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(req_entries: count - gnttab_free_count)) < 0)) {
189 spin_unlock_irqrestore(lock: &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(map: gnttab_free_bitmap, start: head, nbits: 1);
197 if (gnttab_free_tail_ptr == __gnttab_entry(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(lock: &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(addr: gnttab_free_bitmap, size: gnttab_size);
235 from < gnttab_size;
236 from = find_next_bit(addr: gnttab_free_bitmap, size: gnttab_size, offset: to + 1)) {
237 to = find_next_zero_bit(addr: gnttab_free_bitmap, size: gnttab_size,
238 offset: from + 1);
239 if (ret < 0 && to - from >= count) {
240 ret = from;
241 bitmap_clear(map: gnttab_free_bitmap, start: ret, nbits: 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(entry: from);
256 gnttab_last_free = from;
257 from++;
258 }
259 if (to < gnttab_size)
260 gnttab_free_tail_ptr = __gnttab_entry(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(req_entries: 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(req_entries: 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(map: gnttab_free_bitmap, start: ret, nbits: count);
298
299 out:
300 spin_unlock_irqrestore(lock: &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(entry: ref);
342 gnttab_free_count++;
343 bitmap_set(map: gnttab_free_bitmap, start: ref, nbits: 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(lock: &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(map: gnttab_free_bitmap, start, nbits: 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(count: 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(head: &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: &entry->list);
521 spin_unlock_irqrestore(lock: &gnttab_list_lock, flags);
522 if (_gnttab_end_foreign_access_ref(ref: entry->ref)) {
523 uint64_t ret = atomic64_dec_return(v: &deferred_count);
524
525 put_free_entry(ref: 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(page: entry->page);
530 freed++;
531 kfree(objp: 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(new: &entry->list, head: &deferred_list);
542 }
543 if (list_empty(head: &deferred_list))
544 WARN_ON(atomic64_read(&deferred_count));
545 else if (!timer_pending(timer: &deferred_timer)) {
546 deferred_timer.expires = jiffies + HZ;
547 add_timer(timer: &deferred_timer);
548 }
549 spin_unlock_irqrestore(lock: &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(size: sizeof(*entry), flags: 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(new: &entry->list, head: &deferred_list);
575 if (!timer_pending(timer: &deferred_timer)) {
576 deferred_timer.expires = jiffies + HZ;
577 add_timer(timer: &deferred_timer);
578 }
579 spin_unlock_irqrestore(lock: &gnttab_list_lock, flags);
580 deferred = atomic64_inc_return(v: &deferred_count);
581 leaked = atomic64_read(v: &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(v: &deferred_count);
586 leaked = atomic64_inc_return(v: &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(ref: head);
628 head = ref;
629 }
630 check_free_callbacks();
631 spin_unlock_irqrestore(lock: &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(ref: head + i - 1);
643 check_free_callbacks();
644 spin_unlock_irqrestore(lock: &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(count: 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(lock: &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(lock: &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(frames: nr_grant_frames, RPP);
764 new_nr_glist_frames = gnttab_frames(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(start: gnttab_size, n: extra_entries);
772
773 if (!gnttab_free_tail_ptr)
774 gnttab_free_tail_ptr = __gnttab_entry(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, uop: &query, count: 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(offset: addr, XEN_PAGE_SIZE * max_nr_gframes, flags: 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(n: max_nr_gframes, size: sizeof(pfn[0]), GFP_KERNEL);
835 if (!pfn) {
836 memunmap(addr: 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(objp: xen_auto_xlat_grant_frames.pfn);
855 memunmap(addr: 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(lock: &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(lock: &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: page[i]);
996 cache->num_pages += num;
997
998 spin_unlock_irqrestore(lock: &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(lock: &cache->lock, flags);
1015 gnttab_free_pages(nr_pages: i, pages: page);
1016 i = 0;
1017 spin_lock_irqsave(&cache->lock, flags);
1018 }
1019 }
1020
1021 spin_unlock_irqrestore(lock: &cache->lock, flags);
1022
1023 if (i != 0)
1024 gnttab_free_pages(nr_pages: i, pages: 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(page: pages[i])) {
1034#if BITS_PER_LONG < 64
