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          * Read the frame number related to a given grant reference.
 138          */
 139         unsigned long (*read_frame)(grant_ref_t ref);
 140 };
 141
 142 struct unmap_refs_callback_data {
 143         struct completion completion;
 144         int result;
 145 };
 146
 147 static const struct gnttab_ops *gnttab_interface;
 148
 149 /* This reflects status of grant entries, so act as a global value. */
 150 static grant_status_t *grstatus;
 151
 152 static struct gnttab_free_callback *gnttab_free_callback_list;
 153
 154 static int gnttab_expand(unsigned int req_entries);
 155
 156 #define RPP (PAGE_SIZE / sizeof(grant_ref_t))
 157 #define SPP (PAGE_SIZE / sizeof(grant_status_t))
 158
 159 static inline grant_ref_t *__gnttab_entry(grant_ref_t entry)
 160 {
 161         return &gnttab_list[(entry) / RPP][(entry) % RPP];
 162 }
 163 /* This can be used as an l-value */
 164 #define gnttab_entry(entry) (*__gnttab_entry(entry))
 165
 166 static int get_free_entries(unsigned count)
 167 {
 168         unsigned long flags;
 169         int ref, rc = 0;
 170         grant_ref_t head;
 171
 172         spin_lock_irqsave(&gnttab_list_lock, flags);
 173
 174         if ((gnttab_free_count < count) &&
 175             ((rc = gnttab_expand(count - gnttab_free_count)) < 0)) {
 176                 spin_unlock_irqrestore(&gnttab_list_lock, flags);
 177                 return rc;
 178         }
 179
 180         ref = head = gnttab_free_head;
 181         gnttab_free_count -= count;
 182         while (count-- > 1)
 183                 head = gnttab_entry(head);
 184         gnttab_free_head = gnttab_entry(head);
 185         gnttab_entry(head) = GNTTAB_LIST_END;
 186
 187         spin_unlock_irqrestore(&gnttab_list_lock, flags);
 188
 189         return ref;
 190 }
 191
 192 static void do_free_callbacks(void)
 193 {
 194         struct gnttab_free_callback *callback, *next;
 195
 196         callback = gnttab_free_callback_list;
 197         gnttab_free_callback_list = NULL;
 198
 199         while (callback != NULL) {
 200                 next = callback->next;
 201                 if (gnttab_free_count >= callback->count) {
 202                         callback->next = NULL;
 203                         callback->fn(callback->arg);
 204                 } else {
 205                         callback->next = gnttab_free_callback_list;
 206                         gnttab_free_callback_list = callback;
 207                 }
 208                 callback = next;
 209         }
 210 }
 211
 212 static inline void check_free_callbacks(void)
 213 {
 214         if (unlikely(gnttab_free_callback_list))
 215                 do_free_callbacks();
 216 }
 217
 218 static void put_free_entry(grant_ref_t ref)
 219 {
 220         unsigned long flags;
 221         spin_lock_irqsave(&gnttab_list_lock, flags);
 222         gnttab_entry(ref) = gnttab_free_head;
 223         gnttab_free_head = ref;
 224         gnttab_free_count++;
 225         check_free_callbacks();
 226         spin_unlock_irqrestore(&gnttab_list_lock, flags);
 227 }
 228
 229 /*
 230  * Following applies to gnttab_update_entry_v1 and gnttab_update_entry_v2.
 231  * Introducing a valid entry into the grant table:
 232  *  1. Write ent->domid.
 233  *  2. Write ent->frame:
 234  *      GTF_permit_access:   Frame to which access is permitted.
 235  *      GTF_accept_transfer: Pseudo-phys frame slot being filled by new
 236  *                           frame, or zero if none.
 237  *  3. Write memory barrier (WMB).
 238  *  4. Write ent->flags, inc. valid type.
 239  */
 240 static void gnttab_update_entry_v1(grant_ref_t ref, domid_t domid,
 241                                    unsigned long frame, unsigned flags)
 242 {
 243         gnttab_shared.v1[ref].domid = domid;
 244         gnttab_shared.v1[ref].frame = frame;
 245         wmb();
 246         gnttab_shared.v1[ref].flags = flags;
 247 }
 248
 249 static void gnttab_update_entry_v2(grant_ref_t ref, domid_t domid,
 250                                    unsigned long frame, unsigned int flags)
 251 {
 252         gnttab_shared.v2[ref].hdr.domid = domid;
 253         gnttab_shared.v2[ref].full_page.frame = frame;
 254         wmb();  /* Hypervisor concurrent accesses. */
 255         gnttab_shared.v2[ref].hdr.flags = GTF_permit_access | flags;
 256 }
 257
 258 /*
 259  * Public grant-issuing interface functions
 260  */
 261 void gnttab_grant_foreign_access_ref(grant_ref_t ref, domid_t domid,
 262                                      unsigned long frame, int readonly)
 263 {
 264         gnttab_interface->update_entry(ref, domid, frame,
 265                            GTF_permit_access | (readonly ? GTF_readonly : 0));
 266 }
 267 EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access_ref);
 268
 269 int gnttab_grant_foreign_access(domid_t domid, unsigned long frame,
 270                                 int readonly)
 271 {
 272         int ref;
 273
 274         ref = get_free_entries(1);
 275         if (unlikely(ref < 0))
 276                 return -ENOSPC;
 277
 278         gnttab_grant_foreign_access_ref(ref, domid, frame, readonly);
 279
 280         return ref;
 281 }
 282 EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access);
 283
 284 static int gnttab_end_foreign_access_ref_v1(grant_ref_t ref, int readonly)
 285 {
 286         u16 flags, nflags;
 287         u16 *pflags;
 288
 289         pflags = &gnttab_shared.v1[ref].flags;
 290         nflags = *pflags;
 291         do {
 292                 flags = nflags;
 293                 if (flags & (GTF_reading|GTF_writing))
 294                         return 0;
 295         } while ((nflags = sync_cmpxchg(pflags, flags, 0)) != flags);
 296
 297         return 1;
 298 }
 299
 300 static int gnttab_end_foreign_access_ref_v2(grant_ref_t ref, int readonly)
 301 {
 302         gnttab_shared.v2[ref].hdr.flags = 0;
 303         mb();   /* Concurrent access by hypervisor. */
 304         if (grstatus[ref] & (GTF_reading|GTF_writing)) {
 305                 return 0;
 306         } else {
 307                 /*
 308                  * The read of grstatus needs to have acquire semantics.
 309                  *  On x86, reads already have that, and we just need to
 310                  * protect against compiler reorderings.
 311                  * On other architectures we may need a full barrier.
