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/memblock.h>
  37 #include <linux/sched.h>
  38 #include <linux/mm.h>
  39 #include <linux/slab.h>
  40 #include <linux/vmalloc.h>
  41 #include <linux/uaccess.h>
  42 #include <linux/io.h>
  43 #include <linux/delay.h>
  44 #include <linux/hardirq.h>
  45 #include <linux/workqueue.h>
  46 #include <linux/ratelimit.h>
  47 #include <linux/moduleparam.h>
  48 #ifdef CONFIG_XEN_GRANT_DMA_ALLOC
  49 #include <linux/dma-mapping.h>
  50 #endif
  51
  52 #include <xen/xen.h>
  53 #include <xen/interface/xen.h>
  54 #include <xen/page.h>
  55 #include <xen/grant_table.h>
  56 #include <xen/interface/memory.h>
  57 #include <xen/hvc-console.h>
  58 #include <xen/swiotlb-xen.h>
  59 #include <xen/balloon.h>
  60 #ifdef CONFIG_X86
  61 #include <asm/xen/cpuid.h>
  62 #endif
  63 #include <xen/mem-reservation.h>
  64 #include <asm/xen/hypercall.h>
  65 #include <asm/xen/interface.h>
  66
  67 #include <asm/sync_bitops.h>
  68
  69 /* External tools reserve first few grant table entries. */
  70 #define NR_RESERVED_ENTRIES 8
  71 #define GNTTAB_LIST_END 0xffffffff
  72
  73 static grant_ref_t **gnttab_list;
  74 static unsigned int nr_grant_frames;
  75 static int gnttab_free_count;
  76 static grant_ref_t gnttab_free_head;
  77 static DEFINE_SPINLOCK(gnttab_list_lock);
  78 struct grant_frames xen_auto_xlat_grant_frames;
  79 static unsigned int xen_gnttab_version;
  80 module_param_named(version, xen_gnttab_version, uint, 0);
  81
  82 static union {
  83         struct grant_entry_v1 *v1;
  84         union grant_entry_v2 *v2;
  85         void *addr;
  86 } gnttab_shared;
  87
  88 /*This is a structure of function pointers for grant table*/
  89 struct gnttab_ops {
  90         /*
  91          * Version of the grant interface.
  92          */
  93         unsigned int version;
  94         /*
  95          * Grant refs per grant frame.
  96          */
  97         unsigned int grefs_per_grant_frame;
  98         /*
  99          * Mapping a list of frames for storing grant entries. Frames parameter
 100          * is used to store grant table address when grant table being setup,
 101          * nr_gframes is the number of frames to map grant table. Returning
 102          * GNTST_okay means success and negative value means failure.
 103          */
 104         int (*map_frames)(xen_pfn_t *frames, unsigned int nr_gframes);
 105         /*
 106          * Release a list of frames which are mapped in map_frames for grant
 107          * entry status.
 108          */
 109         void (*unmap_frames)(void);
 110         /*
 111          * Introducing a valid entry into the grant table, granting the frame of
 112          * this grant entry to domain for accessing or transfering. Ref
 113          * parameter is reference of this introduced grant entry, domid is id of
 114          * granted domain, frame is the page frame to be granted, and flags is
 115          * status of the grant entry to be updated.
 116          */
 117         void (*update_entry)(grant_ref_t ref, domid_t domid,
 118                              unsigned long frame, unsigned flags);
 119         /*
 120          * Stop granting a grant entry to domain for accessing. Ref parameter is
 121          * reference of a grant entry whose grant access will be stopped,
 122          * readonly is not in use in this function. If the grant entry is
 123          * currently mapped for reading or writing, just return failure(==0)
 124          * directly and don't tear down the grant access. Otherwise, stop grant
 125          * access for this entry and return success(==1).
 126          */
 127         int (*end_foreign_access_ref)(grant_ref_t ref, int readonly);
 128         /*
 129          * Stop granting a grant entry to domain for transfer. Ref parameter is
 130          * reference of a grant entry whose grant transfer will be stopped. If
 131          * tranfer has not started, just reclaim the grant entry and return
 132          * failure(==0). Otherwise, wait for the transfer to complete and then
 133          * return the frame.
 134          */
 135         unsigned long (*end_foreign_transfer_ref)(grant_ref_t ref);
 136 };
 137
 138 struct unmap_refs_callback_data {
 139         struct completion completion;
 140         int result;
 141 };
 142
 143 static const struct gnttab_ops *gnttab_interface;
 144
 145 /* This reflects status of grant entries, so act as a global value. */
 146 static grant_status_t *grstatus;
 147
 148 static struct gnttab_free_callback *gnttab_free_callback_list;
 149
 150 static int gnttab_expand(unsigned int req_entries);
 151
 152 #define RPP (PAGE_SIZE / sizeof(grant_ref_t))
 153 #define SPP (PAGE_SIZE / sizeof(grant_status_t))
 154
 155 static inline grant_ref_t *__gnttab_entry(grant_ref_t entry)
 156 {
 157         return &gnttab_list[(entry) / RPP][(entry) % RPP];
 158 }
 159 /* This can be used as an l-value */
 160 #define gnttab_entry(entry) (*__gnttab_entry(entry))
 161
 162 static int get_free_entries(unsigned count)
 163 {
 164         unsigned long flags;
 165         int ref, rc = 0;
 166         grant_ref_t head;
 167
 168         spin_lock_irqsave(&gnttab_list_lock, flags);
 169
 170         if ((gnttab_free_count < count) &&
 171             ((rc = gnttab_expand(count - gnttab_free_count)) < 0)) {
 172                 spin_unlock_irqrestore(&gnttab_list_lock, flags);
 173                 return rc;
 174         }
 175
 176         ref = head = gnttab_free_head;
 177         gnttab_free_count -= count;
 178         while (count-- > 1)
 179                 head = gnttab_entry(head);
 180         gnttab_free_head = gnttab_entry(head);
 181         gnttab_entry(head) = GNTTAB_LIST_END;
 182
 183         spin_unlock_irqrestore(&gnttab_list_lock, flags);
 184
 185         return ref;
 186 }
 187
 188 static void do_free_callbacks(void)
 189 {
 190         struct gnttab_free_callback *callback, *next;
 191
 192         callback = gnttab_free_callback_list;
 193         gnttab_free_callback_list = NULL;
 194
 195         while (callback != NULL) {
 196                 next = callback->next;
 197                 if (gnttab_free_count >= callback->count) {
 198                         callback->next = NULL;
 199                         callback->fn(callback->arg);
 200                 } else {
 201                         callback->next = gnttab_free_callback_list;
 202                         gnttab_free_callback_list = callback;
 203                 }
 204                 callback = next;
 205         }
 206 }
 207
 208 static inline void check_free_callbacks(void)
 209 {
 210         if (unlikely(gnttab_free_callback_list))
 211                 do_free_callbacks();
 212 }
 213
 214 static void put_free_entry(grant_ref_t ref)
 215 {
 216         unsigned long flags;
 217         spin_lock_irqsave(&gnttab_list_lock, flags);
 218         gnttab_entry(ref) = gnttab_free_head;
 219         gnttab_free_head = ref;
 220         gnttab_free_count++;
 221         check_free_callbacks();
 222         spin_unlock_irqrestore(&gnttab_list_lock, flags);
 223 }
 224
 225 /*
 226  * Following applies to gnttab_update_entry_v1 and gnttab_update_entry_v2.
