Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input
[linux-2.6-block.git] / drivers / xen / grant-table.c
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/module.h>
37 #include <linux/sched.h>
38 #include <linux/mm.h>
39 #include <linux/slab.h>
40 #include <linux/vmalloc.h>
41 #include <linux/uaccess.h>
42 #include <linux/io.h>
43 #include <linux/delay.h>
44 #include <linux/hardirq.h>
45
46 #include <xen/xen.h>
47 #include <xen/interface/xen.h>
48 #include <xen/page.h>
49 #include <xen/grant_table.h>
50 #include <xen/interface/memory.h>
51 #include <xen/hvc-console.h>
52 #include <xen/swiotlb-xen.h>
53 #include <asm/xen/hypercall.h>
54 #include <asm/xen/interface.h>
55
56 #include <asm/pgtable.h>
57 #include <asm/sync_bitops.h>
58
59 /* External tools reserve first few grant table entries. */
60 #define NR_RESERVED_ENTRIES 8
61 #define GNTTAB_LIST_END 0xffffffff
62
63 static grant_ref_t **gnttab_list;
64 static unsigned int nr_grant_frames;
65 static int gnttab_free_count;
66 static grant_ref_t gnttab_free_head;
67 static DEFINE_SPINLOCK(gnttab_list_lock);
68 struct grant_frames xen_auto_xlat_grant_frames;
69
70 static union {
71         struct grant_entry_v1 *v1;
72         void *addr;
73 } gnttab_shared;
74
75 /*This is a structure of function pointers for grant table*/
76 struct gnttab_ops {
77         /*
78          * Mapping a list of frames for storing grant entries. Frames parameter
79          * is used to store grant table address when grant table being setup,
80          * nr_gframes is the number of frames to map grant table. Returning
81          * GNTST_okay means success and negative value means failure.
82          */
83         int (*map_frames)(xen_pfn_t *frames, unsigned int nr_gframes);
84         /*
85          * Release a list of frames which are mapped in map_frames for grant
86          * entry status.
87          */
88         void (*unmap_frames)(void);
89         /*
90          * Introducing a valid entry into the grant table, granting the frame of
91          * this grant entry to domain for accessing or transfering. Ref
92          * parameter is reference of this introduced grant entry, domid is id of
93          * granted domain, frame is the page frame to be granted, and flags is
94          * status of the grant entry to be updated.
95          */
96         void (*update_entry)(grant_ref_t ref, domid_t domid,
97                              unsigned long frame, unsigned flags);
98         /*
99          * Stop granting a grant entry to domain for accessing. Ref parameter is
100          * reference of a grant entry whose grant access will be stopped,
101          * readonly is not in use in this function. If the grant entry is
102          * currently mapped for reading or writing, just return failure(==0)
103          * directly and don't tear down the grant access. Otherwise, stop grant
104          * access for this entry and return success(==1).
105          */
106         int (*end_foreign_access_ref)(grant_ref_t ref, int readonly);
107         /*
108          * Stop granting a grant entry to domain for transfer. Ref parameter is
109          * reference of a grant entry whose grant transfer will be stopped. If
110          * tranfer has not started, just reclaim the grant entry and return
111          * failure(==0). Otherwise, wait for the transfer to complete and then
112          * return the frame.
113          */
114         unsigned long (*end_foreign_transfer_ref)(grant_ref_t ref);
115         /*
116          * Query the status of a grant entry. Ref parameter is reference of
117          * queried grant entry, return value is the status of queried entry.
118          * Detailed status(writing/reading) can be gotten from the return value
119          * by bit operations.