 312                  */
 313 #ifdef CONFIG_X86
 314                 barrier();
 315 #else
 316                 mb();
 317 #endif
 318         }
 319
 320         return 1;
 321 }
 322
 323 static inline int _gnttab_end_foreign_access_ref(grant_ref_t ref, int readonly)
 324 {
 325         return gnttab_interface->end_foreign_access_ref(ref, readonly);
 326 }
 327
 328 int gnttab_end_foreign_access_ref(grant_ref_t ref, int readonly)
 329 {
 330         if (_gnttab_end_foreign_access_ref(ref, readonly))
 331                 return 1;
 332         pr_warn("WARNING: g.e. %#x still in use!\n", ref);
 333         return 0;
 334 }
 335 EXPORT_SYMBOL_GPL(gnttab_end_foreign_access_ref);
 336
 337 static unsigned long gnttab_read_frame_v1(grant_ref_t ref)
 338 {
 339         return gnttab_shared.v1[ref].frame;
 340 }
 341
 342 static unsigned long gnttab_read_frame_v2(grant_ref_t ref)
 343 {
 344         return gnttab_shared.v2[ref].full_page.frame;
 345 }
 346
 347 struct deferred_entry {
 348         struct list_head list;
 349         grant_ref_t ref;
 350         bool ro;
 351         uint16_t warn_delay;
 352         struct page *page;
 353 };
 354 static LIST_HEAD(deferred_list);
 355 static void gnttab_handle_deferred(struct timer_list *);
 356 static DEFINE_TIMER(deferred_timer, gnttab_handle_deferred);
 357
 358 static void gnttab_handle_deferred(struct timer_list *unused)
 359 {
 360         unsigned int nr = 10;
 361         struct deferred_entry *first = NULL;
 362         unsigned long flags;
 363
 364         spin_lock_irqsave(&gnttab_list_lock, flags);
 365         while (nr--) {
 366                 struct deferred_entry *entry
 367                         = list_first_entry(&deferred_list,
 368                                            struct deferred_entry, list);
 369
 370                 if (entry == first)
 371                         break;
 372                 list_del(&entry->list);
 373                 spin_unlock_irqrestore(&gnttab_list_lock, flags);
 374                 if (_gnttab_end_foreign_access_ref(entry->ref, entry->ro)) {
 375                         put_free_entry(entry->ref);
 376                         pr_debug("freeing g.e. %#x (pfn %#lx)\n",
 377                                  entry->ref, page_to_pfn(entry->page));
 378                         put_page(entry->page);
 379                         kfree(entry);
 380                         entry = NULL;
 381                 } else {
 382                         if (!--entry->warn_delay)
 383                                 pr_info("g.e. %#x still pending\n", entry->ref);
 384                         if (!first)
 385                                 first = entry;
 386                 }
 387                 spin_lock_irqsave(&gnttab_list_lock, flags);
 388                 if (entry)
 389                         list_add_tail(&entry->list, &deferred_list);
 390                 else if (list_empty(&deferred_list))
 391                         break;
 392         }
 393         if (!list_empty(&deferred_list) && !timer_pending(&deferred_timer)) {
 394                 deferred_timer.expires = jiffies + HZ;
 395                 add_timer(&deferred_timer);
 396         }
 397         spin_unlock_irqrestore(&gnttab_list_lock, flags);
 398 }
 399
 400 static void gnttab_add_deferred(grant_ref_t ref, bool readonly,
 401                                 struct page *page)
 402 {
 403         struct deferred_entry *entry;
 404         gfp_t gfp = (in_atomic() || irqs_disabled()) ? GFP_ATOMIC : GFP_KERNEL;
 405         const char *what = KERN_WARNING "leaking";
 406
 407         entry = kmalloc(sizeof(*entry), gfp);
 408         if (!page) {
 409                 unsigned long gfn = gnttab_interface->read_frame(ref);
 410
 411                 page = pfn_to_page(gfn_to_pfn(gfn));
 412                 get_page(page);
 413         }
 414
 415         if (entry) {
 416                 unsigned long flags;
 417
 418                 entry->ref = ref;
 419                 entry->ro = readonly;
 420                 entry->page = page;
 421                 entry->warn_delay = 60;
 422                 spin_lock_irqsave(&gnttab_list_lock, flags);
 423                 list_add_tail(&entry->list, &deferred_list);
 424                 if (!timer_pending(&deferred_timer)) {
 425                         deferred_timer.expires = jiffies + HZ;
 426                         add_timer(&deferred_timer);
 427                 }
 428                 spin_unlock_irqrestore(&gnttab_list_lock, flags);
 429                 what = KERN_DEBUG "deferring";
 430         }
 431         printk("%s g.e. %#x (pfn %#lx)\n",
 432                what, ref, page ? page_to_pfn(page) : -1);
 433 }
 434
 435 int gnttab_try_end_foreign_access(grant_ref_t ref)
 436 {
 437         int ret = _gnttab_end_foreign_access_ref(ref, 0);
 438
 439         if (ret)
 440                 put_free_entry(ref);
 441
 442         return ret;
 443 }
 444 EXPORT_SYMBOL_GPL(gnttab_try_end_foreign_access);
 445
 446 void gnttab_end_foreign_access(grant_ref_t ref, int readonly,
 447                                unsigned long page)
 448 {
 449         if (gnttab_try_end_foreign_access(ref)) {
 450                 if (page != 0)
 451                         put_page(virt_to_page(page));
 452         } else
 453                 gnttab_add_deferred(ref, readonly,
 454                                     page ? virt_to_page(page) : NULL);
 455 }
 456 EXPORT_SYMBOL_GPL(gnttab_end_foreign_access);
 457
 458 int gnttab_grant_foreign_transfer(domid_t domid, unsigned long pfn)
 459 {
 460         int ref;
 461
 462         ref = get_free_entries(1);
 463         if (unlikely(ref < 0))
 464                 return -ENOSPC;
 465         gnttab_grant_foreign_transfer_ref(ref, domid, pfn);
 466
 467         return ref;
 468 }
 469 EXPORT_SYMBOL_GPL(gnttab_grant_foreign_transfer);
 470
 471 void gnttab_grant_foreign_transfer_ref(grant_ref_t ref, domid_t domid,
 472                                        unsigned long pfn)
 473 {
 474         gnttab_interface->update_entry(ref, domid, pfn, GTF_accept_transfer);
 475 }
 476 EXPORT_SYMBOL_GPL(gnttab_grant_foreign_transfer_ref);
 477
 478 static unsigned long gnttab_end_foreign_transfer_ref_v1(grant_ref_t ref)
 479 {
 480         unsigned long frame;
 481         u16           flags;
 482         u16          *pflags;
 483
 484         pflags = &gnttab_shared.v1[ref].flags;
 485
 486         /*
 487          * If a transfer is not even yet started, try to reclaim the grant
 488          * reference and return failure (== 0).
 489          */
 490         while (!((flags = *pflags) & GTF_transfer_committed)) {
 491                 if (sync_cmpxchg(pflags, flags, 0) == flags)
 492                         return 0;
 493                 cpu_relax();
 494         }
 495
 496         /* If a transfer is in progress then wait until it is completed. */
 497         while (!(flags & GTF_transfer_completed)) {
 498                 flags = *pflags;
 499                 cpu_relax();
 500         }
 501
 502         rmb();  /* Read the frame number /after/ reading completion status. */
 503         frame = gnttab_shared.v1[ref].frame;
 504         BUG_ON(frame == 0);
 505
 506         return frame;
 507 }
 508
 509 static unsigned long gnttab_end_foreign_transfer_ref_v2(grant_ref_t ref)
 510 {
 511         unsigned long frame;
 512         u16           flags;
 513         u16          *pflags;
 514
 515         pflags = &gnttab_shared.v2[ref].hdr.flags;
 516
 517         /*
 518          * If a transfer is not even yet started, try to reclaim the grant
 519          * reference and return failure (== 0).