 227  * Introducing a valid entry into the grant table:
 228  *  1. Write ent->domid.
 229  *  2. Write ent->frame:
 230  *      GTF_permit_access:   Frame to which access is permitted.
 231  *      GTF_accept_transfer: Pseudo-phys frame slot being filled by new
 232  *                           frame, or zero if none.
 233  *  3. Write memory barrier (WMB).
 234  *  4. Write ent->flags, inc. valid type.
 235  */
 236 static void gnttab_update_entry_v1(grant_ref_t ref, domid_t domid,
 237                                    unsigned long frame, unsigned flags)
 238 {
 239         gnttab_shared.v1[ref].domid = domid;
 240         gnttab_shared.v1[ref].frame = frame;
 241         wmb();
 242         gnttab_shared.v1[ref].flags = flags;
 243 }
 244
 245 static void gnttab_update_entry_v2(grant_ref_t ref, domid_t domid,
 246                                    unsigned long frame, unsigned int flags)
 247 {
 248         gnttab_shared.v2[ref].hdr.domid = domid;
 249         gnttab_shared.v2[ref].full_page.frame = frame;
 250         wmb();  /* Hypervisor concurrent accesses. */
 251         gnttab_shared.v2[ref].hdr.flags = GTF_permit_access | flags;
 252 }
 253
 254 /*
 255  * Public grant-issuing interface functions
 256  */
 257 void gnttab_grant_foreign_access_ref(grant_ref_t ref, domid_t domid,
 258                                      unsigned long frame, int readonly)
 259 {
 260         gnttab_interface->update_entry(ref, domid, frame,
 261                            GTF_permit_access | (readonly ? GTF_readonly : 0));
 262 }
 263 EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access_ref);
 264
 265 int gnttab_grant_foreign_access(domid_t domid, unsigned long frame,
 266                                 int readonly)
 267 {
 268         int ref;
 269
 270         ref = get_free_entries(1);
 271         if (unlikely(ref < 0))
 272                 return -ENOSPC;
 273
 274         gnttab_grant_foreign_access_ref(ref, domid, frame, readonly);
 275
 276         return ref;
 277 }
 278 EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access);
 279
 280 static int gnttab_end_foreign_access_ref_v1(grant_ref_t ref, int readonly)
 281 {
 282         u16 flags, nflags;
 283         u16 *pflags;
 284
 285         pflags = &gnttab_shared.v1[ref].flags;
 286         nflags = *pflags;
 287         do {
 288                 flags = nflags;
 289                 if (flags & (GTF_reading|GTF_writing))
 290                         return 0;
 291         } while ((nflags = sync_cmpxchg(pflags, flags, 0)) != flags);
 292
 293         return 1;
 294 }
 295
 296 static int gnttab_end_foreign_access_ref_v2(grant_ref_t ref, int readonly)
 297 {
 298         gnttab_shared.v2[ref].hdr.flags = 0;
 299         mb();   /* Concurrent access by hypervisor. */
 300         if (grstatus[ref] & (GTF_reading|GTF_writing)) {
 301                 return 0;
 302         } else {
 303                 /*
 304                  * The read of grstatus needs to have acquire semantics.
 305                  *  On x86, reads already have that, and we just need to
 306                  * protect against compiler reorderings.
 307                  * On other architectures we may need a full barrier.
 308                  */
 309 #ifdef CONFIG_X86
 310                 barrier();
 311 #else
 312                 mb();
 313 #endif
 314         }
 315
 316         return 1;
 317 }
 318
 319 static inline int _gnttab_end_foreign_access_ref(grant_ref_t ref, int readonly)
 320 {
 321         return gnttab_interface->end_foreign_access_ref(ref, readonly);
 322 }
 323
 324 int gnttab_end_foreign_access_ref(grant_ref_t ref, int readonly)
 325 {
 326         if (_gnttab_end_foreign_access_ref(ref, readonly))
 327                 return 1;
 328         pr_warn("WARNING: g.e. %#x still in use!\n", ref);
 329         return 0;
 330 }
 331 EXPORT_SYMBOL_GPL(gnttab_end_foreign_access_ref);
 332
 333 struct deferred_entry {
 334         struct list_head list;
 335         grant_ref_t ref;
 336         bool ro;
 337         uint16_t warn_delay;
 338         struct page *page;
 339 };
 340 static LIST_HEAD(deferred_list);
 341 static void gnttab_handle_deferred(struct timer_list *);
 342 static DEFINE_TIMER(deferred_timer, gnttab_handle_deferred);
 343
 344 static void gnttab_handle_deferred(struct timer_list *unused)
 345 {
 346         unsigned int nr = 10;
 347         struct deferred_entry *first = NULL;
 348         unsigned long flags;
 349
 350         spin_lock_irqsave(&gnttab_list_lock, flags);
 351         while (nr--) {
 352                 struct deferred_entry *entry
 353                         = list_first_entry(&deferred_list,
 354                                            struct deferred_entry, list);
 355
 356                 if (entry == first)
 357                         break;
 358                 list_del(&entry->list);
 359                 spin_unlock_irqrestore(&gnttab_list_lock, flags);
 360                 if (_gnttab_end_foreign_access_ref(entry->ref, entry->ro)) {
 361                         put_free_entry(entry->ref);
 362                         if (entry->page) {
 363                                 pr_debug("freeing g.e. %#x (pfn %#lx)\n",
 364                                          entry->ref, page_to_pfn(entry->page));
 365                                 put_page(entry->page);
 366                         } else
 367                                 pr_info("freeing g.e. %#x\n", entry->ref);
 368                         kfree(entry);
 369                         entry = NULL;
 370                 } else {
 371                         if (!--entry->warn_delay)
 372                                 pr_info("g.e. %#x still pending\n", entry->ref);
 373                         if (!first)
 374                                 first = entry;
 375                 }
 376                 spin_lock_irqsave(&gnttab_list_lock, flags);
 377                 if (entry)
 378                         list_add_tail(&entry->list, &deferred_list);
 379                 else if (list_empty(&deferred_list))
 380                         break;
 381         }
 382         if (!list_empty(&deferred_list) && !timer_pending(&deferred_timer)) {
 383                 deferred_timer.expires = jiffies + HZ;
 384                 add_timer(&deferred_timer);
 385         }
 386         spin_unlock_irqrestore(&gnttab_list_lock, flags);
 387 }
 388
 389 static void gnttab_add_deferred(grant_ref_t ref, bool readonly,
 390                                 struct page *page)
 391 {
 392         struct deferred_entry *entry = kmalloc(sizeof(*entry), GFP_ATOMIC);
 393         const char *what = KERN_WARNING "leaking";
 394
 395         if (entry) {
 396                 unsigned long flags;
 397
 398                 entry->ref = ref;
 399                 entry->ro = readonly;
 400                 entry->page = page;
 401                 entry->warn_delay = 60;
 402                 spin_lock_irqsave(&gnttab_list_lock, flags);
 403                 list_add_tail(&entry->list, &deferred_list);
 404                 if (!timer_pending(&deferred_timer)) {
 405                         deferred_timer.expires = jiffies + HZ;
 406                         add_timer(&deferred_timer);
 407                 }
 408                 spin_unlock_irqrestore(&gnttab_list_lock, flags);
 409                 what = KERN_DEBUG "deferring";
 410         }
 411         printk("%s g.e. %#x (pfn %#lx)\n",
 412                what, ref, page ? page_to_pfn(page) : -1);
 413 }
 414
 415 int gnttab_try_end_foreign_access(grant_ref_t ref)
 416 {
 417         int ret = _gnttab_end_foreign_access_ref(ref, 0);
 418
 419         if (ret)
 420                 put_free_entry(ref);
 421
 422         return ret;
 423 }
 424 EXPORT_SYMBOL_GPL(gnttab_try_end_foreign_access);
 425
 426 void gnttab_end_foreign_access(grant_ref_t ref, int readonly,
 427                                unsigned long page)
 428 {
 429         if (gnttab_try_end_foreign_access(ref)) {
 430                 if (page != 0)
 431                         put_page(virt_to_page(page));
 432         } else
 433                 gnttab_add_deferred(ref, readonly,
 434                                     page ? virt_to_page(page) : NULL);
 435 }
 436 EXPORT_SYMBOL_GPL(gnttab_end_foreign_access);
 437
 438 int gnttab_grant_foreign_transfer(domid_t domid, unsigned long pfn)
 439 {
 440         int ref;
 441
 442         ref = get_free_entries(1);
 443         if (unlikely(ref < 0))
 444                 return -ENOSPC;
 445         gnttab_grant_foreign_transfer_ref(ref, domid, pfn);
 446
 447         return ref;
 448 }
 449 EXPORT_SYMBOL_GPL(gnttab_grant_foreign_transfer);
 450
 451 void gnttab_grant_foreign_transfer_ref(grant_ref_t ref, domid_t domid,
 452                                        unsigned long pfn)
 453 {
 454         gnttab_interface->update_entry(ref, domid, pfn, GTF_accept_transfer);
 455 }
 456 EXPORT_SYMBOL_GPL(gnttab_grant_foreign_transfer_ref);
 457
 458 static unsigned long gnttab_end_foreign_transfer_ref_v1(grant_ref_t ref)
 459 {
 460         unsigned long frame;
 461         u16           flags;
 462         u16          *pflags;
 463
 464         pflags = &gnttab_shared.v1[ref].flags;
 465
 466         /*
 467          * If a transfer is not even yet started, try to reclaim the grant
 468          * reference and return failure (== 0).
