void *gop, int16_t *status,
889 const char *func)
890{
891 unsigned delay = 1;
892
893 do {
894 BUG_ON(HYPERVISOR_grant_table_op(cmd, gop, 1));
895 if (*status == GNTST_eagain)
896 msleep(delay++);
897 } while ((*status == GNTST_eagain) && (delay < MAX_DELAY));
898
899 if (delay >= MAX_DELAY) {
900 pr_err("%s: %s eagain grant\n", func, current->comm);
901 *status = GNTST_bad_page;
902 }
903}
904
905void gnttab_batch_map(struct gnttab_map_grant_ref *batch, unsigned count)
906{
907 struct gnttab_map_grant_ref *op;
908
909 if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, batch, count))
910 BUG();
911 for (op = batch; op < batch + count; op++)
912 if (op->status == GNTST_eagain)
913 gnttab_retry_eagain_gop(GNTTABOP_map_grant_ref, op,
914 &op->status, __func__);
915}
916EXPORT_SYMBOL_GPL(gnttab_batch_map);
917
918void gnttab_batch_copy(struct gnttab_copy *batch, unsigned count)
919{
920 struct gnttab_copy *op;
921
922 if (HYPERVISOR_grant_table_op(GNTTABOP_copy, batch, count))
923 BUG();
924 for (op = batch; op < batch + count; op++)
925 if (op->status == GNTST_eagain)
926 gnttab_retry_eagain_gop(GNTTABOP_copy, op,
927 &op->status, __func__);
928}
929EXPORT_SYMBOL_GPL(gnttab_batch_copy);
930
931int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
932 struct gnttab_map_grant_ref *kmap_ops,
933 struct page **pages, unsigned int count)
934{
935 int i, ret;
936
937 ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, map_ops, count);
938 if (ret)
939 return ret;
940
941 /* Retry eagain maps */
942 for (i = 0; i < count; i++)
943 if (map_ops[i].status == GNTST_eagain)
944 gnttab_retry_eagain_gop(GNTTABOP_map_grant_ref, map_ops + i,
945 &map_ops[i].status, __func__);
946
947 return set_foreign_p2m_mapping(map_ops, kmap_ops, pages, count);
948}
949EXPORT_SYMBOL_GPL(gnttab_map_refs);
950
951int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
952 struct gnttab_map_grant_ref *kmap_ops,
953 struct page **pages, unsigned int count)
954{
955 int ret;
956
957 ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap_ops, count);
958 if (ret)
959 return ret;
960
961 return clear_foreign_p2m_mapping(unmap_ops, kmap_ops, pages, count);
962}
963EXPORT_SYMBOL_GPL(gnttab_unmap_refs);
964
965static unsigned nr_status_frames(unsigned nr_grant_frames)
966{
967 BUG_ON(grefs_per_grant_frame == 0);
968 return (nr_grant_frames * grefs_per_grant_frame + SPP - 1) / SPP;
969}
970
971static int gnttab_map_frames_v1(xen_pfn_t *frames, unsigned int nr_gframes)
972{
973 int rc;
974
975 rc = arch_gnttab_map_shared(frames, nr_gframes,
976 gnttab_max_grant_frames(),
977 &gnttab_shared.addr);
978 BUG_ON(rc);
979
980 return 0;
981}
982
983static void gnttab_unmap_frames_v1(void)
984{
985 arch_gnttab_unmap(gnttab_shared.addr, nr_grant_frames);
986}
987
988static int gnttab_map_frames_v2(xen_pfn_t *frames, unsigned int nr_gframes)
989{
990 uint64_t *sframes;
991 unsigned int nr_sframes;
992 struct gnttab_get_status_frames getframes;
993 int rc;
994
995 nr_sframes = nr_status_frames(nr_gframes);
996
997 /* No need for kzalloc as it is initialized in following hypercall
998 * GNTTABOP_get_status_frames.
