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_page_cache_init(struct gnttab_page_cache *cache)
 817 {
 818         spin_lock_init(&cache->lock);
 819         INIT_LIST_HEAD(&cache->pages);
 820         cache->num_pages = 0;
 821 }
 822 EXPORT_SYMBOL_GPL(gnttab_page_cache_init);
 823
 824 int gnttab_page_cache_get(struct gnttab_page_cache *cache, struct page **page)
 825 {
 826         unsigned long flags;
 827
 828         spin_lock_irqsave(&cache->lock, flags);
 829
 830         if (list_empty(&cache->pages)) {
 831                 spin_unlock_irqrestore(&cache->lock, flags);
 832                 return gnttab_alloc_pages(1, page);
 833         }
 834
 835         page[0] = list_first_entry(&cache->pages, struct page, lru);
 836         list_del(&page[0]->lru);
 837         cache->num_pages--;
 838
 839         spin_unlock_irqrestore(&cache->lock, flags);
 840
 841         return 0;
 842 }
 843 EXPORT_SYMBOL_GPL(gnttab_page_cache_get);
 844
 845 void gnttab_page_cache_put(struct gnttab_page_cache *cache, struct page **page,
 846                            unsigned int num)
 847 {
 848         unsigned long flags;
 849         unsigned int i;
 850
 851         spin_lock_irqsave(&cache->lock, flags);
 852
 853         for (i = 0; i < num; i++)
 854                 list_add(&page[i]->lru, &cache->pages);
 855         cache->num_pages += num;
 856
 857         spin_unlock_irqrestore(&cache->lock, flags);
 858 }
 859 EXPORT_SYMBOL_GPL(gnttab_page_cache_put);
 860
 861 void gnttab_page_cache_shrink(struct gnttab_page_cache *cache, unsigned int num)
 862 {
 863         struct page *page[10];
 864         unsigned int i = 0;
 865         unsigned long flags;
 866
 867         spin_lock_irqsave(&cache->lock, flags);
 868
 869         while (cache->num_pages > num) {
 870                 page[i] = list_first_entry(&cache->pages, struct page, lru);
 871                 list_del(&page[i]->lru);
 872                 cache->num_pages--;
 873                 if (++i == ARRAY_SIZE(page)) {
 874                         spin_unlock_irqrestore(&cache->lock, flags);
 875                         gnttab_free_pages(i, page);
 876                         i = 0;
 877                         spin_lock_irqsave(&cache->lock, flags);
 878                 }
 879         }
 880
 881         spin_unlock_irqrestore(&cache->lock, flags);
 882
 883         if (i != 0)
 884                 gnttab_free_pages(i, page);
 885 }
 886 EXPORT_SYMBOL_GPL(gnttab_page_cache_shrink);
 887
 888 void gnttab_pages_clear_private(int nr_pages, struct page **pages)
 889 {
 890         int i;
 891
 892         for (i = 0; i < nr_pages; i++) {
 893                 if (PagePrivate(pages[i])) {
 894 #if BITS_PER_LONG < 64
 895                         kfree((void *)page_private(pages[i]));
 896 #endif
 897                         ClearPagePrivate(pages[i]);
 898                 }
 899         }
 900 }
 901 EXPORT_SYMBOL_GPL(gnttab_pages_clear_private);
 902
 903 /**
 904  * gnttab_free_pages - free pages allocated by gnttab_alloc_pages()
 905  * @nr_pages; number of pages to free
 906  * @pages: the pages
 907  */
 908 void gnttab_free_pages(int nr_pages, struct page **pages)
 909 {
 910         gnttab_pages_clear_private(nr_pages, pages);
 911         xen_free_unpopulated_pages(nr_pages, pages);
 912 }
 913 EXPORT_SYMBOL_GPL(gnttab_free_pages);
 914
 915 #ifdef CONFIG_XEN_GRANT_DMA_ALLOC
 916 /**
 917  * gnttab_dma_alloc_pages - alloc DMAable pages suitable for grant mapping into
 918  * @args: arguments to the function
 919  */
 920 int gnttab_dma_alloc_pages(struct gnttab_dma_alloc_args *args)
 921 {
 922         unsigned long pfn, start_pfn;
 923         size_t size;
 924         int i, ret;
 925
 926         size = args->nr_pages << PAGE_SHIFT;
 927         if (args->coherent)
 928                 args->vaddr = dma_alloc_coherent(args->dev, size,
 929                                                  &args->dev_bus_addr,
 930                                                  GFP_KERNEL | __GFP_NOWARN);
 931         else
 932                 args->vaddr = dma_alloc_wc(args->dev, size,