 469          */
 470         while (!((flags = *pflags) & GTF_transfer_committed)) {
 471                 if (sync_cmpxchg(pflags, flags, 0) == flags)
 472                         return 0;
 473                 cpu_relax();
 474         }
 475
 476         /* If a transfer is in progress then wait until it is completed. */
 477         while (!(flags & GTF_transfer_completed)) {
 478                 flags = *pflags;
 479                 cpu_relax();
 480         }
 481
 482         rmb();  /* Read the frame number /after/ reading completion status. */
 483         frame = gnttab_shared.v1[ref].frame;
 484         BUG_ON(frame == 0);
 485
 486         return frame;
 487 }
 488
 489 static unsigned long gnttab_end_foreign_transfer_ref_v2(grant_ref_t ref)
 490 {
 491         unsigned long frame;
 492         u16           flags;
 493         u16          *pflags;
 494
 495         pflags = &gnttab_shared.v2[ref].hdr.flags;
 496
 497         /*
 498          * If a transfer is not even yet started, try to reclaim the grant
 499          * reference and return failure (== 0).
 500          */
 501         while (!((flags = *pflags) & GTF_transfer_committed)) {
 502                 if (sync_cmpxchg(pflags, flags, 0) == flags)
 503                         return 0;
 504                 cpu_relax();
 505         }
 506
 507         /* If a transfer is in progress then wait until it is completed. */
 508         while (!(flags & GTF_transfer_completed)) {
 509                 flags = *pflags;
 510                 cpu_relax();
 511         }
 512
 513         rmb();  /* Read the frame number /after/ reading completion status. */
 514         frame = gnttab_shared.v2[ref].full_page.frame;
 515         BUG_ON(frame == 0);
 516
 517         return frame;
 518 }
 519
 520 unsigned long gnttab_end_foreign_transfer_ref(grant_ref_t ref)
 521 {
 522         return gnttab_interface->end_foreign_transfer_ref(ref);
 523 }
 524 EXPORT_SYMBOL_GPL(gnttab_end_foreign_transfer_ref);
 525
 526 unsigned long gnttab_end_foreign_transfer(grant_ref_t ref)
 527 {
 528         unsigned long frame = gnttab_end_foreign_transfer_ref(ref);
 529         put_free_entry(ref);
 530         return frame;
 531 }
 532 EXPORT_SYMBOL_GPL(gnttab_end_foreign_transfer);
 533
 534 void gnttab_free_grant_reference(grant_ref_t ref)
 535 {
 536         put_free_entry(ref);
 537 }
 538 EXPORT_SYMBOL_GPL(gnttab_free_grant_reference);
 539
 540 void gnttab_free_grant_references(grant_ref_t head)
 541 {
 542         grant_ref_t ref;
 543         unsigned long flags;
 544         int count = 1;
 545         if (head == GNTTAB_LIST_END)
 546                 return;
 547         spin_lock_irqsave(&gnttab_list_lock, flags);
 548         ref = head;
 549         while (gnttab_entry(ref) != GNTTAB_LIST_END) {
 550                 ref = gnttab_entry(ref);
 551                 count++;
 552         }
 553         gnttab_entry(ref) = gnttab_free_head;
 554         gnttab_free_head = head;
 555         gnttab_free_count += count;
 556         check_free_callbacks();
 557         spin_unlock_irqrestore(&gnttab_list_lock, flags);
 558 }
 559 EXPORT_SYMBOL_GPL(gnttab_free_grant_references);
 560
 561 int gnttab_alloc_grant_references(u16 count, grant_ref_t *head)
 562 {
 563         int h = get_free_entries(count);
 564
 565         if (h < 0)
 566                 return -ENOSPC;
 567
 568         *head = h;
 569
 570         return 0;
 571 }
 572 EXPORT_SYMBOL_GPL(gnttab_alloc_grant_references);
 573
 574 int gnttab_empty_grant_references(const grant_ref_t *private_head)
 575 {
 576         return (*private_head == GNTTAB_LIST_END);
 577 }
 578 EXPORT_SYMBOL_GPL(gnttab_empty_grant_references);
 579
 580 int gnttab_claim_grant_reference(grant_ref_t *private_head)
 581 {
 582         grant_ref_t g = *private_head;
 583         if (unlikely(g == GNTTAB_LIST_END))
 584                 return -ENOSPC;
 585         *private_head = gnttab_entry(g);
 586         return g;
 587 }
 588 EXPORT_SYMBOL_GPL(gnttab_claim_grant_reference);
 589
 590 void gnttab_release_grant_reference(grant_ref_t *private_head,
 591                                     grant_ref_t release)
 592 {
 593         gnttab_entry(release) = *private_head;
 594         *private_head = release;
 595 }
 596 EXPORT_SYMBOL_GPL(gnttab_release_grant_reference);
 597
 598 void gnttab_request_free_callback(struct gnttab_free_callback *callback,
 599                                   void (*fn)(void *), void *arg, u16 count)
 600 {
 601         unsigned long flags;
 602         struct gnttab_free_callback *cb;
 603
 604         spin_lock_irqsave(&gnttab_list_lock, flags);
 605
 606         /* Check if the callback is already on the list */
 607         cb = gnttab_free_callback_list;
 608         while (cb) {
 609                 if (cb == callback)
 610                         goto out;
 611                 cb = cb->next;
 612         }
 613
 614         callback->fn = fn;
 615         callback->arg = arg;
 616         callback->count = count;
 617         callback->next = gnttab_free_callback_list;
 618         gnttab_free_callback_list = callback;
 619         check_free_callbacks();
 620 out:
 621         spin_unlock_irqrestore(&gnttab_list_lock, flags);
 622 }
 623 EXPORT_SYMBOL_GPL(gnttab_request_free_callback);
 624
 625 void gnttab_cancel_free_callback(struct gnttab_free_callback *callback)
 626 {
 627         struct gnttab_free_callback **pcb;
 628         unsigned long flags;
 629
 630         spin_lock_irqsave(&gnttab_list_lock, flags);
 631         for (pcb = &gnttab_free_callback_list; *pcb; pcb = &(*pcb)->next) {
 632                 if (*pcb == callback) {
 633                         *pcb = callback->next;
 634                         break;
 635                 }
 636         }
 637         spin_unlock_irqrestore(&gnttab_list_lock, flags);
 638 }
 639 EXPORT_SYMBOL_GPL(gnttab_cancel_free_callback);
 640
 641 static unsigned int gnttab_frames(unsigned int frames, unsigned int align)
 642 {
 643         return (frames * gnttab_interface->grefs_per_grant_frame + align - 1) /
 644                align;
 645 }
 646
 647 static int grow_gnttab_list(unsigned int more_frames)
 648 {
 649         unsigned int new_nr_grant_frames, extra_entries, i;
 650         unsigned int nr_glist_frames, new_nr_glist_frames;
 651         unsigned int grefs_per_frame;
 652
