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          * Query the status of a grant entry. Ref parameter is reference of
 138          * queried grant entry, return value is the status of queried entry.
 139          * Detailed status(writing/reading) can be gotten from the return value
 140          * by bit operations.
 141          */
 142         int (*query_foreign_access)(grant_ref_t ref);
 143 };
 144
 145 struct unmap_refs_callback_data {
 146         struct completion completion;
 147         int result;
 148 };
 149
 150 static const struct gnttab_ops *gnttab_interface;
 151
 152 /* This reflects status of grant entries, so act as a global value. */
 153 static grant_status_t *grstatus;
 154
 155 static struct gnttab_free_callback *gnttab_free_callback_list;
 156
 157 static int gnttab_expand(unsigned int req_entries);
 158
 159 #define RPP (PAGE_SIZE / sizeof(grant_ref_t))
 160 #define SPP (PAGE_SIZE / sizeof(grant_status_t))
 161
 162 static inline grant_ref_t *__gnttab_entry(grant_ref_t entry)
 163 {
 164         return &gnttab_list[(entry) / RPP][(entry) % RPP];
 165 }
 166 /* This can be used as an l-value */
 167 #define gnttab_entry(entry) (*__gnttab_entry(entry))
 168
 169 static int get_free_entries(unsigned count)
 170 {
 171         unsigned long flags;
 172         int ref, rc = 0;
 173         grant_ref_t head;
 174
 175         spin_lock_irqsave(&gnttab_list_lock, flags);
 176
 177         if ((gnttab_free_count < count) &&
 178             ((rc = gnttab_expand(count - gnttab_free_count)) < 0)) {
 179                 spin_unlock_irqrestore(&gnttab_list_lock, flags);
 180                 return rc;
 181         }
 182
 183         ref = head = gnttab_free_head;
 184         gnttab_free_count -= count;
 185         while (count-- > 1)
 186                 head = gnttab_entry(head);
 187         gnttab_free_head = gnttab_entry(head);
 188         gnttab_entry(head) = GNTTAB_LIST_END;
 189
 190         spin_unlock_irqrestore(&gnttab_list_lock, flags);
 191
 192         return ref;
 193 }
 194
 195 static void do_free_callbacks(void)
 196 {
 197         struct gnttab_free_callback *callback, *next;
 198
 199         callback = gnttab_free_callback_list;
 200         gnttab_free_callback_list = NULL;
 201
 202         while (callback != NULL) {
 203                 next = callback->next;
 204                 if (gnttab_free_count >= callback->count) {
 205                         callback->next = NULL;
 206                         callback->fn(callback->arg);
 207                 } else {
 208                         callback->next = gnttab_free_callback_list;
 209                         gnttab_free_callback_list = callback;
 210                 }
 211                 callback = next;
 212         }
 213 }
 214
 215 static inline void check_free_callbacks(void)
 216 {
 217         if (unlikely(gnttab_free_callback_list))
 218                 do_free_callbacks();
 219 }
 220
 221 static void put_free_entry(grant_ref_t ref)
 222 {
 223         unsigned long flags;
 224         spin_lock_irqsave(&gnttab_list_lock, flags);
 225         gnttab_entry(ref) = gnttab_free_head;
 226         gnttab_free_head = ref;
 227         gnttab_free_count++;
 228         check_free_callbacks();
 229         spin_unlock_irqrestore(&gnttab_list_lock, flags);
 230 }
 231
 232 /*
 233  * Following applies to gnttab_update_entry_v1 and gnttab_update_entry_v2.
 234  * Introducing a valid entry into the grant table:
 235  *  1. Write ent->domid.
 236  *  2. Write ent->frame:
 237  *      GTF_permit_access:   Frame to which access is permitted.
 238  *      GTF_accept_transfer: Pseudo-phys frame slot being filled by new
 239  *                           frame, or zero if none.
 240  *  3. Write memory barrier (WMB).
 241  *  4. Write ent->flags, inc. valid type.
 242  */
 243 static void gnttab_update_entry_v1(grant_ref_t ref, domid_t domid,
 244                                    unsigned long frame, unsigned flags)
 245 {
 246         gnttab_shared.v1[ref].domid = domid;
 247         gnttab_shared.v1[ref].frame = frame;
 248         wmb();
 249         gnttab_shared.v1[ref].flags = flags;
 250 }
 251
 252 static void gnttab_update_entry_v2(grant_ref_t ref, domid_t domid,
 253                                    unsigned long frame, unsigned int flags)
 254 {
 255         gnttab_shared.v2[ref].hdr.domid = domid;
 256         gnttab_shared.v2[ref].full_page.frame = frame;
 257         wmb();  /* Hypervisor concurrent accesses. */
 258         gnttab_shared.v2[ref].hdr.flags = GTF_permit_access | flags;
 259 }
 260
 261 /*
 262  * Public grant-issuing interface functions
 263  */
 264 void gnttab_grant_foreign_access_ref(grant_ref_t ref, domid_t domid,
 265                                      unsigned long frame, int readonly)
 266 {
 267         gnttab_interface->update_entry(ref, domid, frame,
 268                            GTF_permit_access | (readonly ? GTF_readonly : 0));
 269 }
 270 EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access_ref);
 271
 272 int gnttab_grant_foreign_access(domid_t domid, unsigned long frame,
 273                                 int readonly)
 274 {
 275         int ref;
 276
 277         ref = get_free_entries(1);
 278         if (unlikely(ref < 0))
 279                 return -ENOSPC;
 280
 281         gnttab_grant_foreign_access_ref(ref, domid, frame, readonly);
 282
 283         return ref;
 284 }
 285 EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access);
 286
 287 static int gnttab_query_foreign_access_v1(grant_ref_t ref)
 288 {
 289         return gnttab_shared.v1[ref].flags & (GTF_reading|GTF_writing);
 290 }
 291
 292 static int gnttab_query_foreign_access_v2(grant_ref_t ref)
 293 {
 294         return grstatus[ref] & (GTF_reading|GTF_writing);
 295 }
 296
 297 int gnttab_query_foreign_access(grant_ref_t ref)
 298 {
 299         return gnttab_interface->query_foreign_access(ref);
 300 }
 301 EXPORT_SYMBOL_GPL(gnttab_query_foreign_access);
 302
 303 static int gnttab_end_foreign_access_ref_v1(grant_ref_t ref, int readonly)
 304 {
 305         u16 flags, nflags;
 306         u16 *pflags;
 307
 308         pflags = &gnttab_shared.v1[ref].flags;
 309         nflags = *pflags;
 310         do {
 311                 flags = nflags;
 312                 if (flags & (GTF_reading|GTF_writing))
 313                         return 0;
 314         } while ((nflags = sync_cmpxchg(pflags, flags, 0)) != flags);
 315
 316         return 1;
 317 }
 318
 319 static int gnttab_end_foreign_access_ref_v2(grant_ref_t ref, int readonly)
 320 {
 321         gnttab_shared.v2[ref].hdr.flags = 0;
 322         mb();   /* Concurrent access by hypervisor. */
 323         if (grstatus[ref] & (GTF_reading|GTF_writing)) {
 324                 return 0;
 325         } else {
 326                 /*
 327                  * The read of grstatus needs to have acquire semantics.