999 */
1000 sframes = kmalloc(nr_sframes * sizeof(uint64_t), GFP_ATOMIC);
1001 if (!sframes)
1002 return -ENOMEM;
1003
1004 getframes.dom = DOMID_SELF;
1005 getframes.nr_frames = nr_sframes;
1006 set_xen_guest_handle(getframes.frame_list, sframes);
1007
1008 rc = HYPERVISOR_grant_table_op(GNTTABOP_get_status_frames,
1009 &getframes, 1);
1010 if (rc == -ENOSYS) {
1011 kfree(sframes);
1012 return -ENOSYS;
1013 }
1014
1015 BUG_ON(rc || getframes.status);
1016
1017 rc = arch_gnttab_map_status(sframes, nr_sframes,
1018 nr_status_frames(gnttab_max_grant_frames()),
1019 &grstatus);
1020 BUG_ON(rc);
1021 kfree(sframes);
1022
1023 rc = arch_gnttab_map_shared(frames, nr_gframes,
1024 gnttab_max_grant_frames(),
1025 &gnttab_shared.addr);
1026 BUG_ON(rc);
1027
1028 return 0;
1029}
1030
1031static void gnttab_unmap_frames_v2(void)
1032{
1033 arch_gnttab_unmap(gnttab_shared.addr, nr_grant_frames);
1034 arch_gnttab_unmap(grstatus, nr_status_frames(nr_grant_frames));
1035}
1036
1037static int gnttab_map(unsigned int start_idx, unsigned int end_idx)
1038{
1039 struct gnttab_setup_table setup;
1040 xen_pfn_t *frames;
1041 unsigned int nr_gframes = end_idx + 1;
1042 int rc;
1043
1044 if (xen_feature(XENFEAT_auto_translated_physmap)) {
1045 struct xen_add_to_physmap xatp;
1046 unsigned int i = end_idx;
1047 rc = 0;
1048 BUG_ON(xen_auto_xlat_grant_frames.count < nr_gframes);
1049 /*
1050 * Loop backwards, so that the first hypercall has the largest
1051 * index, ensuring that the table will grow only once.
1052 */
1053 do {
1054 xatp.domid = DOMID_SELF;
1055 xatp.idx = i;
1056 xatp.space = XENMAPSPACE_grant_table;
1057 xatp.gpfn = xen_auto_xlat_grant_frames.pfn[i];
1058 rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp);
1059 if (rc != 0) {
1060 pr_warn("grant table add_to_physmap failed, err=%d\n",
1061 rc);
1062 break;
1063 }
1064 } while (i-- > start_idx);
1065
1066 return rc;
1067 }
1068
1069 /* No need for kzalloc as it is initialized in following hypercall
1070 * GNTTABOP_setup_table.
1071 */
1072 frames = kmalloc(nr_gframes * sizeof(unsigned long), GFP_ATOMIC);
1073 if (!frames)
1074 return -ENOMEM;
1075
1076 setup.dom = DOMID_SELF;
1077 setup.nr_frames = nr_gframes;
1078 set_xen_guest_handle(setup.frame_list, frames);
1079
1080 rc = HYPERVISOR_grant_table_op(GNTTABOP_setup_table, &setup, 1);
1081 if (rc == -ENOSYS) {
1082 kfree(frames);
1083 return -ENOSYS;
1084 }
1085
1086 BUG_ON(rc || setup.status);
1087
1088 rc = gnttab_interface->map_frames(frames, nr_gframes);
1089
1090 kfree(frames);
1091
1092 return rc;
1093}
1094
1095static struct gnttab_ops gnttab_v1_ops = {
1096 .map_frames = gnttab_map_frames_v1,
1097 .unmap_frames = gnttab_unmap_frames_v1,
1098 .update_entry = gnttab_update_entry_v1,
1099 .end_foreign_access_ref = gnttab_end_foreign_access_ref_v1,
1100 .end_foreign_transfer_ref = gnttab_end_foreign_transfer_ref_v1,
1101 .query_foreign_access = gnttab_query_foreign_access_v1,
1102};
1103
1104static struct gnttab_ops gnttab_v2_ops = {
1105 .map_frames = gnttab_map_frames_v2,
1106 .unmap_frames = gnttab_unmap_frames_v2,
1107 .update_entry = gnttab_update_entry_v2,
1108 .end_foreign_access_ref = gnttab_end_foreign_access_ref_v2,
1109 .end_foreign_transfer_ref = gnttab_end_foreign_transfer_ref_v2,
1110 .query_foreign_access = gnttab_query_foreign_access_v2,
1111 .update_subpage_entry = gnttab_update_subpage_entry_v2,
1112 .update_trans_entry = gnttab_update_trans_entry_v2,
1113};
1114
1115static void gnttab_request_version(void)
1116{
1117 int rc;
1118 struct gnttab_set_version gsv;
1119
1120 gsv.version = 1;
1121
1122 rc = HYPERVISOR_grant_table_op(GNTTABOP_set_version, &gsv, 1);
1123 if (rc == 0 && gsv.version == 2) {
1124 grant_table_version = 2;
1125 grefs_per_grant_frame = PAGE_SIZE / sizeof(union grant_entry_v2);
1126 gnttab_interface = &gnttab_v2_ops;
1127 } else if (grant_table_version == 2) {
1128 /*
1129 * If we've already used version 2 features,
1130 * but then suddenly discover that they're not
1131 * available (e.g. migrating to an older
1132 * version of Xen), almost unbounded badness
1133 * can happen.