 653         grefs_per_frame = gnttab_interface->grefs_per_grant_frame;
 654
 655         new_nr_grant_frames = nr_grant_frames + more_frames;
 656         extra_entries = more_frames * grefs_per_frame;
 657
 658         nr_glist_frames = gnttab_frames(nr_grant_frames, RPP);
 659         new_nr_glist_frames = gnttab_frames(new_nr_grant_frames, RPP);
 660         for (i = nr_glist_frames; i < new_nr_glist_frames; i++) {
 661                 gnttab_list[i] = (grant_ref_t *)__get_free_page(GFP_ATOMIC);
 662                 if (!gnttab_list[i])
 663                         goto grow_nomem;
 664         }
 665
 666
 667         for (i = grefs_per_frame * nr_grant_frames;
 668              i < grefs_per_frame * new_nr_grant_frames - 1; i++)
 669                 gnttab_entry(i) = i + 1;
 670
 671         gnttab_entry(i) = gnttab_free_head;
 672         gnttab_free_head = grefs_per_frame * nr_grant_frames;
 673         gnttab_free_count += extra_entries;
 674
 675         nr_grant_frames = new_nr_grant_frames;
 676
 677         check_free_callbacks();
 678
 679         return 0;
 680
 681 grow_nomem:
 682         while (i-- > nr_glist_frames)
 683                 free_page((unsigned long) gnttab_list[i]);
 684         return -ENOMEM;
 685 }
 686
 687 static unsigned int __max_nr_grant_frames(void)
 688 {
 689         struct gnttab_query_size query;
 690         int rc;
 691
 692         query.dom = DOMID_SELF;
 693
 694         rc = HYPERVISOR_grant_table_op(GNTTABOP_query_size, &query, 1);
 695         if ((rc < 0) || (query.status != GNTST_okay))
 696                 return 4; /* Legacy max supported number of frames */
 697
 698         return query.max_nr_frames;
 699 }
 700
 701 unsigned int gnttab_max_grant_frames(void)
 702 {
 703         unsigned int xen_max = __max_nr_grant_frames();
 704         static unsigned int boot_max_nr_grant_frames;
 705
 706         /* First time, initialize it properly. */
 707         if (!boot_max_nr_grant_frames)
 708                 boot_max_nr_grant_frames = __max_nr_grant_frames();
 709
 710         if (xen_max > boot_max_nr_grant_frames)
 711                 return boot_max_nr_grant_frames;
 712         return xen_max;
 713 }
 714 EXPORT_SYMBOL_GPL(gnttab_max_grant_frames);
 715
 716 int gnttab_setup_auto_xlat_frames(phys_addr_t addr)
 717 {
 718         xen_pfn_t *pfn;
 719         unsigned int max_nr_gframes = __max_nr_grant_frames();
 720         unsigned int i;
 721         void *vaddr;
 722
 723         if (xen_auto_xlat_grant_frames.count)
 724                 return -EINVAL;
 725
 726         vaddr = xen_remap(addr, XEN_PAGE_SIZE * max_nr_gframes);
 727         if (vaddr == NULL) {
 728                 pr_warn("Failed to ioremap gnttab share frames (addr=%pa)!\n",
 729                         &addr);
 730                 return -ENOMEM;
 731         }
 732         pfn = kcalloc(max_nr_gframes, sizeof(pfn[0]), GFP_KERNEL);
 733         if (!pfn) {
 734                 xen_unmap(vaddr);
 735                 return -ENOMEM;
 736         }
 737         for (i = 0; i < max_nr_gframes; i++)
 738                 pfn[i] = XEN_PFN_DOWN(addr) + i;
 739
 740         xen_auto_xlat_grant_frames.vaddr = vaddr;
 741         xen_auto_xlat_grant_frames.pfn = pfn;
 742         xen_auto_xlat_grant_frames.count = max_nr_gframes;
 743
 744         return 0;
 745 }
 746 EXPORT_SYMBOL_GPL(gnttab_setup_auto_xlat_frames);
 747
 748 void gnttab_free_auto_xlat_frames(void)
 749 {
 750         if (!xen_auto_xlat_grant_frames.count)
 751                 return;
 752         kfree(xen_auto_xlat_grant_frames.pfn);
 753         xen_unmap(xen_auto_xlat_grant_frames.vaddr);
 754
 755         xen_auto_xlat_grant_frames.pfn = NULL;
 756         xen_auto_xlat_grant_frames.count = 0;
 757         xen_auto_xlat_grant_frames.vaddr = NULL;
 758 }
 759 EXPORT_SYMBOL_GPL(gnttab_free_auto_xlat_frames);
 760
 761 int gnttab_pages_set_private(int nr_pages, struct page **pages)
 762 {
 763         int i;
 764
 765         for (i = 0; i < nr_pages; i++) {
 766 #if BITS_PER_LONG < 64
 767                 struct xen_page_foreign *foreign;
 768
 769                 foreign = kzalloc(sizeof(*foreign), GFP_KERNEL);
 770                 if (!foreign)
 771                         return -ENOMEM;
 772
 773                 set_page_private(pages[i], (unsigned long)foreign);
 774 #endif
 775                 SetPagePrivate(pages[i]);
 776         }
 777
 778         return 0;
 779 }
 780 EXPORT_SYMBOL_GPL(gnttab_pages_set_private);
 781
 782 /**
 783  * gnttab_alloc_pages - alloc pages suitable for grant mapping into
 784  * @nr_pages: number of pages to alloc
 785  * @pages: returns the pages
 786  */
 787 int gnttab_alloc_pages(int nr_pages, struct page **pages)
 788 {
 789         int ret;
 790
 791         ret = xen_alloc_unpopulated_pages(nr_pages, pages);
 792         if (ret < 0)
 793                 return ret;
 794
 795         ret = gnttab_pages_set_private(nr_pages, pages);
 796         if (ret < 0)
 797                 gnttab_free_pages(nr_pages, pages);
 798
 799         return ret;
 800 }
 801 EXPORT_SYMBOL_GPL(gnttab_alloc_pages);
 802
 803 #ifdef CONFIG_XEN_UNPOPULATED_ALLOC
 804 static inline void cache_init(struct gnttab_page_cache *cache)
 805 {
 806         cache->pages = NULL;
 807 }
 808
 809 static inline bool cache_empty(struct gnttab_page_cache *cache)
 810 {
 811         return !cache->pages;
 812 }
 813
 814 static inline struct page *cache_deq(struct gnttab_page_cache *cache)
 815 {
 816         struct page *page;
 817
 818         page = cache->pages;
 819         cache->pages = page->zone_device_data;
 820
 821         return page;
 822 }
 823
 824 static inline void cache_enq(struct gnttab_page_cache *cache, struct page *page)
 825 {
 826         page->zone_device_data = cache->pages;
 827         cache->pages = page;
 828 }
 829 #else
 830 static inline void cache_init(struct gnttab_page_cache *cache)
 831 {
 832         INIT_LIST_HEAD(&cache->pages);
 833 }
 834
 835 static inline bool cache_empty(struct gnttab_page_cache *cache)
 836 {
 837         return list_empty(&cache->pages);
 838 }
 839
 840 static inline struct page *cache_deq(struct gnttab_page_cache *cache)
 841 {
 842         struct page *page;
 843
 844         page = list_first_entry(&cache->pages, struct page, lru);
 845         list_del(&page->lru);
 846
 847         return page;
 848 }
 849