 328                  *  On x86, reads already have that, and we just need to
 329                  * protect against compiler reorderings.
 330                  * On other architectures we may need a full barrier.
 331                  */
 332 #ifdef CONFIG_X86
 333                 barrier();
 334 #else
 335                 mb();
 336 #endif
 337         }
 338
 339         return 1;
 340 }
 341
 342 static inline int _gnttab_end_foreign_access_ref(grant_ref_t ref, int readonly)
 343 {
 344         return gnttab_interface->end_foreign_access_ref(ref, readonly);
 345 }
 346
 347 int gnttab_end_foreign_access_ref(grant_ref_t ref, int readonly)
 348 {
 349         if (_gnttab_end_foreign_access_ref(ref, readonly))
 350                 return 1;
 351         pr_warn("WARNING: g.e. %#x still in use!\n", ref);
 352         return 0;
 353 }
 354 EXPORT_SYMBOL_GPL(gnttab_end_foreign_access_ref);
 355
 356 struct deferred_entry {
 357         struct list_head list;
 358         grant_ref_t ref;
 359         bool ro;
 360         uint16_t warn_delay;
 361         struct page *page;
 362 };
 363 static LIST_HEAD(deferred_list);
 364 static void gnttab_handle_deferred(struct timer_list *);
 365 static DEFINE_TIMER(deferred_timer, gnttab_handle_deferred);
 366
 367 static void gnttab_handle_deferred(struct timer_list *unused)
 368 {
 369         unsigned int nr = 10;
 370         struct deferred_entry *first = NULL;
 371         unsigned long flags;
 372
 373         spin_lock_irqsave(&gnttab_list_lock, flags);
 374         while (nr--) {
 375                 struct deferred_entry *entry
 376                         = list_first_entry(&deferred_list,
 377                                            struct deferred_entry, list);
 378
 379                 if (entry == first)
 380                         break;
 381                 list_del(&entry->list);
 382                 spin_unlock_irqrestore(&gnttab_list_lock, flags);
 383                 if (_gnttab_end_foreign_access_ref(entry->ref, entry->ro)) {
 384                         put_free_entry(entry->ref);
 385                         if (entry->page) {
 386                                 pr_debug("freeing g.e. %#x (pfn %#lx)\n",
 387                                          entry->ref, page_to_pfn(entry->page));
 388                                 put_page(entry->page);
 389                         } else
 390                                 pr_info("freeing g.e. %#x\n", entry->ref);
 391                         kfree(entry);
 392                         entry = NULL;
 393                 } else {
 394                         if (!--entry->warn_delay)
 395                                 pr_info("g.e. %#x still pending\n", entry->ref);
 396                         if (!first)
 397                                 first = entry;
 398                 }
 399                 spin_lock_irqsave(&gnttab_list_lock, flags);
 400                 if (entry)
 401                         list_add_tail(&entry->list, &deferred_list);
 402                 else if (list_empty(&deferred_list))
 403                         break;
 404         }
 405         if (!list_empty(&deferred_list) && !timer_pending(&deferred_timer)) {
 406                 deferred_timer.expires = jiffies + HZ;
 407                 add_timer(&deferred_timer);
 408         }
 409         spin_unlock_irqrestore(&gnttab_list_lock, flags);
 410 }
 411
 412 static void gnttab_add_deferred(grant_ref_t ref, bool readonly,
 413                                 struct page *page)
 414 {
 415         struct deferred_entry *entry = kmalloc(sizeof(*entry), GFP_ATOMIC);
 416         const char *what = KERN_WARNING "leaking";
 417
 418         if (entry) {
 419                 unsigned long flags;
 420
 421                 entry->ref = ref;
 422                 entry->ro = readonly;
 423                 entry->page = page;
 424                 entry->warn_delay = 60;
 425                 spin_lock_irqsave(&gnttab_list_lock, flags);
 426                 list_add_tail(&entry->list, &deferred_list);
 427                 if (!timer_pending(&deferred_timer)) {
 428                         deferred_timer.expires = jiffies + HZ;
 429                         add_timer(&deferred_timer);
 430                 }
 431                 spin_unlock_irqrestore(&gnttab_list_lock, flags);
 432                 what = KERN_DEBUG "deferring";
 433         }
 434         printk("%s g.e. %#x (pfn %#lx)\n",
 435                what, ref, page ? page_to_pfn(page) : -1);
 436 }
 437
 438 void gnttab_end_foreign_access(grant_ref_t ref, int readonly,
 439                                unsigned long page)
 440 {
 441         if (gnttab_end_foreign_access_ref(ref, readonly)) {
 442                 put_free_entry(ref);
 443                 if (page != 0)
 444                         put_page(virt_to_page(page));
 445         } else
 446                 gnttab_add_deferred(ref, readonly,
 447                                     page ? virt_to_page(page) : NULL);
 448 }
 449 EXPORT_SYMBOL_GPL(gnttab_end_foreign_access);
 450
 451 int gnttab_grant_foreign_transfer(domid_t domid, unsigned long pfn)
 452 {
 453         int ref;
 454
 455         ref = get_free_entries(1);
 456         if (unlikely(ref < 0))
 457                 return -ENOSPC;
 458         gnttab_grant_foreign_transfer_ref(ref, domid, pfn);
 459
 460         return ref;
 461 }
 462 EXPORT_SYMBOL_GPL(gnttab_grant_foreign_transfer);
 463
 464 void gnttab_grant_foreign_transfer_ref(grant_ref_t ref, domid_t domid,
 465                                        unsigned long pfn)
 466 {
 467         gnttab_interface->update_entry(ref, domid, pfn, GTF_accept_transfer);
 468 }
 469 EXPORT_SYMBOL_GPL(gnttab_grant_foreign_transfer_ref);
 470
 471 static unsigned long gnttab_end_foreign_transfer_ref_v1(grant_ref_t ref)
 472 {
 473         unsigned long frame;
 474         u16           flags;
 475         u16          *pflags;
 476
 477         pflags = &gnttab_shared.v1[ref].flags;
 478
 479         /*
 480          * If a transfer is not even yet started, try to reclaim the grant
 481          * reference and return failure (== 0).
