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