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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/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);