 850 static inline void cache_enq(struct gnttab_page_cache *cache, struct page *page)
 851 {
 852         list_add(&page->lru, &cache->pages);
 853 }
 854 #endif
 855
 856 void gnttab_page_cache_init(struct gnttab_page_cache *cache)
 857 {
 858         spin_lock_init(&cache->lock);
 859         cache_init(cache);
 860         cache->num_pages = 0;
 861 }
 862 EXPORT_SYMBOL_GPL(gnttab_page_cache_init);
 863
 864 int gnttab_page_cache_get(struct gnttab_page_cache *cache, struct page **page)
 865 {
 866         unsigned long flags;
 867
 868         spin_lock_irqsave(&cache->lock, flags);
 869
 870         if (cache_empty(cache)) {
 871                 spin_unlock_irqrestore(&cache->lock, flags);
 872                 return gnttab_alloc_pages(1, page);
 873         }
 874
 875         page[0] = cache_deq(cache);
 876         cache->num_pages--;
 877
 878         spin_unlock_irqrestore(&cache->lock, flags);
 879
 880         return 0;
 881 }
 882 EXPORT_SYMBOL_GPL(gnttab_page_cache_get);
 883
 884 void gnttab_page_cache_put(struct gnttab_page_cache *cache, struct page **page,
 885                            unsigned int num)
 886 {
 887         unsigned long flags;
 888         unsigned int i;
 889
 890         spin_lock_irqsave(&cache->lock, flags);
 891
 892         for (i = 0; i < num; i++)
 893                 cache_enq(cache, page[i]);
 894         cache->num_pages += num;
 895
 896         spin_unlock_irqrestore(&cache->lock, flags);
 897 }
 898 EXPORT_SYMBOL_GPL(gnttab_page_cache_put);
 899
 900 void gnttab_page_cache_shrink(struct gnttab_page_cache *cache, unsigned int num)
 901 {
 902         struct page *page[10];
 903         unsigned int i = 0;
 904         unsigned long flags;
 905
 906         spin_lock_irqsave(&cache->lock, flags);
 907
 908         while (cache->num_pages > num) {
 909                 page[i] = cache_deq(cache);
 910                 cache->num_pages--;
 911                 if (++i == ARRAY_SIZE(page)) {
 912                         spin_unlock_irqrestore(&cache->lock, flags);
 913                         gnttab_free_pages(i, page);
 914                         i = 0;
 915                         spin_lock_irqsave(&cache->lock, flags);
 916                 }
 917         }
 918
 919         spin_unlock_irqrestore(&cache->lock, flags);
 920
 921         if (i != 0)
 922                 gnttab_free_pages(i, page);
 923 }
 924 EXPORT_SYMBOL_GPL(gnttab_page_cache_shrink);
 925
 926 void gnttab_pages_clear_private(int nr_pages, struct page **pages)
 927 {
 928         int i;
 929
 930         for (i = 0; i < nr_pages; i++) {
 931                 if (PagePrivate(pages[i])) {
 932 #if BITS_PER_LONG < 64
 933                         kfree((void *)page_private(pages[i]));
 934 #endif
 935                         ClearPagePrivate(pages[i]);
 936                 }
 937         }
 938 }
 939 EXPORT_SYMBOL_GPL(gnttab_pages_clear_private);
 940
 941 /**
 942  * gnttab_free_pages - free pages allocated by gnttab_alloc_pages()
 943  * @nr_pages; number of pages to free
 944  * @pages: the pages
 945  */
 946 void gnttab_free_pages(int nr_pages, struct page **pages)
 947 {
 948         gnttab_pages_clear_private(nr_pages, pages);
 949         xen_free_unpopulated_pages(nr_pages, pages);
 950 }
 951 EXPORT_SYMBOL_GPL(gnttab_free_pages);
 952
 953 #ifdef CONFIG_XEN_GRANT_DMA_ALLOC
 954 /**
 955  * gnttab_dma_alloc_pages - alloc DMAable pages suitable for grant mapping into
 956  * @args: arguments to the function
 957  */
 958 int gnttab_dma_alloc_pages(struct gnttab_dma_alloc_args *args)
 959 {
 960         unsigned long pfn, start_pfn;
 961         size_t size;
 962         int i, ret;
 963
 964         size = args->nr_pages << PAGE_SHIFT;
 965         if (args->coherent)
 966                 args->vaddr = dma_alloc_coherent(args->dev, size,
 967                                                  &args->dev_bus_addr,
 968                                                  GFP_KERNEL | __GFP_NOWARN);
 969         else
 970                 args->vaddr = dma_alloc_wc(args->dev, size,
 971                                            &args->dev_bus_addr,
 972                                            GFP_KERNEL | __GFP_NOWARN);
 973         if (!args->vaddr) {
 974                 pr_debug("Failed to allocate DMA buffer of size %zu\n", size);
 975                 return -ENOMEM;
 976         }
 977
 978         start_pfn = __phys_to_pfn(args->dev_bus_addr);
 979         for (pfn = start_pfn, i = 0; pfn < start_pfn + args->nr_pages;
 980                         pfn++, i++) {
 981                 struct page *page = pfn_to_page(pfn);
 982
 983                 args->pages[i] = page;
 984                 args->frames[i] = xen_page_to_gfn(page);
 985                 xenmem_reservation_scrub_page(page);
 986         }
 987
 988         xenmem_reservation_va_mapping_reset(args->nr_pages, args->pages);
 989
 990         ret = xenmem_reservation_decrease(args->nr_pages, args->frames);
 991         if (ret != args->nr_pages) {
 992                 pr_debug("Failed to decrease reservation for DMA buffer\n");
 993                 ret = -EFAULT;
 994                 goto fail;
 995         }
 996
 997         ret = gnttab_pages_set_private(args->nr_pages, args->pages);
 998         if (ret < 0)
 999                 goto fail;
1000
1001         return 0;
1002
1003 fail:
1004         gnttab_dma_free_pages(args);
1005         return ret;
1006 }
1007 EXPORT_SYMBOL_GPL(gnttab_dma_alloc_pages);
1008
1009 /**
1010  * gnttab_dma_free_pages - free DMAable pages
1011  * @args: arguments to the function
1012  */
1013 int gnttab_dma_free_pages(struct gnttab_dma_alloc_args *args)
1014 {
1015         size_t size;
1016         int i, ret;
1017
1018         gnttab_pages_clear_private(args->nr_pages, args->pages);
1019
1020         for (i = 0; i < args->nr_pages; i++)
1021                 args->frames[i] = page_to_xen_pfn(args->pages[i]);
1022
1023         ret = xenmem_reservation_increase(args->nr_pages, args->frames);
1024         if (ret != args->nr_pages) {
1025                 pr_debug("Failed to increase reservation for DMA buffer\n");
1026                 ret = -EFAULT;
1027         } else {
1028                 ret = 0;
1029         }
1030
1031         xenmem_reservation_va_mapping_update(args->nr_pages, args->pages,
1032                                              args->frames);
1033
1034         size = args->nr_pages << PAGE_SHIFT;