 520          */
 521         while (!((flags = *pflags) & GTF_transfer_committed)) {
 522                 if (sync_cmpxchg(pflags, flags, 0) == flags)
 523                         return 0;
 524                 cpu_relax();
 525         }
 526
 527         /* If a transfer is in progress then wait until it is completed. */
 528         while (!(flags & GTF_transfer_completed)) {
 529                 flags = *pflags;
 530                 cpu_relax();
 531         }
 532
 533         rmb();  /* Read the frame number /after/ reading completion status. */
 534         frame = gnttab_shared.v2[ref].full_page.frame;
 535         BUG_ON(frame == 0);
 536
 537         return frame;
 538 }
 539
 540 unsigned long gnttab_end_foreign_transfer_ref(grant_ref_t ref)
 541 {
 542         return gnttab_interface->end_foreign_transfer_ref(ref);
 543 }
 544 EXPORT_SYMBOL_GPL(gnttab_end_foreign_transfer_ref);
 545
 546 unsigned long gnttab_end_foreign_transfer(grant_ref_t ref)
 547 {
 548         unsigned long frame = gnttab_end_foreign_transfer_ref(ref);
 549         put_free_entry(ref);
 550         return frame;
 551 }
 552 EXPORT_SYMBOL_GPL(gnttab_end_foreign_transfer);
 553
 554 void gnttab_free_grant_reference(grant_ref_t ref)
 555 {
 556         put_free_entry(ref);
 557 }
 558 EXPORT_SYMBOL_GPL(gnttab_free_grant_reference);
 559
 560 void gnttab_free_grant_references(grant_ref_t head)
 561 {
 562         grant_ref_t ref;
 563         unsigned long flags;
 564         int count = 1;
 565         if (head == GNTTAB_LIST_END)
 566                 return;
 567         spin_lock_irqsave(&gnttab_list_lock, flags);
 568         ref = head;
 569         while (gnttab_entry(ref) != GNTTAB_LIST_END) {
 570                 ref = gnttab_entry(ref);
 571                 count++;
 572         }
 573         gnttab_entry(ref) = gnttab_free_head;
 574         gnttab_free_head = head;
 575         gnttab_free_count += count;
 576         check_free_callbacks();
 577         spin_unlock_irqrestore(&gnttab_list_lock, flags);
 578 }
 579 EXPORT_SYMBOL_GPL(gnttab_free_grant_references);
 580
 581 int gnttab_alloc_grant_references(u16 count, grant_ref_t *head)
 582 {
 583         int h = get_free_entries(count);
 584
 585         if (h < 0)
 586                 return -ENOSPC;
 587
 588         *head = h;
 589
 590         return 0;
 591 }
 592 EXPORT_SYMBOL_GPL(gnttab_alloc_grant_references);
 593
 594 int gnttab_empty_grant_references(const grant_ref_t *private_head)
 595 {
 596         return (*private_head == GNTTAB_LIST_END);
 597 }
 598 EXPORT_SYMBOL_GPL(gnttab_empty_grant_references);
 599
 600 int gnttab_claim_grant_reference(grant_ref_t *private_head)
 601 {
 602         grant_ref_t g = *private_head;
 603         if (unlikely(g == GNTTAB_LIST_END))
 604                 return -ENOSPC;
 605         *private_head = gnttab_entry(g);
 606         return g;
 607 }
 608 EXPORT_SYMBOL_GPL(gnttab_claim_grant_reference);
 609
 610 void gnttab_release_grant_reference(grant_ref_t *private_head,
 611                                     grant_ref_t release)
 612 {
 613         gnttab_entry(release) = *private_head;
 614         *private_head = release;
 615 }
 616 EXPORT_SYMBOL_GPL(gnttab_release_grant_reference);
 617
 618 void gnttab_request_free_callback(struct gnttab_free_callback *callback,
 619                                   void (*fn)(void *), void *arg, u16 count)
 620 {
 621         unsigned long flags;
 622         struct gnttab_free_callback *cb;
 623
 624         spin_lock_irqsave(&gnttab_list_lock, flags);
 625
 626         /* Check if the callback is already on the list */
 627         cb = gnttab_free_callback_list;
 628         while (cb) {
 629                 if (cb == callback)
 630                         goto out;
 631                 cb = cb->next;
 632         }
 633
 634         callback->fn = fn;
 635         callback->arg = arg;
 636         callback->count = count;
 637         callback->next = gnttab_free_callback_list;
 638         gnttab_free_callback_list = callback;
 639         check_free_callbacks();
 640 out:
 641         spin_unlock_irqrestore(&gnttab_list_lock, flags);
 642 }
 643 EXPORT_SYMBOL_GPL(gnttab_request_free_callback);
 644
 645 void gnttab_cancel_free_callback(struct gnttab_free_callback *callback)
 646 {
 647         struct gnttab_free_callback **pcb;
 648         unsigned long flags;
 649
 650         spin_lock_irqsave(&gnttab_list_lock, flags);
 651         for (pcb = &gnttab_free_callback_list; *pcb; pcb = &(*pcb)->next) {
 652                 if (*pcb == callback) {
 653                         *pcb = callback->next;
 654                         break;
 655                 }
 656         }
 657         spin_unlock_irqrestore(&gnttab_list_lock, flags);
 658 }
 659 EXPORT_SYMBOL_GPL(gnttab_cancel_free_callback);
 660
 661 static unsigned int gnttab_frames(unsigned int frames, unsigned int align)
 662 {
 663         return (frames * gnttab_interface->grefs_per_grant_frame + align - 1) /
 664                align;
 665 }
 666
 667 static int grow_gnttab_list(unsigned int more_frames)
 668 {
 669         unsigned int new_nr_grant_frames, extra_entries, i;
 670         unsigned int nr_glist_frames, new_nr_glist_frames;
 671         unsigned int grefs_per_frame;
 672
 673         grefs_per_frame = gnttab_interface->grefs_per_grant_frame;
 674
 675         new_nr_grant_frames = nr_grant_frames + more_frames;
 676         extra_entries = more_frames * grefs_per_frame;
 677
 678         nr_glist_frames = gnttab_frames(nr_grant_frames, RPP);
 679         new_nr_glist_frames = gnttab_frames(new_nr_grant_frames, RPP);
 680         for (i = nr_glist_frames; i < new_nr_glist_frames; i++) {
 681                 gnttab_list[i] = (grant_ref_t *)__get_free_page(GFP_ATOMIC);
 682                 if (!gnttab_list[i])
 683                         goto grow_nomem;
 684         }
 685
 686
 687         for (i = grefs_per_frame * nr_grant_frames;
 688              i < grefs_per_frame * new_nr_grant_frames - 1; i++)
 689                 gnttab_entry(i) = i + 1;
 690
 691         gnttab_entry(i) = gnttab_free_head;
 692         gnttab_free_head = grefs_per_frame * nr_grant_frames;
