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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/bitmap.h>
37#include <linux/memblock.h>
38#include <linux/sched.h>
39#include <linux/mm.h>
40#include <linux/slab.h>
41#include <linux/vmalloc.h>
42#include <linux/uaccess.h>
43#include <linux/io.h>
44#include <linux/delay.h>
45#include <linux/hardirq.h>
46#include <linux/workqueue.h>
47#include <linux/ratelimit.h>
48#include <linux/moduleparam.h>
49#ifdef CONFIG_XEN_GRANT_DMA_ALLOC
50#include <linux/dma-mapping.h>
51#endif
52
53#include <xen/xen.h>
54#include <xen/interface/xen.h>
55#include <xen/page.h>
56#include <xen/grant_table.h>
57#include <xen/interface/memory.h>
58#include <xen/hvc-console.h>
59#include <xen/swiotlb-xen.h>
60#include <xen/balloon.h>
61#ifdef CONFIG_X86
62#include <asm/xen/cpuid.h>
63#endif
64#include <xen/mem-reservation.h>
65#include <asm/xen/hypercall.h>
66#include <asm/xen/interface.h>
67
68#include <asm/sync_bitops.h>
69
70#define GNTTAB_LIST_END 0xffffffff
71
72static grant_ref_t **gnttab_list;
73static unsigned int nr_grant_frames;
74
75/*
76 * Handling of free grants:
77 *
78 * Free grants are in a simple list anchored in gnttab_free_head. They are
79 * linked by grant ref, the last element contains GNTTAB_LIST_END. The number
80 * of free entries is stored in gnttab_free_count.
81 * Additionally there is a bitmap of free entries anchored in
82 * gnttab_free_bitmap. This is being used for simplifying allocation of
83 * multiple consecutive grants, which is needed e.g. for support of virtio.
84 * gnttab_last_free is used to add free entries of new frames at the end of
85 * the free list.
86 * gnttab_free_tail_ptr specifies the variable which references the start
87 * of consecutive free grants ending with gnttab_last_free. This pointer is
88 * updated in a rather defensive way, in order to avoid performance hits in
89 * hot paths.
90 * All those variables are protected by gnttab_list_lock.
91 */
92static int gnttab_free_count;
93static unsigned int gnttab_size;
94static grant_ref_t gnttab_free_head = GNTTAB_LIST_END;
95static grant_ref_t gnttab_last_free = GNTTAB_LIST_END;
96static grant_ref_t *gnttab_free_tail_ptr;
97static unsigned long *gnttab_free_bitmap;
98static DEFINE_SPINLOCK(gnttab_list_lock);
99
100struct grant_frames xen_auto_xlat_grant_frames;
101static unsigned int xen_gnttab_version;
102module_param_named(version, xen_gnttab_version, uint, 0);
103
104static union {
105 struct grant_entry_v1 *v1;
106 union grant_entry_v2 *v2;
107 void *addr;
108} gnttab_shared;
109
110/*This is a structure of function pointers for grant table*/
111struct gnttab_ops {
112 /*
113 * Version of the grant interface.
114 */
115 unsigned int version;
116 /*
117 * Grant refs per grant frame.
118 */
119 unsigned int grefs_per_grant_frame;
120 /*
121 * Mapping a list of frames for storing grant entries. Frames parameter
122 * is used to store grant table address when grant table being setup,
123 * nr_gframes is the number of frames to map grant table. Returning
124 * GNTST_okay means success and negative value means failure.
125 */
126 int (*map_frames)(xen_pfn_t *frames, unsigned int nr_gframes);
127 /*
128 * Release a list of frames which are mapped in map_frames for grant
129 * entry status.
130 */
131 void (*unmap_frames)(void);
132 /*
133 * Introducing a valid entry into the grant table, granting the frame of
134 * this grant entry to domain for accessing. Ref
135 * parameter is reference of this introduced grant entry, domid is id of
136 * granted domain, frame is the page frame to be granted, and flags is
137 * status of the grant entry to be updated.
138 */
139 void (*update_entry)(grant_ref_t ref, domid_t domid,
140 unsigned long frame, unsigned flags);
141 /*
142 * Stop granting a grant entry to domain for accessing. Ref parameter is
143 * reference of a grant entry whose grant access will be stopped.
144 * If the grant entry is currently mapped for reading or writing, just
145 * return failure(==0) directly and don't tear down the grant access.
146 * Otherwise, stop grant access for this entry and return success(==1).
147 */
148 int (*end_foreign_access_ref)(grant_ref_t ref);
149 /*
150 * Read the frame number related to a given grant reference.
151 */
152 unsigned long (*read_frame)(grant_ref_t ref);
153};
154
155struct unmap_refs_callback_data {
156 struct completion completion;
157 int result;
158};
159
160static const struct gnttab_ops *gnttab_interface;
161
162/* This reflects status of grant entries, so act as a global value. */
163static grant_status_t *grstatus;
164
165static struct gnttab_free_callback *gnttab_free_callback_list;
166
167static int gnttab_expand(unsigned int req_entries);
168
169#define RPP (PAGE_SIZE / sizeof(grant_ref_t))
170#define SPP (PAGE_SIZE / sizeof(grant_status_t))
171
172static inline grant_ref_t *__gnttab_entry(grant_ref_t entry)
173{
174 return &gnttab_list[(entry) / RPP][(entry) % RPP];
175}
176/* This can be used as an l-value */
177#define gnttab_entry(entry) (*__gnttab_entry(entry))
178
179static int get_free_entries(unsigned count)
180{
181 unsigned long flags;
182 int ref, rc = 0;
183 grant_ref_t head;
184
185 spin_lock_irqsave(&gnttab_list_lock, flags);
186
187 if ((gnttab_free_count < count) &&
188 ((rc = gnttab_expand(count - gnttab_free_count)) < 0)) {
189 spin_unlock_irqrestore(&gnttab_list_lock, flags);
190 return rc;
191 }
192
193 ref = head = gnttab_free_head;
194 gnttab_free_count -= count;
195 while (count--) {
196 bitmap_clear(gnttab_free_bitmap, head, 1);
197 if (gnttab_free_tail_ptr == __gnttab_entry(head))
198 gnttab_free_tail_ptr = &gnttab_free_head;
199 if (count)
200 head = gnttab_entry(head);
201 }
202 gnttab_free_head = gnttab_entry(head);
203 gnttab_entry(head) = GNTTAB_LIST_END;
204
205 if (!gnttab_free_count) {
206 gnttab_last_free = GNTTAB_LIST_END;
207 gnttab_free_tail_ptr = NULL;
208 }
209
210 spin_unlock_irqrestore(&gnttab_list_lock, flags);
211
212 return ref;
213}
214
215static int get_seq_entry_count(void)
216{
217 if (gnttab_last_free == GNTTAB_LIST_END || !gnttab_free_tail_ptr ||
218 *gnttab_free_tail_ptr == GNTTAB_LIST_END)
219 return 0;
220
221 return gnttab_last_free - *gnttab_free_tail_ptr + 1;
222}
223
224/* Rebuilds the free grant list and tries to find count consecutive entries. */
225static int get_free_seq(unsigned int count)
226{
227 int ret = -ENOSPC;
228 unsigned int from, to;
229 grant_ref_t *last;
230
231 gnttab_free_tail_ptr = &gnttab_free_head;
232 last = &gnttab_free_head;
233
234 for (from = find_first_bit(gnttab_free_bitmap, gnttab_size);
235 from < gnttab_size;
236 from = find_next_bit(gnttab_free_bitmap, gnttab_size, to + 1)) {
237 to = find_next_zero_bit(gnttab_free_bitmap, gnttab_size,
238 from + 1);
239 if (ret < 0 && to - from >= count) {
240 ret = from;
241 bitmap_clear(gnttab_free_bitmap, ret, count);
242 from += count;
243 gnttab_free_count -= count;
244 if (from == to)
245 continue;
246 }
247
248 /*
249 * Recreate the free list in order to have it properly sorted.