120          */
121         int (*query_foreign_access)(grant_ref_t ref);
122 };
123
124 static struct gnttab_ops *gnttab_interface;
125
126 static int grant_table_version;
127 static int grefs_per_grant_frame;
128
129 static struct gnttab_free_callback *gnttab_free_callback_list;
130
131 static int gnttab_expand(unsigned int req_entries);
132
133 #define RPP (PAGE_SIZE / sizeof(grant_ref_t))
134 #define SPP (PAGE_SIZE / sizeof(grant_status_t))
135
136 static inline grant_ref_t *__gnttab_entry(grant_ref_t entry)
137 {
138         return &gnttab_list[(entry) / RPP][(entry) % RPP];
139 }
140 /* This can be used as an l-value */
141 #define gnttab_entry(entry) (*__gnttab_entry(entry))
142
143 static int get_free_entries(unsigned count)
144 {
145         unsigned long flags;
146         int ref, rc = 0;
147         grant_ref_t head;
148
149         spin_lock_irqsave(&gnttab_list_lock, flags);
150
151         if ((gnttab_free_count < count) &&
152             ((rc = gnttab_expand(count - gnttab_free_count)) < 0)) {
153                 spin_unlock_irqrestore(&gnttab_list_lock, flags);
154                 return rc;
155         }
156
157         ref = head = gnttab_free_head;
158         gnttab_free_count -= count;
159         while (count-- > 1)
160                 head = gnttab_entry(head);
161         gnttab_free_head = gnttab_entry(head);
162         gnttab_entry(head) = GNTTAB_LIST_END;
163
164         spin_unlock_irqrestore(&gnttab_list_lock, flags);
165
166         return ref;
167 }
168
169 static void do_free_callbacks(void)
170 {
171         struct gnttab_free_callback *callback, *next;
172
173         callback = gnttab_free_callback_list;
174         gnttab_free_callback_list = NULL;
175
176         while (callback != NULL) {
177                 next = callback->next;
178                 if (gnttab_free_count >= callback->count) {
179                         callback->next = NULL;
180                         callback->fn(callback->arg);
181                 } else {
182                         callback->next = gnttab_free_callback_list;
183                         gnttab_free_callback_list = callback;
184                 }
185                 callback = next;
186         }
187 }
188
189 static inline void check_free_callbacks(void)
190 {
191         if (unlikely(gnttab_free_callback_list))
192                 do_free_callbacks();
193 }
194
195 static void put_free_entry(grant_ref_t ref)
196 {
197         unsigned long flags;
198         spin_lock_irqsave(&gnttab_list_lock, flags);
199         gnttab_entry(ref) = gnttab_free_head;
200         gnttab_free_head = ref;
201         gnttab_free_count++;
202         check_free_callbacks();
203         spin_unlock_irqrestore(&gnttab_list_lock, flags);
204 }
205
206 /*
207  * Following applies to gnttab_update_entry_v1.
208  * Introducing a valid entry into the grant table:
209  *  1. Write ent->domid.
210  *  2. Write ent->frame:
211  *      GTF_permit_access:   Frame to which access is permitted.
212  *      GTF_accept_transfer: Pseudo-phys frame slot being filled by new
213  *                           frame, or zero if none.
214  *  3. Write memory barrier (WMB).
215  *  4. Write ent->flags, inc. valid type.
216  */
217 static void gnttab_update_entry_v1(grant_ref_t ref, domid_t domid,
218                                    unsigned long frame, unsigned flags)
219 {
220         gnttab_shared.v1[ref].domid = domid;
221         gnttab_shared.v1[ref].frame = frame;
222         wmb();
223         gnttab_shared.v1[ref].flags = flags;
224 }
225
226 /*
227  * Public grant-issuing interface functions
228  */
229 void gnttab_grant_foreign_access_ref(grant_ref_t ref, domid_t domid,
230                                      unsigned long frame, int readonly)
231 {
232         gnttab_interface->update_entry(ref, domid, frame,
233                            GTF_permit_access | (readonly ? GTF_readonly : 0));
234 }
235 EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access_ref);
236
237 int gnttab_grant_foreign_access(domid_t domid, unsigned long frame,
238                                 int readonly)
239 {
240         int ref;
241
242         ref = get_free_entries(1);
243         if (unlikely(ref < 0))
244                 return -ENOSPC;
245
246         gnttab_grant_foreign_access_ref(ref, domid, frame, readonly);
247
248         return ref;
249 }
250 EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access);
251
252 static int gnttab_query_foreign_access_v1(grant_ref_t ref)
253 {
254         return gnttab_shared.v1[ref].flags & (GTF_reading|GTF_writing);
255 }
256
257 int gnttab_query_foreign_access(grant_ref_t ref)
258 {
259         return gnttab_interface->query_foreign_access(ref);
260 }
261 EXPORT_SYMBOL_GPL(gnttab_query_foreign_access);
262
263 static int gnttab_end_foreign_access_ref_v1(grant_ref_t ref, int readonly)
264 {
265         u16 flags, nflags;
266         u16 *pflags;
267
268         pflags = &gnttab_shared.v1[ref].flags;
269         nflags = *pflags;
270         do {
271                 flags = nflags;
272                 if (flags & (GTF_reading|GTF_writing))
273                         return 0;
274         } while ((nflags = sync_cmpxchg(pflags, flags, 0)) != flags);
275
276         return 1;
277 }
278
279 static inline int _gnttab_end_foreign_access_ref(grant_ref_t ref, int readonly)
280 {
281         return gnttab_interface->end_foreign_access_ref(ref, readonly);