 933                                            &args->dev_bus_addr,
 934                                            GFP_KERNEL | __GFP_NOWARN);
 935         if (!args->vaddr) {
 936                 pr_debug("Failed to allocate DMA buffer of size %zu\n", size);
 937                 return -ENOMEM;
 938         }
 939
 940         start_pfn = __phys_to_pfn(args->dev_bus_addr);
 941         for (pfn = start_pfn, i = 0; pfn < start_pfn + args->nr_pages;
 942                         pfn++, i++) {
 943                 struct page *page = pfn_to_page(pfn);
 944
 945                 args->pages[i] = page;
 946                 args->frames[i] = xen_page_to_gfn(page);
 947                 xenmem_reservation_scrub_page(page);
 948         }
 949
 950         xenmem_reservation_va_mapping_reset(args->nr_pages, args->pages);
 951
 952         ret = xenmem_reservation_decrease(args->nr_pages, args->frames);
 953         if (ret != args->nr_pages) {
 954                 pr_debug("Failed to decrease reservation for DMA buffer\n");
 955                 ret = -EFAULT;
 956                 goto fail;
 957         }
 958
 959         ret = gnttab_pages_set_private(args->nr_pages, args->pages);
 960         if (ret < 0)
 961                 goto fail;
 962
 963         return 0;
 964
 965 fail:
 966         gnttab_dma_free_pages(args);
 967         return ret;
 968 }
 969 EXPORT_SYMBOL_GPL(gnttab_dma_alloc_pages);
 970
 971 /**
 972  * gnttab_dma_free_pages - free DMAable pages
 973  * @args: arguments to the function
 974  */
 975 int gnttab_dma_free_pages(struct gnttab_dma_alloc_args *args)
 976 {
 977         size_t size;
 978         int i, ret;
 979
 980         gnttab_pages_clear_private(args->nr_pages, args->pages);
 981
 982         for (i = 0; i < args->nr_pages; i++)
 983                 args->frames[i] = page_to_xen_pfn(args->pages[i]);
 984
 985         ret = xenmem_reservation_increase(args->nr_pages, args->frames);
 986         if (ret != args->nr_pages) {
 987                 pr_debug("Failed to increase reservation for DMA buffer\n");
 988                 ret = -EFAULT;
 989         } else {
 990                 ret = 0;
 991         }
 992
 993         xenmem_reservation_va_mapping_update(args->nr_pages, args->pages,
 994                                              args->frames);
 995
 996         size = args->nr_pages << PAGE_SHIFT;
 997         if (args->coherent)
 998                 dma_free_coherent(args->dev, size,
 999                                   args->vaddr, args->dev_bus_addr);
1000         else
1001                 dma_free_wc(args->dev, size,
1002                             args->vaddr, args->dev_bus_addr);
1003         return ret;
1004 }
1005 EXPORT_SYMBOL_GPL(gnttab_dma_free_pages);
1006 #endif
1007
1008 /* Handling of paged out grant targets (GNTST_eagain) */
1009 #define MAX_DELAY 256
1010 static inline void
1011 gnttab_retry_eagain_gop(unsigned int cmd, void *gop, int16_t *status,
1012                                                 const char *func)
1013 {
1014         unsigned delay = 1;
1015
1016         do {
1017                 BUG_ON(HYPERVISOR_grant_table_op(cmd, gop, 1));
1018                 if (*status == GNTST_eagain)
1019                         msleep(delay++);
1020         } while ((*status == GNTST_eagain) && (delay < MAX_DELAY));
1021
1022         if (delay >= MAX_DELAY) {
1023                 pr_err("%s: %s eagain grant\n", func, current->comm);
1024                 *status = GNTST_bad_page;
1025         }
1026 }
1027
1028 void gnttab_batch_map(struct gnttab_map_grant_ref *batch, unsigned count)
1029 {
1030         struct gnttab_map_grant_ref *op;
1031
1032         if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, batch, count))
1033                 BUG();
1034         for (op = batch; op < batch + count; op++)
1035                 if (op->status == GNTST_eagain)
1036                         gnttab_retry_eagain_gop(GNTTABOP_map_grant_ref, op,
1037                                                 &op->status, __func__);
1038 }