 693         gnttab_free_count += extra_entries;
 694
 695         nr_grant_frames = new_nr_grant_frames;
 696
 697         check_free_callbacks();
 698
 699         return 0;
 700
 701 grow_nomem:
 702         while (i-- > nr_glist_frames)
 703                 free_page((unsigned long) gnttab_list[i]);
 704         return -ENOMEM;
 705 }
 706
 707 static unsigned int __max_nr_grant_frames(void)
 708 {
 709         struct gnttab_query_size query;
 710         int rc;
 711
 712         query.dom = DOMID_SELF;
 713
 714         rc = HYPERVISOR_grant_table_op(GNTTABOP_query_size, &query, 1);
 715         if ((rc < 0) || (query.status != GNTST_okay))
 716                 return 4; /* Legacy max supported number of frames */
 717
 718         return query.max_nr_frames;
 719 }
 720
 721 unsigned int gnttab_max_grant_frames(void)
 722 {
 723         unsigned int xen_max = __max_nr_grant_frames();
 724         static unsigned int boot_max_nr_grant_frames;
 725
 726         /* First time, initialize it properly. */
 727         if (!boot_max_nr_grant_frames)
 728                 boot_max_nr_grant_frames = __max_nr_grant_frames();
 729
 730         if (xen_max > boot_max_nr_grant_frames)
 731                 return boot_max_nr_grant_frames;
 732         return xen_max;
 733 }
 734 EXPORT_SYMBOL_GPL(gnttab_max_grant_frames);
 735
 736 int gnttab_setup_auto_xlat_frames(phys_addr_t addr)
 737 {
 738         xen_pfn_t *pfn;
 739         unsigned int max_nr_gframes = __max_nr_grant_frames();
 740         unsigned int i;
 741         void *vaddr;
 742
 743         if (xen_auto_xlat_grant_frames.count)
 744                 return -EINVAL;
 745
 746         vaddr = xen_remap(addr, XEN_PAGE_SIZE * max_nr_gframes);
 747         if (vaddr == NULL) {
 748                 pr_warn("Failed to ioremap gnttab share frames (addr=%pa)!\n",
 749                         &addr);
 750                 return -ENOMEM;
 751         }
 752         pfn = kcalloc(max_nr_gframes, sizeof(pfn[0]), GFP_KERNEL);
 753         if (!pfn) {
 754                 xen_unmap(vaddr);
 755                 return -ENOMEM;
 756         }
 757         for (i = 0; i < max_nr_gframes; i++)
 758                 pfn[i] = XEN_PFN_DOWN(addr) + i;
 759
 760         xen_auto_xlat_grant_frames.vaddr = vaddr;
 761         xen_auto_xlat_grant_frames.pfn = pfn;
 762         xen_auto_xlat_grant_frames.count = max_nr_gframes;
 763
 764         return 0;
 765 }
 766 EXPORT_SYMBOL_GPL(gnttab_setup_auto_xlat_frames);
 767
 768 void gnttab_free_auto_xlat_frames(void)
 769 {
 770         if (!xen_auto_xlat_grant_frames.count)
 771                 return;
 772         kfree(xen_auto_xlat_grant_frames.pfn);
 773         xen_unmap(xen_auto_xlat_grant_frames.vaddr);
 774
 775         xen_auto_xlat_grant_frames.pfn = NULL;
 776         xen_auto_xlat_grant_frames.count = 0;
 777         xen_auto_xlat_grant_frames.vaddr = NULL;
 778 }
 779 EXPORT_SYMBOL_GPL(gnttab_free_auto_xlat_frames);
 780
 781 int gnttab_pages_set_private(int nr_pages, struct page **pages)
 782 {
 783         int i;
 784
 785         for (i = 0; i < nr_pages; i++) {
 786 #if BITS_PER_LONG < 64
 787                 struct xen_page_foreign *foreign;
 788
 789                 foreign = kzalloc(sizeof(*foreign), GFP_KERNEL);
 790                 if (!foreign)
 791                         return -ENOMEM;
 792
 793                 set_page_private(pages[i], (unsigned long)foreign);
 794 #endif
 795                 SetPagePrivate(pages[i]);
 796         }
 797
 798         return 0;
 799 }
 800 EXPORT_SYMBOL_GPL(gnttab_pages_set_private);
 801
 802 /**
 803  * gnttab_alloc_pages - alloc pages suitable for grant mapping into
 804  * @nr_pages: number of pages to alloc
 805  * @pages: returns the pages
 806  */
 807 int gnttab_alloc_pages(int nr_pages, struct page **pages)
 808 {
 809         int ret;
 810
 811         ret = xen_alloc_unpopulated_pages(nr_pages, pages);
 812         if (ret < 0)
 813                 return ret;
 814
 815         ret = gnttab_pages_set_private(nr_pages, pages);
 816         if (ret < 0)
 817                 gnttab_free_pages(nr_pages, pages);
 818
 819         return ret;
 820 }
 821 EXPORT_SYMBOL_GPL(gnttab_alloc_pages);
 822
 823 #ifdef CONFIG_XEN_UNPOPULATED_ALLOC
 824 static inline void cache_init(struct gnttab_page_cache *cache)
 825 {
 826         cache->pages = NULL;
 827 }
 828
 829 static inline bool cache_empty(struct gnttab_page_cache *cache)
 830 {
 831         return !cache->pages;
 832 }
 833
 834 static inline struct page *cache_deq(struct gnttab_page_cache *cache)
 835 {
 836         struct page *page;
 837
 838         page = cache->pages;
 839         cache->pages = page->zone_device_data;
 840
 841         return page;
 842 }
 843
 844 static inline void cache_enq(struct gnttab_page_cache *cache, struct page *page)
 845 {
 846         page->zone_device_data = cache->pages;
 847         cache->pages = page;
 848 }
 849 #else
 850 static inline void cache_init(struct gnttab_page_cache *cache)
 851 {
 852         INIT_LIST_HEAD(&cache->pages);
 853 }
 854
 855 static inline bool cache_empty(struct gnttab_page_cache *cache)
 856 {
 857         return list_empty(&cache->pages);
 858 }
 859
 860 static inline struct page *cache_deq(struct gnttab_page_cache *cache)
 861 {
 862         struct page *page;
 863
 864         page = list_first_entry(&cache->pages, struct page, lru);
 865         list_del(&page->lru);
 866
 867         return page;
 868 }
 869
 870 static inline void cache_enq(struct gnttab_page_cache *cache, struct page *page)
 871 {
 872         list_add(&page->lru, &cache->pages);
 873 }
 874 #endif
 875
 876 void gnttab_page_cache_init(struct gnttab_page_cache *cache)
 877 {
 878         spin_lock_init(&cache->lock);
 879         cache_init(cache);
 880         cache->num_pages = 0;
 881 }
 882 EXPORT_SYMBOL_GPL(gnttab_page_cache_init);
 883
 884 int gnttab_page_cache_get(struct gnttab_page_cache *cache, struct page **page)
 885 {
 886         unsigned long flags;
 887
 888         spin_lock_irqsave(&cache->lock, flags);
 889
 890         if (cache_empty(cache)) {
 891                 spin_unlock_irqrestore(&cache->lock, flags);