282 }
283
284 int gnttab_end_foreign_access_ref(grant_ref_t ref, int readonly)
285 {
286         if (_gnttab_end_foreign_access_ref(ref, readonly))
287                 return 1;
288         pr_warn("WARNING: g.e. %#x still in use!\n", ref);
289         return 0;
290 }
291 EXPORT_SYMBOL_GPL(gnttab_end_foreign_access_ref);
292
293 struct deferred_entry {
294         struct list_head list;
295         grant_ref_t ref;
296         bool ro;
297         uint16_t warn_delay;
298         struct page *page;
299 };
300 static LIST_HEAD(deferred_list);
301 static void gnttab_handle_deferred(unsigned long);
302 static DEFINE_TIMER(deferred_timer, gnttab_handle_deferred, 0, 0);
303
304 static void gnttab_handle_deferred(unsigned long unused)
305 {
306         unsigned int nr = 10;
307         struct deferred_entry *first = NULL;
308         unsigned long flags;
309
310         spin_lock_irqsave(&gnttab_list_lock, flags);
311         while (nr--) {
312                 struct deferred_entry *entry
313                         = list_first_entry(&deferred_list,
314                                            struct deferred_entry, list);
315
316                 if (entry == first)
317                         break;
318                 list_del(&entry->list);
319                 spin_unlock_irqrestore(&gnttab_list_lock, flags);
320                 if (_gnttab_end_foreign_access_ref(entry->ref, entry->ro)) {
321                         put_free_entry(entry->ref);
322                         if (entry->page) {
323                                 pr_debug("freeing g.e. %#x (pfn %#lx)\n",
324                                          entry->ref, page_to_pfn(entry->page));
325                                 __free_page(entry->page);
326                         } else
327                                 pr_info("freeing g.e. %#x\n", entry->ref);
328                         kfree(entry);
329                         entry = NULL;
330                 } else {
331                         if (!--entry->warn_delay)
332                                 pr_info("g.e. %#x still pending\n", entry->ref);
333                         if (!first)
334                                 first = entry;
335                 }
336                 spin_lock_irqsave(&gnttab_list_lock, flags);
337                 if (entry)
338                         list_add_tail(&entry->list, &deferred_list);
339                 else if (list_empty(&deferred_list))
340                         break;
341         }
342         if (!list_empty(&deferred_list) && !timer_pending(&deferred_timer)) {
343                 deferred_timer.expires = jiffies + HZ;
344                 add_timer(&deferred_timer);
345         }
346         spin_unlock_irqrestore(&gnttab_list_lock, flags);
347 }
348
349 static void gnttab_add_deferred(grant_ref_t ref, bool readonly,
350                                 struct page *page)
351 {
352         struct deferred_entry *entry = kmalloc(sizeof(*entry), GFP_ATOMIC);
353         const char *what = KERN_WARNING "leaking";
354
355         if (entry) {
356                 unsigned long flags;
357
358                 entry->ref = ref;
359                 entry->ro = readonly;
360                 entry->page = page;
361                 entry->warn_delay = 60;
362                 spin_lock_irqsave(&gnttab_list_lock, flags);
363                 list_add_tail(&entry->list, &deferred_list);
364                 if (!timer_pending(&deferred_timer)) {
365                         deferred_timer.expires = jiffies + HZ;
366                         add_timer(&deferred_timer);
367                 }
368                 spin_unlock_irqrestore(&gnttab_list_lock, flags);
369                 what = KERN_DEBUG "deferring";
370         }
371         printk("%s g.e. %#x (pfn %#lx)\n",
372                what, ref, page ? page_to_pfn(page) : -1);
373 }
374
375 void gnttab_end_foreign_access(grant_ref_t ref, int readonly,
376                                unsigned long page)
377 {
378         if (gnttab_end_foreign_access_ref(ref, readonly)) {
379                 put_free_entry(ref);
380                 if (page != 0)
381                         free_page(page);
382         } else
383                 gnttab_add_deferred(ref, readonly,
384                                     page ? virt_to_page(page) : NULL);
385 }
386 EXPORT_SYMBOL_GPL(gnttab_end_foreign_access);
387
388 int gnttab_grant_foreign_transfer(domid_t domid, unsigned long pfn)
389 {
390         int ref;
391
392         ref = get_free_entries(1);
393         if (unlikely(ref < 0))
394                 return -ENOSPC;
395         gnttab_grant_foreign_transfer_ref(ref, domid, pfn);
396
397         return ref;
398 }
399 EXPORT_SYMBOL_GPL(gnttab_grant_foreign_transfer);
400
401 void gnttab_grant_foreign_transfer_ref(grant_ref_t ref, domid_t domid,
402                                        unsigned long pfn)
403 {
404         gnttab_interface->update_entry(ref, domid, pfn, GTF_accept_transfer);
405 }
406 EXPORT_SYMBOL_GPL(gnttab_grant_foreign_transfer_ref);
407
408 static unsigned long gnttab_end_foreign_transfer_ref_v1(grant_ref_t ref)
409 {
410         unsigned long frame;
411         u16           flags;
412         u16          *pflags;
413
414         pflags = &gnttab_shared.v1[ref].flags;
415
416         /*
417          * If a transfer is not even yet started, try to reclaim the grant
418          * reference and return failure (== 0).