1039 EXPORT_SYMBOL_GPL(gnttab_batch_map);
1040
1041 void gnttab_batch_copy(struct gnttab_copy *batch, unsigned count)
1042 {
1043         struct gnttab_copy *op;
1044
1045         if (HYPERVISOR_grant_table_op(GNTTABOP_copy, batch, count))
1046                 BUG();
1047         for (op = batch; op < batch + count; op++)
1048                 if (op->status == GNTST_eagain)
1049                         gnttab_retry_eagain_gop(GNTTABOP_copy, op,
1050                                                 &op->status, __func__);
1051 }
1052 EXPORT_SYMBOL_GPL(gnttab_batch_copy);
1053
1054 void gnttab_foreach_grant_in_range(struct page *page,
1055                                    unsigned int offset,
1056                                    unsigned int len,
1057                                    xen_grant_fn_t fn,
1058                                    void *data)
1059 {
1060         unsigned int goffset;
1061         unsigned int glen;
1062         unsigned long xen_pfn;
1063
1064         len = min_t(unsigned int, PAGE_SIZE - offset, len);
1065         goffset = xen_offset_in_page(offset);
1066
1067         xen_pfn = page_to_xen_pfn(page) + XEN_PFN_DOWN(offset);
1068
1069         while (len) {
1070                 glen = min_t(unsigned int, XEN_PAGE_SIZE - goffset, len);
1071                 fn(pfn_to_gfn(xen_pfn), goffset, glen, data);
1072
1073                 goffset = 0;
1074                 xen_pfn++;
1075                 len -= glen;
1076         }
1077 }
1078 EXPORT_SYMBOL_GPL(gnttab_foreach_grant_in_range);
1079
1080 void gnttab_foreach_grant(struct page **pages,
1081                           unsigned int nr_grefs,
1082                           xen_grant_fn_t fn,
1083                           void *data)
1084 {
1085         unsigned int goffset = 0;
1086         unsigned long xen_pfn = 0;
1087         unsigned int i;
1088
1089         for (i = 0; i < nr_grefs; i++) {
1090                 if ((i % XEN_PFN_PER_PAGE) == 0) {
1091                         xen_pfn = page_to_xen_pfn(pages[i / XEN_PFN_PER_PAGE]);
1092                         goffset = 0;
1093                 }
1094
1095                 fn(pfn_to_gfn(xen_pfn), goffset, XEN_PAGE_SIZE, data);
1096
1097                 goffset += XEN_PAGE_SIZE;
1098                 xen_pfn++;
1099         }
1100 }
1101
1102 int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
1103                     struct gnttab_map_grant_ref *kmap_ops,
1104                     struct page **pages, unsigned int count)
1105 {
1106         int i, ret;
1107
1108         ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, map_ops, count);
1109         if (ret)
1110                 return ret;
1111
1112         for (i = 0; i < count; i++) {
1113                 switch (map_ops[i].status) {
1114                 case GNTST_okay:
1115                 {
1116                         struct xen_page_foreign *foreign;
1117
1118                         SetPageForeign(pages[i]);
1119                         foreign = xen_page_foreign(pages[i]);
1120                         foreign->domid = map_ops[i].dom;
1121                         foreign->gref = map_ops[i].ref;
1122                         break;
1123                 }
1124
1125                 case GNTST_no_device_space:
1126                         pr_warn_ratelimited("maptrack limit reached, can't map all guest pages\n");
1127                         break;
1128
1129                 case GNTST_eagain:
1130                         /* Retry eagain maps */
1131                         gnttab_retry_eagain_gop(GNTTABOP_map_grant_ref,
1132                                                 map_ops + i,
1133                                                 &map_ops[i].status, __func__);
1134                         /* Test status in next loop iteration. */
1135                         i--;
1136                         break;
1137
1138                 default:
1139                         break;
1140                 }
1141         }
1142
1143         return set_foreign_p2m_mapping(map_ops, kmap_ops, pages, count);
1144 }
1145 EXPORT_SYMBOL_GPL(gnttab_map_refs);