250 * This is needed to make sure that the free tail has the maximum
251 * possible size.
252 */
253 while (from < to) {
254 *last = from;
255 last = __gnttab_entry(from);
256 gnttab_last_free = from;
257 from++;
258 }
259 if (to < gnttab_size)
260 gnttab_free_tail_ptr = __gnttab_entry(to - 1);
261 }
262
263 *last = GNTTAB_LIST_END;
264 if (gnttab_last_free != gnttab_size - 1)
265 gnttab_free_tail_ptr = NULL;
266
267 return ret;
268}
269
270static int get_free_entries_seq(unsigned int count)
271{
272 unsigned long flags;
273 int ret = 0;
274
275 spin_lock_irqsave(&gnttab_list_lock, flags);
276
277 if (gnttab_free_count < count) {
278 ret = gnttab_expand(count - gnttab_free_count);
279 if (ret < 0)
280 goto out;
281 }
282
283 if (get_seq_entry_count() < count) {
284 ret = get_free_seq(count);
285 if (ret >= 0)
286 goto out;
287 ret = gnttab_expand(count - get_seq_entry_count());
288 if (ret < 0)
289 goto out;
290 }
291
292 ret = *gnttab_free_tail_ptr;
293 *gnttab_free_tail_ptr = gnttab_entry(ret + count - 1);
294 gnttab_free_count -= count;
295 if (!gnttab_free_count)
296 gnttab_free_tail_ptr = NULL;
297 bitmap_clear(gnttab_free_bitmap, ret, count);
298
299 out:
300 spin_unlock_irqrestore(&gnttab_list_lock, flags);
301
302 return ret;
303}
304
305static void do_free_callbacks(void)
306{
307 struct gnttab_free_callback *callback, *next;
308
309 callback = gnttab_free_callback_list;
310 gnttab_free_callback_list = NULL;
311
312 while (callback != NULL) {
313 next = callback->next;
314 if (gnttab_free_count >= callback->count) {
315 callback->next = NULL;
316 callback->fn(callback->arg);
317 } else {
318 callback->next = gnttab_free_callback_list;
319 gnttab_free_callback_list = callback;
320 }
321 callback = next;
322 }
323}
324
325static inline void check_free_callbacks(void)
326{
327 if (unlikely(gnttab_free_callback_list))
328 do_free_callbacks();
329}
330
331static void put_free_entry_locked(grant_ref_t ref)
332{
333 if (unlikely(ref < GNTTAB_NR_RESERVED_ENTRIES))
334 return;
335
336 gnttab_entry(ref) = gnttab_free_head;
337 gnttab_free_head = ref;
338 if (!gnttab_free_count)
339 gnttab_last_free = ref;
340 if (gnttab_free_tail_ptr == &gnttab_free_head)
341 gnttab_free_tail_ptr = __gnttab_entry(ref);
342 gnttab_free_count++;
343 bitmap_set(gnttab_free_bitmap, ref, 1);
344}
345
346static void put_free_entry(grant_ref_t ref)
347{
348 unsigned long flags;
349
350 spin_lock_irqsave(&gnttab_list_lock, flags);
351 put_free_entry_locked(ref);
352 check_free_callbacks();
353 spin_unlock_irqrestore(&gnttab_list_lock, flags);
354}
355
356static void gnttab_set_free(unsigned int start, unsigned int n)
357{
358 unsigned int i;
359
360 for (i = start; i < start + n - 1; i++)
361 gnttab_entry(i) = i + 1;
362
363 gnttab_entry(i) = GNTTAB_LIST_END;
364 if (!gnttab_free_count) {
365 gnttab_free_head = start;
366 gnttab_free_tail_ptr = &gnttab_free_head;
367 } else {
368 gnttab_entry(gnttab_last_free) = start;
369 }
370 gnttab_free_count += n;
371 gnttab_last_free = i;
372
373 bitmap_set(gnttab_free_bitmap, start, n);
374}
375
376/*
377 * Following applies to gnttab_update_entry_v1 and gnttab_update_entry_v2.
378 * Introducing a valid entry into the grant table:
379 * 1. Write ent->domid.
380 * 2. Write ent->frame: Frame to which access is permitted.
381 * 3. Write memory barrier (WMB).
382 * 4. Write ent->flags, inc. valid type.
383 */
384static void gnttab_update_entry_v1(grant_ref_t ref, domid_t domid,
385 unsigned long frame, unsigned flags)
386{
387 gnttab_shared.v1[ref].domid = domid;
388 gnttab_shared.v1[ref].frame = frame;
389 wmb();
390 gnttab_shared.v1[ref].flags = flags;
391}
392
393static void gnttab_update_entry_v2(grant_ref_t ref, domid_t domid,
394 unsigned long frame, unsigned int flags)
395{
396 gnttab_shared.v2[ref].hdr.domid = domid;
397 gnttab_shared.v2[ref].full_page.frame = frame;
398 wmb(); /* Hypervisor concurrent accesses. */
399 gnttab_shared.v2[ref].hdr.flags = GTF_permit_access | flags;
400}
401
402/*
403 * Public grant-issuing interface functions
404 */
405void gnttab_grant_foreign_access_ref(grant_ref_t ref, domid_t domid,
406 unsigned long frame, int readonly)
407{
408 gnttab_interface->update_entry(ref, domid, frame,
409 GTF_permit_access | (readonly ? GTF_readonly : 0));
410}
411EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access_ref);
412
413int gnttab_grant_foreign_access(domid_t domid, unsigned long frame,
414 int readonly)
415{
416 int ref;
417
418 ref = get_free_entries(1);
419 if (unlikely(ref < 0))
420 return -ENOSPC;
421
422 gnttab_grant_foreign_access_ref(ref, domid, frame, readonly);
423
424 return ref;
425}
426EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access);
427
428static int gnttab_end_foreign_access_ref_v1(grant_ref_t ref)
429{
430 u16 *pflags = &gnttab_shared.v1[ref].flags;
431 u16 flags;
432
433 flags = *pflags;
434 do {
435 if (flags & (GTF_reading|GTF_writing))
436 return 0;
437 } while (!sync_try_cmpxchg(pflags, &flags, 0));
438
439 return 1;
440}
441
442static int gnttab_end_foreign_access_ref_v2(grant_ref_t ref)
443{
444 gnttab_shared.v2[ref].hdr.flags = 0;
445 mb(); /* Concurrent access by hypervisor. */
446 if (grstatus[ref] & (GTF_reading|GTF_writing)) {
447 return 0;
448 } else {
449 /*
450 * The read of grstatus needs to have acquire semantics.
451 * On x86, reads already have that, and we just need to
452 * protect against compiler reorderings.
453 * On other architectures we may need a full barrier.
