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
72 static grant_ref_t **gnttab_list;
73 static 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 */
92 static int gnttab_free_count;
93 static unsigned int gnttab_size;
94 static grant_ref_t gnttab_free_head = GNTTAB_LIST_END;
95 static grant_ref_t gnttab_last_free = GNTTAB_LIST_END;
96 static grant_ref_t *gnttab_free_tail_ptr;
97 static unsigned long *gnttab_free_bitmap;
98 static DEFINE_SPINLOCK(gnttab_list_lock);
99
100 struct grant_frames xen_auto_xlat_grant_frames;
101 static unsigned int xen_gnttab_version;
102 module_param_named(version, xen_gnttab_version, uint, 0);
103
104 static 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*/
111 struct 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
155 struct unmap_refs_callback_data {
156 struct completion completion;
157 int result;
158 };
159
160 static const struct gnttab_ops *gnttab_interface;
161
162 /* This reflects status of grant entries, so act as a global value. */
163 static grant_status_t *grstatus;
164
165 static struct gnttab_free_callback *gnttab_free_callback_list;
166
167 static 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
__gnttab_entry(grant_ref_t entry)172 static 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
get_free_entries(unsigned count)179 static 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
get_seq_entry_count(void)215 static 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. */
get_free_seq(unsigned int count)225 static 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
get_free_entries_seq(unsigned int count)270 static 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
do_free_callbacks(void)305 static 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
check_free_callbacks(void)325 static inline void check_free_callbacks(void)
326 {
327 if (unlikely(gnttab_free_callback_list))
328 do_free_callbacks();
329 }
330
put_free_entry_locked(grant_ref_t ref)331 static 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
put_free_entry(grant_ref_t ref)346 static 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
gnttab_set_free(unsigned int start,unsigned int n)356 static 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 */
gnttab_update_entry_v1(grant_ref_t ref,domid_t domid,unsigned long frame,unsigned flags)384 static 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
gnttab_update_entry_v2(grant_ref_t ref,domid_t domid,unsigned long frame,unsigned int flags)393 static 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 */
gnttab_grant_foreign_access_ref(grant_ref_t ref,domid_t domid,unsigned long frame,int readonly)405 void 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 }
411 EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access_ref);
412
gnttab_grant_foreign_access(domid_t domid,unsigned long frame,int readonly)413 int 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 }
426 EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access);
427
gnttab_end_foreign_access_ref_v1(grant_ref_t ref)428 static int gnttab_end_foreign_access_ref_v1(grant_ref_t ref)
429 {
430 u16 flags, nflags;
431 u16 *pflags;
432
433 pflags = &gnttab_shared.v1[ref].flags;
434 nflags = *pflags;
435 do {
436 flags = nflags;
437 if (flags & (GTF_reading|GTF_writing))
438 return 0;
439 } while ((nflags = sync_cmpxchg(pflags, flags, 0)) != flags);
440
441 return 1;
442 }
443
gnttab_end_foreign_access_ref_v2(grant_ref_t ref)444 static int gnttab_end_foreign_access_ref_v2(grant_ref_t ref)
445 {
446 gnttab_shared.v2[ref].hdr.flags = 0;
447 mb(); /* Concurrent access by hypervisor. */
448 if (grstatus[ref] & (GTF_reading|GTF_writing)) {
449 return 0;
450 } else {
451 /*
452 * The read of grstatus needs to have acquire semantics.
453 * On x86, reads already have that, and we just need to
454 * protect against compiler reorderings.
455 * On other architectures we may need a full barrier.
456 */
457 #ifdef CONFIG_X86
458 barrier();
459 #else
460 mb();
461 #endif
462 }
463
464 return 1;
465 }
466
_gnttab_end_foreign_access_ref(grant_ref_t ref)467 static inline int _gnttab_end_foreign_access_ref(grant_ref_t ref)
468 {
469 return gnttab_interface->end_foreign_access_ref(ref);
470 }
471
gnttab_end_foreign_access_ref(grant_ref_t ref)472 int gnttab_end_foreign_access_ref(grant_ref_t ref)
473 {
474 if (_gnttab_end_foreign_access_ref(ref))
475 return 1;
476 pr_warn("WARNING: g.e. %#x still in use!\n", ref);
477 return 0;
478 }
479 EXPORT_SYMBOL_GPL(gnttab_end_foreign_access_ref);
480
gnttab_read_frame_v1(grant_ref_t ref)481 static unsigned long gnttab_read_frame_v1(grant_ref_t ref)
482 {
483 return gnttab_shared.v1[ref].frame;
484 }
485
gnttab_read_frame_v2(grant_ref_t ref)486 static unsigned long gnttab_read_frame_v2(grant_ref_t ref)
487 {
488 return gnttab_shared.v2[ref].full_page.frame;
489 }
490
491 struct deferred_entry {
492 struct list_head list;
493 grant_ref_t ref;
494 uint16_t warn_delay;
495 struct page *page;
496 };
497 static LIST_HEAD(deferred_list);
498 static void gnttab_handle_deferred(struct timer_list *);
499 static DEFINE_TIMER(deferred_timer, gnttab_handle_deferred);
500
501 static atomic64_t deferred_count;
502 static atomic64_t leaked_count;
503 static unsigned int free_per_iteration = 10;
504 module_param(free_per_iteration, uint, 0600);
505
gnttab_handle_deferred(struct timer_list * unused)506 static void gnttab_handle_deferred(struct timer_list *unused)
507 {
508 unsigned int nr = READ_ONCE(free_per_iteration);
509 const bool ignore_limit = nr == 0;
510 struct deferred_entry *first = NULL;