419          */
420         while (!((flags = *pflags) & GTF_transfer_committed)) {
421                 if (sync_cmpxchg(pflags, flags, 0) == flags)
422                         return 0;
423                 cpu_relax();
424         }
425
426         /* If a transfer is in progress then wait until it is completed. */
427         while (!(flags & GTF_transfer_completed)) {
428                 flags = *pflags;
429                 cpu_relax();
430         }
431
432         rmb();  /* Read the frame number /after/ reading completion status. */
433         frame = gnttab_shared.v1[ref].frame;
434         BUG_ON(frame == 0);
435
436         return frame;
437 }
438
439 unsigned long gnttab_end_foreign_transfer_ref(grant_ref_t ref)
440 {
441         return gnttab_interface->end_foreign_transfer_ref(ref);
442 }
443 EXPORT_SYMBOL_GPL(gnttab_end_foreign_transfer_ref);
444
445 unsigned long gnttab_end_foreign_transfer(grant_ref_t ref)
446 {
447         unsigned long frame = gnttab_end_foreign_transfer_ref(ref);
448         put_free_entry(ref);
449         return frame;
450 }
451 EXPORT_SYMBOL_GPL(gnttab_end_foreign_transfer);
452
453 void gnttab_free_grant_reference(grant_ref_t ref)
454 {
455         put_free_entry(ref);
456 }
457 EXPORT_SYMBOL_GPL(gnttab_free_grant_reference);
458
459 void gnttab_free_grant_references(grant_ref_t head)
460 {
461         grant_ref_t ref;
462         unsigned long flags;
463         int count = 1;
464         if (head == GNTTAB_LIST_END)
465                 return;
466         spin_lock_irqsave(&gnttab_list_lock, flags);
467         ref = head;
468         while (gnttab_entry(ref) != GNTTAB_LIST_END) {
469                 ref = gnttab_entry(ref);
470                 count++;
471         }
472         gnttab_entry(ref) = gnttab_free_head;
473         gnttab_free_head = head;
474         gnttab_free_count += count;
475         check_free_callbacks();
476         spin_unlock_irqrestore(&gnttab_list_lock, flags);
477 }
478 EXPORT_SYMBOL_GPL(gnttab_free_grant_references);
479
480 int gnttab_alloc_grant_references(u16 count, grant_ref_t *head)
481 {
482         int h = get_free_entries(count);
483
484         if (h < 0)
485                 return -ENOSPC;
486
487         *head = h;
488
489         return 0;
490 }
491 EXPORT_SYMBOL_GPL(gnttab_alloc_grant_references);
492
493 int gnttab_empty_grant_references(const grant_ref_t *private_head)
494 {
495         return (*private_head == GNTTAB_LIST_END);
496 }
497 EXPORT_SYMBOL_GPL(gnttab_empty_grant_references);
498
499 int gnttab_claim_grant_reference(grant_ref_t *private_head)
500 {
501         grant_ref_t g = *private_head;
502         if (unlikely(g == GNTTAB_LIST_END))
503                 return -ENOSPC;
504         *private_head = gnttab_entry(g);
505         return g;
506 }
507 EXPORT_SYMBOL_GPL(gnttab_claim_grant_reference);
508
509 void gnttab_release_grant_reference(grant_ref_t *private_head,
510                                     grant_ref_t release)
511 {
512         gnttab_entry(release) = *private_head;
513         *private_head = release;
514 }
515 EXPORT_SYMBOL_GPL(gnttab_release_grant_reference);
516
517 void gnttab_request_free_callback(struct gnttab_free_callback *callback,
518                                   void (*fn)(void *), void *arg, u16 count)
519 {
520         unsigned long flags;
521         struct gnttab_free_callback *cb;
522
523         spin_lock_irqsave(&gnttab_list_lock, flags);
524
525         /* Check if the callback is already on the list */
526         cb = gnttab_free_callback_list;
527         while (cb) {
528                 if (cb == callback)
529                         goto out;
530                 cb = cb->next;
531         }
532
533         callback->fn = fn;
534         callback->arg = arg;
535         callback->count = count;
536         callback->next = gnttab_free_callback_list;
537         gnttab_free_callback_list = callback;
538         check_free_callbacks();