1146
1147 int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
1148                       struct gnttab_unmap_grant_ref *kunmap_ops,
1149                       struct page **pages, unsigned int count)
1150 {
1151         unsigned int i;
1152         int ret;
1153
1154         ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap_ops, count);
1155         if (ret)
1156                 return ret;
1157
1158         for (i = 0; i < count; i++)
1159                 ClearPageForeign(pages[i]);
1160
1161         return clear_foreign_p2m_mapping(unmap_ops, kunmap_ops, pages, count);
1162 }
1163 EXPORT_SYMBOL_GPL(gnttab_unmap_refs);
1164
1165 #define GNTTAB_UNMAP_REFS_DELAY 5
1166
1167 static void __gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item);
1168
1169 static void gnttab_unmap_work(struct work_struct *work)
1170 {
1171         struct gntab_unmap_queue_data
1172                 *unmap_data = container_of(work,
1173                                            struct gntab_unmap_queue_data,
1174                                            gnttab_work.work);
1175         if (unmap_data->age != UINT_MAX)
1176                 unmap_data->age++;
1177         __gnttab_unmap_refs_async(unmap_data);
1178 }
1179
1180 static void __gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item)
1181 {
1182         int ret;
1183         int pc;
1184
1185         for (pc = 0; pc < item->count; pc++) {
1186                 if (page_count(item->pages[pc]) > 1) {
1187                         unsigned long delay = GNTTAB_UNMAP_REFS_DELAY * (item->age + 1);
1188                         schedule_delayed_work(&item->gnttab_work,
1189                                               msecs_to_jiffies(delay));
1190                         return;
1191                 }
1192         }
1193
1194         ret = gnttab_unmap_refs(item->unmap_ops, item->kunmap_ops,
1195                                 item->pages, item->count);
1196         item->done(ret, item);
1197 }
1198
1199 void gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item)
1200 {
1201         INIT_DELAYED_WORK(&item->gnttab_work, gnttab_unmap_work);
1202         item->age = 0;
1203
1204         __gnttab_unmap_refs_async(item);
1205 }
1206 EXPORT_SYMBOL_GPL(gnttab_unmap_refs_async);
1207
1208 static void unmap_refs_callback(int result,
1209                 struct gntab_unmap_queue_data *data)
1210 {
1211         struct unmap_refs_callback_data *d = data->data;
1212
1213         d->result = result;
1214         complete(&d->completion);
1215 }
1216
1217 int gnttab_unmap_refs_sync(struct gntab_unmap_queue_data *item)
1218 {
1219         struct unmap_refs_callback_data data;
1220
1221         init_completion(&data.completion);
1222         item->data = &data;
1223         item->done = &unmap_refs_callback;
1224         gnttab_unmap_refs_async(item);
1225         wait_for_completion(&data.completion);
1226
1227         return data.result;
1228 }
1229 EXPORT_SYMBOL_GPL(gnttab_unmap_refs_sync);
1230
1231 static unsigned int nr_status_frames(unsigned int nr_grant_frames)
1232 {
1233         return gnttab_frames(nr_grant_frames, SPP);
1234 }
1235
1236 static int gnttab_map_frames_v1(xen_pfn_t *frames, unsigned int nr_gframes)
1237 {
1238         int rc;
1239
1240         rc = arch_gnttab_map_shared(frames, nr_gframes,
1241                                     gnttab_max_grant_frames(),
1242                                     &gnttab_shared.addr);
1243         BUG_ON(rc);
1244
1245         return 0;
1246 }
1247
1248 static void gnttab_unmap_frames_v1(void)
1249 {
1250         arch_gnttab_unmap(gnttab_shared.addr, nr_grant_frames);
1251 }
1252
1253 static int gnttab_map_frames_v2(xen_pfn_t *frames, unsigned int nr_gframes)
1254 {
1255         uint64_t *sframes;
1256         unsigned int nr_sframes;
1257         struct gnttab_get_status_frames getframes;
1258         int rc;
1259
1260         nr_sframes = nr_status_frames(nr_gframes);
1261
1262         /* No need for kzalloc as it is initialized in following hypercall
1263          * GNTTABOP_get_status_frames.