511 unsigned long flags;
512 size_t freed = 0;
513
514 spin_lock_irqsave(&gnttab_list_lock, flags);
515 while ((ignore_limit || nr--) && !list_empty(&deferred_list)) {
516 struct deferred_entry *entry
517 = list_first_entry(&deferred_list,
518 struct deferred_entry, list);
519
520 if (entry == first)
521 break;
522 list_del(&entry->list);
523 spin_unlock_irqrestore(&gnttab_list_lock, flags);
524 if (_gnttab_end_foreign_access_ref(entry->ref)) {
525 uint64_t ret = atomic64_dec_return(&deferred_count);
526
527 put_free_entry(entry->ref);
528 pr_debug("freeing g.e. %#x (pfn %#lx), %llu remaining\n",
529 entry->ref, page_to_pfn(entry->page),
530 (unsigned long long)ret);
531 put_page(entry->page);
532 freed++;
533 kfree(entry);
534 entry = NULL;
535 } else {
536 if (!--entry->warn_delay)
537 pr_info("g.e. %#x still pending\n", entry->ref);
538 if (!first)
539 first = entry;
540 }
541 spin_lock_irqsave(&gnttab_list_lock, flags);
542 if (entry)
543 list_add_tail(&entry->list, &deferred_list);
544 }
545 if (list_empty(&deferred_list))
546 WARN_ON(atomic64_read(&deferred_count));
547 else if (!timer_pending(&deferred_timer)) {
548 deferred_timer.expires = jiffies + HZ;
549 add_timer(&deferred_timer);
550 }
551 spin_unlock_irqrestore(&gnttab_list_lock, flags);
552 pr_debug("Freed %zu references", freed);
553 }
554
gnttab_add_deferred(grant_ref_t ref,struct page * page)555 static void gnttab_add_deferred(grant_ref_t ref, struct page *page)
556 {
557 struct deferred_entry *entry;
558 gfp_t gfp = (in_atomic() || irqs_disabled()) ? GFP_ATOMIC : GFP_KERNEL;
559 uint64_t leaked, deferred;
560
561 entry = kmalloc(sizeof(*entry), gfp);
562 if (!page) {
563 unsigned long gfn = gnttab_interface->read_frame(ref);
564
565 page = pfn_to_page(gfn_to_pfn(gfn));
566 get_page(page);
567 }
568
569 if (entry) {
570 unsigned long flags;
571
572 entry->ref = ref;
573 entry->page = page;
574 entry->warn_delay = 60;
575 spin_lock_irqsave(&gnttab_list_lock, flags);
576 list_add_tail(&entry->list, &deferred_list);
577 if (!timer_pending(&deferred_timer)) {
578 deferred_timer.expires = jiffies + HZ;
579 add_timer(&deferred_timer);
580 }
581 spin_unlock_irqrestore(&gnttab_list_lock, flags);
582 deferred = atomic64_inc_return(&deferred_count);
583 leaked = atomic64_read(&leaked_count);
584 pr_debug("deferring g.e. %#x (pfn %#lx) (total deferred %llu, total leaked %llu)\n",
585 ref, page ? page_to_pfn(page) : -1, deferred, leaked);
586 } else {
587 deferred = atomic64_read(&deferred_count);
588 leaked = atomic64_inc_return(&leaked_count);
589 pr_warn("leaking g.e. %#x (pfn %#lx) (total deferred %llu, total leaked %llu)\n",
590 ref, page ? page_to_pfn(page) : -1, deferred, leaked);
591 }
592 }
593
gnttab_try_end_foreign_access(grant_ref_t ref)594 int gnttab_try_end_foreign_access(grant_ref_t ref)
595 {
596 int ret = _gnttab_end_foreign_access_ref(ref);
597
598 if (ret)
599 put_free_entry(ref);
600
601 return ret;
602 }
603 EXPORT_SYMBOL_GPL(gnttab_try_end_foreign_access);
604
gnttab_end_foreign_access(grant_ref_t ref,struct page * page)605 void gnttab_end_foreign_access(grant_ref_t ref, struct page *page)
606 {
607 if (gnttab_try_end_foreign_access(ref)) {
608 if (page)
609 put_page(page);
610 } else
611 gnttab_add_deferred(ref, page);
612 }
613 EXPORT_SYMBOL_GPL(gnttab_end_foreign_access);
614
gnttab_free_grant_reference(grant_ref_t ref)615 void gnttab_free_grant_reference(grant_ref_t ref)
616 {
617 put_free_entry(ref);
618 }
619 EXPORT_SYMBOL_GPL(gnttab_free_grant_reference);
620
gnttab_free_grant_references(grant_ref_t head)621 void gnttab_free_grant_references(grant_ref_t head)
622 {
623 grant_ref_t ref;
624 unsigned long flags;
625
626 spin_lock_irqsave(&gnttab_list_lock, flags);
627 while (head != GNTTAB_LIST_END) {
628 ref = gnttab_entry(head);
629 put_free_entry_locked(head);
630 head = ref;
631 }
632 check_free_callbacks();
633 spin_unlock_irqrestore(&gnttab_list_lock, flags);
634 }
635 EXPORT_SYMBOL_GPL(gnttab_free_grant_references);
636
gnttab_free_grant_reference_seq(grant_ref_t head,unsigned int count)637 void gnttab_free_grant_reference_seq(grant_ref_t head, unsigned int count)
638 {
639 unsigned long flags;
640 unsigned int i;
641
642 spin_lock_irqsave(&gnttab_list_lock, flags);
643 for (i = count; i > 0; i--)
644 put_free_entry_locked(head + i - 1);
645 check_free_callbacks();
646 spin_unlock_irqrestore(&gnttab_list_lock, flags);
647 }
648 EXPORT_SYMBOL_GPL(gnttab_free_grant_reference_seq);
649
gnttab_alloc_grant_references(u16 count,grant_ref_t * head)650 int gnttab_alloc_grant_references(u16 count, grant_ref_t *head)
651 {
652 int h = get_free_entries(count);
653
654 if (h < 0)
655 return -ENOSPC;
656
657 *head = h;
658
659 return 0;
660 }
661 EXPORT_SYMBOL_GPL(gnttab_alloc_grant_references);
662
gnttab_alloc_grant_reference_seq(unsigned int count,grant_ref_t * first)663 int gnttab_alloc_grant_reference_seq(unsigned int count, grant_ref_t *first)
664 {
665 int h;
666
667 if (count == 1)
668 h = get_free_entries(1);
669 else
670 h = get_free_entries_seq(count);
671
672 if (h < 0)
673 return -ENOSPC;
674
675 *first = h;
676
677 return 0;
678 }
679 EXPORT_SYMBOL_GPL(gnttab_alloc_grant_reference_seq);
680
gnttab_empty_grant_references(const grant_ref_t * private_head)681 int gnttab_empty_grant_references(const grant_ref_t *private_head)
682 {
683 return (*private_head == GNTTAB_LIST_END);
684 }
685 EXPORT_SYMBOL_GPL(gnttab_empty_grant_references);
686
gnttab_claim_grant_reference(grant_ref_t * private_head)687 int gnttab_claim_grant_reference(grant_ref_t *private_head)
688 {