539 out:
540         spin_unlock_irqrestore(&gnttab_list_lock, flags);
541 }
542 EXPORT_SYMBOL_GPL(gnttab_request_free_callback);
543
544 void gnttab_cancel_free_callback(struct gnttab_free_callback *callback)
545 {
546         struct gnttab_free_callback **pcb;
547         unsigned long flags;
548
549         spin_lock_irqsave(&gnttab_list_lock, flags);
550         for (pcb = &gnttab_free_callback_list; *pcb; pcb = &(*pcb)->next) {
551                 if (*pcb == callback) {
552                         *pcb = callback->next;
553                         break;
554                 }
555         }
556         spin_unlock_irqrestore(&gnttab_list_lock, flags);
557 }
558 EXPORT_SYMBOL_GPL(gnttab_cancel_free_callback);
559
560 static int grow_gnttab_list(unsigned int more_frames)
561 {
562         unsigned int new_nr_grant_frames, extra_entries, i;
563         unsigned int nr_glist_frames, new_nr_glist_frames;
564
565         BUG_ON(grefs_per_grant_frame == 0);
566
567         new_nr_grant_frames = nr_grant_frames + more_frames;
568         extra_entries       = more_frames * grefs_per_grant_frame;
569
570         nr_glist_frames = (nr_grant_frames * grefs_per_grant_frame + RPP - 1) / RPP;
571         new_nr_glist_frames =
572                 (new_nr_grant_frames * grefs_per_grant_frame + RPP - 1) / RPP;
573         for (i = nr_glist_frames; i < new_nr_glist_frames; i++) {
574                 gnttab_list[i] = (grant_ref_t *)__get_free_page(GFP_ATOMIC);
575                 if (!gnttab_list[i])
576                         goto grow_nomem;
577         }
578
579
580         for (i = grefs_per_grant_frame * nr_grant_frames;
581              i < grefs_per_grant_frame * new_nr_grant_frames - 1; i++)
582                 gnttab_entry(i) = i + 1;
583
584         gnttab_entry(i) = gnttab_free_head;
585         gnttab_free_head = grefs_per_grant_frame * nr_grant_frames;
586         gnttab_free_count += extra_entries;
587
588         nr_grant_frames = new_nr_grant_frames;
589
590         check_free_callbacks();
591
592         return 0;
593
594 grow_nomem:
595         while (i-- > nr_glist_frames)
596                 free_page((unsigned long) gnttab_list[i]);
597         return -ENOMEM;
598 }
599
600 static unsigned int __max_nr_grant_frames(void)
601 {
602         struct gnttab_query_size query;
603         int rc;
604
605         query.dom = DOMID_SELF;
606
607         rc = HYPERVISOR_grant_table_op(GNTTABOP_query_size, &query, 1);
608         if ((rc < 0) || (query.status != GNTST_okay))
609                 return 4; /* Legacy max supported number of frames */
610
611         return query.max_nr_frames;
612 }
613
614 unsigned int gnttab_max_grant_frames(void)
615 {
616         unsigned int xen_max = __max_nr_grant_frames();
617         static unsigned int boot_max_nr_grant_frames;
618
619         /* First time, initialize it properly. */
620         if (!boot_max_nr_grant_frames)
621                 boot_max_nr_grant_frames = __max_nr_grant_frames();
622
623         if (xen_max > boot_max_nr_grant_frames)
624                 return boot_max_nr_grant_frames;
625         return xen_max;
626 }
627 EXPORT_SYMBOL_GPL(gnttab_max_grant_frames);
628
629 int gnttab_setup_auto_xlat_frames(phys_addr_t addr)
630 {
631         xen_pfn_t *pfn;
632         unsigned int max_nr_gframes = __max_nr_grant_frames();
633         unsigned int i;
634         void *vaddr;
635
636         if (xen_auto_xlat_grant_frames.count)
637                 return -EINVAL;
638
639         vaddr = xen_remap(addr, PAGE_SIZE * max_nr_gframes);
640         if (vaddr == NULL) {
641                 pr_warn("Failed to ioremap gnttab share frames (addr=%pa)!\n",
642                         &addr);
643                 return -ENOMEM;
644         }
645         pfn = kcalloc(max_nr_gframes, sizeof(pfn[0]), GFP_KERNEL);
646         if (!pfn) {
647                 xen_unmap(vaddr);
648                 return -ENOMEM;
649         }