454 */
455#ifdef CONFIG_X86
456 barrier();
457#else
458 mb();
459#endif
460 }
461
462 return 1;
463}
464
465static inline int _gnttab_end_foreign_access_ref(grant_ref_t ref)
466{
467 return gnttab_interface->end_foreign_access_ref(ref);
468}
469
470int gnttab_end_foreign_access_ref(grant_ref_t ref)
471{
472 if (_gnttab_end_foreign_access_ref(ref))
473 return 1;
474 pr_warn("WARNING: g.e. %#x still in use!\n", ref);
475 return 0;
476}
477EXPORT_SYMBOL_GPL(gnttab_end_foreign_access_ref);
478
479static unsigned long gnttab_read_frame_v1(grant_ref_t ref)
480{
481 return gnttab_shared.v1[ref].frame;
482}
483
484static unsigned long gnttab_read_frame_v2(grant_ref_t ref)
485{
486 return gnttab_shared.v2[ref].full_page.frame;
487}
488
489struct deferred_entry {
490 struct list_head list;
491 grant_ref_t ref;
492 uint16_t warn_delay;
493 struct page *page;
494};
495static LIST_HEAD(deferred_list);
496static void gnttab_handle_deferred(struct timer_list *);
497static DEFINE_TIMER(deferred_timer, gnttab_handle_deferred);
498
499static atomic64_t deferred_count;
500static atomic64_t leaked_count;
501static unsigned int free_per_iteration = 10;
502module_param(free_per_iteration, uint, 0600);
503
504static void gnttab_handle_deferred(struct timer_list *unused)
505{
506 unsigned int nr = READ_ONCE(free_per_iteration);
507 const bool ignore_limit = nr == 0;
508 struct deferred_entry *first = NULL;
509 unsigned long flags;
510 size_t freed = 0;
511
512 spin_lock_irqsave(&gnttab_list_lock, flags);
513 while ((ignore_limit || nr--) && !list_empty(&deferred_list)) {
514 struct deferred_entry *entry
515 = list_first_entry(&deferred_list,
516 struct deferred_entry, list);
517
518 if (entry == first)
519 break;
520 list_del(&entry->list);
521 spin_unlock_irqrestore(&gnttab_list_lock, flags);
522 if (_gnttab_end_foreign_access_ref(entry->ref)) {
523 uint64_t ret = atomic64_dec_return(&deferred_count);
524
525 put_free_entry(entry->ref);
526 pr_debug("freeing g.e. %#x (pfn %#lx), %llu remaining\n",
527 entry->ref, page_to_pfn(entry->page),
528 (unsigned long long)ret);
529 put_page(entry->page);
530 freed++;
531 kfree(entry);
532 entry = NULL;
533 } else {
534 if (!--entry->warn_delay)
535 pr_info("g.e. %#x still pending\n", entry->ref);
536 if (!first)
537 first = entry;
538 }
539 spin_lock_irqsave(&gnttab_list_lock, flags);
540 if (entry)
541 list_add_tail(&entry->list, &deferred_list);
542 }
543 if (list_empty(&deferred_list))
544 WARN_ON(atomic64_read(&deferred_count));
545 else if (!timer_pending(&deferred_timer)) {
546 deferred_timer.expires = jiffies + HZ;
547 add_timer(&deferred_timer);
548 }
549 spin_unlock_irqrestore(&gnttab_list_lock, flags);
550 pr_debug("Freed %zu references", freed);
551}
552
553static void gnttab_add_deferred(grant_ref_t ref, struct page *page)
554{
555 struct deferred_entry *entry;
556 gfp_t gfp = (in_atomic() || irqs_disabled()) ? GFP_ATOMIC : GFP_KERNEL;
557 uint64_t leaked, deferred;
558
559 entry = kmalloc(sizeof(*entry), gfp);
560 if (!page) {
561 unsigned long gfn = gnttab_interface->read_frame(ref);
562
563 page = pfn_to_page(gfn_to_pfn(gfn));
564 get_page(page);
565 }
566
567 if (entry) {
568 unsigned long flags;
569
570 entry->ref = ref;
571 entry->page = page;
572 entry->warn_delay = 60;
573 spin_lock_irqsave(&gnttab_list_lock, flags);
574 list_add_tail(&entry->list, &deferred_list);
575 if (!timer_pending(&deferred_timer)) {
576 deferred_timer.expires = jiffies + HZ;
577 add_timer(&deferred_timer);
578 }
579 spin_unlock_irqrestore(&gnttab_list_lock, flags);
580 deferred = atomic64_inc_return(&deferred_count);
581 leaked = atomic64_read(&leaked_count);
582 pr_debug("deferring g.e. %#x (pfn %#lx) (total deferred %llu, total leaked %llu)\n",
583 ref, page ? page_to_pfn(page) : -1, deferred, leaked);
584 } else {
585 deferred = atomic64_read(&deferred_count);
586 leaked = atomic64_inc_return(&leaked_count);
587 pr_warn("leaking g.e. %#x (pfn %#lx) (total deferred %llu, total leaked %llu)\n",
588 ref, page ? page_to_pfn(page) : -1, deferred, leaked);
589 }
590}
591
592int gnttab_try_end_foreign_access(grant_ref_t ref)
593{
594 int ret = _gnttab_end_foreign_access_ref(ref);
595
596 if (ret)
597 put_free_entry(ref);
598
599 return ret;
600}
601EXPORT_SYMBOL_GPL(gnttab_try_end_foreign_access);
602
603void gnttab_end_foreign_access(grant_ref_t ref, struct page *page)
604{
605 if (gnttab_try_end_foreign_access(ref)) {
606 if (page)
607 put_page(page);
608 } else
609 gnttab_add_deferred(ref, page);
610}
611EXPORT_SYMBOL_GPL(gnttab_end_foreign_access);
612
613void gnttab_free_grant_reference(grant_ref_t ref)
614{
615 put_free_entry(ref);
616}
617EXPORT_SYMBOL_GPL(gnttab_free_grant_reference);
618
619void gnttab_free_grant_references(grant_ref_t head)
620{
621 grant_ref_t ref;
622 unsigned long flags;
623
624 spin_lock_irqsave(&gnttab_list_lock, flags);
625 while (head != GNTTAB_LIST_END) {
626 ref = gnttab_entry(head);
627 put_free_entry_locked(head);
628 head = ref;
629 }
630 check_free_callbacks();
631 spin_unlock_irqrestore(&gnttab_list_lock, flags);
632}
633EXPORT_SYMBOL_GPL(gnttab_free_grant_references);
634
635void gnttab_free_grant_reference_seq(grant_ref_t head, unsigned int count)
636{
637 unsigned long flags;
638 unsigned int i;
639
640 spin_lock_irqsave(&gnttab_list_lock, flags);
641 for (i = count; i > 0; i--)
642 put_free_entry_locked(head + i - 1);
643 check_free_callbacks();
644 spin_unlock_irqrestore(&gnttab_list_lock, flags);
645}
646EXPORT_SYMBOL_GPL(gnttab_free_grant_reference_seq);
647
648int gnttab_alloc_grant_references(u16 count, grant_ref_t *head)