689 grant_ref_t g = *private_head;
690 if (unlikely(g == GNTTAB_LIST_END))
691 return -ENOSPC;
692 *private_head = gnttab_entry(g);
693 return g;
694 }
695 EXPORT_SYMBOL_GPL(gnttab_claim_grant_reference);
696
gnttab_release_grant_reference(grant_ref_t * private_head,grant_ref_t release)697 void gnttab_release_grant_reference(grant_ref_t *private_head,
698 grant_ref_t release)
699 {
700 gnttab_entry(release) = *private_head;
701 *private_head = release;
702 }
703 EXPORT_SYMBOL_GPL(gnttab_release_grant_reference);
704
gnttab_request_free_callback(struct gnttab_free_callback * callback,void (* fn)(void *),void * arg,u16 count)705 void gnttab_request_free_callback(struct gnttab_free_callback *callback,
706 void (*fn)(void *), void *arg, u16 count)
707 {
708 unsigned long flags;
709 struct gnttab_free_callback *cb;
710
711 spin_lock_irqsave(&gnttab_list_lock, flags);
712
713 /* Check if the callback is already on the list */
714 cb = gnttab_free_callback_list;
715 while (cb) {
716 if (cb == callback)
717 goto out;
718 cb = cb->next;
719 }
720
721 callback->fn = fn;
722 callback->arg = arg;
723 callback->count = count;
724 callback->next = gnttab_free_callback_list;
725 gnttab_free_callback_list = callback;
726 check_free_callbacks();
727 out:
728 spin_unlock_irqrestore(&gnttab_list_lock, flags);
729 }
730 EXPORT_SYMBOL_GPL(gnttab_request_free_callback);
731
gnttab_cancel_free_callback(struct gnttab_free_callback * callback)732 void gnttab_cancel_free_callback(struct gnttab_free_callback *callback)
733 {
734 struct gnttab_free_callback **pcb;
735 unsigned long flags;
736
737 spin_lock_irqsave(&gnttab_list_lock, flags);
738 for (pcb = &gnttab_free_callback_list; *pcb; pcb = &(*pcb)->next) {
739 if (*pcb == callback) {
740 *pcb = callback->next;
741 break;
742 }
743 }
744 spin_unlock_irqrestore(&gnttab_list_lock, flags);
745 }
746 EXPORT_SYMBOL_GPL(gnttab_cancel_free_callback);
747
gnttab_frames(unsigned int frames,unsigned int align)748 static unsigned int gnttab_frames(unsigned int frames, unsigned int align)
749 {
750 return (frames * gnttab_interface->grefs_per_grant_frame + align - 1) /
751 align;
752 }
753
grow_gnttab_list(unsigned int more_frames)754 static int grow_gnttab_list(unsigned int more_frames)
755 {
756 unsigned int new_nr_grant_frames, extra_entries, i;
757 unsigned int nr_glist_frames, new_nr_glist_frames;
758 unsigned int grefs_per_frame;
759
760 grefs_per_frame = gnttab_interface->grefs_per_grant_frame;
761
762 new_nr_grant_frames = nr_grant_frames + more_frames;
763 extra_entries = more_frames * grefs_per_frame;
764
765 nr_glist_frames = gnttab_frames(nr_grant_frames, RPP);
766 new_nr_glist_frames = gnttab_frames(new_nr_grant_frames, RPP);
767 for (i = nr_glist_frames; i < new_nr_glist_frames; i++) {
768 gnttab_list[i] = (grant_ref_t *)__get_free_page(GFP_ATOMIC);
769 if (!gnttab_list[i])
770 goto grow_nomem;
771 }
772
773 gnttab_set_free(gnttab_size, extra_entries);
774
775 if (!gnttab_free_tail_ptr)
776 gnttab_free_tail_ptr = __gnttab_entry(gnttab_size);
777
778 nr_grant_frames = new_nr_grant_frames;
779 gnttab_size += extra_entries;
780
781 check_free_callbacks();
782
783 return 0;
784
785 grow_nomem:
786 while (i-- > nr_glist_frames)
787 free_page((unsigned long) gnttab_list[i]);
788 return -ENOMEM;
789 }
790
__max_nr_grant_frames(void)791 static unsigned int __max_nr_grant_frames(void)
792 {
793 struct gnttab_query_size query;
794 int rc;
795
796 query.dom = DOMID_SELF;
797
798 rc = HYPERVISOR_grant_table_op(GNTTABOP_query_size, &query, 1);
799 if ((rc < 0) || (query.status != GNTST_okay))
800 return 4; /* Legacy max supported number of frames */
801
802 return query.max_nr_frames;
803 }
804
gnttab_max_grant_frames(void)805 unsigned int gnttab_max_grant_frames(void)
806 {
807 unsigned int xen_max = __max_nr_grant_frames();
808 static unsigned int boot_max_nr_grant_frames;
809
810 /* First time, initialize it properly. */
811 if (!boot_max_nr_grant_frames)
812 boot_max_nr_grant_frames = __max_nr_grant_frames();
813
814 if (xen_max > boot_max_nr_grant_frames)
815 return boot_max_nr_grant_frames;
816 return xen_max;
817 }
818 EXPORT_SYMBOL_GPL(gnttab_max_grant_frames);
819
gnttab_setup_auto_xlat_frames(phys_addr_t addr)820 int gnttab_setup_auto_xlat_frames(phys_addr_t addr)
821 {
822 xen_pfn_t *pfn;
823 unsigned int max_nr_gframes = __max_nr_grant_frames();
824 unsigned int i;
825 void *vaddr;
826
827 if (xen_auto_xlat_grant_frames.count)
828 return -EINVAL;
829
830 vaddr = memremap(addr, XEN_PAGE_SIZE * max_nr_gframes, MEMREMAP_WB);
831 if (vaddr == NULL) {
832 pr_warn("Failed to ioremap gnttab share frames (addr=%pa)!\n",
833 &addr);
834 return -ENOMEM;
835 }
836 pfn = kcalloc(max_nr_gframes, sizeof(pfn[0]), GFP_KERNEL);
837 if (!pfn) {
838 memunmap(vaddr);
839 return -ENOMEM;
840 }
841 for (i = 0; i < max_nr_gframes; i++)
842 pfn[i] = XEN_PFN_DOWN(addr) + i;
843
844 xen_auto_xlat_grant_frames.vaddr = vaddr;
845 xen_auto_xlat_grant_frames.pfn = pfn;
846 xen_auto_xlat_grant_frames.count = max_nr_gframes;
847
848 return 0;
849 }
850 EXPORT_SYMBOL_GPL(gnttab_setup_auto_xlat_frames);
851
gnttab_free_auto_xlat_frames(void)852 void gnttab_free_auto_xlat_frames(void)
853 {
854 if (!xen_auto_xlat_grant_frames.count)
855 return;
856 kfree(xen_auto_xlat_grant_frames.pfn);
857 memunmap(xen_auto_xlat_grant_frames.vaddr);
858
859 xen_auto_xlat_grant_frames.pfn = NULL;
860 xen_auto_xlat_grant_frames.count = 0;
861 xen_auto_xlat_grant_frames.vaddr = NULL;
862 }
863 EXPORT_SYMBOL_GPL(gnttab_free_auto_xlat_frames);
864
gnttab_pages_set_private(int nr_pages,struct page ** pages)865 int gnttab_pages_set_private(int nr_pages, struct page **pages)