650         for (i = 0; i < max_nr_gframes; i++)
651                 pfn[i] = PFN_DOWN(addr) + i;
652
653         xen_auto_xlat_grant_frames.vaddr = vaddr;
654         xen_auto_xlat_grant_frames.pfn = pfn;
655         xen_auto_xlat_grant_frames.count = max_nr_gframes;
656
657         return 0;
658 }
659 EXPORT_SYMBOL_GPL(gnttab_setup_auto_xlat_frames);
660
661 void gnttab_free_auto_xlat_frames(void)
662 {
663         if (!xen_auto_xlat_grant_frames.count)
664                 return;
665         kfree(xen_auto_xlat_grant_frames.pfn);
666         xen_unmap(xen_auto_xlat_grant_frames.vaddr);
667
668         xen_auto_xlat_grant_frames.pfn = NULL;
669         xen_auto_xlat_grant_frames.count = 0;
670         xen_auto_xlat_grant_frames.vaddr = NULL;
671 }
672 EXPORT_SYMBOL_GPL(gnttab_free_auto_xlat_frames);
673
674 /* Handling of paged out grant targets (GNTST_eagain) */
675 #define MAX_DELAY 256
676 static inline void
677 gnttab_retry_eagain_gop(unsigned int cmd, void *gop, int16_t *status,
678                                                 const char *func)
679 {
680         unsigned delay = 1;
681
682         do {
683                 BUG_ON(HYPERVISOR_grant_table_op(cmd, gop, 1));
684                 if (*status == GNTST_eagain)
685                         msleep(delay++);
686         } while ((*status == GNTST_eagain) && (delay < MAX_DELAY));
687
688         if (delay >= MAX_DELAY) {
689                 pr_err("%s: %s eagain grant\n", func, current->comm);
690                 *status = GNTST_bad_page;
691         }
692 }
693
694 void gnttab_batch_map(struct gnttab_map_grant_ref *batch, unsigned count)
695 {
696         struct gnttab_map_grant_ref *op;
697
698         if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, batch, count))
699                 BUG();
700         for (op = batch; op < batch + count; op++)
701                 if (op->status == GNTST_eagain)
702                         gnttab_retry_eagain_gop(GNTTABOP_map_grant_ref, op,
703                                                 &op->status, __func__);
704 }
705 EXPORT_SYMBOL_GPL(gnttab_batch_map);
706
707 void gnttab_batch_copy(struct gnttab_copy *batch, unsigned count)
708 {
709         struct gnttab_copy *op;
710
711         if (HYPERVISOR_grant_table_op(GNTTABOP_copy, batch, count))
712                 BUG();
713         for (op = batch; op < batch + count; op++)
714                 if (op->status == GNTST_eagain)
715                         gnttab_retry_eagain_gop(GNTTABOP_copy, op,
716                                                 &op->status, __func__);
717 }
718 EXPORT_SYMBOL_GPL(gnttab_batch_copy);
719
720 int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
721                     struct gnttab_map_grant_ref *kmap_ops,
722                     struct page **pages, unsigned int count)
723 {
724         int i, ret;
725
726         ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, map_ops, count);
727         if (ret)
728                 return ret;
729
730         /* Retry eagain maps */
731         for (i = 0; i < count; i++)
732                 if (map_ops[i].status == GNTST_eagain)
733                         gnttab_retry_eagain_gop(GNTTABOP_map_grant_ref, map_ops + i,
734                                                 &map_ops[i].status, __func__);
735
736         return set_foreign_p2m_mapping(map_ops, kmap_ops, pages, count);
737 }
738 EXPORT_SYMBOL_GPL(gnttab_map_refs);
739
740 int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
741                       struct gnttab_map_grant_ref *kmap_ops,
742                       struct page **pages, unsigned int count)
743 {
744         int ret;
745
746         ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap_ops, count);
747         if (ret)
748                 return ret;
749
750         return clear_foreign_p2m_mapping(unmap_ops, kmap_ops, pages, count);
751 }
752 EXPORT_SYMBOL_GPL(gnttab_unmap_refs);
753