1035         if (args->coherent)
1036                 dma_free_coherent(args->dev, size,
1037                                   args->vaddr, args->dev_bus_addr);
1038         else
1039                 dma_free_wc(args->dev, size,
1040                             args->vaddr, args->dev_bus_addr);
1041         return ret;
1042 }
1043 EXPORT_SYMBOL_GPL(gnttab_dma_free_pages);
1044 #endif
1045
1046 /* Handling of paged out grant targets (GNTST_eagain) */
1047 #define MAX_DELAY 256
1048 static inline void
1049 gnttab_retry_eagain_gop(unsigned int cmd, void *gop, int16_t *status,
1050                                                 const char *func)
1051 {
1052         unsigned delay = 1;
1053
1054         do {
1055                 BUG_ON(HYPERVISOR_grant_table_op(cmd, gop, 1));
1056                 if (*status == GNTST_eagain)
1057                         msleep(delay++);
1058         } while ((*status == GNTST_eagain) && (delay < MAX_DELAY));
1059
1060         if (delay >= MAX_DELAY) {
1061                 pr_err("%s: %s eagain grant\n", func, current->comm);
1062                 *status = GNTST_bad_page;
1063         }
1064 }
1065
1066 void gnttab_batch_map(struct gnttab_map_grant_ref *batch, unsigned count)
1067 {
1068         struct gnttab_map_grant_ref *op;
1069
1070         if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, batch, count))
1071                 BUG();
1072         for (op = batch; op < batch + count; op++)
1073                 if (op->status == GNTST_eagain)
1074                         gnttab_retry_eagain_gop(GNTTABOP_map_grant_ref, op,
1075                                                 &op->status, __func__);
1076 }
1077 EXPORT_SYMBOL_GPL(gnttab_batch_map);
1078
1079 void gnttab_batch_copy(struct gnttab_copy *batch, unsigned count)
1080 {
1081         struct gnttab_copy *op;
1082
1083         if (HYPERVISOR_grant_table_op(GNTTABOP_copy, batch, count))
1084                 BUG();
1085         for (op = batch; op < batch + count; op++)
1086                 if (op->status == GNTST_eagain)
1087                         gnttab_retry_eagain_gop(GNTTABOP_copy, op,
1088                                                 &op->status, __func__);
1089 }
1090 EXPORT_SYMBOL_GPL(gnttab_batch_copy);
1091
1092 void gnttab_foreach_grant_in_range(struct page *page,
1093                                    unsigned int offset,
1094                                    unsigned int len,
1095                                    xen_grant_fn_t fn,
1096                                    void *data)
1097 {
1098         unsigned int goffset;
1099         unsigned int glen;
1100         unsigned long xen_pfn;
1101
1102         len = min_t(unsigned int, PAGE_SIZE - offset, len);
1103         goffset = xen_offset_in_page(offset);
1104
1105         xen_pfn = page_to_xen_pfn(page) + XEN_PFN_DOWN(offset);
1106
1107         while (len) {
1108                 glen = min_t(unsigned int, XEN_PAGE_SIZE - goffset, len);
1109                 fn(pfn_to_gfn(xen_pfn), goffset, glen, data);
1110
1111                 goffset = 0;
1112                 xen_pfn++;
1113                 len -= glen;
1114         }
1115 }
1116 EXPORT_SYMBOL_GPL(gnttab_foreach_grant_in_range);
1117
1118 void gnttab_foreach_grant(struct page **pages,
1119                           unsigned int nr_grefs,
1120                           xen_grant_fn_t fn,
1121                           void *data)
1122 {
1123         unsigned int goffset = 0;
1124         unsigned long xen_pfn = 0;
1125         unsigned int i;
1126
1127         for (i = 0; i < nr_grefs; i++) {
1128                 if ((i % XEN_PFN_PER_PAGE) == 0) {
1129                         xen_pfn = page_to_xen_pfn(pages[i / XEN_PFN_PER_PAGE]);
1130                         goffset = 0;
1131                 }
1132
1133                 fn(pfn_to_gfn(xen_pfn), goffset, XEN_PAGE_SIZE, data);
1134
1135                 goffset += XEN_PAGE_SIZE;
1136                 xen_pfn++;
1137         }
1138 }
1139
1140 int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
1141                     struct gnttab_map_grant_ref *kmap_ops,
1142                     struct page **pages, unsigned int count)
1143 {
1144         int i, ret;
1145
1146         ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, map_ops, count);
1147         if (ret)
1148                 return ret;
1149
1150         for (i = 0; i < count; i++) {
1151                 switch (map_ops[i].status) {
1152                 case GNTST_okay:
1153                 {
1154                         struct xen_page_foreign *foreign;
1155
1156                         SetPageForeign(pages[i]);
1157                         foreign = xen_page_foreign(pages[i]);
1158                         foreign->domid = map_ops[i].dom;
1159                         foreign->gref = map_ops[i].ref;
1160                         break;
1161                 }
1162
1163                 case GNTST_no_device_space:
1164                         pr_warn_ratelimited("maptrack limit reached, can't map all guest pages\n");
1165                         break;
1166
1167                 case GNTST_eagain:
1168                         /* Retry eagain maps */
1169                         gnttab_retry_eagain_gop(GNTTABOP_map_grant_ref,
1170                                                 map_ops + i,
1171                                                 &map_ops[i].status, __func__);
1172                         /* Test status in next loop iteration. */
1173                         i--;
1174                         break;
1175
1176                 default:
1177                         break;
1178                 }
1179         }
1180
1181         return set_foreign_p2m_mapping(map_ops, kmap_ops, pages, count);
1182 }
1183 EXPORT_SYMBOL_GPL(gnttab_map_refs);
1184
1185 int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
1186                       struct gnttab_unmap_grant_ref *kunmap_ops,
1187                       struct page **pages, unsigned int count)
1188 {
1189         unsigned int i;
1190         int ret;
1191
1192         ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap_ops, count);
1193         if (ret)
1194                 return ret;
1195
1196         for (i = 0; i < count; i++)
1197                 ClearPageForeign(pages[i]);
1198
1199         return clear_foreign_p2m_mapping(unmap_ops, kunmap_ops, pages, count);
1200 }