866 {
867 int i;
868
869 for (i = 0; i < nr_pages; i++) {
870 #if BITS_PER_LONG < 64
871 struct xen_page_foreign *foreign;
872
873 foreign = kzalloc(sizeof(*foreign), GFP_KERNEL);
874 if (!foreign)
875 return -ENOMEM;
876
877 set_page_private(pages[i], (unsigned long)foreign);
878 #endif
879 SetPagePrivate(pages[i]);
880 }
881
882 return 0;
883 }
884 EXPORT_SYMBOL_GPL(gnttab_pages_set_private);
885
886 /**
887 * gnttab_alloc_pages - alloc pages suitable for grant mapping into
888 * @nr_pages: number of pages to alloc
889 * @pages: returns the pages
890 */
gnttab_alloc_pages(int nr_pages,struct page ** pages)891 int gnttab_alloc_pages(int nr_pages, struct page **pages)
892 {
893 int ret;
894
895 ret = xen_alloc_unpopulated_pages(nr_pages, pages);
896 if (ret < 0)
897 return ret;
898
899 ret = gnttab_pages_set_private(nr_pages, pages);
900 if (ret < 0)
901 gnttab_free_pages(nr_pages, pages);
902
903 return ret;
904 }
905 EXPORT_SYMBOL_GPL(gnttab_alloc_pages);
906
907 #ifdef CONFIG_XEN_UNPOPULATED_ALLOC
cache_init(struct gnttab_page_cache * cache)908 static inline void cache_init(struct gnttab_page_cache *cache)
909 {
910 cache->pages = NULL;
911 }
912
cache_empty(struct gnttab_page_cache * cache)913 static inline bool cache_empty(struct gnttab_page_cache *cache)
914 {
915 return !cache->pages;
916 }
917
cache_deq(struct gnttab_page_cache * cache)918 static inline struct page *cache_deq(struct gnttab_page_cache *cache)
919 {
920 struct page *page;
921
922 page = cache->pages;
923 cache->pages = page->zone_device_data;
924
925 return page;
926 }
927
cache_enq(struct gnttab_page_cache * cache,struct page * page)928 static inline void cache_enq(struct gnttab_page_cache *cache, struct page *page)
929 {
930 page->zone_device_data = cache->pages;
931 cache->pages = page;
932 }
933 #else
cache_init(struct gnttab_page_cache * cache)934 static inline void cache_init(struct gnttab_page_cache *cache)
935 {
936 INIT_LIST_HEAD(&cache->pages);
937 }
938
cache_empty(struct gnttab_page_cache * cache)939 static inline bool cache_empty(struct gnttab_page_cache *cache)
940 {
941 return list_empty(&cache->pages);
942 }
943
cache_deq(struct gnttab_page_cache * cache)944 static inline struct page *cache_deq(struct gnttab_page_cache *cache)
945 {
946 struct page *page;
947
948 page = list_first_entry(&cache->pages, struct page, lru);
949 list_del(&page->lru);
950
951 return page;
952 }
953
cache_enq(struct gnttab_page_cache * cache,struct page * page)954 static inline void cache_enq(struct gnttab_page_cache *cache, struct page *page)
955 {
956 list_add(&page->lru, &cache->pages);
957 }
958 #endif
959
gnttab_page_cache_init(struct gnttab_page_cache * cache)960 void gnttab_page_cache_init(struct gnttab_page_cache *cache)
961 {
962 spin_lock_init(&cache->lock);
963 cache_init(cache);
964 cache->num_pages = 0;
965 }
966 EXPORT_SYMBOL_GPL(gnttab_page_cache_init);
967
gnttab_page_cache_get(struct gnttab_page_cache * cache,struct page ** page)968 int gnttab_page_cache_get(struct gnttab_page_cache *cache, struct page **page)
969 {
970 unsigned long flags;
971
972 spin_lock_irqsave(&cache->lock, flags);
973
974 if (cache_empty(cache)) {
975 spin_unlock_irqrestore(&cache->lock, flags);
976 return gnttab_alloc_pages(1, page);
977 }
978
979 page[0] = cache_deq(cache);
980 cache->num_pages--;
981
982 spin_unlock_irqrestore(&cache->lock, flags);
983
984 return 0;
985 }
986 EXPORT_SYMBOL_GPL(gnttab_page_cache_get);
987
gnttab_page_cache_put(struct gnttab_page_cache * cache,struct page ** page,unsigned int num)988 void gnttab_page_cache_put(struct gnttab_page_cache *cache, struct page **page,
989 unsigned int num)
990 {
991 unsigned long flags;
992 unsigned int i;
993
994 spin_lock_irqsave(&cache->lock, flags);
995
996 for (i = 0; i < num; i++)
997 cache_enq(cache, page[i]);
998 cache->num_pages += num;
999
1000 spin_unlock_irqrestore(&cache->lock, flags);
1001 }
1002 EXPORT_SYMBOL_GPL(gnttab_page_cache_put);
1003
gnttab_page_cache_shrink(struct gnttab_page_cache * cache,unsigned int num)1004 void gnttab_page_cache_shrink(struct gnttab_page_cache *cache, unsigned int num)
1005 {
1006 struct page *page[10];
1007 unsigned int i = 0;
1008 unsigned long flags;
1009
1010 spin_lock_irqsave(&cache->lock, flags);
1011
1012 while (cache->num_pages > num) {
1013 page[i] = cache_deq(cache);
1014 cache->num_pages--;
1015 if (++i == ARRAY_SIZE(page)) {
1016 spin_unlock_irqrestore(&cache->lock, flags);
1017 gnttab_free_pages(i, page);
1018 i = 0;
1019 spin_lock_irqsave(&cache->lock, flags);
1020 }
1021 }
1022
1023 spin_unlock_irqrestore(&cache->lock, flags);
1024
1025 if (i != 0)
1026 gnttab_free_pages(i, page);
1027 }
1028 EXPORT_SYMBOL_GPL(gnttab_page_cache_shrink);
1029
gnttab_pages_clear_private(int nr_pages,struct page ** pages)1030 void gnttab_pages_clear_private(int nr_pages, struct page **pages)
1031 {
1032 int i;
1033
1034 for (i = 0; i < nr_pages; i++) {
1035 if (PagePrivate(pages[i])) {
1036 #if BITS_PER_LONG < 64
1037 kfree((void *)page_private(pages[i]));
1038 #endif
1039 ClearPagePrivate(pages[i]);
1040 }
1041 }
1042 }
1043 EXPORT_SYMBOL_GPL(gnttab_pages_clear_private);
1044
1045 /**
1046 * gnttab_free_pages - free pages allocated by gnttab_alloc_pages()
1047 * @nr_pages: number of pages to free
1048 * @pages: the pages
1049 */
gnttab_free_pages(int nr_pages,struct page ** pages)1050 void gnttab_free_pages(int nr_pages, struct page **pages)
1051 {
1052 gnttab_pages_clear_private(nr_pages, pages);
1053 xen_free_unpopulated_pages(nr_pages, pages);