1035 kfree((void *)page_private(pages[i]));
1036#endif
1037 ClearPagePrivate(page: 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(dev: args->dev, size,
1072 dma_handle: &args->dev_bus_addr,
1073 GFP_KERNEL | __GFP_NOWARN);
1074 else
1075 args->vaddr = dma_alloc_wc(dev: args->dev, size,
1076 dma_addr: &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(count: args->nr_pages, pages: args->pages);
1094
1095 ret = xenmem_reservation_decrease(count: args->nr_pages, frames: 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(count: args->nr_pages, frames: 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(count: args->nr_pages, pages: args->pages,
1137 frames: args->frames);
1138
1139 size = args->nr_pages << PAGE_SHIFT;
1140 if (args->coherent)
1141 dma_free_coherent(dev: args->dev, size,
1142 cpu_addr: args->vaddr, dma_handle: args->dev_bus_addr);
1143 else
1144 dma_free_wc(dev: args->dev, size,
1145 cpu_addr: args->vaddr, dma_addr: 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(msecs: 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, uop: 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, gop: op,
1180 status: &op->status, func: __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, uop: 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, gop: op,
1193 status: &op->status, func: __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(pfn: 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(pfn: 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, uop: 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(page: 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 gop: map_ops + i,
1276 status: &map_ops[i].status, func: __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, uop: unmap_ops, count);
1298 if (ret)
1299 return ret;
1300
1301 for (i = 0; i < count; i++)
1302 ClearPageForeign(page: 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(item: 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(page: item->pages[pc]) > 1) {
1330 unsigned long delay = GNTTAB_UNMAP_REFS_DELAY * (item->age + 1);
1331 schedule_delayed_work(dwork: &item->gnttab_work,
1332 delay: msecs_to_jiffies(m: 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(x: &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(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 max_nr_gframes: gnttab_max_grant_frames(),
1385 shared: &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(shared: gnttab_shared.addr, nr_gframes: 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_grant_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(n: nr_sframes, size: 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 uop: &getframes, count: 1);
1418 if (rc == -ENOSYS) {
1419 kfree(objp: sframes);
1420 return -ENOSYS;
1421 }
1422
1423 BUG_ON(rc || getframes.status);
1424
1425 rc = arch_gnttab_map_status(frames: sframes, nr_gframes: nr_sframes,
1426 max_nr_gframes: nr_status_frames(nr_grant_frames: gnttab_max_grant_frames()),
1427 shared: &grstatus);
1428 BUG_ON(rc);
1429 kfree(objp: sframes);
1430
1431 rc = arch_gnttab_map_shared(frames, nr_gframes,
1432 max_nr_gframes: gnttab_max_grant_frames(),
1433 shared: &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(shared: gnttab_shared.addr, nr_gframes: nr_grant_frames);
1442 arch_gnttab_unmap(shared: grstatus, nr_gframes: 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, arg: &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(n: nr_gframes, size: 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, uop: &setup, count: 1);
1489 if (rc == -ENOSYS) {
1490 kfree(objp: 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(objp: 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(op: base) < 5)
1533 return false; /* Information not available, use V1. */
1534 width = cpuid_ebx(op: 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, uop: &gsv, count: 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(start_idx: 0, end_idx: 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(start_idx: cur, end_idx: cur + extra - 1);
1614 if (rc == 0)
1615 rc = grow_gnttab_list(more_frames: 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(n: max_nr_glist_frames,
1639 size: sizeof(grant_ref_t *),
1640 GFP_KERNEL);
1641 if (gnttab_list == NULL)
1642 return -ENOMEM;
1643
1644 nr_glist_frames = gnttab_frames(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(nbits: max_nr_grefs, GFP_KERNEL);
1654 if (!gnttab_free_bitmap) {
1655 ret = -ENOMEM;
1656 goto ini_nomem;
1657 }
1658
1659 ret = arch_gnttab_init(nr_shared: max_nr_grant_frames,
1660 nr_status: nr_status_frames(nr_grant_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 n: 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(objp: gnttab_list);
1681 bitmap_free(bitmap: 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);
1700

source code of linux/drivers/xen/grant-table.c