 892                 return gnttab_alloc_pages(1, page);
 893         }
 894
 895         page[0] = cache_deq(cache);
 896         cache->num_pages--;
 897
 898         spin_unlock_irqrestore(&cache->lock, flags);
 899
 900         return 0;
 901 }
 902 EXPORT_SYMBOL_GPL(gnttab_page_cache_get);
 903
 904 void gnttab_page_cache_put(struct gnttab_page_cache *cache, struct page **page,
 905                            unsigned int num)
 906 {
 907         unsigned long flags;
 908         unsigned int i;
 909
 910         spin_lock_irqsave(&cache->lock, flags);
 911
 912         for (i = 0; i < num; i++)
 913                 cache_enq(cache, page[i]);
 914         cache->num_pages += num;
 915
 916         spin_unlock_irqrestore(&cache->lock, flags);
 917 }
 918 EXPORT_SYMBOL_GPL(gnttab_page_cache_put);
 919
 920 void gnttab_page_cache_shrink(struct gnttab_page_cache *cache, unsigned int num)
 921 {
 922         struct page *page[10];
 923         unsigned int i = 0;
 924         unsigned long flags;
 925
 926         spin_lock_irqsave(&cache->lock, flags);
 927
 928         while (cache->num_pages > num) {
 929                 page[i] = cache_deq(cache);
 930                 cache->num_pages--;
 931                 if (++i == ARRAY_SIZE(page)) {
 932                         spin_unlock_irqrestore(&cache->lock, flags);
 933                         gnttab_free_pages(i, page);
 934                         i = 0;
 935                         spin_lock_irqsave(&cache->lock, flags);
 936                 }
 937         }
 938
 939         spin_unlock_irqrestore(&cache->lock, flags);
 940
 941         if (i != 0)
 942                 gnttab_free_pages(i, page);
 943 }
 944 EXPORT_SYMBOL_GPL(gnttab_page_cache_shrink);
 945
 946 void gnttab_pages_clear_private(int nr_pages, struct page **pages)
 947 {
 948         int i;
 949
 950         for (i = 0; i < nr_pages; i++) {
 951                 if (PagePrivate(pages[i])) {
 952 #if BITS_PER_LONG < 64
 953                         kfree((void *)page_private(pages[i]));
 954 #endif
 955                         ClearPagePrivate(pages[i]);
 956                 }
 957         }
 958 }
 959 EXPORT_SYMBOL_GPL(gnttab_pages_clear_private);
 960
 961 /**
 962  * gnttab_free_pages - free pages allocated by gnttab_alloc_pages()
 963  * @nr_pages; number of pages to free
 964  * @pages: the pages
 965  */
 966 void gnttab_free_pages(int nr_pages, struct page **pages)
 967 {
 968         gnttab_pages_clear_private(nr_pages, pages);
 969         xen_free_unpopulated_pages(nr_pages, pages);
 970 }
 971 EXPORT_SYMBOL_GPL(gnttab_free_pages);
 972
 973 #ifdef CONFIG_XEN_GRANT_DMA_ALLOC
 974 /**
 975  * gnttab_dma_alloc_pages - alloc DMAable pages suitable for grant mapping into
 976  * @args: arguments to the function
 977  */
 978 int gnttab_dma_alloc_pages(struct gnttab_dma_alloc_args *args)
 979 {
 980         unsigned long pfn, start_pfn;
 981         size_t size;
 982         int i, ret;
 983
 984         if (args->nr_pages < 0 || args->nr_pages > (INT_MAX >> PAGE_SHIFT))
 985                 return -ENOMEM;
 986
 987         size = args->nr_pages << PAGE_SHIFT;
 988         if (args->coherent)
 989                 args->vaddr = dma_alloc_coherent(args->dev, size,
 990                                                  &args->dev_bus_addr,
 991                                                  GFP_KERNEL | __GFP_NOWARN);
 992         else
 993                 args->vaddr = dma_alloc_wc(args->dev, size,
 994                                            &args->dev_bus_addr,
 995                                            GFP_KERNEL | __GFP_NOWARN);
 996         if (!args->vaddr) {
 997                 pr_debug("Failed to allocate DMA buffer of size %zu\n", size);
 998                 return -ENOMEM;
 999         }
1000
1001         start_pfn = __phys_to_pfn(args->dev_bus_addr);
1002         for (pfn = start_pfn, i = 0; pfn < start_pfn + args->nr_pages;
1003                         pfn++, i++) {
1004                 struct page *page = pfn_to_page(pfn);
1005
1006                 args->pages[i] = page;
1007                 args->frames[i] = xen_page_to_gfn(page);
1008                 xenmem_reservation_scrub_page(page);
1009         }
1010
1011         xenmem_reservation_va_mapping_reset(args->nr_pages, args->pages);
1012
1013         ret = xenmem_reservation_decrease(args->nr_pages, args->frames);
1014         if (ret != args->nr_pages) {
1015                 pr_debug("Failed to decrease reservation for DMA buffer\n");
1016                 ret = -EFAULT;
1017                 goto fail;
1018         }
1019
1020         ret = gnttab_pages_set_private(args->nr_pages, args->pages);
1021         if (ret < 0)
1022                 goto fail;
1023
1024         return 0;
1025
1026 fail:
1027         gnttab_dma_free_pages(args);
1028         return ret;
1029 }
1030 EXPORT_SYMBOL_GPL(gnttab_dma_alloc_pages);
1031
1032 /**
1033  * gnttab_dma_free_pages - free DMAable pages
1034  * @args: arguments to the function
1035  */
1036 int gnttab_dma_free_pages(struct gnttab_dma_alloc_args *args)
1037 {
1038         size_t size;
1039         int i, ret;
1040
1041         gnttab_pages_clear_private(args->nr_pages, args->pages);
1042
1043         for (i = 0; i < args->nr_pages; i++)
1044                 args->frames[i] = page_to_xen_pfn(args->pages[i]);
1045
1046         ret = xenmem_reservation_increase(args->nr_pages, args->frames);
1047         if (ret != args->nr_pages) {
1048                 pr_debug("Failed to increase reservation for DMA buffer\n");
1049                 ret = -EFAULT;
1050         } else {
1051                 ret = 0;
1052         }
1053
1054         xenmem_reservation_va_mapping_update(args->nr_pages, args->pages,
1055                                              args->frames);
1056
1057         size = args->nr_pages << PAGE_SHIFT;
1058         if (args->coherent)
1059                 dma_free_coherent(args->dev, size,
1060                                   args->vaddr, args->dev_bus_addr);
1061         else
1062                 dma_free_wc(args->dev, size,
1063                             args->vaddr, args->dev_bus_addr);
1064         return ret;
1065 }
1066 EXPORT_SYMBOL_GPL(gnttab_dma_free_pages);