1054 }
1055 EXPORT_SYMBOL_GPL(gnttab_free_pages);
1056
1057 #ifdef CONFIG_XEN_GRANT_DMA_ALLOC
1058 /**
1059 * gnttab_dma_alloc_pages - alloc DMAable pages suitable for grant mapping into
1060 * @args: arguments to the function
1061 */
gnttab_dma_alloc_pages(struct gnttab_dma_alloc_args * args)1062 int gnttab_dma_alloc_pages(struct gnttab_dma_alloc_args *args)
1063 {
1064 unsigned long pfn, start_pfn;
1065 size_t size;
1066 int i, ret;
1067
1068 if (args->nr_pages < 0 || args->nr_pages > (INT_MAX >> PAGE_SHIFT))
1069 return -ENOMEM;
1070
1071 size = args->nr_pages << PAGE_SHIFT;
1072 if (args->coherent)
1073 args->vaddr = dma_alloc_coherent(args->dev, size,
1074 &args->dev_bus_addr,
1075 GFP_KERNEL | __GFP_NOWARN);
1076 else
1077 args->vaddr = dma_alloc_wc(args->dev, size,
1078 &args->dev_bus_addr,
1079 GFP_KERNEL | __GFP_NOWARN);
1080 if (!args->vaddr) {
1081 pr_debug("Failed to allocate DMA buffer of size %zu\n", size);
1082 return -ENOMEM;
1083 }
1084
1085 start_pfn = __phys_to_pfn(args->dev_bus_addr);
1086 for (pfn = start_pfn, i = 0; pfn < start_pfn + args->nr_pages;
1087 pfn++, i++) {
1088 struct page *page = pfn_to_page(pfn);
1089
1090 args->pages[i] = page;
1091 args->frames[i] = xen_page_to_gfn(page);
1092 xenmem_reservation_scrub_page(page);
1093 }
1094
1095 xenmem_reservation_va_mapping_reset(args->nr_pages, args->pages);
1096
1097 ret = xenmem_reservation_decrease(args->nr_pages, args->frames);
1098 if (ret != args->nr_pages) {
1099 pr_debug("Failed to decrease reservation for DMA buffer\n");
1100 ret = -EFAULT;
1101 goto fail;
1102 }
1103
1104 ret = gnttab_pages_set_private(args->nr_pages, args->pages);
1105 if (ret < 0)
1106 goto fail;
1107
1108 return 0;
1109
1110 fail:
1111 gnttab_dma_free_pages(args);
1112 return ret;
1113 }
1114 EXPORT_SYMBOL_GPL(gnttab_dma_alloc_pages);
1115
1116 /**
1117 * gnttab_dma_free_pages - free DMAable pages
1118 * @args: arguments to the function
1119 */
gnttab_dma_free_pages(struct gnttab_dma_alloc_args * args)1120 int gnttab_dma_free_pages(struct gnttab_dma_alloc_args *args)
1121 {
1122 size_t size;
1123 int i, ret;
1124
1125 gnttab_pages_clear_private(args->nr_pages, args->pages);
1126
1127 for (i = 0; i < args->nr_pages; i++)
1128 args->frames[i] = page_to_xen_pfn(args->pages[i]);
1129
1130 ret = xenmem_reservation_increase(args->nr_pages, args->frames);
1131 if (ret != args->nr_pages) {
1132 pr_debug("Failed to increase reservation for DMA buffer\n");
1133 ret = -EFAULT;
1134 } else {
1135 ret = 0;
1136 }
1137
1138 xenmem_reservation_va_mapping_update(args->nr_pages, args->pages,
1139 args->frames);
1140
1141 size = args->nr_pages << PAGE_SHIFT;
1142 if (args->coherent)
1143 dma_free_coherent(args->dev, size,
1144 args->vaddr, args->dev_bus_addr);
1145 else
1146 dma_free_wc(args->dev, size,
1147 args->vaddr, args->dev_bus_addr);
1148 return ret;
1149 }
1150 EXPORT_SYMBOL_GPL(gnttab_dma_free_pages);
1151 #endif
1152
1153 /* Handling of paged out grant targets (GNTST_eagain) */
1154 #define MAX_DELAY 256
1155 static inline void
gnttab_retry_eagain_gop(unsigned int cmd,void * gop,int16_t * status,const char * func)1156 gnttab_retry_eagain_gop(unsigned int cmd, void *gop, int16_t *status,
1157 const char *func)
1158 {
1159 unsigned delay = 1;
1160
1161 do {
1162 BUG_ON(HYPERVISOR_grant_table_op(cmd, gop, 1));
1163 if (*status == GNTST_eagain)
1164 msleep(delay++);
1165 } while ((*status == GNTST_eagain) && (delay < MAX_DELAY));
1166
1167 if (delay >= MAX_DELAY) {
1168 pr_err("%s: %s eagain grant\n", func, current->comm);
1169 *status = GNTST_bad_page;
1170 }
1171 }
1172
gnttab_batch_map(struct gnttab_map_grant_ref * batch,unsigned count)1173 void gnttab_batch_map(struct gnttab_map_grant_ref *batch, unsigned count)
1174 {
1175 struct gnttab_map_grant_ref *op;
1176
1177 if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, batch, count))
1178 BUG();
1179 for (op = batch; op < batch + count; op++)
1180 if (op->status == GNTST_eagain)
1181 gnttab_retry_eagain_gop(GNTTABOP_map_grant_ref, op,
1182 &op->status, __func__);
1183 }
1184 EXPORT_SYMBOL_GPL(gnttab_batch_map);
1185
gnttab_batch_copy(struct gnttab_copy * batch,unsigned count)1186 void gnttab_batch_copy(struct gnttab_copy *batch, unsigned count)
1187 {
1188 struct gnttab_copy *op;
1189
1190 if (HYPERVISOR_grant_table_op(GNTTABOP_copy, batch, count))
1191 BUG();
1192 for (op = batch; op < batch + count; op++)
1193 if (op->status == GNTST_eagain)
1194 gnttab_retry_eagain_gop(GNTTABOP_copy, op,
1195 &op->status, __func__);
1196 }
1197 EXPORT_SYMBOL_GPL(gnttab_batch_copy);
1198
gnttab_foreach_grant_in_range(struct page * page,unsigned int offset,unsigned int len,xen_grant_fn_t fn,void * data)1199 void gnttab_foreach_grant_in_range(struct page *page,
1200 unsigned int offset,
1201 unsigned int len,
1202 xen_grant_fn_t fn,
1203 void *data)
1204 {
1205 unsigned int goffset;
1206 unsigned int glen;
1207 unsigned long xen_pfn;
1208
1209 len = min_t(unsigned int, PAGE_SIZE - offset, len);
1210 goffset = xen_offset_in_page(offset);
1211
1212 xen_pfn = page_to_xen_pfn(page) + XEN_PFN_DOWN(offset);
1213
1214 while (len) {
1215 glen = min_t(unsigned int, XEN_PAGE_SIZE - goffset, len);
1216 fn(pfn_to_gfn(xen_pfn), goffset, glen, data);
1217
1218 goffset = 0;
1219 xen_pfn++;
1220 len -= glen;
1221 }
1222 }
1223 EXPORT_SYMBOL_GPL(gnttab_foreach_grant_in_range);
1224
gnttab_foreach_grant(struct page ** pages,unsigned int nr_grefs,xen_grant_fn_t fn,void * data)1225 void gnttab_foreach_grant(struct page **pages,
1226 unsigned int nr_grefs,
1227 xen_grant_fn_t fn,
1228 void *data)
1229 {