1134 */
1135 panic("we need grant tables version 2, but only version 1 is available");
1136 } else {
1137 grant_table_version = 1;
1138 grefs_per_grant_frame = PAGE_SIZE / sizeof(struct grant_entry_v1);
1139 gnttab_interface = &gnttab_v1_ops;
1140 }
1141 pr_info("Grant tables using version %d layout\n", grant_table_version);
1142}
1143
1144static int gnttab_setup(void)
1145{
1146 unsigned int max_nr_gframes;
1147
1148 max_nr_gframes = gnttab_max_grant_frames();
1149 if (max_nr_gframes < nr_grant_frames)
1150 return -ENOSYS;
1151
1152 if (xen_feature(XENFEAT_auto_translated_physmap) && gnttab_shared.addr == NULL) {
1153 gnttab_shared.addr = xen_auto_xlat_grant_frames.vaddr;
1154 if (gnttab_shared.addr == NULL) {
1155 pr_warn("gnttab share frames (addr=0x%08lx) is not mapped!\n",
1156 (unsigned long)xen_auto_xlat_grant_frames.vaddr);
1157 return -ENOMEM;
1158 }
1159 }
1160 return gnttab_map(0, nr_grant_frames - 1);
1161}
1162
1163int gnttab_resume(void)
1164{
1165 gnttab_request_version();
1166 return gnttab_setup();
1167}
1168
1169int gnttab_suspend(void)
1170{
1171 gnttab_interface->unmap_frames();
1172 return 0;
1173}
1174
1175static int gnttab_expand(unsigned int req_entries)
1176{
1177 int rc;
1178 unsigned int cur, extra;
1179
1180 BUG_ON(grefs_per_grant_frame == 0);
1181 cur = nr_grant_frames;
1182 extra = ((req_entries + (grefs_per_grant_frame-1)) /
1183 grefs_per_grant_frame);
1184 if (cur + extra > gnttab_max_grant_frames())
1185 return -ENOSPC;
1186
1187 rc = gnttab_map(cur, cur + extra - 1);
1188 if (rc == 0)
1189 rc = grow_gnttab_list(extra);
1190
1191 return rc;
1192}
1193
1194int gnttab_init(void)
1195{
1196 int i;
1197 unsigned int max_nr_glist_frames, nr_glist_frames;
1198 unsigned int nr_init_grefs;
1199 int ret;
1200
1201 gnttab_request_version();
1202 nr_grant_frames = 1;
1203
1204 /* Determine the maximum number of frames required for the
1205 * grant reference free list on the current hypervisor.
1206 */
1207 BUG_ON(grefs_per_grant_frame == 0);
1208 max_nr_glist_frames = (gnttab_max_grant_frames() *
1209 grefs_per_grant_frame / RPP);
1210
1211 gnttab_list = kmalloc(max_nr_glist_frames * sizeof(grant_ref_t *),
1212 GFP_KERNEL);
1213 if (gnttab_list == NULL)
1214 return -ENOMEM;
1215
1216 nr_glist_frames = (nr_grant_frames * grefs_per_grant_frame + RPP - 1) / RPP;
1217 for (i = 0; i < nr_glist_frames; i++) {
1218 gnttab_list[i] = (grant_ref_t *)__get_free_page(GFP_KERNEL);
1219 if (gnttab_list[i] == NULL) {
1220 ret = -ENOMEM;
1221 goto ini_nomem;
1222 }
1223 }
1224
1225 if (gnttab_setup() < 0) {
1226 ret = -ENODEV;
1227 goto ini_nomem;
1228 }
1229
1230 nr_init_grefs = nr_grant_frames * grefs_per_grant_frame;
1231
1232 for (i = NR_RESERVED_ENTRIES; i < nr_init_grefs - 1; i++)
1233 gnttab_entry(i) = i + 1;
1234
1235 gnttab_entry(nr_init_grefs - 1) = GNTTAB_LIST_END;
1236 gnttab_free_count = nr_init_grefs - NR_RESERVED_ENTRIES;
1237 gnttab_free_head = NR_RESERVED_ENTRIES;
1238
1239 printk("Grant table initialized\n");
1240 return 0;
1241
1242 ini_nomem:
1243 for (i--; i >= 0; i--)
1244 free_page((unsigned long)gnttab_list[i]);
1245 kfree(gnttab_list);
1246 return ret;
1247}
1248EXPORT_SYMBOL_GPL(gnttab_init);
1249
1250static int __gnttab_init(void)
1251{
1252 /* Delay grant-table initialization in the PV on HVM case */
1253 if (xen_hvm_domain())
1254 return 0;
1255
1256 if (!xen_pv_domain())
1257 return -ENODEV;
1258
1259 return gnttab_init();
1260}
1261/* Starts after core_initcall so that xen_pvh_gnttab_setup can be called
1262 * beforehand to initialize xen_auto_xlat_grant_frames. */
1263core_initcall_sync(__gnttab_init);