1067 #endif
1068
1069 /* Handling of paged out grant targets (GNTST_eagain) */
1070 #define MAX_DELAY 256
1071 static inline void
1072 gnttab_retry_eagain_gop(unsigned int cmd, void *gop, int16_t *status,
1073                                                 const char *func)
1074 {
1075         unsigned delay = 1;
1076
1077         do {
1078                 BUG_ON(HYPERVISOR_grant_table_op(cmd, gop, 1));
1079                 if (*status == GNTST_eagain)
1080                         msleep(delay++);
1081         } while ((*status == GNTST_eagain) && (delay < MAX_DELAY));
1082
1083         if (delay >= MAX_DELAY) {
1084                 pr_err("%s: %s eagain grant\n", func, current->comm);
1085                 *status = GNTST_bad_page;
1086         }
1087 }
1088
1089 void gnttab_batch_map(struct gnttab_map_grant_ref *batch, unsigned count)
1090 {
1091         struct gnttab_map_grant_ref *op;
1092
1093         if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, batch, count))
1094                 BUG();
1095         for (op = batch; op < batch + count; op++)
1096                 if (op->status == GNTST_eagain)
1097                         gnttab_retry_eagain_gop(GNTTABOP_map_grant_ref, op,
1098                                                 &op->status, __func__);
1099 }
1100 EXPORT_SYMBOL_GPL(gnttab_batch_map);
1101
1102 void gnttab_batch_copy(struct gnttab_copy *batch, unsigned count)
1103 {
1104         struct gnttab_copy *op;
1105
1106         if (HYPERVISOR_grant_table_op(GNTTABOP_copy, batch, count))
1107                 BUG();
1108         for (op = batch; op < batch + count; op++)
1109                 if (op->status == GNTST_eagain)
1110                         gnttab_retry_eagain_gop(GNTTABOP_copy, op,
1111                                                 &op->status, __func__);
1112 }
1113 EXPORT_SYMBOL_GPL(gnttab_batch_copy);
1114
1115 void gnttab_foreach_grant_in_range(struct page *page,
1116                                    unsigned int offset,
1117                                    unsigned int len,
1118                                    xen_grant_fn_t fn,
1119                                    void *data)
1120 {
1121         unsigned int goffset;
1122         unsigned int glen;
1123         unsigned long xen_pfn;
1124
1125         len = min_t(unsigned int, PAGE_SIZE - offset, len);
1126         goffset = xen_offset_in_page(offset);
1127
1128         xen_pfn = page_to_xen_pfn(page) + XEN_PFN_DOWN(offset);
1129
1130         while (len) {
1131                 glen = min_t(unsigned int, XEN_PAGE_SIZE - goffset, len);
1132                 fn(pfn_to_gfn(xen_pfn), goffset, glen, data);
1133
1134                 goffset = 0;
1135                 xen_pfn++;
1136                 len -= glen;
1137         }
1138 }
1139 EXPORT_SYMBOL_GPL(gnttab_foreach_grant_in_range);
1140
1141 void gnttab_foreach_grant(struct page **pages,
1142                           unsigned int nr_grefs,
1143                           xen_grant_fn_t fn,
1144                           void *data)
1145 {
1146         unsigned int goffset = 0;
1147         unsigned long xen_pfn = 0;
1148         unsigned int i;
1149
1150         for (i = 0; i < nr_grefs; i++) {
1151                 if ((i % XEN_PFN_PER_PAGE) == 0) {
1152                         xen_pfn = page_to_xen_pfn(pages[i / XEN_PFN_PER_PAGE]);
1153                         goffset = 0;
1154                 }
1155
1156                 fn(pfn_to_gfn(xen_pfn), goffset, XEN_PAGE_SIZE, data);
1157
1158                 goffset += XEN_PAGE_SIZE;
1159                 xen_pfn++;
1160         }
1161 }
1162
1163 int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
1164                     struct gnttab_map_grant_ref *kmap_ops,
1165                     struct page **pages, unsigned int count)
1166 {
1167         int i, ret;
1168
1169         ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, map_ops, count);
1170         if (ret)
1171                 return ret;
1172
1173         for (i = 0; i < count; i++) {
1174                 switch (map_ops[i].status) {
1175                 case GNTST_okay:
1176                 {
1177                         struct xen_page_foreign *foreign;
1178
1179                         SetPageForeign(pages[i]);
1180                         foreign = xen_page_foreign(pages[i]);
1181                         foreign->domid = map_ops[i].dom;
1182                         foreign->gref = map_ops[i].ref;
1183                         break;
1184                 }
1185
1186                 case GNTST_no_device_space:
1187                         pr_warn_ratelimited("maptrack limit reached, can't map all guest pages\n");
1188                         break;
1189
1190                 case GNTST_eagain:
1191                         /* Retry eagain maps */
1192                         gnttab_retry_eagain_gop(GNTTABOP_map_grant_ref,
1193                                                 map_ops + i,
1194                                                 &map_ops[i].status, __func__);
1195                         /* Test status in next loop iteration. */
1196                         i--;
1197                         break;
1198
1199                 default:
1200                         break;
1201                 }
1202         }
1203
1204         return set_foreign_p2m_mapping(map_ops, kmap_ops, pages, count);
1205 }
1206 EXPORT_SYMBOL_GPL(gnttab_map_refs);
1207
1208 int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
1209                       struct gnttab_unmap_grant_ref *kunmap_ops,
1210                       struct page **pages, unsigned int count)
1211 {
1212         unsigned int i;
1213         int ret;
1214
1215         ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap_ops, count);
1216         if (ret)
1217                 return ret;
1218
1219         for (i = 0; i < count; i++)
1220                 ClearPageForeign(pages[i]);
1221
1222         return clear_foreign_p2m_mapping(unmap_ops, kunmap_ops, pages, count);
1223 }
1224 EXPORT_SYMBOL_GPL(gnttab_unmap_refs);
1225
1226 #define GNTTAB_UNMAP_REFS_DELAY 5
1227
1228 static void __gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item);
1229