649{
650 int h = get_free_entries(count);
651
652 if (h < 0)
653 return -ENOSPC;
654
655 *head = h;
656
657 return 0;
658}
659EXPORT_SYMBOL_GPL(gnttab_alloc_grant_references);
660
661int gnttab_alloc_grant_reference_seq(unsigned int count, grant_ref_t *first)
662{
663 int h;
664
665 if (count == 1)
666 h = get_free_entries(1);
667 else
668 h = get_free_entries_seq(count);
669
670 if (h < 0)
671 return -ENOSPC;
672
673 *first = h;
674
675 return 0;
676}
677EXPORT_SYMBOL_GPL(gnttab_alloc_grant_reference_seq);
678
679int gnttab_empty_grant_references(const grant_ref_t *private_head)
680{
681 return (*private_head == GNTTAB_LIST_END);
682}
683EXPORT_SYMBOL_GPL(gnttab_empty_grant_references);
684
685int gnttab_claim_grant_reference(grant_ref_t *private_head)
686{
687 grant_ref_t g = *private_head;
688 if (unlikely(g == GNTTAB_LIST_END))
689 return -ENOSPC;
690 *private_head = gnttab_entry(g);
691 return g;
692}
693EXPORT_SYMBOL_GPL(gnttab_claim_grant_reference);
694
695void gnttab_release_grant_reference(grant_ref_t *private_head,
696 grant_ref_t release)
697{
698 gnttab_entry(release) = *private_head;
699 *private_head = release;
700}
701EXPORT_SYMBOL_GPL(gnttab_release_grant_reference);
702
703void gnttab_request_free_callback(struct gnttab_free_callback *callback,
704 void (*fn)(void *), void *arg, u16 count)
705{
706 unsigned long flags;
707 struct gnttab_free_callback *cb;
708
709 spin_lock_irqsave(&gnttab_list_lock, flags);
710
711 /* Check if the callback is already on the list */
712 cb = gnttab_free_callback_list;
713 while (cb) {
714 if (cb == callback)
715 goto out;
716 cb = cb->next;
717 }
718
719 callback->fn = fn;
720 callback->arg = arg;
721 callback->count = count;
722 callback->next = gnttab_free_callback_list;
723 gnttab_free_callback_list = callback;
724 check_free_callbacks();
725out:
726 spin_unlock_irqrestore(&gnttab_list_lock, flags);
727}
728EXPORT_SYMBOL_GPL(gnttab_request_free_callback);
729
730void gnttab_cancel_free_callback(struct gnttab_free_callback *callback)
731{
732 struct gnttab_free_callback **pcb;
733 unsigned long flags;
734
735 spin_lock_irqsave(&gnttab_list_lock, flags);
736 for (pcb = &gnttab_free_callback_list; *pcb; pcb = &(*pcb)->next) {
737 if (*pcb == callback) {
738 *pcb = callback->next;
739 break;
740 }
741 }
742 spin_unlock_irqrestore(&gnttab_list_lock, flags);
743}
744EXPORT_SYMBOL_GPL(gnttab_cancel_free_callback);
745
746static unsigned int gnttab_frames(unsigned int frames, unsigned int align)
747{
748 return (frames * gnttab_interface->grefs_per_grant_frame + align - 1) /
749 align;
750}
751
752static int grow_gnttab_list(unsigned int more_frames)
753{
754 unsigned int new_nr_grant_frames, extra_entries, i;
755 unsigned int nr_glist_frames, new_nr_glist_frames;
756 unsigned int grefs_per_frame;
757
758 grefs_per_frame = gnttab_interface->grefs_per_grant_frame;
759
760 new_nr_grant_frames = nr_grant_frames + more_frames;
761 extra_entries = more_frames * grefs_per_frame;
762
763 nr_glist_frames = gnttab_frames(nr_grant_frames, RPP);
764 new_nr_glist_frames = gnttab_frames(new_nr_grant_frames, RPP);
765 for (i = nr_glist_frames; i < new_nr_glist_frames; i++) {
766 gnttab_list[i] = (grant_ref_t *)__get_free_page(GFP_ATOMIC);
767 if (!gnttab_list[i])
768 goto grow_nomem;
769 }
770
771 gnttab_set_free(gnttab_size, extra_entries);
772
773 if (!gnttab_free_tail_ptr)
774 gnttab_free_tail_ptr = __gnttab_entry(gnttab_size);
775
776 nr_grant_frames = new_nr_grant_frames;
777 gnttab_size += extra_entries;
778
779 check_free_callbacks();
780
781 return 0;
782
783grow_nomem:
784 while (i-- > nr_glist_frames)
785 free_page((unsigned long) gnttab_list[i]);
786 return -ENOMEM;
787}
788
789static unsigned int __max_nr_grant_frames(void)
790{
791 struct gnttab_query_size query;
792 int rc;
793
794 query.dom = DOMID_SELF;
795
796 rc = HYPERVISOR_grant_table_op(GNTTABOP_query_size, &query, 1);
797 if ((rc < 0) || (query.status != GNTST_okay))
798 return 4; /* Legacy max supported number of frames */
799
800 return query.max_nr_frames;
801}
802
803unsigned int gnttab_max_grant_frames(void)
804{
805 unsigned int xen_max = __max_nr_grant_frames();
806 static unsigned int boot_max_nr_grant_frames;
807
808 /* First time, initialize it properly. */
809 if (!boot_max_nr_grant_frames)
810 boot_max_nr_grant_frames = __max_nr_grant_frames();
811
812 if (xen_max > boot_max_nr_grant_frames)
813 return boot_max_nr_grant_frames;
814 return xen_max;
815}
816EXPORT_SYMBOL_GPL(gnttab_max_grant_frames);
817
818int gnttab_setup_auto_xlat_frames(phys_addr_t addr)
819{
820 xen_pfn_t *pfn;
821 unsigned int max_nr_gframes = __max_nr_grant_frames();
822 unsigned int i;
823 void *vaddr;
824
825 if (xen_auto_xlat_grant_frames.count)
826 return -EINVAL;
827
828 vaddr = memremap(addr, XEN_PAGE_SIZE * max_nr_gframes, MEMREMAP_WB);
829 if (vaddr == NULL) {
830 pr_warn("Failed to ioremap gnttab share frames (addr=%pa)!\n",
831 &addr);
832 return -ENOMEM;
833 }
834 pfn = kcalloc(max_nr_gframes, sizeof(pfn[0]), GFP_KERNEL);
835 if (!pfn) {
836 memunmap(vaddr);
837 return -ENOMEM;
838 }
839 for (i = 0; i < max_nr_gframes; i++)
840 pfn[i] = XEN_PFN_DOWN(addr) + i;
841
842 xen_auto_xlat_grant_frames.vaddr = vaddr;
843 xen_auto_xlat_grant_frames.pfn = pfn;
844 xen_auto_xlat_grant_frames.count = max_nr_gframes;
845
846 return 0;
847}
848EXPORT_SYMBOL_GPL(gnttab_setup_auto_xlat_frames);
849
850void gnttab_free_auto_xlat_frames(void)
851{
852 if (!xen_auto_xlat_grant_frames.count)
853 return;
854 kfree(xen_auto_xlat_grant_frames.pfn);