 482          */
 483         while (!((flags = *pflags) & GTF_transfer_committed)) {
 484                 if (sync_cmpxchg(pflags, flags, 0) == flags)
 485                         return 0;
 486                 cpu_relax();
 487         }
 488
 489         /* If a transfer is in progress then wait until it is completed. */
 490         while (!(flags & GTF_transfer_completed)) {
 491                 flags = *pflags;
 492                 cpu_relax();
 493         }
 494
 495         rmb();  /* Read the frame number /after/ reading completion status. */
 496         frame = gnttab_shared.v1[ref].frame;
 497         BUG_ON(frame == 0);
 498
 499         return frame;
 500 }
 501
 502 static unsigned long gnttab_end_foreign_transfer_ref_v2(grant_ref_t ref)
 503 {
 504         unsigned long frame;
 505         u16           flags;
 506         u16          *pflags;
 507
 508         pflags = &gnttab_shared.v2[ref].hdr.flags;
 509
 510         /*
 511          * If a transfer is not even yet started, try to reclaim the grant
 512          * reference and return failure (== 0).
 513          */
 514         while (!((flags = *pflags) & GTF_transfer_committed)) {
 515                 if (sync_cmpxchg(pflags, flags, 0) == flags)
 516                         return 0;
 517                 cpu_relax();
 518         }
 519
 520         /* If a transfer is in progress then wait until it is completed. */
 521         while (!(flags & GTF_transfer_completed)) {
 522                 flags = *pflags;
 523                 cpu_relax();
 524         }
 525
 526         rmb();  /* Read the frame number /after/ reading completion status. */
 527         frame = gnttab_shared.v2[ref].full_page.frame;
 528         BUG_ON(frame == 0);
 529
 530         return frame;
 531 }
 532
 533 unsigned long gnttab_end_foreign_transfer_ref(grant_ref_t ref)
 534 {
 535         return gnttab_interface->end_foreign_transfer_ref(ref);
 536 }
 537 EXPORT_SYMBOL_GPL(gnttab_end_foreign_transfer_ref);
 538
 539 unsigned long gnttab_end_foreign_transfer(grant_ref_t ref)
 540 {
 541         unsigned long frame = gnttab_end_foreign_transfer_ref(ref);
 542         put_free_entry(ref);
 543         return frame;
 544 }
 545 EXPORT_SYMBOL_GPL(gnttab_end_foreign_transfer);
 546
 547 void gnttab_free_grant_reference(grant_ref_t ref)
 548 {
 549         put_free_entry(ref);
 550 }
 551 EXPORT_SYMBOL_GPL(gnttab_free_grant_reference);
 552
 553 void gnttab_free_grant_references(grant_ref_t head)
 554 {
 555         grant_ref_t ref;
 556         unsigned long flags;
 557         int count = 1;
 558         if (head == GNTTAB_LIST_END)
 559                 return;
 560         spin_lock_irqsave(&gnttab_list_lock, flags);
 561         ref = head;
 562         while (gnttab_entry(ref) != GNTTAB_LIST_END) {
 563                 ref = gnttab_entry(ref);
 564                 count++;
 565         }
 566         gnttab_entry(ref) = gnttab_free_head;
 567         gnttab_free_head = head;
 568         gnttab_free_count += count;
 569         check_free_callbacks();
 570         spin_unlock_irqrestore(&gnttab_list_lock, flags);
 571 }
 572 EXPORT_SYMBOL_GPL(gnttab_free_grant_references);
 573
 574 int gnttab_alloc_grant_references(u16 count, grant_ref_t *head)
 575 {
 576         int h = get_free_entries(count);
 577
 578         if (h < 0)
 579                 return -ENOSPC;
 580
 581         *head = h;
 582
 583         return 0;
 584 }
 585 EXPORT_SYMBOL_GPL(gnttab_alloc_grant_references);
 586
 587 int gnttab_empty_grant_references(const grant_ref_t *private_head)
 588 {
 589         return (*private_head == GNTTAB_LIST_END);
 590 }
 591 EXPORT_SYMBOL_GPL(gnttab_empty_grant_references);
 592
 593 int gnttab_claim_grant_reference(grant_ref_t *private_head)
 594 {
 595         grant_ref_t g = *private_head;
 596         if (unlikely(g == GNTTAB_LIST_END))
 597                 return -ENOSPC;
 598         *private_head = gnttab_entry(g);
 599         return g;
 600 }
 601 EXPORT_SYMBOL_GPL(gnttab_claim_grant_reference);
 602
 603 void gnttab_release_grant_reference(grant_ref_t *private_head,
 604                                     grant_ref_t release)
 605 {
 606         gnttab_entry(release) = *private_head;
 607         *private_head = release;
 608 }
 609 EXPORT_SYMBOL_GPL(gnttab_release_grant_reference);
 610
 611 void gnttab_request_free_callback(struct gnttab_free_callback *callback,
 612                                   void (*fn)(void *), void *arg, u16 count)
 613 {
 614         unsigned long flags;
 615         struct gnttab_free_callback *cb;
 616
 617         spin_lock_irqsave(&gnttab_list_lock, flags);
 618
 619         /* Check if the callback is already on the list */
 620         cb = gnttab_free_callback_list;
 621         while (cb) {
 622                 if (cb == callback)
 623                         goto out;
 624                 cb = cb->next;
 625         }
 626
 627         callback->fn = fn;
 628         callback->arg = arg;
 629         callback->count = count;
 630         callback->next = gnttab_free_callback_list;
 631         gnttab_free_callback_list = callback;
 632         check_free_callbacks();
 633 out:
 634         spin_unlock_irqrestore(&gnttab_list_lock, flags);
 635 }
 636 EXPORT_SYMBOL_GPL(gnttab_request_free_callback);
 637
 638 void gnttab_cancel_free_callback(struct gnttab_free_callback *callback)
 639 {
 640         struct gnttab_free_callback **pcb;
 641         unsigned long flags;
 642
 643         spin_lock_irqsave(&gnttab_list_lock, flags);
 644         for (pcb = &gnttab_free_callback_list; *pcb; pcb = &(*pcb)->next) {
 645                 if (*pcb == callback) {
 646                         *pcb = callback->next;
 647                         break;
 648                 }
 649         }
 650         spin_unlock_irqrestore(&gnttab_list_lock, flags);
 651 }
 652 EXPORT_SYMBOL_GPL(gnttab_cancel_free_callback);
 653
 654 static unsigned int gnttab_frames(unsigned int frames, unsigned int align)
 655 {
 656         return (frames * gnttab_interface->grefs_per_grant_frame + align - 1) /
 657                align;
 658 }
 659
 660 static int grow_gnttab_list(unsigned int more_frames)
 661 {
 662         unsigned int new_nr_grant_frames, extra_entries, i;
 663         unsigned int nr_glist_frames, new_nr_glist_frames;