1230 unsigned int goffset = 0;
1231 unsigned long xen_pfn = 0;
1232 unsigned int i;
1233
1234 for (i = 0; i < nr_grefs; i++) {
1235 if ((i % XEN_PFN_PER_PAGE) == 0) {
1236 xen_pfn = page_to_xen_pfn(pages[i / XEN_PFN_PER_PAGE]);
1237 goffset = 0;
1238 }
1239
1240 fn(pfn_to_gfn(xen_pfn), goffset, XEN_PAGE_SIZE, data);
1241
1242 goffset += XEN_PAGE_SIZE;
1243 xen_pfn++;
1244 }
1245 }
1246
gnttab_map_refs(struct gnttab_map_grant_ref * map_ops,struct gnttab_map_grant_ref * kmap_ops,struct page ** pages,unsigned int count)1247 int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
1248 struct gnttab_map_grant_ref *kmap_ops,
1249 struct page **pages, unsigned int count)
1250 {
1251 int i, ret;
1252
1253 ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, map_ops, count);
1254 if (ret)
1255 return ret;
1256
1257 for (i = 0; i < count; i++) {
1258 switch (map_ops[i].status) {
1259 case GNTST_okay:
1260 {
1261 struct xen_page_foreign *foreign;
1262
1263 SetPageForeign(pages[i]);
1264 foreign = xen_page_foreign(pages[i]);
1265 foreign->domid = map_ops[i].dom;
1266 foreign->gref = map_ops[i].ref;
1267 break;
1268 }
1269
1270 case GNTST_no_device_space:
1271 pr_warn_ratelimited("maptrack limit reached, can't map all guest pages\n");
1272 break;
1273
1274 case GNTST_eagain:
1275 /* Retry eagain maps */
1276 gnttab_retry_eagain_gop(GNTTABOP_map_grant_ref,
1277 map_ops + i,
1278 &map_ops[i].status, __func__);
1279 /* Test status in next loop iteration. */
1280 i--;
1281 break;
1282
1283 default:
1284 break;
1285 }
1286 }
1287
1288 return set_foreign_p2m_mapping(map_ops, kmap_ops, pages, count);
1289 }
1290 EXPORT_SYMBOL_GPL(gnttab_map_refs);
1291
gnttab_unmap_refs(struct gnttab_unmap_grant_ref * unmap_ops,struct gnttab_unmap_grant_ref * kunmap_ops,struct page ** pages,unsigned int count)1292 int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
1293 struct gnttab_unmap_grant_ref *kunmap_ops,
1294 struct page **pages, unsigned int count)
1295 {
1296 unsigned int i;
1297 int ret;
1298
1299 ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap_ops, count);
1300 if (ret)
1301 return ret;
1302
1303 for (i = 0; i < count; i++)
1304 ClearPageForeign(pages[i]);
1305
1306 return clear_foreign_p2m_mapping(unmap_ops, kunmap_ops, pages, count);
1307 }
1308 EXPORT_SYMBOL_GPL(gnttab_unmap_refs);
1309
1310 #define GNTTAB_UNMAP_REFS_DELAY 5
1311
1312 static void __gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item);
1313
gnttab_unmap_work(struct work_struct * work)1314 static void gnttab_unmap_work(struct work_struct *work)
1315 {
1316 struct gntab_unmap_queue_data
1317 *unmap_data = container_of(work,
1318 struct gntab_unmap_queue_data,
1319 gnttab_work.work);
1320 if (unmap_data->age != UINT_MAX)
1321 unmap_data->age++;
1322 __gnttab_unmap_refs_async(unmap_data);
1323 }
1324
__gnttab_unmap_refs_async(struct gntab_unmap_queue_data * item)1325 static void __gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item)
1326 {
1327 int ret;
1328 int pc;
1329
1330 for (pc = 0; pc < item->count; pc++) {
1331 if (page_count(item->pages[pc]) > 1) {
1332 unsigned long delay = GNTTAB_UNMAP_REFS_DELAY * (item->age + 1);
1333 schedule_delayed_work(&item->gnttab_work,
1334 msecs_to_jiffies(delay));
1335 return;
1336 }
1337 }
1338
1339 ret = gnttab_unmap_refs(item->unmap_ops, item->kunmap_ops,
1340 item->pages, item->count);
1341 item->done(ret, item);
1342 }
1343
gnttab_unmap_refs_async(struct gntab_unmap_queue_data * item)1344 void gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item)
1345 {
1346 INIT_DELAYED_WORK(&item->gnttab_work, gnttab_unmap_work);
1347 item->age = 0;
1348
1349 __gnttab_unmap_refs_async(item);
1350 }
1351 EXPORT_SYMBOL_GPL(gnttab_unmap_refs_async);
1352
unmap_refs_callback(int result,struct gntab_unmap_queue_data * data)1353 static void unmap_refs_callback(int result,
1354 struct gntab_unmap_queue_data *data)
1355 {
1356 struct unmap_refs_callback_data *d = data->data;
1357
1358 d->result = result;
1359 complete(&d->completion);
1360 }
1361
gnttab_unmap_refs_sync(struct gntab_unmap_queue_data * item)1362 int gnttab_unmap_refs_sync(struct gntab_unmap_queue_data *item)
1363 {
1364 struct unmap_refs_callback_data data;
1365
1366 init_completion(&data.completion);
1367 item->data = &data;
1368 item->done = &unmap_refs_callback;
1369 gnttab_unmap_refs_async(item);
1370 wait_for_completion(&data.completion);
1371
1372 return data.result;
1373 }
1374 EXPORT_SYMBOL_GPL(gnttab_unmap_refs_sync);
1375
nr_status_frames(unsigned int nr_grant_frames)1376 static unsigned int nr_status_frames(unsigned int nr_grant_frames)
1377 {
1378 return gnttab_frames(nr_grant_frames, SPP);
1379 }
1380
gnttab_map_frames_v1(xen_pfn_t * frames,unsigned int nr_gframes)1381 static int gnttab_map_frames_v1(xen_pfn_t *frames, unsigned int nr_gframes)
1382 {
1383 int rc;
1384
1385 rc = arch_gnttab_map_shared(frames, nr_gframes,
1386 gnttab_max_grant_frames(),
1387 &gnttab_shared.addr);
1388 BUG_ON(rc);
1389
1390 return 0;
1391 }
1392
gnttab_unmap_frames_v1(void)1393 static void gnttab_unmap_frames_v1(void)
1394 {
1395 arch_gnttab_unmap(gnttab_shared.addr, nr_grant_frames);
1396 }
1397
gnttab_map_frames_v2(xen_pfn_t * frames,unsigned int nr_gframes)1398 static int gnttab_map_frames_v2(xen_pfn_t *frames, unsigned int nr_gframes)
1399 {
1400 uint64_t *sframes;
1401 unsigned int nr_sframes;
1402 struct gnttab_get_status_frames getframes;
1403 int rc;
1404
1405 nr_sframes = nr_status_frames(nr_gframes);
1406
1407 /* No need for kzalloc as it is initialized in following hypercall
1408 * GNTTABOP_get_status_frames.