855 memunmap(xen_auto_xlat_grant_frames.vaddr);
856
857 xen_auto_xlat_grant_frames.pfn = NULL;
858 xen_auto_xlat_grant_frames.count = 0;
859 xen_auto_xlat_grant_frames.vaddr = NULL;
860}
861EXPORT_SYMBOL_GPL(gnttab_free_auto_xlat_frames);
862
863int gnttab_pages_set_private(int nr_pages, struct page **pages)
864{
865 int i;
866
867 for (i = 0; i < nr_pages; i++) {
868#if BITS_PER_LONG < 64
869 struct xen_page_foreign *foreign;
870
871 foreign = kzalloc(sizeof(*foreign), GFP_KERNEL);
872 if (!foreign)
873 return -ENOMEM;
874
875 set_page_private(pages[i], (unsigned long)foreign);
876#endif
877 SetPagePrivate(pages[i]);
878 }
879
880 return 0;
881}
882EXPORT_SYMBOL_GPL(gnttab_pages_set_private);
883
884/**
885 * gnttab_alloc_pages - alloc pages suitable for grant mapping into
886 * @nr_pages: number of pages to alloc
887 * @pages: returns the pages
888 */
889int gnttab_alloc_pages(int nr_pages, struct page **pages)
890{
891 int ret;
892
893 ret = xen_alloc_unpopulated_pages(nr_pages, pages);
894 if (ret < 0)
895 return ret;
896
897 ret = gnttab_pages_set_private(nr_pages, pages);
898 if (ret < 0)
899 gnttab_free_pages(nr_pages, pages);
900
901 return ret;
902}
903EXPORT_SYMBOL_GPL(gnttab_alloc_pages);
904
905#ifdef CONFIG_XEN_UNPOPULATED_ALLOC
906static inline void cache_init(struct gnttab_page_cache *cache)
907{
908 cache->pages = NULL;
909}
910
911static inline bool cache_empty(struct gnttab_page_cache *cache)
912{
913 return !cache->pages;
914}
915
916static inline struct page *cache_deq(struct gnttab_page_cache *cache)
917{
918 struct page *page;
919
920 page = cache->pages;
921 cache->pages = page->zone_device_data;
922
923 return page;
924}
925
926static inline void cache_enq(struct gnttab_page_cache *cache, struct page *page)
927{
928 page->zone_device_data = cache->pages;
929 cache->pages = page;
930}
931#else
932static inline void cache_init(struct gnttab_page_cache *cache)
933{
934 INIT_LIST_HEAD(&cache->pages);
935}
936
937static inline bool cache_empty(struct gnttab_page_cache *cache)
938{
939 return list_empty(&cache->pages);
940}
941
942static inline struct page *cache_deq(struct gnttab_page_cache *cache)
943{
944 struct page *page;
945
946 page = list_first_entry(&cache->pages, struct page, lru);
947 list_del(&page->lru);
948
949 return page;
950}
951
952static inline void cache_enq(struct gnttab_page_cache *cache, struct page *page)
953{
954 list_add(&page->lru, &cache->pages);
955}
956#endif
957
958void gnttab_page_cache_init(struct gnttab_page_cache *cache)
959{
960 spin_lock_init(&cache->lock);
961 cache_init(cache);
962 cache->num_pages = 0;
963}
964EXPORT_SYMBOL_GPL(gnttab_page_cache_init);
965
966int gnttab_page_cache_get(struct gnttab_page_cache *cache, struct page **page)
967{
968 unsigned long flags;
969
970 spin_lock_irqsave(&cache->lock, flags);
971
972 if (cache_empty(cache)) {
973 spin_unlock_irqrestore(&cache->lock, flags);
974 return gnttab_alloc_pages(1, page);
975 }
976
977 page[0] = cache_deq(cache);
978 cache->num_pages--;
979
980 spin_unlock_irqrestore(&cache->lock, flags);
981
982 return 0;
983}
984EXPORT_SYMBOL_GPL(gnttab_page_cache_get);
985
986void gnttab_page_cache_put(struct gnttab_page_cache *cache, struct page **page,
987 unsigned int num)
988{
989 unsigned long flags;
990 unsigned int i;
991
992 spin_lock_irqsave(&cache->lock, flags);
993
994 for (i = 0; i < num; i++)
995 cache_enq(cache, page[i]);
996 cache->num_pages += num;
997
998 spin_unlock_irqrestore(&cache->lock, flags);
999}
1000EXPORT_SYMBOL_GPL(gnttab_page_cache_put);
1001
1002void gnttab_page_cache_shrink(struct gnttab_page_cache *cache, unsigned int num)
1003{
1004 struct page *page[10];
1005 unsigned int i = 0;
1006 unsigned long flags;
1007
1008 spin_lock_irqsave(&cache->lock, flags);
1009
1010 while (cache->num_pages > num) {
1011 page[i] = cache_deq(cache);
1012 cache->num_pages--;
1013 if (++i == ARRAY_SIZE(page)) {
1014 spin_unlock_irqrestore(&cache->lock, flags);
1015 gnttab_free_pages(i, page);
1016 i = 0;
1017 spin_lock_irqsave(&cache->lock, flags);
1018 }
1019 }
1020
1021 spin_unlock_irqrestore(&cache->lock, flags);
1022
1023 if (i != 0)
1024 gnttab_free_pages(i, page);
1025}
1026EXPORT_SYMBOL_GPL(gnttab_page_cache_shrink);
1027
1028void gnttab_pages_clear_private(int nr_pages, struct page **pages)
1029{
1030 int i;
1031
1032 for (i = 0; i < nr_pages; i++) {
1033 if (PagePrivate(pages[i])) {
1034#if BITS_PER_LONG < 64
1035 kfree((void *)page_private(pages[i]));
1036#endif
1037 ClearPagePrivate(pages[i]);
1038 }
1039 }
1040}
1041EXPORT_SYMBOL_GPL(gnttab_pages_clear_private);
1042
1043/**
1044 * gnttab_free_pages - free pages allocated by gnttab_alloc_pages()
1045 * @nr_pages: number of pages to free
1046 * @pages: the pages
1047 */
1048void gnttab_free_pages(int nr_pages, struct page **pages)
1049{
1050 gnttab_pages_clear_private(nr_pages, pages);
1051 xen_free_unpopulated_pages(nr_pages, pages);
1052}
1053EXPORT_SYMBOL_GPL(gnttab_free_pages);
1054
1055#ifdef CONFIG_XEN_GRANT_DMA_ALLOC
1056/**
1057 * gnttab_dma_alloc_pages - alloc DMAable pages suitable for grant mapping into
1058 * @args: arguments to the function
1059 */
1060int gnttab_dma_alloc_pages(struct gnttab_dma_alloc_args *args)
1061{
1062 unsigned long pfn, start_pfn;
1063 size_t size;
1064 int i, ret;
1065
1066 if (args->nr_pages < 0 || args->nr_pages > (INT_MAX >> PAGE_SHIFT))
1067 return -ENOMEM;
1068
1069 size = args->nr_pages << PAGE_SHIFT;
1070 if (args->coherent)
1071 args->vaddr = dma_alloc_coherent(args->dev, size,
1072 &args->dev_bus_addr,
1073 GFP_KERNEL | __GFP_NOWARN);