 664         unsigned int grefs_per_frame;
 665
 666         grefs_per_frame = gnttab_interface->grefs_per_grant_frame;
 667
 668         new_nr_grant_frames = nr_grant_frames + more_frames;
 669         extra_entries = more_frames * grefs_per_frame;
 670
 671         nr_glist_frames = gnttab_frames(nr_grant_frames, RPP);
 672         new_nr_glist_frames = gnttab_frames(new_nr_grant_frames, RPP);
 673         for (i = nr_glist_frames; i < new_nr_glist_frames; i++) {
 674                 gnttab_list[i] = (grant_ref_t *)__get_free_page(GFP_ATOMIC);
 675                 if (!gnttab_list[i])
 676                         goto grow_nomem;
 677         }
 678
 679
 680         for (i = grefs_per_frame * nr_grant_frames;
 681              i < grefs_per_frame * new_nr_grant_frames - 1; i++)
 682                 gnttab_entry(i) = i + 1;
 683
 684         gnttab_entry(i) = gnttab_free_head;
 685         gnttab_free_head = grefs_per_frame * nr_grant_frames;
 686         gnttab_free_count += extra_entries;
 687
 688         nr_grant_frames = new_nr_grant_frames;
 689
 690         check_free_callbacks();
 691
 692         return 0;
 693
 694 grow_nomem:
 695         while (i-- > nr_glist_frames)
 696                 free_page((unsigned long) gnttab_list[i]);
 697         return -ENOMEM;
 698 }
 699
 700 static unsigned int __max_nr_grant_frames(void)
 701 {
 702         struct gnttab_query_size query;
 703         int rc;
 704
 705         query.dom = DOMID_SELF;
 706
 707         rc = HYPERVISOR_grant_table_op(GNTTABOP_query_size, &query, 1);
 708         if ((rc < 0) || (query.status != GNTST_okay))
 709                 return 4; /* Legacy max supported number of frames */
 710
 711         return query.max_nr_frames;
 712 }
 713
 714 unsigned int gnttab_max_grant_frames(void)
 715 {
 716         unsigned int xen_max = __max_nr_grant_frames();
 717         static unsigned int boot_max_nr_grant_frames;
 718
 719         /* First time, initialize it properly. */
 720         if (!boot_max_nr_grant_frames)
 721                 boot_max_nr_grant_frames = __max_nr_grant_frames();
 722
 723         if (xen_max > boot_max_nr_grant_frames)
 724                 return boot_max_nr_grant_frames;
 725         return xen_max;
 726 }
 727 EXPORT_SYMBOL_GPL(gnttab_max_grant_frames);
 728
 729 int gnttab_setup_auto_xlat_frames(phys_addr_t addr)
 730 {
 731         xen_pfn_t *pfn;
 732         unsigned int max_nr_gframes = __max_nr_grant_frames();
 733         unsigned int i;
 734         void *vaddr;
 735
 736         if (xen_auto_xlat_grant_frames.count)
 737                 return -EINVAL;
 738
 739         vaddr = xen_remap(addr, XEN_PAGE_SIZE * max_nr_gframes);
 740         if (vaddr == NULL) {
 741                 pr_warn("Failed to ioremap gnttab share frames (addr=%pa)!\n",
 742                         &addr);
 743                 return -ENOMEM;
 744         }
 745         pfn = kcalloc(max_nr_gframes, sizeof(pfn[0]), GFP_KERNEL);
 746         if (!pfn) {
 747                 xen_unmap(vaddr);
 748                 return -ENOMEM;
 749         }
 750         for (i = 0; i < max_nr_gframes; i++)
 751                 pfn[i] = XEN_PFN_DOWN(addr) + i;
 752
 753         xen_auto_xlat_grant_frames.vaddr = vaddr;
 754         xen_auto_xlat_grant_frames.pfn = pfn;
 755         xen_auto_xlat_grant_frames.count = max_nr_gframes;
 756
 757         return 0;
 758 }
 759 EXPORT_SYMBOL_GPL(gnttab_setup_auto_xlat_frames);
 760
 761 void gnttab_free_auto_xlat_frames(void)
 762 {
 763         if (!xen_auto_xlat_grant_frames.count)
 764                 return;
 765         kfree(xen_auto_xlat_grant_frames.pfn);
 766         xen_unmap(xen_auto_xlat_grant_frames.vaddr);
 767
 768         xen_auto_xlat_grant_frames.pfn = NULL;
 769         xen_auto_xlat_grant_frames.count = 0;
 770         xen_auto_xlat_grant_frames.vaddr = NULL;
 771 }
 772 EXPORT_SYMBOL_GPL(gnttab_free_auto_xlat_frames);
 773
 774 int gnttab_pages_set_private(int nr_pages, struct page **pages)
 775 {
 776         int i;
 777
 778         for (i = 0; i < nr_pages; i++) {
 779 #if BITS_PER_LONG < 64
 780                 struct xen_page_foreign *foreign;
 781
 782                 foreign = kzalloc(sizeof(*foreign), GFP_KERNEL);
 783                 if (!foreign)
 784                         return -ENOMEM;
 785
 786                 set_page_private(pages[i], (unsigned long)foreign);
 787 #endif
 788                 SetPagePrivate(pages[i]);
 789         }
 790
 791         return 0;
 792 }
 793 EXPORT_SYMBOL_GPL(gnttab_pages_set_private);
 794
 795 /**
 796  * gnttab_alloc_pages - alloc pages suitable for grant mapping into
 797  * @nr_pages: number of pages to alloc
 798  * @pages: returns the pages
 799  */
 800 int gnttab_alloc_pages(int nr_pages, struct page **pages)
 801 {
 802         int ret;
 803
 804         ret = xen_alloc_unpopulated_pages(nr_pages, pages);
 805         if (ret < 0)
 806                 return ret;
 807
 808         ret = gnttab_pages_set_private(nr_pages, pages);
 809         if (ret < 0)
 810                 gnttab_free_pages(nr_pages, pages);
 811
 812         return ret;
 813 }
 814 EXPORT_SYMBOL_GPL(gnttab_alloc_pages);
 815
 816 void gnttab_pages_clear_private(int nr_pages, struct page **pages)
 817 {
 818         int i;
 819
 820         for (i = 0; i < nr_pages; i++) {
 821                 if (PagePrivate(pages[i])) {
 822 #if BITS_PER_LONG < 64
 823                         kfree((void *)page_private(pages[i]));
 824 #endif
 825                         ClearPagePrivate(pages[i]);
 826                 }
 827         }
 828 }
 829 EXPORT_SYMBOL_GPL(gnttab_pages_clear_private);
 830
 831 /**
 832  * gnttab_free_pages - free pages allocated by gnttab_alloc_pages()
 833  * @nr_pages; number of pages to free
 834  * @pages: the pages
 835  */
 836 void gnttab_free_pages(int nr_pages, struct page **pages)
 837 {
 838         gnttab_pages_clear_private(nr_pages, pages);
 839         xen_free_unpopulated_pages(nr_pages, pages);
 840 }
 841 EXPORT_SYMBOL_GPL(gnttab_free_pages);
 842
 843 #ifdef CONFIG_XEN_GRANT_DMA_ALLOC
 844 /**
 845  * gnttab_dma_alloc_pages - alloc DMAable pages suitable for grant mapping into
 846  * @args: arguments to the function
 847  */
 848 int gnttab_dma_alloc_pages(struct gnttab_dma_alloc_args *args)
 849 {
 850         unsigned long pfn, start_pfn;