1264          */
1265         sframes = kmalloc_array(nr_sframes, sizeof(uint64_t), GFP_ATOMIC);
1266         if (!sframes)
1267                 return -ENOMEM;
1268
1269         getframes.dom        = DOMID_SELF;
1270         getframes.nr_frames  = nr_sframes;
1271         set_xen_guest_handle(getframes.frame_list, sframes);
1272
1273         rc = HYPERVISOR_grant_table_op(GNTTABOP_get_status_frames,
1274                                        &getframes, 1);
1275         if (rc == -ENOSYS) {
1276                 kfree(sframes);
1277                 return -ENOSYS;
1278         }
1279
1280         BUG_ON(rc || getframes.status);
1281
1282         rc = arch_gnttab_map_status(sframes, nr_sframes,
1283                                     nr_status_frames(gnttab_max_grant_frames()),
1284                                     &grstatus);
1285         BUG_ON(rc);
1286         kfree(sframes);
1287
1288         rc = arch_gnttab_map_shared(frames, nr_gframes,
1289                                     gnttab_max_grant_frames(),
1290                                     &gnttab_shared.addr);
1291         BUG_ON(rc);
1292
1293         return 0;
1294 }
1295
1296 static void gnttab_unmap_frames_v2(void)
1297 {
1298         arch_gnttab_unmap(gnttab_shared.addr, nr_grant_frames);
1299         arch_gnttab_unmap(grstatus, nr_status_frames(nr_grant_frames));
1300 }
1301
1302 static int gnttab_map(unsigned int start_idx, unsigned int end_idx)
1303 {
1304         struct gnttab_setup_table setup;
1305         xen_pfn_t *frames;
1306         unsigned int nr_gframes = end_idx + 1;
1307         int rc;
1308
1309         if (xen_feature(XENFEAT_auto_translated_physmap)) {
1310                 struct xen_add_to_physmap xatp;
1311                 unsigned int i = end_idx;
1312                 rc = 0;
1313                 BUG_ON(xen_auto_xlat_grant_frames.count < nr_gframes);
1314                 /*
1315                  * Loop backwards, so that the first hypercall has the largest
1316                  * index, ensuring that the table will grow only once.
1317                  */
1318                 do {
1319                         xatp.domid = DOMID_SELF;
1320                         xatp.idx = i;
1321                         xatp.space = XENMAPSPACE_grant_table;
1322                         xatp.gpfn = xen_auto_xlat_grant_frames.pfn[i];
1323                         rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp);
1324                         if (rc != 0) {
1325                                 pr_warn("grant table add_to_physmap failed, err=%d\n",
1326                                         rc);
1327                                 break;
1328                         }
1329                 } while (i-- > start_idx);
1330
1331                 return rc;
1332         }
1333
1334         /* No need for kzalloc as it is initialized in following hypercall
1335          * GNTTABOP_setup_table.