1074 else
1075 args->vaddr = dma_alloc_wc(args->dev, size,
1076 &args->dev_bus_addr,
1077 GFP_KERNEL | __GFP_NOWARN);
1078 if (!args->vaddr) {
1079 pr_debug("Failed to allocate DMA buffer of size %zu\n", size);
1080 return -ENOMEM;
1081 }
1082
1083 start_pfn = __phys_to_pfn(args->dev_bus_addr);
1084 for (pfn = start_pfn, i = 0; pfn < start_pfn + args->nr_pages;
1085 pfn++, i++) {
1086 struct page *page = pfn_to_page(pfn);
1087
1088 args->pages[i] = page;
1089 args->frames[i] = xen_page_to_gfn(page);
1090 xenmem_reservation_scrub_page(page);
1091 }
1092
1093 xenmem_reservation_va_mapping_reset(args->nr_pages, args->pages);
1094
1095 ret = xenmem_reservation_decrease(args->nr_pages, args->frames);
1096 if (ret != args->nr_pages) {
1097 pr_debug("Failed to decrease reservation for DMA buffer\n");
1098 ret = -EFAULT;
1099 goto fail;
1100 }
1101
1102 ret = gnttab_pages_set_private(args->nr_pages, args->pages);
1103 if (ret < 0)
1104 goto fail;
1105
1106 return 0;
1107
1108fail:
1109 gnttab_dma_free_pages(args);
1110 return ret;
1111}
1112EXPORT_SYMBOL_GPL(gnttab_dma_alloc_pages);
1113
1114/**
1115 * gnttab_dma_free_pages - free DMAable pages
1116 * @args: arguments to the function
1117 */
1118int gnttab_dma_free_pages(struct gnttab_dma_alloc_args *args)
1119{
1120 size_t size;
1121 int i, ret;
1122
1123 gnttab_pages_clear_private(args->nr_pages, args->pages);
1124
1125 for (i = 0; i < args->nr_pages; i++)
1126 args->frames[i] = page_to_xen_pfn(args->pages[i]);
1127
1128 ret = xenmem_reservation_increase(args->nr_pages, args->frames);
1129 if (ret != args->nr_pages) {
1130 pr_debug("Failed to increase reservation for DMA buffer\n");
1131 ret = -EFAULT;
1132 } else {
1133 ret = 0;
1134 }
1135
1136 xenmem_reservation_va_mapping_update(args->nr_pages, args->pages,
1137 args->frames);
1138
1139 size = args->nr_pages << PAGE_SHIFT;
1140 if (args->coherent)
1141 dma_free_coherent(args->dev, size,
1142 args->vaddr, args->dev_bus_addr);
1143 else
1144 dma_free_wc(args->dev, size,
1145 args->vaddr, args->dev_bus_addr);
1146 return ret;
1147}
1148EXPORT_SYMBOL_GPL(gnttab_dma_free_pages);
1149#endif
1150
1151/* Handling of paged out grant targets (GNTST_eagain) */
1152#define MAX_DELAY 256
1153static inline void
1154gnttab_retry_eagain_gop(unsigned int cmd, void *gop, int16_t *status,
1155 const char *func)
1156{
1157 unsigned delay = 1;
1158
1159 do {
1160 BUG_ON(HYPERVISOR_grant_table_op(cmd, gop, 1));
1161 if (*status == GNTST_eagain)
1162 msleep(delay++);
1163 } while ((*status == GNTST_eagain) && (delay < MAX_DELAY));
1164
1165 if (delay >= MAX_DELAY) {
1166 pr_err("%s: %s eagain grant\n", func, current->comm);
1167 *status = GNTST_bad_page;
1168 }
1169}
1170
1171void gnttab_batch_map(struct gnttab_map_grant_ref *batch, unsigned count)
1172{
1173 struct gnttab_map_grant_ref *op;
1174
1175 if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, batch, count))
1176 BUG();
1177 for (op = batch; op < batch + count; op++)
1178 if (op->status == GNTST_eagain)
1179 gnttab_retry_eagain_gop(GNTTABOP_map_grant_ref, op,
1180 &op->status, __func__);
1181}
1182EXPORT_SYMBOL_GPL(gnttab_batch_map);
1183
1184void gnttab_batch_copy(struct gnttab_copy *batch, unsigned count)
1185{
1186 struct gnttab_copy *op;
1187
1188 if (HYPERVISOR_grant_table_op(GNTTABOP_copy, batch, count))
1189 BUG();
1190 for (op = batch; op < batch + count; op++)
1191 if (op->status == GNTST_eagain)
1192 gnttab_retry_eagain_gop(GNTTABOP_copy, op,
1193 &op->status, __func__);
1194}
1195EXPORT_SYMBOL_GPL(gnttab_batch_copy);
1196
1197void gnttab_foreach_grant_in_range(struct page *page,
1198 unsigned int offset,
1199 unsigned int len,
1200 xen_grant_fn_t fn,
1201 void *data)
1202{
1203 unsigned int goffset;
1204 unsigned int glen;
1205 unsigned long xen_pfn;
1206
1207 len = min_t(unsigned int, PAGE_SIZE - offset, len);
1208 goffset = xen_offset_in_page(offset);
1209
1210 xen_pfn = page_to_xen_pfn(page) + XEN_PFN_DOWN(offset);
1211
1212 while (len) {
1213 glen = min_t(unsigned int, XEN_PAGE_SIZE - goffset, len);
1214 fn(pfn_to_gfn(xen_pfn), goffset, glen, data);
1215
1216 goffset = 0;
1217 xen_pfn++;
1218 len -= glen;
1219 }
1220}
1221EXPORT_SYMBOL_GPL(gnttab_foreach_grant_in_range);
1222
1223void gnttab_foreach_grant(struct page **pages,
1224 unsigned int nr_grefs,
1225 xen_grant_fn_t fn,
1226 void *data)
1227{
1228 unsigned int goffset = 0;
1229 unsigned long xen_pfn = 0;
1230 unsigned int i;
1231
1232 for (i = 0; i < nr_grefs; i++) {
1233 if ((i % XEN_PFN_PER_PAGE) == 0) {
1234 xen_pfn = page_to_xen_pfn(pages[i / XEN_PFN_PER_PAGE]);
1235 goffset = 0;
1236 }
1237
1238 fn(pfn_to_gfn(xen_pfn), goffset, XEN_PAGE_SIZE, data);
1239
1240 goffset += XEN_PAGE_SIZE;
1241 xen_pfn++;
1242 }
1243}
1244
1245int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
1246 struct gnttab_map_grant_ref *kmap_ops,
1247 struct page **pages, unsigned int count)
1248{
1249 int i, ret;
1250
1251 ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, map_ops, count);
1252 if (ret)
1253 return ret;
1254
1255 for (i = 0; i < count; i++) {
1256 switch (map_ops[i].status) {
1257 case GNTST_okay:
1258 {
1259 struct xen_page_foreign *foreign;
1260
1261 SetPageForeign(pages[i]);
1262 foreign = xen_page_foreign(pages[i]);
1263 foreign->domid = map_ops[i].dom;
1264 foreign->gref = map_ops[i].ref;
1265 break;
1266 }
1267
1268 case GNTST_no_device_space:
1269 pr_warn_ratelimited("maptrack limit reached, can't map all guest pages\n");
1270 break;
1271
1272 case GNTST_eagain:
1273 /* Retry eagain maps */
1274 gnttab_retry_eagain_gop(GNTTABOP_map_grant_ref,