1409 */
1410 sframes = kmalloc_array(nr_sframes, sizeof(uint64_t), GFP_ATOMIC);
1411 if (!sframes)
1412 return -ENOMEM;
1413
1414 getframes.dom = DOMID_SELF;
1415 getframes.nr_frames = nr_sframes;
1416 set_xen_guest_handle(getframes.frame_list, sframes);
1417
1418 rc = HYPERVISOR_grant_table_op(GNTTABOP_get_status_frames,
1419 &getframes, 1);
1420 if (rc == -ENOSYS) {
1421 kfree(sframes);
1422 return -ENOSYS;
1423 }
1424
1425 BUG_ON(rc || getframes.status);
1426
1427 rc = arch_gnttab_map_status(sframes, nr_sframes,
1428 nr_status_frames(gnttab_max_grant_frames()),
1429 &grstatus);
1430 BUG_ON(rc);
1431 kfree(sframes);
1432
1433 rc = arch_gnttab_map_shared(frames, nr_gframes,
1434 gnttab_max_grant_frames(),
1435 &gnttab_shared.addr);
1436 BUG_ON(rc);
1437
1438 return 0;
1439 }
1440
gnttab_unmap_frames_v2(void)1441 static void gnttab_unmap_frames_v2(void)
1442 {
1443 arch_gnttab_unmap(gnttab_shared.addr, nr_grant_frames);
1444 arch_gnttab_unmap(grstatus, nr_status_frames(nr_grant_frames));
1445 }
1446
gnttab_map(unsigned int start_idx,unsigned int end_idx)1447 static int gnttab_map(unsigned int start_idx, unsigned int end_idx)
1448 {
1449 struct gnttab_setup_table setup;
1450 xen_pfn_t *frames;
1451 unsigned int nr_gframes = end_idx + 1;
1452 int rc;
1453
1454 if (xen_feature(XENFEAT_auto_translated_physmap)) {
1455 struct xen_add_to_physmap xatp;
1456 unsigned int i = end_idx;
1457 rc = 0;
1458 BUG_ON(xen_auto_xlat_grant_frames.count < nr_gframes);
1459 /*
1460 * Loop backwards, so that the first hypercall has the largest
1461 * index, ensuring that the table will grow only once.
1462 */
1463 do {
1464 xatp.domid = DOMID_SELF;
1465 xatp.idx = i;
1466 xatp.space = XENMAPSPACE_grant_table;
1467 xatp.gpfn = xen_auto_xlat_grant_frames.pfn[i];
1468 rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp);
1469 if (rc != 0) {
1470 pr_warn("grant table add_to_physmap failed, err=%d\n",
1471 rc);
1472 break;
1473 }
1474 } while (i-- > start_idx);
1475
1476 return rc;
1477 }
1478
1479 /* No need for kzalloc as it is initialized in following hypercall
1480 * GNTTABOP_setup_table.
1481 */
1482 frames = kmalloc_array(nr_gframes, sizeof(unsigned long), GFP_ATOMIC);
1483 if (!frames)
1484 return -ENOMEM;
1485
1486 setup.dom = DOMID_SELF;
1487 setup.nr_frames = nr_gframes;
1488 set_xen_guest_handle(setup.frame_list, frames);
1489
1490 rc = HYPERVISOR_grant_table_op(GNTTABOP_setup_table, &setup, 1);
1491 if (rc == -ENOSYS) {
1492 kfree(frames);
1493 return -ENOSYS;
1494 }
1495
1496 BUG_ON(rc || setup.status);
1497
1498 rc = gnttab_interface->map_frames(frames, nr_gframes);
1499
1500 kfree(frames);
1501
1502 return rc;
1503 }
1504
1505 static const struct gnttab_ops gnttab_v1_ops = {
1506 .version = 1,
1507 .grefs_per_grant_frame = XEN_PAGE_SIZE /
1508 sizeof(struct grant_entry_v1),
1509 .map_frames = gnttab_map_frames_v1,
1510 .unmap_frames = gnttab_unmap_frames_v1,
1511 .update_entry = gnttab_update_entry_v1,
1512 .end_foreign_access_ref = gnttab_end_foreign_access_ref_v1,
1513 .read_frame = gnttab_read_frame_v1,
1514 };
1515
1516 static const struct gnttab_ops gnttab_v2_ops = {
1517 .version = 2,
1518 .grefs_per_grant_frame = XEN_PAGE_SIZE /
1519 sizeof(union grant_entry_v2),
1520 .map_frames = gnttab_map_frames_v2,
1521 .unmap_frames = gnttab_unmap_frames_v2,
1522 .update_entry = gnttab_update_entry_v2,
1523 .end_foreign_access_ref = gnttab_end_foreign_access_ref_v2,
1524 .read_frame = gnttab_read_frame_v2,
1525 };
1526
gnttab_need_v2(void)1527 static bool gnttab_need_v2(void)
1528 {
1529 #ifdef CONFIG_X86
1530 uint32_t base, width;
1531
1532 if (xen_pv_domain()) {
1533 base = xen_cpuid_base();
1534 if (cpuid_eax(base) < 5)
1535 return false; /* Information not available, use V1. */
1536 width = cpuid_ebx(base + 5) &
1537 XEN_CPUID_MACHINE_ADDRESS_WIDTH_MASK;
1538 return width > 32 + PAGE_SHIFT;
1539 }
1540 #endif
1541 return !!(max_possible_pfn >> 32);
1542 }
1543
gnttab_request_version(void)1544 static void gnttab_request_version(void)
1545 {
1546 long rc;
1547 struct gnttab_set_version gsv;
1548
1549 if (gnttab_need_v2())
1550 gsv.version = 2;
1551 else
1552 gsv.version = 1;
1553
1554 /* Boot parameter overrides automatic selection. */
1555 if (xen_gnttab_version >= 1 && xen_gnttab_version <= 2)