754 static int gnttab_map_frames_v1(xen_pfn_t *frames, unsigned int nr_gframes)
755 {
756         int rc;
757
758         rc = arch_gnttab_map_shared(frames, nr_gframes,
759                                     gnttab_max_grant_frames(),
760                                     &gnttab_shared.addr);
761         BUG_ON(rc);
762
763         return 0;
764 }
765
766 static void gnttab_unmap_frames_v1(void)
767 {
768         arch_gnttab_unmap(gnttab_shared.addr, nr_grant_frames);
769 }
770
771 static int gnttab_map(unsigned int start_idx, unsigned int end_idx)
772 {
773         struct gnttab_setup_table setup;
774         xen_pfn_t *frames;
775         unsigned int nr_gframes = end_idx + 1;
776         int rc;
777
778         if (xen_feature(XENFEAT_auto_translated_physmap)) {
779                 struct xen_add_to_physmap xatp;
780                 unsigned int i = end_idx;
781                 rc = 0;
782                 BUG_ON(xen_auto_xlat_grant_frames.count < nr_gframes);
783                 /*
784                  * Loop backwards, so that the first hypercall has the largest
785                  * index, ensuring that the table will grow only once.
786                  */
787                 do {
788                         xatp.domid = DOMID_SELF;
789                         xatp.idx = i;
790                         xatp.space = XENMAPSPACE_grant_table;
791                         xatp.gpfn = xen_auto_xlat_grant_frames.pfn[i];
792                         rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp);
793                         if (rc != 0) {
794                                 pr_warn("grant table add_to_physmap failed, err=%d\n",
795                                         rc);
796                                 break;
797                         }
798                 } while (i-- > start_idx);
799
800                 return rc;
801         }
802
803         /* No need for kzalloc as it is initialized in following hypercall
804          * GNTTABOP_setup_table.
805          */
806         frames = kmalloc(nr_gframes * sizeof(unsigned long), GFP_ATOMIC);
807         if (!frames)
808                 return -ENOMEM;
809
810         setup.dom        = DOMID_SELF;
811         setup.nr_frames  = nr_gframes;
812         set_xen_guest_handle(setup.frame_list, frames);
813
814         rc = HYPERVISOR_grant_table_op(GNTTABOP_setup_table, &setup, 1);
815         if (rc == -ENOSYS) {
816                 kfree(frames);
817                 return -ENOSYS;
818         }
819
820         BUG_ON(rc || setup.status);
821
822         rc = gnttab_interface->map_frames(frames, nr_gframes);
823
824         kfree(frames);
825
826         return rc;
827 }
828
829 static struct gnttab_ops gnttab_v1_ops = {
830         .map_frames                     = gnttab_map_frames_v1,
831         .unmap_frames                   = gnttab_unmap_frames_v1,
832         .update_entry                   = gnttab_update_entry_v1,
833         .end_foreign_access_ref         = gnttab_end_foreign_access_ref_v1,
834         .end_foreign_transfer_ref       = gnttab_end_foreign_transfer_ref_v1,
835         .query_foreign_access           = gnttab_query_foreign_access_v1,
836 };
837
838 static void gnttab_request_version(void)
839 {
840         /* Only version 1 is used, which will always be available. */
841         grant_table_version = 1;
842         grefs_per_grant_frame = PAGE_SIZE / sizeof(struct grant_entry_v1);
843         gnttab_interface = &gnttab_v1_ops;
844
845         pr_info("Grant tables using version %d layout\n", grant_table_version);
846 }
847
848 static int gnttab_setup(void)
849 {
850         unsigned int max_nr_gframes;
851
852         max_nr_gframes = gnttab_max_grant_frames();
853         if (max_nr_gframes < nr_grant_frames)
854                 return -ENOSYS;
855
856         if (xen_feature(XENFEAT_auto_translated_physmap) && gnttab_shared.addr == NULL) {
857                 gnttab_shared.addr = xen_auto_xlat_grant_frames.vaddr;