1275 map_ops + i,
1276 &map_ops[i].status, __func__);
1277 /* Test status in next loop iteration. */
1278 i--;
1279 break;
1280
1281 default:
1282 break;
1283 }
1284 }
1285
1286 return set_foreign_p2m_mapping(map_ops, kmap_ops, pages, count);
1287}
1288EXPORT_SYMBOL_GPL(gnttab_map_refs);
1289
1290int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
1291 struct gnttab_unmap_grant_ref *kunmap_ops,
1292 struct page **pages, unsigned int count)
1293{
1294 unsigned int i;
1295 int ret;
1296
1297 ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap_ops, count);
1298 if (ret)
1299 return ret;
1300
1301 for (i = 0; i < count; i++)
1302 ClearPageForeign(pages[i]);
1303
1304 return clear_foreign_p2m_mapping(unmap_ops, kunmap_ops, pages, count);
1305}
1306EXPORT_SYMBOL_GPL(gnttab_unmap_refs);
1307
1308#define GNTTAB_UNMAP_REFS_DELAY 5
1309
1310static void __gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item);
1311
1312static void gnttab_unmap_work(struct work_struct *work)
1313{
1314 struct gntab_unmap_queue_data
1315 *unmap_data = container_of(work,
1316 struct gntab_unmap_queue_data,
1317 gnttab_work.work);
1318 if (unmap_data->age != UINT_MAX)
1319 unmap_data->age++;
1320 __gnttab_unmap_refs_async(unmap_data);
1321}
1322
1323static void __gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item)
1324{
1325 int ret;
1326 int pc;
1327
1328 for (pc = 0; pc < item->count; pc++) {
1329 if (page_count(item->pages[pc]) > 1) {
1330 unsigned long delay = GNTTAB_UNMAP_REFS_DELAY * (item->age + 1);
1331 schedule_delayed_work(&item->gnttab_work,
1332 msecs_to_jiffies(delay));
1333 return;
1334 }
1335 }
1336
1337 ret = gnttab_unmap_refs(item->unmap_ops, item->kunmap_ops,
1338 item->pages, item->count);
1339 item->done(ret, item);
1340}
1341
1342void gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item)
1343{
1344 INIT_DELAYED_WORK(&item->gnttab_work, gnttab_unmap_work);
1345 item->age = 0;
1346
1347 __gnttab_unmap_refs_async(item);
1348}
1349EXPORT_SYMBOL_GPL(gnttab_unmap_refs_async);
1350
1351static void unmap_refs_callback(int result,
1352 struct gntab_unmap_queue_data *data)
1353{
1354 struct unmap_refs_callback_data *d = data->data;
1355
1356 d->result = result;
1357 complete(&d->completion);
1358}
1359
1360int gnttab_unmap_refs_sync(struct gntab_unmap_queue_data *item)
1361{
1362 struct unmap_refs_callback_data data;
1363
1364 init_completion(&data.completion);
1365 item->data = &data;
1366 item->done = &unmap_refs_callback;
1367 gnttab_unmap_refs_async(item);
1368 wait_for_completion(&data.completion);
1369
1370 return data.result;
1371}
1372EXPORT_SYMBOL_GPL(gnttab_unmap_refs_sync);
1373
1374static unsigned int nr_status_frames(unsigned int nr_grant_frames)
1375{
1376 return gnttab_frames(nr_grant_frames, SPP);
1377}
1378
1379static int gnttab_map_frames_v1(xen_pfn_t *frames, unsigned int nr_gframes)
1380{
1381 int rc;
1382
1383 rc = arch_gnttab_map_shared(frames, nr_gframes,
1384 gnttab_max_grant_frames(),
1385 &gnttab_shared.addr);
1386 BUG_ON(rc);
1387
1388 return 0;
1389}
1390
1391static void gnttab_unmap_frames_v1(void)
1392{
1393 arch_gnttab_unmap(gnttab_shared.addr, nr_grant_frames);
1394}
1395
1396static int gnttab_map_frames_v2(xen_pfn_t *frames, unsigned int nr_gframes)
1397{
1398 uint64_t *sframes;
1399 unsigned int nr_sframes;
1400 struct gnttab_get_status_frames getframes;
1401 int rc;
1402
1403 nr_sframes = nr_status_frames(nr_gframes);
1404
1405 /* No need for kzalloc as it is initialized in following hypercall
1406 * GNTTABOP_get_status_frames.
1407 */
1408 sframes = kmalloc_array(nr_sframes, sizeof(uint64_t), GFP_ATOMIC);
1409 if (!sframes)
1410 return -ENOMEM;
1411
1412 getframes.dom = DOMID_SELF;
1413 getframes.nr_frames = nr_sframes;
1414 set_xen_guest_handle(getframes.frame_list, sframes);
1415
1416 rc = HYPERVISOR_grant_table_op(GNTTABOP_get_status_frames,
1417 &getframes, 1);
1418 if (rc == -ENOSYS) {
1419 kfree(sframes);
1420 return -ENOSYS;
1421 }
1422
1423 BUG_ON(rc || getframes.status);
1424
1425 rc = arch_gnttab_map_status(sframes, nr_sframes,
1426 nr_status_frames(gnttab_max_grant_frames()),
1427 &grstatus);
1428 BUG_ON(rc);
1429 kfree(sframes);
1430
1431 rc = arch_gnttab_map_shared(frames, nr_gframes,
1432 gnttab_max_grant_frames(),
1433 &gnttab_shared.addr);
1434 BUG_ON(rc);
1435
1436 return 0;
1437}
1438
1439static void gnttab_unmap_frames_v2(void)
1440{
1441 arch_gnttab_unmap(gnttab_shared.addr, nr_grant_frames);
1442 arch_gnttab_unmap(grstatus, nr_status_frames(nr_grant_frames));
1443}
1444
1445static int gnttab_map(unsigned int start_idx, unsigned int end_idx)
1446{
1447 struct gnttab_setup_table setup;
1448 xen_pfn_t *frames;
1449 unsigned int nr_gframes = end_idx + 1;
1450 int rc;
1451
1452 if (xen_feature(XENFEAT_auto_translated_physmap)) {
1453 struct xen_add_to_physmap xatp;
1454 unsigned int i = end_idx;
1455 rc = 0;
1456 BUG_ON(xen_auto_xlat_grant_frames.count < nr_gframes);
1457 /*
1458 * Loop backwards, so that the first hypercall has the largest
1459 * index, ensuring that the table will grow only once.
1460 */
1461 do {
1462 xatp.domid = DOMID_SELF;
1463 xatp.idx = i;
1464 xatp.space = XENMAPSPACE_grant_table;
1465 xatp.gpfn = xen_auto_xlat_grant_frames.pfn[i];
1466 rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp);
1467 if (rc != 0) {
1468 pr_warn("grant table add_to_physmap failed, err=%d\n",
1469 rc);
1470 break;
1471 }
1472 } while (i-- > start_idx);
1473
1474 return rc;
1475 }
1476
1477 /* No need for kzalloc as it is initialized in following hypercall
1478 * GNTTABOP_setup_table.