 851         size_t size;
 852         int i, ret;
 853
 854         size = args->nr_pages << PAGE_SHIFT;
 855         if (args->coherent)
 856                 args->vaddr = dma_alloc_coherent(args->dev, size,
 857                                                  &args->dev_bus_addr,
 858                                                  GFP_KERNEL | __GFP_NOWARN);
 859         else
 860                 args->vaddr = dma_alloc_wc(args->dev, size,
 861                                            &args->dev_bus_addr,
 862                                            GFP_KERNEL | __GFP_NOWARN);
 863         if (!args->vaddr) {
 864                 pr_debug("Failed to allocate DMA buffer of size %zu\n", size);
 865                 return -ENOMEM;
 866         }
 867
 868         start_pfn = __phys_to_pfn(args->dev_bus_addr);
 869         for (pfn = start_pfn, i = 0; pfn < start_pfn + args->nr_pages;
 870                         pfn++, i++) {
 871                 struct page *page = pfn_to_page(pfn);
 872
 873                 args->pages[i] = page;
 874                 args->frames[i] = xen_page_to_gfn(page);
 875                 xenmem_reservation_scrub_page(page);
 876         }
 877
 878         xenmem_reservation_va_mapping_reset(args->nr_pages, args->pages);
 879
 880         ret = xenmem_reservation_decrease(args->nr_pages, args->frames);
 881         if (ret != args->nr_pages) {
 882                 pr_debug("Failed to decrease reservation for DMA buffer\n");
 883                 ret = -EFAULT;
 884                 goto fail;
 885         }
 886
 887         ret = gnttab_pages_set_private(args->nr_pages, args->pages);
 888         if (ret < 0)
 889                 goto fail;
 890
 891         return 0;
 892
 893 fail:
 894         gnttab_dma_free_pages(args);
 895         return ret;
 896 }
 897 EXPORT_SYMBOL_GPL(gnttab_dma_alloc_pages);
 898
 899 /**
 900  * gnttab_dma_free_pages - free DMAable pages
 901  * @args: arguments to the function
 902  */
 903 int gnttab_dma_free_pages(struct gnttab_dma_alloc_args *args)
 904 {
 905         size_t size;
 906         int i, ret;
 907
 908         gnttab_pages_clear_private(args->nr_pages, args->pages);
 909
 910         for (i = 0; i < args->nr_pages; i++)
 911                 args->frames[i] = page_to_xen_pfn(args->pages[i]);
 912
 913         ret = xenmem_reservation_increase(args->nr_pages, args->frames);
 914         if (ret != args->nr_pages) {
 915                 pr_debug("Failed to increase reservation for DMA buffer\n");
 916                 ret = -EFAULT;
 917         } else {
 918                 ret = 0;
 919         }
 920
 921         xenmem_reservation_va_mapping_update(args->nr_pages, args->pages,
 922                                              args->frames);
 923
 924         size = args->nr_pages << PAGE_SHIFT;
 925         if (args->coherent)
 926                 dma_free_coherent(args->dev, size,
 927                                   args->vaddr, args->dev_bus_addr);
 928         else
 929                 dma_free_wc(args->dev, size,
 930                             args->vaddr, args->dev_bus_addr);
 931         return ret;
 932 }
 933 EXPORT_SYMBOL_GPL(gnttab_dma_free_pages);
 934 #endif
 935
 936 /* Handling of paged out grant targets (GNTST_eagain) */
 937 #define MAX_DELAY 256
 938 static inline void
 939 gnttab_retry_eagain_gop(unsigned int cmd, void *gop, int16_t *status,
 940                                                 const char *func)
 941 {
 942         unsigned delay = 1;
 943
 944         do {
 945                 BUG_ON(HYPERVISOR_grant_table_op(cmd, gop, 1));
 946                 if (*status == GNTST_eagain)
 947                         msleep(delay++);
 948         } while ((*status == GNTST_eagain) && (delay < MAX_DELAY));
 949
 950         if (delay >= MAX_DELAY) {
 951                 pr_err("%s: %s eagain grant\n", func, current->comm);
 952                 *status = GNTST_bad_page;
 953         }
 954 }
 955
 956 void gnttab_batch_map(struct gnttab_map_grant_ref *batch, unsigned count)
 957 {
 958         struct gnttab_map_grant_ref *op;
 959
 960         if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, batch, count))
 961                 BUG();
 962         for (op = batch; op < batch + count; op++)
 963                 if (op->status == GNTST_eagain)
 964                         gnttab_retry_eagain_gop(GNTTABOP_map_grant_ref, op,
 965                                                 &op->status, __func__);
 966 }
 967 EXPORT_SYMBOL_GPL(gnttab_batch_map);
 968
 969 void gnttab_batch_copy(struct gnttab_copy *batch, unsigned count)
 970 {
 971         struct gnttab_copy *op;
 972
 973         if (HYPERVISOR_grant_table_op(GNTTABOP_copy, batch, count))
 974                 BUG();
 975         for (op = batch; op < batch + count; op++)
 976                 if (op->status == GNTST_eagain)
 977                         gnttab_retry_eagain_gop(GNTTABOP_copy, op,
 978                                                 &op->status, __func__);
 979 }
 980 EXPORT_SYMBOL_GPL(gnttab_batch_copy);
 981
 982 void gnttab_foreach_grant_in_range(struct page *page,
 983                                    unsigned int offset,
 984                                    unsigned int len,
 985                                    xen_grant_fn_t fn,
 986                                    void *data)
 987 {
 988         unsigned int goffset;
 989         unsigned int glen;
 990         unsigned long xen_pfn;
 991
 992         len = min_t(unsigned int, PAGE_SIZE - offset, len);
 993         goffset = xen_offset_in_page(offset);
 994
 995         xen_pfn = page_to_xen_pfn(page) + XEN_PFN_DOWN(offset);
 996
 997         while (len) {
 998                 glen = min_t(unsigned int, XEN_PAGE_SIZE - goffset, len);
 999                 fn(pfn_to_gfn(xen_pfn), goffset, glen, data);
1000
1001                 goffset = 0;
1002                 xen_pfn++;
1003                 len -= glen;
1004         }
1005 }
1006 EXPORT_SYMBOL_GPL(gnttab_foreach_grant_in_range);
1007
1008 void gnttab_foreach_grant(struct page **pages,
1009                           unsigned int nr_grefs,
1010                           xen_grant_fn_t fn,
1011                           void *data)
1012 {
1013         unsigned int goffset = 0;
1014         unsigned long xen_pfn = 0;
1015         unsigned int i;