1556 gsv.version = xen_gnttab_version;
1557
1558 rc = HYPERVISOR_grant_table_op(GNTTABOP_set_version, &gsv, 1);
1559 if (rc == 0 && gsv.version == 2)
1560 gnttab_interface = &gnttab_v2_ops;
1561 else
1562 gnttab_interface = &gnttab_v1_ops;
1563 pr_info("Grant tables using version %d layout\n",
1564 gnttab_interface->version);
1565 }
1566
gnttab_setup(void)1567 static int gnttab_setup(void)
1568 {
1569 unsigned int max_nr_gframes;
1570
1571 max_nr_gframes = gnttab_max_grant_frames();
1572 if (max_nr_gframes < nr_grant_frames)
1573 return -ENOSYS;
1574
1575 if (xen_feature(XENFEAT_auto_translated_physmap) && gnttab_shared.addr == NULL) {
1576 gnttab_shared.addr = xen_auto_xlat_grant_frames.vaddr;
1577 if (gnttab_shared.addr == NULL) {
1578 pr_warn("gnttab share frames is not mapped!\n");
1579 return -ENOMEM;
1580 }
1581 }
1582 return gnttab_map(0, nr_grant_frames - 1);
1583 }
1584
gnttab_resume(void)1585 int gnttab_resume(void)
1586 {
1587 gnttab_request_version();
1588 return gnttab_setup();
1589 }
1590
gnttab_suspend(void)1591 int gnttab_suspend(void)
1592 {
1593 if (!xen_feature(XENFEAT_auto_translated_physmap))
1594 gnttab_interface->unmap_frames();
1595 return 0;
1596 }
1597
gnttab_expand(unsigned int req_entries)1598 static int gnttab_expand(unsigned int req_entries)
1599 {
1600 int rc;
1601 unsigned int cur, extra;
1602
1603 cur = nr_grant_frames;
1604 extra = ((req_entries + gnttab_interface->grefs_per_grant_frame - 1) /
1605 gnttab_interface->grefs_per_grant_frame);
1606 if (cur + extra > gnttab_max_grant_frames()) {
1607 pr_warn_ratelimited("xen/grant-table: max_grant_frames reached"
1608 " cur=%u extra=%u limit=%u"
1609 " gnttab_free_count=%u req_entries=%u\n",
1610 cur, extra, gnttab_max_grant_frames(),
1611 gnttab_free_count, req_entries);
1612 return -ENOSPC;
1613 }
1614
1615 rc = gnttab_map(cur, cur + extra - 1);
1616 if (rc == 0)
1617 rc = grow_gnttab_list(extra);
1618
1619 return rc;
1620 }
1621
gnttab_init(void)1622 int gnttab_init(void)
1623 {
1624 int i;
1625 unsigned long max_nr_grant_frames, max_nr_grefs;
1626 unsigned int max_nr_glist_frames, nr_glist_frames;
1627 int ret;
1628
1629 gnttab_request_version();
1630 max_nr_grant_frames = gnttab_max_grant_frames();
1631 max_nr_grefs = max_nr_grant_frames *
1632 gnttab_interface->grefs_per_grant_frame;
1633 nr_grant_frames = 1;
1634
1635 /* Determine the maximum number of frames required for the
1636 * grant reference free list on the current hypervisor.
1637 */
1638 max_nr_glist_frames = max_nr_grefs / RPP;
1639
1640 gnttab_list = kmalloc_array(max_nr_glist_frames,
1641 sizeof(grant_ref_t *),
1642 GFP_KERNEL);
1643 if (gnttab_list == NULL)
1644 return -ENOMEM;
1645
1646 nr_glist_frames = gnttab_frames(nr_grant_frames, RPP);
1647 for (i = 0; i < nr_glist_frames; i++) {
1648 gnttab_list[i] = (grant_ref_t *)__get_free_page(GFP_KERNEL);
1649 if (gnttab_list[i] == NULL) {
1650 ret = -ENOMEM;
1651 goto ini_nomem;
1652 }
1653 }
1654
1655 gnttab_free_bitmap = bitmap_zalloc(max_nr_grefs, GFP_KERNEL);
1656 if (!gnttab_free_bitmap) {
1657 ret = -ENOMEM;
1658 goto ini_nomem;
1659 }
1660
1661 ret = arch_gnttab_init(max_nr_grant_frames,
1662 nr_status_frames(max_nr_grant_frames));
1663 if (ret < 0)
1664 goto ini_nomem;
1665
1666 if (gnttab_setup() < 0) {
1667 ret = -ENODEV;
1668 goto ini_nomem;
1669 }
1670
1671 gnttab_size = nr_grant_frames * gnttab_interface->grefs_per_grant_frame;
1672
1673 gnttab_set_free(GNTTAB_NR_RESERVED_ENTRIES,
1674 gnttab_size - GNTTAB_NR_RESERVED_ENTRIES);
1675
1676 printk("Grant table initialized\n");
1677 return 0;
1678
1679 ini_nomem:
1680 for (i--; i >= 0; i--)
1681 free_page((unsigned long)gnttab_list[i]);
1682 kfree(gnttab_list);
1683 bitmap_free(gnttab_free_bitmap);
1684 return ret;
1685 }
1686 EXPORT_SYMBOL_GPL(gnttab_init);
1687
__gnttab_init(void)1688 static int __gnttab_init(void)
1689 {
1690 if (!xen_domain())
1691 return -ENODEV;
1692
1693 /* Delay grant-table initialization in the PV on HVM case */
1694 if (xen_hvm_domain() && !xen_pvh_domain())
1695 return 0;
1696
1697 return gnttab_init();
1698 }
1699 /* Starts after core_initcall so that xen_pvh_gnttab_setup can be called
1700 * beforehand to initialize xen_auto_xlat_grant_frames. */
1701 core_initcall_sync(__gnttab_init);
1702