1479 */
1480 frames = kmalloc_array(nr_gframes, sizeof(unsigned long), GFP_ATOMIC);
1481 if (!frames)
1482 return -ENOMEM;
1483
1484 setup.dom = DOMID_SELF;
1485 setup.nr_frames = nr_gframes;
1486 set_xen_guest_handle(setup.frame_list, frames);
1487
1488 rc = HYPERVISOR_grant_table_op(GNTTABOP_setup_table, &setup, 1);
1489 if (rc == -ENOSYS) {
1490 kfree(frames);
1491 return -ENOSYS;
1492 }
1493
1494 BUG_ON(rc || setup.status);
1495
1496 rc = gnttab_interface->map_frames(frames, nr_gframes);
1497
1498 kfree(frames);
1499
1500 return rc;
1501}
1502
1503static const struct gnttab_ops gnttab_v1_ops = {
1504 .version = 1,
1505 .grefs_per_grant_frame = XEN_PAGE_SIZE /
1506 sizeof(struct grant_entry_v1),
1507 .map_frames = gnttab_map_frames_v1,
1508 .unmap_frames = gnttab_unmap_frames_v1,
1509 .update_entry = gnttab_update_entry_v1,
1510 .end_foreign_access_ref = gnttab_end_foreign_access_ref_v1,
1511 .read_frame = gnttab_read_frame_v1,
1512};
1513
1514static const struct gnttab_ops gnttab_v2_ops = {
1515 .version = 2,
1516 .grefs_per_grant_frame = XEN_PAGE_SIZE /
1517 sizeof(union grant_entry_v2),
1518 .map_frames = gnttab_map_frames_v2,
1519 .unmap_frames = gnttab_unmap_frames_v2,
1520 .update_entry = gnttab_update_entry_v2,
1521 .end_foreign_access_ref = gnttab_end_foreign_access_ref_v2,
1522 .read_frame = gnttab_read_frame_v2,
1523};
1524
1525static bool gnttab_need_v2(void)
1526{
1527#ifdef CONFIG_X86
1528 uint32_t base, width;
1529
1530 if (xen_pv_domain()) {
1531 base = xen_cpuid_base();
1532 if (cpuid_eax(base) < 5)
1533 return false; /* Information not available, use V1. */
1534 width = cpuid_ebx(base + 5) &
1535 XEN_CPUID_MACHINE_ADDRESS_WIDTH_MASK;
1536 return width > 32 + PAGE_SHIFT;
1537 }
1538#endif
1539 return !!(max_possible_pfn >> 32);
1540}
1541
1542static void gnttab_request_version(void)
1543{
1544 long rc;
1545 struct gnttab_set_version gsv;
1546
1547 if (gnttab_need_v2())
1548 gsv.version = 2;
1549 else
1550 gsv.version = 1;
1551
1552 /* Boot parameter overrides automatic selection. */
1553 if (xen_gnttab_version >= 1 && xen_gnttab_version <= 2)
1554 gsv.version = xen_gnttab_version;
1555
1556 rc = HYPERVISOR_grant_table_op(GNTTABOP_set_version, &gsv, 1);
1557 if (rc == 0 && gsv.version == 2)
1558 gnttab_interface = &gnttab_v2_ops;
1559 else
1560 gnttab_interface = &gnttab_v1_ops;
1561 pr_info("Grant tables using version %d layout\n",
1562 gnttab_interface->version);
1563}
1564
1565static int gnttab_setup(void)
1566{
1567 unsigned int max_nr_gframes;
1568
1569 max_nr_gframes = gnttab_max_grant_frames();
1570 if (max_nr_gframes < nr_grant_frames)
1571 return -ENOSYS;
1572
1573 if (xen_feature(XENFEAT_auto_translated_physmap) && gnttab_shared.addr == NULL) {
1574 gnttab_shared.addr = xen_auto_xlat_grant_frames.vaddr;
1575 if (gnttab_shared.addr == NULL) {
1576 pr_warn("gnttab share frames is not mapped!\n");
1577 return -ENOMEM;
1578 }
1579 }
1580 return gnttab_map(0, nr_grant_frames - 1);
1581}
1582
1583int gnttab_resume(void)
1584{
1585 gnttab_request_version();
1586 return gnttab_setup();
1587}
1588
1589int gnttab_suspend(void)
1590{
1591 if (!xen_feature(XENFEAT_auto_translated_physmap))
1592 gnttab_interface->unmap_frames();
1593 return 0;
1594}
1595
1596static int gnttab_expand(unsigned int req_entries)
1597{
1598 int rc;
1599 unsigned int cur, extra;
1600
1601 cur = nr_grant_frames;
1602 extra = ((req_entries + gnttab_interface->grefs_per_grant_frame - 1) /
1603 gnttab_interface->grefs_per_grant_frame);
1604 if (cur + extra > gnttab_max_grant_frames()) {
1605 pr_warn_ratelimited("xen/grant-table: max_grant_frames reached"
1606 " cur=%u extra=%u limit=%u"
1607 " gnttab_free_count=%u req_entries=%u\n",
1608 cur, extra, gnttab_max_grant_frames(),
1609 gnttab_free_count, req_entries);
1610 return -ENOSPC;
1611 }
1612
1613 rc = gnttab_map(cur, cur + extra - 1);
1614 if (rc == 0)
1615 rc = grow_gnttab_list(extra);
1616
1617 return rc;
1618}
1619
1620int gnttab_init(void)
1621{
1622 int i;
1623 unsigned long max_nr_grant_frames, max_nr_grefs;
1624 unsigned int max_nr_glist_frames, nr_glist_frames;
1625 int ret;
1626
1627 gnttab_request_version();
1628 max_nr_grant_frames = gnttab_max_grant_frames();
1629 max_nr_grefs = max_nr_grant_frames *
1630 gnttab_interface->grefs_per_grant_frame;
1631 nr_grant_frames = 1;
1632
1633 /* Determine the maximum number of frames required for the
1634 * grant reference free list on the current hypervisor.
1635 */
1636 max_nr_glist_frames = max_nr_grefs / RPP;
1637
1638 gnttab_list = kmalloc_array(max_nr_glist_frames,
1639 sizeof(grant_ref_t *),
1640 GFP_KERNEL);
1641 if (gnttab_list == NULL)
1642 return -ENOMEM;
1643
1644 nr_glist_frames = gnttab_frames(nr_grant_frames, RPP);
1645 for (i = 0; i < nr_glist_frames; i++) {
1646 gnttab_list[i] = (grant_ref_t *)__get_free_page(GFP_KERNEL);
1647 if (gnttab_list[i] == NULL) {
1648 ret = -ENOMEM;
1649 goto ini_nomem;
1650 }
1651 }
1652
1653 gnttab_free_bitmap = bitmap_zalloc(max_nr_grefs, GFP_KERNEL);
1654 if (!gnttab_free_bitmap) {
1655 ret = -ENOMEM;
1656 goto ini_nomem;
1657 }
1658
1659 ret = arch_gnttab_init(max_nr_grant_frames,
1660 nr_status_frames(max_nr_grant_frames));
1661 if (ret < 0)
1662 goto ini_nomem;
1663
1664 if (gnttab_setup() < 0) {
1665 ret = -ENODEV;
1666 goto ini_nomem;
1667 }
1668
1669 gnttab_size = nr_grant_frames * gnttab_interface->grefs_per_grant_frame;
1670
1671 gnttab_set_free(GNTTAB_NR_RESERVED_ENTRIES,
1672 gnttab_size - GNTTAB_NR_RESERVED_ENTRIES);
1673
1674 printk("Grant table initialized\n");
1675 return 0;
1676
1677 ini_nomem:
1678 for (i--; i >= 0; i--)
1679 free_page((unsigned long)gnttab_list[i]);
1680 kfree(gnttab_list);
1681 bitmap_free(gnttab_free_bitmap);
1682 return ret;
1683}
1684EXPORT_SYMBOL_GPL(gnttab_init);
1685
1686static int __gnttab_init(void)
1687{
1688 if (!xen_domain())
1689 return -ENODEV;
1690
1691 /* Delay grant-table initialization in the PV on HVM case */
1692 if (xen_hvm_domain() && !xen_pvh_domain())
1693 return 0;
1694
1695 return gnttab_init();
1696}
1697/* Starts after core_initcall so that xen_pvh_gnttab_setup can be called
1698 * beforehand to initialize xen_auto_xlat_grant_frames. */
1699core_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);