1201 EXPORT_SYMBOL_GPL(gnttab_unmap_refs);
1202
1203 #define GNTTAB_UNMAP_REFS_DELAY 5
1204
1205 static void __gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item);
1206
1207 static void gnttab_unmap_work(struct work_struct *work)
1208 {
1209         struct gntab_unmap_queue_data
1210                 *unmap_data = container_of(work,
1211                                            struct gntab_unmap_queue_data,
1212                                            gnttab_work.work);
1213         if (unmap_data->age != UINT_MAX)
1214                 unmap_data->age++;
1215         __gnttab_unmap_refs_async(unmap_data);
1216 }
1217
1218 static void __gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item)
1219 {
1220         int ret;
1221         int pc;
1222
1223         for (pc = 0; pc < item->count; pc++) {
1224                 if (page_count(item->pages[pc]) > 1) {
1225                         unsigned long delay = GNTTAB_UNMAP_REFS_DELAY * (item->age + 1);
1226                         schedule_delayed_work(&item->gnttab_work,
1227                                               msecs_to_jiffies(delay));
1228                         return;
1229                 }
1230         }
1231
1232         ret = gnttab_unmap_refs(item->unmap_ops, item->kunmap_ops,
1233                                 item->pages, item->count);
1234         item->done(ret, item);
1235 }
1236
1237 void gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item)
1238 {
1239         INIT_DELAYED_WORK(&item->gnttab_work, gnttab_unmap_work);
1240         item->age = 0;
1241
1242         __gnttab_unmap_refs_async(item);
1243 }
1244 EXPORT_SYMBOL_GPL(gnttab_unmap_refs_async);
1245
1246 static void unmap_refs_callback(int result,
1247                 struct gntab_unmap_queue_data *data)
1248 {
1249         struct unmap_refs_callback_data *d = data->data;
1250
1251         d->result = result;
1252         complete(&d->completion);
1253 }
1254
1255 int gnttab_unmap_refs_sync(struct gntab_unmap_queue_data *item)
1256 {
1257         struct unmap_refs_callback_data data;
1258
1259         init_completion(&data.completion);
1260         item->data = &data;
1261         item->done = &unmap_refs_callback;
1262         gnttab_unmap_refs_async(item);
1263         wait_for_completion(&data.completion);
1264
1265         return data.result;
1266 }
1267 EXPORT_SYMBOL_GPL(gnttab_unmap_refs_sync);
1268
1269 static unsigned int nr_status_frames(unsigned int nr_grant_frames)
1270 {
1271         return gnttab_frames(nr_grant_frames, SPP);
1272 }
1273
1274 static int gnttab_map_frames_v1(xen_pfn_t *frames, unsigned int nr_gframes)
1275 {
1276         int rc;
1277
1278         rc = arch_gnttab_map_shared(frames, nr_gframes,
1279                                     gnttab_max_grant_frames(),
1280                                     &gnttab_shared.addr);
1281         BUG_ON(rc);
1282
1283         return 0;
1284 }
1285
1286 static void gnttab_unmap_frames_v1(void)
1287 {
1288         arch_gnttab_unmap(gnttab_shared.addr, nr_grant_frames);
1289 }
1290
1291 static int gnttab_map_frames_v2(xen_pfn_t *frames, unsigned int nr_gframes)
1292 {
1293         uint64_t *sframes;
1294         unsigned int nr_sframes;
1295         struct gnttab_get_status_frames getframes;
1296         int rc;
1297
1298         nr_sframes = nr_status_frames(nr_gframes);
1299
1300         /* No need for kzalloc as it is initialized in following hypercall
1301          * GNTTABOP_get_status_frames.
1302          */
1303         sframes = kmalloc_array(nr_sframes, sizeof(uint64_t), GFP_ATOMIC);
1304         if (!sframes)
1305                 return -ENOMEM;
1306
1307         getframes.dom        = DOMID_SELF;
1308         getframes.nr_frames  = nr_sframes;
1309         set_xen_guest_handle(getframes.frame_list, sframes);
1310
1311         rc = HYPERVISOR_grant_table_op(GNTTABOP_get_status_frames,
1312                                        &getframes, 1);
1313         if (rc == -ENOSYS) {
1314                 kfree(sframes);
1315                 return -ENOSYS;
1316         }
1317
1318         BUG_ON(rc || getframes.status);
1319
1320         rc = arch_gnttab_map_status(sframes, nr_sframes,
1321                                     nr_status_frames(gnttab_max_grant_frames()),
1322                                     &grstatus);
1323         BUG_ON(rc);
1324         kfree(sframes);
1325
1326         rc = arch_gnttab_map_shared(frames, nr_gframes,
1327                                     gnttab_max_grant_frames(),
1328                                     &gnttab_shared.addr);
1329         BUG_ON(rc);
1330
1331         return 0;
1332 }
1333
1334 static void gnttab_unmap_frames_v2(void)
1335 {
1336         arch_gnttab_unmap(gnttab_shared.addr, nr_grant_frames);
1337         arch_gnttab_unmap(grstatus, nr_status_frames(nr_grant_frames));
1338 }
1339
1340 static int gnttab_map(unsigned int start_idx, unsigned int end_idx)
1341 {
1342         struct gnttab_setup_table setup;
1343         xen_pfn_t *frames;
1344         unsigned int nr_gframes = end_idx + 1;
1345         int rc;
1346
1347         if (xen_feature(XENFEAT_auto_translated_physmap)) {
1348                 struct xen_add_to_physmap xatp;
1349                 unsigned int i = end_idx;
1350                 rc = 0;
1351                 BUG_ON(xen_auto_xlat_grant_frames.count < nr_gframes);
1352                 /*
1353                  * Loop backwards, so that the first hypercall has the largest
1354                  * index, ensuring that the table will grow only once.
1355                  */
1356                 do {
1357                         xatp.domid = DOMID_SELF;
1358                         xatp.idx = i;
1359                         xatp.space = XENMAPSPACE_grant_table;
1360                         xatp.gpfn = xen_auto_xlat_grant_frames.pfn[i];
1361                         rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp);
1362                         if (rc != 0) {
1363                                 pr_warn("grant table add_to_physmap failed, err=%d\n",
1364                                         rc);
1365                                 break;
1366                         }
1367                 } while (i-- > start_idx);
1368
1369                 return rc;
1370         }
1371
1372         /* No need for kzalloc as it is initialized in following hypercall
1373          * GNTTABOP_setup_table.
