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