1230 static void gnttab_unmap_work(struct work_struct *work)
1231 {
1232         struct gntab_unmap_queue_data
1233                 *unmap_data = container_of(work,
1234                                            struct gntab_unmap_queue_data,
1235                                            gnttab_work.work);
1236         if (unmap_data->age != UINT_MAX)
1237                 unmap_data->age++;
1238         __gnttab_unmap_refs_async(unmap_data);
1239 }
1240
1241 static void __gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item)
1242 {
1243         int ret;
1244         int pc;
1245
1246         for (pc = 0; pc < item->count; pc++) {
1247                 if (page_count(item->pages[pc]) > 1) {
1248                         unsigned long delay = GNTTAB_UNMAP_REFS_DELAY * (item->age + 1);
1249                         schedule_delayed_work(&item->gnttab_work,
1250                                               msecs_to_jiffies(delay));
1251                         return;
1252                 }
1253         }
1254
1255         ret = gnttab_unmap_refs(item->unmap_ops, item->kunmap_ops,
1256                                 item->pages, item->count);
1257         item->done(ret, item);
1258 }
1259
1260 void gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item)
1261 {
1262         INIT_DELAYED_WORK(&item->gnttab_work, gnttab_unmap_work);
1263         item->age = 0;
1264
1265         __gnttab_unmap_refs_async(item);
1266 }
1267 EXPORT_SYMBOL_GPL(gnttab_unmap_refs_async);
1268
1269 static void unmap_refs_callback(int result,
1270                 struct gntab_unmap_queue_data *data)
1271 {
1272         struct unmap_refs_callback_data *d = data->data;
1273
1274         d->result = result;
1275         complete(&d->completion);
1276 }
1277
1278 int gnttab_unmap_refs_sync(struct gntab_unmap_queue_data *item)
1279 {
1280         struct unmap_refs_callback_data data;
1281
1282         init_completion(&data.completion);
1283         item->data = &data;
1284         item->done = &unmap_refs_callback;
1285         gnttab_unmap_refs_async(item);
1286         wait_for_completion(&data.completion);
1287
1288         return data.result;
1289 }
1290 EXPORT_SYMBOL_GPL(gnttab_unmap_refs_sync);
1291
1292 static unsigned int nr_status_frames(unsigned int nr_grant_frames)
1293 {
1294         return gnttab_frames(nr_grant_frames, SPP);
1295 }
1296
1297 static int gnttab_map_frames_v1(xen_pfn_t *frames, unsigned int nr_gframes)
1298 {
1299         int rc;
1300
1301         rc = arch_gnttab_map_shared(frames, nr_gframes,
1302                                     gnttab_max_grant_frames(),
1303                                     &gnttab_shared.addr);
1304         BUG_ON(rc);
1305
1306         return 0;
1307 }
1308
1309 static void gnttab_unmap_frames_v1(void)
1310 {
1311         arch_gnttab_unmap(gnttab_shared.addr, nr_grant_frames);
1312 }
1313
1314 static int gnttab_map_frames_v2(xen_pfn_t *frames, unsigned int nr_gframes)
1315 {
1316         uint64_t *sframes;
1317         unsigned int nr_sframes;
1318         struct gnttab_get_status_frames getframes;
1319         int rc;
1320
1321         nr_sframes = nr_status_frames(nr_gframes);
1322
1323         /* No need for kzalloc as it is initialized in following hypercall
1324          * GNTTABOP_get_status_frames.
1325          */
1326         sframes = kmalloc_array(nr_sframes, sizeof(uint64_t), GFP_ATOMIC);
1327         if (!sframes)
1328                 return -ENOMEM;
1329
1330         getframes.dom        = DOMID_SELF;
1331         getframes.nr_frames  = nr_sframes;
1332         set_xen_guest_handle(getframes.frame_list, sframes);
1333
1334         rc = HYPERVISOR_grant_table_op(GNTTABOP_get_status_frames,
1335                                        &getframes, 1);
1336         if (rc == -ENOSYS) {
1337                 kfree(sframes);
1338                 return -ENOSYS;
1339         }
1340
1341         BUG_ON(rc || getframes.status);
1342
1343         rc = arch_gnttab_map_status(sframes, nr_sframes,
1344                                     nr_status_frames(gnttab_max_grant_frames()),
1345                                     &grstatus);
1346         BUG_ON(rc);
1347         kfree(sframes);
1348
1349         rc = arch_gnttab_map_shared(frames, nr_gframes,
1350                                     gnttab_max_grant_frames(),
1351                                     &gnttab_shared.addr);
1352         BUG_ON(rc);
1353
1354         return 0;
1355 }
1356
1357 static void gnttab_unmap_frames_v2(void)
1358 {
1359         arch_gnttab_unmap(gnttab_shared.addr, nr_grant_frames);
1360         arch_gnttab_unmap(grstatus, nr_status_frames(nr_grant_frames));
1361 }
1362
1363 static int gnttab_map(unsigned int start_idx, unsigned int end_idx)
1364 {
1365         struct gnttab_setup_table setup;
1366         xen_pfn_t *frames;
1367         unsigned int nr_gframes = end_idx + 1;
1368         int rc;
1369
1370         if (xen_feature(XENFEAT_auto_translated_physmap)) {
1371                 struct xen_add_to_physmap xatp;
1372                 unsigned int i = end_idx;
1373                 rc = 0;
1374                 BUG_ON(xen_auto_xlat_grant_frames.count < nr_gframes);
1375                 /*
1376                  * Loop backwards, so that the first hypercall has the largest
1377                  * index, ensuring that the table will grow only once.
1378                  */
1379                 do {
1380                         xatp.domid = DOMID_SELF;
1381                         xatp.idx = i;
1382                         xatp.space = XENMAPSPACE_grant_table;
1383                         xatp.gpfn = xen_auto_xlat_grant_frames.pfn[i];
1384                         rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp);
1385                         if (rc != 0) {
1386                                 pr_warn("grant table add_to_physmap failed, err=%d\n",
1387                                         rc);
1388                                 break;
1389                         }
1390                 } while (i-- > start_idx);
1391
1392                 return rc;
1393         }
1394
1395         /* No need for kzalloc as it is initialized in following hypercall
1396          * GNTTABOP_setup_table.