858                 if (gnttab_shared.addr == NULL) {
859                         pr_warn("gnttab share frames (addr=0x%08lx) is not mapped!\n",
860                                 (unsigned long)xen_auto_xlat_grant_frames.vaddr);
861                         return -ENOMEM;
862                 }
863         }
864         return gnttab_map(0, nr_grant_frames - 1);
865 }
866
867 int gnttab_resume(void)
868 {
869         gnttab_request_version();
870         return gnttab_setup();
871 }
872
873 int gnttab_suspend(void)
874 {
875         if (!xen_feature(XENFEAT_auto_translated_physmap))
876                 gnttab_interface->unmap_frames();
877         return 0;
878 }
879
880 static int gnttab_expand(unsigned int req_entries)
881 {
882         int rc;
883         unsigned int cur, extra;
884
885         BUG_ON(grefs_per_grant_frame == 0);
886         cur = nr_grant_frames;
887         extra = ((req_entries + (grefs_per_grant_frame-1)) /
888                  grefs_per_grant_frame);
889         if (cur + extra > gnttab_max_grant_frames())
890                 return -ENOSPC;
891
892         rc = gnttab_map(cur, cur + extra - 1);
893         if (rc == 0)
894                 rc = grow_gnttab_list(extra);
895
896         return rc;
897 }
898
899 int gnttab_init(void)
900 {
901         int i;
902         unsigned long max_nr_grant_frames;
903         unsigned int max_nr_glist_frames, nr_glist_frames;
904         unsigned int nr_init_grefs;
905         int ret;
906
907         gnttab_request_version();
908         max_nr_grant_frames = gnttab_max_grant_frames();
909         nr_grant_frames = 1;
910
911         /* Determine the maximum number of frames required for the
912          * grant reference free list on the current hypervisor.
913          */
914         BUG_ON(grefs_per_grant_frame == 0);
915         max_nr_glist_frames = (max_nr_grant_frames *
916                                grefs_per_grant_frame / RPP);
917
918         gnttab_list = kmalloc(max_nr_glist_frames * sizeof(grant_ref_t *),
919                               GFP_KERNEL);
920         if (gnttab_list == NULL)
921                 return -ENOMEM;
922
923         nr_glist_frames = (nr_grant_frames * grefs_per_grant_frame + RPP - 1) / RPP;
924         for (i = 0; i < nr_glist_frames; i++) {
925                 gnttab_list[i] = (grant_ref_t *)__get_free_page(GFP_KERNEL);
926                 if (gnttab_list[i] == NULL) {
927                         ret = -ENOMEM;
928                         goto ini_nomem;
929                 }
930         }
931
932         ret = arch_gnttab_init(max_nr_grant_frames);
933         if (ret < 0)
934                 goto ini_nomem;
935
936         if (gnttab_setup() < 0) {
937                 ret = -ENODEV;
938                 goto ini_nomem;
939         }
940
941         nr_init_grefs = nr_grant_frames * grefs_per_grant_frame;
942
943         for (i = NR_RESERVED_ENTRIES; i < nr_init_grefs - 1; i++)
944                 gnttab_entry(i) = i + 1;
945
946         gnttab_entry(nr_init_grefs - 1) = GNTTAB_LIST_END;
947         gnttab_free_count = nr_init_grefs - NR_RESERVED_ENTRIES;
948         gnttab_free_head  = NR_RESERVED_ENTRIES;
949
950         printk("Grant table initialized\n");
951         return 0;
952
953  ini_nomem:
954         for (i--; i >= 0; i--)
955                 free_page((unsigned long)gnttab_list[i]);
956         kfree(gnttab_list);
957         return ret;
958 }
959 EXPORT_SYMBOL_GPL(gnttab_init);
960
961 static int __gnttab_init(void)
962 {
963         /* Delay grant-table initialization in the PV on HVM case */
964         if (xen_hvm_domain())
965                 return 0;
966
967         if (!xen_pv_domain())
968                 return -ENODEV;
969
970         return gnttab_init();
971 }
972 /* Starts after core_initcall so that xen_pvh_gnttab_setup can be called
973  * beforehand to initialize xen_auto_xlat_grant_frames. */
974 core_initcall_sync(__gnttab_init);