1016
1017         for (i = 0; i < nr_grefs; i++) {
1018                 if ((i % XEN_PFN_PER_PAGE) == 0) {
1019                         xen_pfn = page_to_xen_pfn(pages[i / XEN_PFN_PER_PAGE]);
1020                         goffset = 0;
1021                 }
1022
1023                 fn(pfn_to_gfn(xen_pfn), goffset, XEN_PAGE_SIZE, data);
1024
1025                 goffset += XEN_PAGE_SIZE;
1026                 xen_pfn++;
1027         }
1028 }
1029
1030 int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
1031                     struct gnttab_map_grant_ref *kmap_ops,
1032                     struct page **pages, unsigned int count)
1033 {
1034         int i, ret;
1035
1036         ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, map_ops, count);
1037         if (ret)
1038                 return ret;
1039
1040         for (i = 0; i < count; i++) {
1041                 switch (map_ops[i].status) {
1042                 case GNTST_okay:
1043                 {
1044                         struct xen_page_foreign *foreign;
1045
1046                         SetPageForeign(pages[i]);
1047                         foreign = xen_page_foreign(pages[i]);
1048                         foreign->domid = map_ops[i].dom;
1049                         foreign->gref = map_ops[i].ref;
1050                         break;
1051                 }
1052
1053                 case GNTST_no_device_space:
1054                         pr_warn_ratelimited("maptrack limit reached, can't map all guest pages\n");
1055                         break;
1056
1057                 case GNTST_eagain:
1058                         /* Retry eagain maps */
1059                         gnttab_retry_eagain_gop(GNTTABOP_map_grant_ref,
1060                                                 map_ops + i,
1061                                                 &map_ops[i].status, __func__);
1062                         /* Test status in next loop iteration. */
1063                         i--;
1064                         break;
1065
1066                 default:
1067                         break;
1068                 }
1069         }
1070
1071         return set_foreign_p2m_mapping(map_ops, kmap_ops, pages, count);
1072 }
1073 EXPORT_SYMBOL_GPL(gnttab_map_refs);
1074
1075 int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
1076                       struct gnttab_unmap_grant_ref *kunmap_ops,
1077                       struct page **pages, unsigned int count)
1078 {
1079         unsigned int i;
1080         int ret;
1081
1082         ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap_ops, count);
1083         if (ret)
1084                 return ret;
1085
1086         for (i = 0; i < count; i++)
1087                 ClearPageForeign(pages[i]);
1088
1089         return clear_foreign_p2m_mapping(unmap_ops, kunmap_ops, pages, count);
1090 }
1091 EXPORT_SYMBOL_GPL(gnttab_unmap_refs);
1092
1093 #define GNTTAB_UNMAP_REFS_DELAY 5
1094
1095 static void __gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item);
1096
1097 static void gnttab_unmap_work(struct work_struct *work)
1098 {
1099         struct gntab_unmap_queue_data
1100                 *unmap_data = container_of(work,
1101                                            struct gntab_unmap_queue_data,
1102                                            gnttab_work.work);
1103         if (unmap_data->age != UINT_MAX)
1104                 unmap_data->age++;
1105         __gnttab_unmap_refs_async(unmap_data);
1106 }
1107
1108 static void __gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item)
1109 {
1110         int ret;
1111         int pc;
1112
1113         for (pc = 0; pc < item->count; pc++) {
1114                 if (page_count(item->pages[pc]) > 1) {
1115                         unsigned long delay = GNTTAB_UNMAP_REFS_DELAY * (item->age + 1);
1116                         schedule_delayed_work(&item->gnttab_work,
1117                                               msecs_to_jiffies(delay));
1118                         return;
1119                 }
1120         }
1121
1122         ret = gnttab_unmap_refs(item->unmap_ops, item->kunmap_ops,
1123                                 item->pages, item->count);
1124         item->done(ret, item);
1125 }
1126
1127 void gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item)
1128 {
1129         INIT_DELAYED_WORK(&item->gnttab_work, gnttab_unmap_work);
1130         item->age = 0;
1131
1132         __gnttab_unmap_refs_async(item);
1133 }
1134 EXPORT_SYMBOL_GPL(gnttab_unmap_refs_async);
1135
1136 static void unmap_refs_callback(int result,
1137                 struct gntab_unmap_queue_data *data)
1138 {
1139         struct unmap_refs_callback_data *d = data->data;
1140
1141         d->result = result;
1142         complete(&d->completion);
1143 }
1144
1145 int gnttab_unmap_refs_sync(struct gntab_unmap_queue_data *item)
1146 {
1147         struct unmap_refs_callback_data data;
1148
1149         init_completion(&data.completion);
1150         item->data = &data;
1151         item->done = &unmap_refs_callback;
1152         gnttab_unmap_refs_async(item);
1153         wait_for_completion(&data.completion);
1154
1155         return data.result;
1156 }
1157 EXPORT_SYMBOL_GPL(gnttab_unmap_refs_sync);
1158
1159 static unsigned int nr_status_frames(unsigned int nr_grant_frames)
1160 {
1161         return gnttab_frames(nr_grant_frames, SPP);
1162 }
1163
1164 static int gnttab_map_frames_v1(xen_pfn_t *frames, unsigned int nr_gframes)
1165 {
1166         int rc;
1167
1168         rc = arch_gnttab_map_shared(frames, nr_gframes,
1169                                     gnttab_max_grant_frames(),
1170                                     &gnttab_shared.addr);
1171         BUG_ON(rc);
1172
1173         return 0;
1174 }
1175
1176 static void gnttab_unmap_frames_v1(void)
1177 {
1178         arch_gnttab_unmap(gnttab_shared.addr, nr_grant_frames);
1179 }
1180
1181 static int gnttab_map_frames_v2(xen_pfn_t *frames, unsigned int nr_gframes)
1182 {
1183         uint64_t *sframes;
1184         unsigned int nr_sframes;
1185         struct gnttab_get_status_frames getframes;
1186         int rc;
1187
1188         nr_sframes = nr_status_frames(nr_gframes);
1189
1190         /* No need for kzalloc as it is initialized in following hypercall
1191          * GNTTABOP_get_status_frames.