1336          */
1337         frames = kmalloc_array(nr_gframes, sizeof(unsigned long), GFP_ATOMIC);
1338         if (!frames)
1339                 return -ENOMEM;
1340
1341         setup.dom        = DOMID_SELF;
1342         setup.nr_frames  = nr_gframes;
1343         set_xen_guest_handle(setup.frame_list, frames);
1344
1345         rc = HYPERVISOR_grant_table_op(GNTTABOP_setup_table, &setup, 1);
1346         if (rc == -ENOSYS) {
1347                 kfree(frames);
1348                 return -ENOSYS;
1349         }
1350
1351         BUG_ON(rc || setup.status);
1352
1353         rc = gnttab_interface->map_frames(frames, nr_gframes);
1354
1355         kfree(frames);
1356
1357         return rc;
1358 }
1359
1360 static const struct gnttab_ops gnttab_v1_ops = {
1361         .version                        = 1,
1362         .grefs_per_grant_frame          = XEN_PAGE_SIZE /
1363                                           sizeof(struct grant_entry_v1),
1364         .map_frames                     = gnttab_map_frames_v1,
1365         .unmap_frames                   = gnttab_unmap_frames_v1,
1366         .update_entry                   = gnttab_update_entry_v1,
1367         .end_foreign_access_ref         = gnttab_end_foreign_access_ref_v1,
1368         .end_foreign_transfer_ref       = gnttab_end_foreign_transfer_ref_v1,
1369         .query_foreign_access           = gnttab_query_foreign_access_v1,
1370 };
1371
1372 static const struct gnttab_ops gnttab_v2_ops = {
1373         .version                        = 2,
1374         .grefs_per_grant_frame          = XEN_PAGE_SIZE /
1375                                           sizeof(union grant_entry_v2),
1376         .map_frames                     = gnttab_map_frames_v2,
1377         .unmap_frames                   = gnttab_unmap_frames_v2,
1378         .update_entry                   = gnttab_update_entry_v2,
1379         .end_foreign_access_ref         = gnttab_end_foreign_access_ref_v2,
1380         .end_foreign_transfer_ref       = gnttab_end_foreign_transfer_ref_v2,
1381         .query_foreign_access           = gnttab_query_foreign_access_v2,
1382 };
1383
1384 static bool gnttab_need_v2(void)
1385 {
1386 #ifdef CONFIG_X86
1387         uint32_t base, width;
1388
1389         if (xen_pv_domain()) {
1390                 base = xen_cpuid_base();
1391                 if (cpuid_eax(base) < 5)
1392                         return false;   /* Information not available, use V1. */
1393                 width = cpuid_ebx(base + 5) &
1394                         XEN_CPUID_MACHINE_ADDRESS_WIDTH_MASK;
1395                 return width > 32 + PAGE_SHIFT;
1396         }
1397 #endif
1398         return !!(max_possible_pfn >> 32);
1399 }
1400
1401 static void gnttab_request_version(void)
1402 {
1403         long rc;
1404         struct gnttab_set_version gsv;
1405
1406         if (gnttab_need_v2())
1407                 gsv.version = 2;
1408         else
1409                 gsv.version = 1;
1410
1411         /* Boot parameter overrides automatic selection. */
1412         if (xen_gnttab_version >= 1 && xen_gnttab_version <= 2)
1413                 gsv.version = xen_gnttab_version;
1414
1415         rc = HYPERVISOR_grant_table_op(GNTTABOP_set_version, &gsv, 1);
1416         if (rc == 0 && gsv.version == 2)
1417                 gnttab_interface = &gnttab_v2_ops;
1418         else
1419                 gnttab_interface = &gnttab_v1_ops;
1420         pr_info("Grant tables using version %d layout\n",
1421                 gnttab_interface->version);
1422 }
1423
1424 static int gnttab_setup(void)
1425 {
1426         unsigned int max_nr_gframes;
1427
1428         max_nr_gframes = gnttab_max_grant_frames();
1429         if (max_nr_gframes < nr_grant_frames)
1430                 return -ENOSYS;
1431
1432         if (xen_feature(XENFEAT_auto_translated_physmap) && gnttab_shared.addr == NULL) {
1433                 gnttab_shared.addr = xen_auto_xlat_grant_frames.vaddr;
1434                 if (gnttab_shared.addr == NULL) {
1435                         pr_warn("gnttab share frames is not mapped!\n");
1436                         return -ENOMEM;
1437                 }
1438         }
1439         return gnttab_map(0, nr_grant_frames - 1);