1397          */
1398         frames = kmalloc_array(nr_gframes, sizeof(unsigned long), GFP_ATOMIC);
1399         if (!frames)
1400                 return -ENOMEM;
1401
1402         setup.dom        = DOMID_SELF;
1403         setup.nr_frames  = nr_gframes;
1404         set_xen_guest_handle(setup.frame_list, frames);
1405
1406         rc = HYPERVISOR_grant_table_op(GNTTABOP_setup_table, &setup, 1);
1407         if (rc == -ENOSYS) {
1408                 kfree(frames);
1409                 return -ENOSYS;
1410         }
1411
1412         BUG_ON(rc || setup.status);
1413
1414         rc = gnttab_interface->map_frames(frames, nr_gframes);
1415
1416         kfree(frames);
1417
1418         return rc;
1419 }
1420
1421 static const struct gnttab_ops gnttab_v1_ops = {
1422         .version                        = 1,
1423         .grefs_per_grant_frame          = XEN_PAGE_SIZE /
1424                                           sizeof(struct grant_entry_v1),
1425         .map_frames                     = gnttab_map_frames_v1,
1426         .unmap_frames                   = gnttab_unmap_frames_v1,
1427         .update_entry                   = gnttab_update_entry_v1,
1428         .end_foreign_access_ref         = gnttab_end_foreign_access_ref_v1,
1429         .end_foreign_transfer_ref       = gnttab_end_foreign_transfer_ref_v1,
1430         .read_frame                     = gnttab_read_frame_v1,
1431 };
1432
1433 static const struct gnttab_ops gnttab_v2_ops = {
1434         .version                        = 2,
1435         .grefs_per_grant_frame          = XEN_PAGE_SIZE /
1436                                           sizeof(union grant_entry_v2),
1437         .map_frames                     = gnttab_map_frames_v2,
1438         .unmap_frames                   = gnttab_unmap_frames_v2,
1439         .update_entry                   = gnttab_update_entry_v2,
1440         .end_foreign_access_ref         = gnttab_end_foreign_access_ref_v2,
1441         .end_foreign_transfer_ref       = gnttab_end_foreign_transfer_ref_v2,
1442         .read_frame                     = gnttab_read_frame_v2,
1443 };
1444
1445 static bool gnttab_need_v2(void)
1446 {
1447 #ifdef CONFIG_X86
1448         uint32_t base, width;
1449
1450         if (xen_pv_domain()) {
1451                 base = xen_cpuid_base();
1452                 if (cpuid_eax(base) < 5)
1453                         return false;   /* Information not available, use V1. */
1454                 width = cpuid_ebx(base + 5) &
1455                         XEN_CPUID_MACHINE_ADDRESS_WIDTH_MASK;
1456                 return width > 32 + PAGE_SHIFT;
1457         }
1458 #endif
1459         return !!(max_possible_pfn >> 32);
1460 }
1461
1462 static void gnttab_request_version(void)
1463 {
1464         long rc;
1465         struct gnttab_set_version gsv;
1466
1467         if (gnttab_need_v2())
1468                 gsv.version = 2;
1469         else
1470                 gsv.version = 1;
1471
1472         /* Boot parameter overrides automatic selection. */
1473         if (xen_gnttab_version >= 1 && xen_gnttab_version <= 2)
1474                 gsv.version = xen_gnttab_version;
1475
1476         rc = HYPERVISOR_grant_table_op(GNTTABOP_set_version, &gsv, 1);
1477         if (rc == 0 && gsv.version == 2)
1478                 gnttab_interface = &gnttab_v2_ops;
1479         else
1480                 gnttab_interface = &gnttab_v1_ops;
1481         pr_info("Grant tables using version %d layout\n",
1482                 gnttab_interface->version);
1483 }
1484
1485 static int gnttab_setup(void)
1486 {
1487         unsigned int max_nr_gframes;
1488
1489         max_nr_gframes = gnttab_max_grant_frames();
1490         if (max_nr_gframes < nr_grant_frames)
1491                 return -ENOSYS;
1492
1493         if (xen_feature(XENFEAT_auto_translated_physmap) && gnttab_shared.addr == NULL) {
1494                 gnttab_shared.addr = xen_auto_xlat_grant_frames.vaddr;
1495                 if (gnttab_shared.addr == NULL) {
1496                         pr_warn("gnttab share frames is not mapped!\n");
1497                         return -ENOMEM;
1498                 }
1499         }
1500         return gnttab_map(0, nr_grant_frames - 1);
1501 }
1502
1503 int gnttab_resume(void)
1504 {
1505         gnttab_request_version();
1506         return gnttab_setup();
1507 }
1508
1509 int gnttab_suspend(void)
1510 {
1511         if (!xen_feature(XENFEAT_auto_translated_physmap))
1512                 gnttab_interface->unmap_frames();
1513         return 0;
1514 }
1515
1516 static int gnttab_expand(unsigned int req_entries)
1517 {
1518         int rc;
1519         unsigned int cur, extra;
1520
1521         cur = nr_grant_frames;
1522         extra = ((req_entries + gnttab_interface->grefs_per_grant_frame - 1) /
1523                  gnttab_interface->grefs_per_grant_frame);
1524         if (cur + extra > gnttab_max_grant_frames()) {
1525                 pr_warn_ratelimited("xen/grant-table: max_grant_frames reached"
1526                                     " cur=%u extra=%u limit=%u"
1527                                     " gnttab_free_count=%u req_entries=%u\n",
1528                                     cur, extra, gnttab_max_grant_frames(),
1529                                     gnttab_free_count, req_entries);
1530                 return -ENOSPC;
1531         }
1532
1533         rc = gnttab_map(cur, cur + extra - 1);
1534         if (rc == 0)
1535                 rc = grow_gnttab_list(extra);
1536
1537         return rc;
1538 }
1539
1540 int gnttab_init(void)
1541 {
1542         int i;
1543         unsigned long max_nr_grant_frames;
1544         unsigned int max_nr_glist_frames, nr_glist_frames;
1545         unsigned int nr_init_grefs;
1546         int ret;
1547
1548         gnttab_request_version();
1549         max_nr_grant_frames = gnttab_max_grant_frames();
1550         nr_grant_frames = 1;
1551
1552         /* Determine the maximum number of frames required for the
1553          * grant reference free list on the current hypervisor.
1554          */
1555         max_nr_glist_frames = (max_nr_grant_frames *
1556                                gnttab_interface->grefs_per_grant_frame / RPP);
1557
1558         gnttab_list = kmalloc_array(max_nr_glist_frames,
1559                                     sizeof(grant_ref_t *),
1560                                     GFP_KERNEL);
1561         if (gnttab_list == NULL)
1562                 return -ENOMEM;
1563
1564         nr_glist_frames = gnttab_frames(nr_grant_frames, RPP);
1565         for (i = 0; i < nr_glist_frames; i++) {
1566                 gnttab_list[i] = (grant_ref_t *)__get_free_page(GFP_KERNEL);
1567                 if (gnttab_list[i] == NULL) {
1568                         ret = -ENOMEM;
1569                         goto ini_nomem;
1570                 }
1571         }
1572
1573         ret = arch_gnttab_init(max_nr_grant_frames,
1574                                nr_status_frames(max_nr_grant_frames));
1575         if (ret < 0)
1576                 goto ini_nomem;
1577
1578         if (gnttab_setup() < 0) {
1579                 ret = -ENODEV;
1580                 goto ini_nomem;
1581         }
1582
1583         nr_init_grefs = nr_grant_frames *
1584                         gnttab_interface->grefs_per_grant_frame;
1585
1586         for (i = NR_RESERVED_ENTRIES; i < nr_init_grefs - 1; i++)
1587                 gnttab_entry(i) = i + 1;
1588
1589         gnttab_entry(nr_init_grefs - 1) = GNTTAB_LIST_END;
1590         gnttab_free_count = nr_init_grefs - NR_RESERVED_ENTRIES;
1591         gnttab_free_head  = NR_RESERVED_ENTRIES;
1592
1593         printk("Grant table initialized\n");
1594         return 0;
1595
1596  ini_nomem:
1597         for (i--; i >= 0; i--)
1598                 free_page((unsigned long)gnttab_list[i]);
1599         kfree(gnttab_list);
1600         return ret;
1601 }
1602 EXPORT_SYMBOL_GPL(gnttab_init);
1603
1604 static int __gnttab_init(void)
1605 {
1606         if (!xen_domain())
1607                 return -ENODEV;
1608
1609         /* Delay grant-table initialization in the PV on HVM case */
1610         if (xen_hvm_domain() && !xen_pvh_domain())
1611                 return 0;
1612
1613         return gnttab_init();
1614 }
1615 /* Starts after core_initcall so that xen_pvh_gnttab_setup can be called
1616  * beforehand to initialize xen_auto_xlat_grant_frames. */
1617 core_initcall_sync(__gnttab_init);