1192          */
1193         sframes = kmalloc_array(nr_sframes, sizeof(uint64_t), GFP_ATOMIC);
1194         if (!sframes)
1195                 return -ENOMEM;
1196
1197         getframes.dom        = DOMID_SELF;
1198         getframes.nr_frames  = nr_sframes;
1199         set_xen_guest_handle(getframes.frame_list, sframes);
1200
1201         rc = HYPERVISOR_grant_table_op(GNTTABOP_get_status_frames,
1202                                        &getframes, 1);
1203         if (rc == -ENOSYS) {
1204                 kfree(sframes);
1205                 return -ENOSYS;
1206         }
1207
1208         BUG_ON(rc || getframes.status);
1209
1210         rc = arch_gnttab_map_status(sframes, nr_sframes,
1211                                     nr_status_frames(gnttab_max_grant_frames()),
1212                                     &grstatus);
1213         BUG_ON(rc);
1214         kfree(sframes);
1215
1216         rc = arch_gnttab_map_shared(frames, nr_gframes,
1217                                     gnttab_max_grant_frames(),
1218                                     &gnttab_shared.addr);
1219         BUG_ON(rc);
1220
1221         return 0;
1222 }
1223
1224 static void gnttab_unmap_frames_v2(void)
1225 {
1226         arch_gnttab_unmap(gnttab_shared.addr, nr_grant_frames);
1227         arch_gnttab_unmap(grstatus, nr_status_frames(nr_grant_frames));
1228 }
1229
1230 static int gnttab_map(unsigned int start_idx, unsigned int end_idx)
1231 {
1232         struct gnttab_setup_table setup;
1233         xen_pfn_t *frames;
1234         unsigned int nr_gframes = end_idx + 1;
1235         int rc;
1236
1237         if (xen_feature(XENFEAT_auto_translated_physmap)) {
1238                 struct xen_add_to_physmap xatp;
1239                 unsigned int i = end_idx;
1240                 rc = 0;
1241                 BUG_ON(xen_auto_xlat_grant_frames.count < nr_gframes);
1242                 /*
1243                  * Loop backwards, so that the first hypercall has the largest
1244                  * index, ensuring that the table will grow only once.
1245                  */
1246                 do {
1247                         xatp.domid = DOMID_SELF;
1248                         xatp.idx = i;
1249                         xatp.space = XENMAPSPACE_grant_table;
1250                         xatp.gpfn = xen_auto_xlat_grant_frames.pfn[i];
1251                         rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp);
1252                         if (rc != 0) {
1253                                 pr_warn("grant table add_to_physmap failed, err=%d\n",
1254                                         rc);
1255                                 break;
1256                         }
1257                 } while (i-- > start_idx);
1258
1259                 return rc;
1260         }
1261
1262         /* No need for kzalloc as it is initialized in following hypercall
1263          * GNTTABOP_setup_table.
1264          */
1265         frames = kmalloc_array(nr_gframes, sizeof(unsigned long), GFP_ATOMIC);
1266         if (!frames)
1267                 return -ENOMEM;
1268
1269         setup.dom        = DOMID_SELF;
1270         setup.nr_frames  = nr_gframes;
1271         set_xen_guest_handle(setup.frame_list, frames);
1272
1273         rc = HYPERVISOR_grant_table_op(GNTTABOP_setup_table, &setup, 1);
1274         if (rc == -ENOSYS) {
1275                 kfree(frames);
1276                 return -ENOSYS;
1277         }
1278
1279         BUG_ON(rc || setup.status);
1280
1281         rc = gnttab_interface->map_frames(frames, nr_gframes);
1282
1283         kfree(frames);
1284
1285         return rc;
1286 }
1287
1288 static const struct gnttab_ops gnttab_v1_ops = {
1289         .version                        = 1,
1290         .grefs_per_grant_frame          = XEN_PAGE_SIZE /
1291                                           sizeof(struct grant_entry_v1),
1292         .map_frames                     = gnttab_map_frames_v1,
1293         .unmap_frames                   = gnttab_unmap_frames_v1,
1294         .update_entry                   = gnttab_update_entry_v1,
1295         .end_foreign_access_ref         = gnttab_end_foreign_access_ref_v1,
1296         .end_foreign_transfer_ref       = gnttab_end_foreign_transfer_ref_v1,
1297         .query_foreign_access           = gnttab_query_foreign_access_v1,
1298 };
1299
1300 static const struct gnttab_ops gnttab_v2_ops = {
1301         .version                        = 2,
1302         .grefs_per_grant_frame          = XEN_PAGE_SIZE /
1303                                           sizeof(union grant_entry_v2),
1304         .map_frames                     = gnttab_map_frames_v2,
1305         .unmap_frames                   = gnttab_unmap_frames_v2,
1306         .update_entry                   = gnttab_update_entry_v2,
1307         .end_foreign_access_ref         = gnttab_end_foreign_access_ref_v2,
1308         .end_foreign_transfer_ref       = gnttab_end_foreign_transfer_ref_v2,
1309         .query_foreign_access           = gnttab_query_foreign_access_v2,
1310 };
1311
1312 static bool gnttab_need_v2(void)
1313 {
1314 #ifdef CONFIG_X86
1315         uint32_t base, width;
1316
1317         if (xen_pv_domain()) {
1318                 base = xen_cpuid_base();
1319                 if (cpuid_eax(base) < 5)
1320                         return false;   /* Information not available, use V1. */
1321                 width = cpuid_ebx(base + 5) &
1322                         XEN_CPUID_MACHINE_ADDRESS_WIDTH_MASK;
1323                 return width > 32 + PAGE_SHIFT;
1324         }
1325 #endif
1326         return !!(max_possible_pfn >> 32);
1327 }
1328
1329 static void gnttab_request_version(void)