1440 }
1441
1442 int gnttab_resume(void)
1443 {
1444         gnttab_request_version();
1445         return gnttab_setup();
1446 }
1447
1448 int gnttab_suspend(void)
1449 {
1450         if (!xen_feature(XENFEAT_auto_translated_physmap))
1451                 gnttab_interface->unmap_frames();
1452         return 0;
1453 }
1454
1455 static int gnttab_expand(unsigned int req_entries)
1456 {
1457         int rc;
1458         unsigned int cur, extra;
1459
1460         cur = nr_grant_frames;
1461         extra = ((req_entries + gnttab_interface->grefs_per_grant_frame - 1) /
1462                  gnttab_interface->grefs_per_grant_frame);
1463         if (cur + extra > gnttab_max_grant_frames()) {
1464                 pr_warn_ratelimited("xen/grant-table: max_grant_frames reached"
1465                                     " cur=%u extra=%u limit=%u"
1466                                     " gnttab_free_count=%u req_entries=%u\n",
1467                                     cur, extra, gnttab_max_grant_frames(),
1468                                     gnttab_free_count, req_entries);
1469                 return -ENOSPC;
1470         }
1471
1472         rc = gnttab_map(cur, cur + extra - 1);
1473         if (rc == 0)
1474                 rc = grow_gnttab_list(extra);
1475
1476         return rc;
1477 }
1478
1479 int gnttab_init(void)
1480 {
1481         int i;
1482         unsigned long max_nr_grant_frames;
1483         unsigned int max_nr_glist_frames, nr_glist_frames;
1484         unsigned int nr_init_grefs;
1485         int ret;
1486
1487         gnttab_request_version();
1488         max_nr_grant_frames = gnttab_max_grant_frames();
1489         nr_grant_frames = 1;
1490
1491         /* Determine the maximum number of frames required for the
1492          * grant reference free list on the current hypervisor.
1493          */
1494         max_nr_glist_frames = (max_nr_grant_frames *
1495                                gnttab_interface->grefs_per_grant_frame / RPP);
1496
1497         gnttab_list = kmalloc_array(max_nr_glist_frames,
1498                                     sizeof(grant_ref_t *),
1499                                     GFP_KERNEL);
1500         if (gnttab_list == NULL)
1501                 return -ENOMEM;
1502
1503         nr_glist_frames = gnttab_frames(nr_grant_frames, RPP);
1504         for (i = 0; i < nr_glist_frames; i++) {
1505                 gnttab_list[i] = (grant_ref_t *)__get_free_page(GFP_KERNEL);
1506                 if (gnttab_list[i] == NULL) {
1507                         ret = -ENOMEM;
1508                         goto ini_nomem;
1509                 }
1510         }
1511
1512         ret = arch_gnttab_init(max_nr_grant_frames,
1513                                nr_status_frames(max_nr_grant_frames));
1514         if (ret < 0)
1515                 goto ini_nomem;
1516
1517         if (gnttab_setup() < 0) {
1518                 ret = -ENODEV;
1519                 goto ini_nomem;
1520         }
1521
1522         nr_init_grefs = nr_grant_frames *
1523                         gnttab_interface->grefs_per_grant_frame;
1524
1525         for (i = NR_RESERVED_ENTRIES; i < nr_init_grefs - 1; i++)
1526                 gnttab_entry(i) = i + 1;
1527
1528         gnttab_entry(nr_init_grefs - 1) = GNTTAB_LIST_END;
1529         gnttab_free_count = nr_init_grefs - NR_RESERVED_ENTRIES;
1530         gnttab_free_head  = NR_RESERVED_ENTRIES;
1531
1532         printk("Grant table initialized\n");
1533         return 0;
1534
1535  ini_nomem:
1536         for (i--; i >= 0; i--)
1537                 free_page((unsigned long)gnttab_list[i]);
1538         kfree(gnttab_list);
1539         return ret;
1540 }
1541 EXPORT_SYMBOL_GPL(gnttab_init);
1542
1543 static int __gnttab_init(void)
1544 {
1545         if (!xen_domain())
1546                 return -ENODEV;
1547
1548         /* Delay grant-table initialization in the PV on HVM case */
1549         if (xen_hvm_domain() && !xen_pvh_domain())
1550                 return 0;
1551
1552         return gnttab_init();
1553 }
1554 /* Starts after core_initcall so that xen_pvh_gnttab_setup can be called
1555  * beforehand to initialize xen_auto_xlat_grant_frames. */
1556 core_initcall_sync(__gnttab_init);