1374          */
1375         frames = kmalloc_array(nr_gframes, sizeof(unsigned long), GFP_ATOMIC);
1376         if (!frames)
1377                 return -ENOMEM;
1378
1379         setup.dom        = DOMID_SELF;
1380         setup.nr_frames  = nr_gframes;
1381         set_xen_guest_handle(setup.frame_list, frames);
1382
1383         rc = HYPERVISOR_grant_table_op(GNTTABOP_setup_table, &setup, 1);
1384         if (rc == -ENOSYS) {
1385                 kfree(frames);
1386                 return -ENOSYS;
1387         }
1388
1389         BUG_ON(rc || setup.status);
1390
1391         rc = gnttab_interface->map_frames(frames, nr_gframes);
1392
1393         kfree(frames);
1394
1395         return rc;
1396 }
1397
1398 static const struct gnttab_ops gnttab_v1_ops = {
1399         .version                        = 1,
1400         .grefs_per_grant_frame          = XEN_PAGE_SIZE /
1401                                           sizeof(struct grant_entry_v1),
1402         .map_frames                     = gnttab_map_frames_v1,
1403         .unmap_frames                   = gnttab_unmap_frames_v1,
1404         .update_entry                   = gnttab_update_entry_v1,
1405         .end_foreign_access_ref         = gnttab_end_foreign_access_ref_v1,
1406         .end_foreign_transfer_ref       = gnttab_end_foreign_transfer_ref_v1,
1407 };
1408
1409 static const struct gnttab_ops gnttab_v2_ops = {
1410         .version                        = 2,
1411         .grefs_per_grant_frame          = XEN_PAGE_SIZE /
1412                                           sizeof(union grant_entry_v2),
1413         .map_frames                     = gnttab_map_frames_v2,
1414         .unmap_frames                   = gnttab_unmap_frames_v2,
1415         .update_entry                   = gnttab_update_entry_v2,
1416         .end_foreign_access_ref         = gnttab_end_foreign_access_ref_v2,
1417         .end_foreign_transfer_ref       = gnttab_end_foreign_transfer_ref_v2,
1418 };
1419
1420 static bool gnttab_need_v2(void)
1421 {
1422 #ifdef CONFIG_X86
1423         uint32_t base, width;
1424
1425         if (xen_pv_domain()) {
1426                 base = xen_cpuid_base();
1427                 if (cpuid_eax(base) < 5)
1428                         return false;   /* Information not available, use V1. */
1429                 width = cpuid_ebx(base + 5) &
1430                         XEN_CPUID_MACHINE_ADDRESS_WIDTH_MASK;
1431                 return width > 32 + PAGE_SHIFT;
1432         }
1433 #endif
1434         return !!(max_possible_pfn >> 32);
1435 }
1436
1437 static void gnttab_request_version(void)
1438 {
1439         long rc;
1440         struct gnttab_set_version gsv;
1441
1442         if (gnttab_need_v2())
1443                 gsv.version = 2;
1444         else
1445                 gsv.version = 1;
1446
1447         /* Boot parameter overrides automatic selection. */
1448         if (xen_gnttab_version >= 1 && xen_gnttab_version <= 2)
1449                 gsv.version = xen_gnttab_version;
1450
1451         rc = HYPERVISOR_grant_table_op(GNTTABOP_set_version, &gsv, 1);
1452         if (rc == 0 && gsv.version == 2)
1453                 gnttab_interface = &gnttab_v2_ops;
1454         else
1455                 gnttab_interface = &gnttab_v1_ops;
1456         pr_info("Grant tables using version %d layout\n",
1457                 gnttab_interface->version);
1458 }
1459
1460 static int gnttab_setup(void)
1461 {
1462         unsigned int max_nr_gframes;
1463
1464         max_nr_gframes = gnttab_max_grant_frames();
1465         if (max_nr_gframes < nr_grant_frames)
1466                 return -ENOSYS;
1467
1468         if (xen_feature(XENFEAT_auto_translated_physmap) && gnttab_shared.addr == NULL) {
1469                 gnttab_shared.addr = xen_auto_xlat_grant_frames.vaddr;
1470                 if (gnttab_shared.addr == NULL) {
1471                         pr_warn("gnttab share frames is not mapped!\n");
1472                         return -ENOMEM;
1473                 }
1474         }
1475         return gnttab_map(0, nr_grant_frames - 1);
1476 }
1477
1478 int gnttab_resume(void)
1479 {
1480         gnttab_request_version();
1481         return gnttab_setup();
1482 }
1483
1484 int gnttab_suspend(void)
1485 {
1486         if (!xen_feature(XENFEAT_auto_translated_physmap))
1487                 gnttab_interface->unmap_frames();
1488         return 0;
1489 }
1490
1491 static int gnttab_expand(unsigned int req_entries)
1492 {
1493         int rc;
1494         unsigned int cur, extra;
1495
1496         cur = nr_grant_frames;
1497         extra = ((req_entries + gnttab_interface->grefs_per_grant_frame - 1) /
1498                  gnttab_interface->grefs_per_grant_frame);
1499         if (cur + extra > gnttab_max_grant_frames()) {
1500                 pr_warn_ratelimited("xen/grant-table: max_grant_frames reached"
1501                                     " cur=%u extra=%u limit=%u"
1502                                     " gnttab_free_count=%u req_entries=%u\n",
1503                                     cur, extra, gnttab_max_grant_frames(),
1504                                     gnttab_free_count, req_entries);
1505                 return -ENOSPC;
1506         }
1507
1508         rc = gnttab_map(cur, cur + extra - 1);
1509         if (rc == 0)
1510                 rc = grow_gnttab_list(extra);
1511
1512         return rc;
1513 }
1514
1515 int gnttab_init(void)
1516 {
1517         int i;
1518         unsigned long max_nr_grant_frames;
1519         unsigned int max_nr_glist_frames, nr_glist_frames;
1520         unsigned int nr_init_grefs;
1521         int ret;
1522
1523         gnttab_request_version();
1524         max_nr_grant_frames = gnttab_max_grant_frames();
1525         nr_grant_frames = 1;
1526
1527         /* Determine the maximum number of frames required for the
1528          * grant reference free list on the current hypervisor.
1529          */
1530         max_nr_glist_frames = (max_nr_grant_frames *
1531                                gnttab_interface->grefs_per_grant_frame / RPP);
1532
1533         gnttab_list = kmalloc_array(max_nr_glist_frames,
1534                                     sizeof(grant_ref_t *),
1535                                     GFP_KERNEL);
1536         if (gnttab_list == NULL)
1537                 return -ENOMEM;
1538
1539         nr_glist_frames = gnttab_frames(nr_grant_frames, RPP);
1540         for (i = 0; i < nr_glist_frames; i++) {
1541                 gnttab_list[i] = (grant_ref_t *)__get_free_page(GFP_KERNEL);
1542                 if (gnttab_list[i] == NULL) {
1543                         ret = -ENOMEM;
1544                         goto ini_nomem;
1545                 }
1546         }
1547
1548         ret = arch_gnttab_init(max_nr_grant_frames,
1549                                nr_status_frames(max_nr_grant_frames));
1550         if (ret < 0)
1551                 goto ini_nomem;
1552
1553         if (gnttab_setup() < 0) {
1554                 ret = -ENODEV;
1555                 goto ini_nomem;
1556         }
1557
1558         nr_init_grefs = nr_grant_frames *
1559                         gnttab_interface->grefs_per_grant_frame;
1560
1561         for (i = NR_RESERVED_ENTRIES; i < nr_init_grefs - 1; i++)
1562                 gnttab_entry(i) = i + 1;
1563
1564         gnttab_entry(nr_init_grefs - 1) = GNTTAB_LIST_END;
1565         gnttab_free_count = nr_init_grefs - NR_RESERVED_ENTRIES;
1566         gnttab_free_head  = NR_RESERVED_ENTRIES;
1567
1568         printk("Grant table initialized\n");
1569         return 0;
1570
1571  ini_nomem:
1572         for (i--; i >= 0; i--)
1573                 free_page((unsigned long)gnttab_list[i]);
1574         kfree(gnttab_list);
1575         return ret;
1576 }
1577 EXPORT_SYMBOL_GPL(gnttab_init);
1578
1579 static int __gnttab_init(void)
1580 {
1581         if (!xen_domain())
1582                 return -ENODEV;
1583
1584         /* Delay grant-table initialization in the PV on HVM case */
1585         if (xen_hvm_domain() && !xen_pvh_domain())
1586                 return 0;
1587
1588         return gnttab_init();
1589 }
1590 /* Starts after core_initcall so that xen_pvh_gnttab_setup can be called
1591  * beforehand to initialize xen_auto_xlat_grant_frames. */
1592 core_initcall_sync(__gnttab_init);