1330 {
1331         long rc;
1332         struct gnttab_set_version gsv;
1333
1334         if (gnttab_need_v2())
1335                 gsv.version = 2;
1336         else
1337                 gsv.version = 1;
1338
1339         /* Boot parameter overrides automatic selection. */
1340         if (xen_gnttab_version >= 1 && xen_gnttab_version <= 2)
1341                 gsv.version = xen_gnttab_version;
1342
1343         rc = HYPERVISOR_grant_table_op(GNTTABOP_set_version, &gsv, 1);
1344         if (rc == 0 && gsv.version == 2)
1345                 gnttab_interface = &gnttab_v2_ops;
1346         else
1347                 gnttab_interface = &gnttab_v1_ops;
1348         pr_info("Grant tables using version %d layout\n",
1349                 gnttab_interface->version);
1350 }
1351
1352 static int gnttab_setup(void)
1353 {
1354         unsigned int max_nr_gframes;
1355
1356         max_nr_gframes = gnttab_max_grant_frames();
1357         if (max_nr_gframes < nr_grant_frames)
1358                 return -ENOSYS;
1359
1360         if (xen_feature(XENFEAT_auto_translated_physmap) && gnttab_shared.addr == NULL) {
1361                 gnttab_shared.addr = xen_auto_xlat_grant_frames.vaddr;
1362                 if (gnttab_shared.addr == NULL) {
1363                         pr_warn("gnttab share frames is not mapped!\n");
1364                         return -ENOMEM;
1365                 }
1366         }
1367         return gnttab_map(0, nr_grant_frames - 1);
1368 }
1369
1370 int gnttab_resume(void)
1371 {
1372         gnttab_request_version();
1373         return gnttab_setup();
1374 }
1375
1376 int gnttab_suspend(void)
1377 {
1378         if (!xen_feature(XENFEAT_auto_translated_physmap))
1379                 gnttab_interface->unmap_frames();
1380         return 0;
1381 }
1382
1383 static int gnttab_expand(unsigned int req_entries)
1384 {
1385         int rc;
1386         unsigned int cur, extra;
1387
1388         cur = nr_grant_frames;
1389         extra = ((req_entries + gnttab_interface->grefs_per_grant_frame - 1) /
1390                  gnttab_interface->grefs_per_grant_frame);
1391         if (cur + extra > gnttab_max_grant_frames()) {
1392                 pr_warn_ratelimited("xen/grant-table: max_grant_frames reached"
1393                                     " cur=%u extra=%u limit=%u"
1394                                     " gnttab_free_count=%u req_entries=%u\n",
1395                                     cur, extra, gnttab_max_grant_frames(),
1396                                     gnttab_free_count, req_entries);
1397                 return -ENOSPC;
1398         }
1399
1400         rc = gnttab_map(cur, cur + extra - 1);
1401         if (rc == 0)
1402                 rc = grow_gnttab_list(extra);
1403
1404         return rc;
1405 }
1406
1407 int gnttab_init(void)
1408 {
1409         int i;
1410         unsigned long max_nr_grant_frames;
1411         unsigned int max_nr_glist_frames, nr_glist_frames;
1412         unsigned int nr_init_grefs;
1413         int ret;
1414
1415         gnttab_request_version();
1416         max_nr_grant_frames = gnttab_max_grant_frames();
1417         nr_grant_frames = 1;
1418
1419         /* Determine the maximum number of frames required for the
1420          * grant reference free list on the current hypervisor.
1421          */
1422         max_nr_glist_frames = (max_nr_grant_frames *
1423                                gnttab_interface->grefs_per_grant_frame / RPP);
1424
1425         gnttab_list = kmalloc_array(max_nr_glist_frames,
1426                                     sizeof(grant_ref_t *),
1427                                     GFP_KERNEL);
1428         if (gnttab_list == NULL)
1429                 return -ENOMEM;
1430
1431         nr_glist_frames = gnttab_frames(nr_grant_frames, RPP);
1432         for (i = 0; i < nr_glist_frames; i++) {
1433                 gnttab_list[i] = (grant_ref_t *)__get_free_page(GFP_KERNEL);
1434                 if (gnttab_list[i] == NULL) {
1435                         ret = -ENOMEM;
1436                         goto ini_nomem;
1437                 }
1438         }
1439
1440         ret = arch_gnttab_init(max_nr_grant_frames,
1441                                nr_status_frames(max_nr_grant_frames));
1442         if (ret < 0)
1443                 goto ini_nomem;
1444
1445         if (gnttab_setup() < 0) {
1446                 ret = -ENODEV;
1447                 goto ini_nomem;
1448         }
1449
1450         nr_init_grefs = nr_grant_frames *
1451                         gnttab_interface->grefs_per_grant_frame;
1452
1453         for (i = NR_RESERVED_ENTRIES; i < nr_init_grefs - 1; i++)
1454                 gnttab_entry(i) = i + 1;
1455
1456         gnttab_entry(nr_init_grefs - 1) = GNTTAB_LIST_END;
1457         gnttab_free_count = nr_init_grefs - NR_RESERVED_ENTRIES;
1458         gnttab_free_head  = NR_RESERVED_ENTRIES;
1459
1460         printk("Grant table initialized\n");
1461         return 0;
1462
1463  ini_nomem:
1464         for (i--; i >= 0; i--)
1465                 free_page((unsigned long)gnttab_list[i]);
1466         kfree(gnttab_list);
1467         return ret;
1468 }
1469 EXPORT_SYMBOL_GPL(gnttab_init);
1470
1471 static int __gnttab_init(void)
1472 {
1473         if (!xen_domain())
1474                 return -ENODEV;
1475
1476         /* Delay grant-table initialization in the PV on HVM case */
1477         if (xen_hvm_domain() && !xen_pvh_domain())
1478                 return 0;
1479
1480         return gnttab_init();
1481 }
1482 /* Starts after core_initcall so that xen_pvh_gnttab_setup can be called
1483  * beforehand to initialize xen_auto_xlat_grant_frames. */
1484 core_initcall_sync(__gnttab_init);