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         size = args->nr_pages << PAGE_SHIFT;
 985         if (args->coherent)
 986                 args->vaddr = dma_alloc_coherent(args->dev, size,
 987                                                  &args->dev_bus_addr,
 988                                                  GFP_KERNEL | __GFP_NOWARN);
 989         else
 990                 args->vaddr = dma_alloc_wc(args->dev, size,
 991                                            &args->dev_bus_addr,
 992                                            GFP_KERNEL | __GFP_NOWARN);
 993         if (!args->vaddr) {
 994                 pr_debug("Failed to allocate DMA buffer of size %zu\n", size);
 995                 return -ENOMEM;
 996         }
 997
 998         start_pfn = __phys_to_pfn(args->dev_bus_addr);
 999         for (pfn = start_pfn, i = 0; pfn < start_pfn + args->nr_pages;
1000                         pfn++, i++) {
1001                 struct page *page = pfn_to_page(pfn);
1002
1003                 args->pages[i] = page;
1004                 args->frames[i] = xen_page_to_gfn(page);
1005                 xenmem_reservation_scrub_page(page);
1006         }
1007
1008         xenmem_reservation_va_mapping_reset(args->nr_pages, args->pages);
1009
1010         ret = xenmem_reservation_decrease(args->nr_pages, args->frames);
1011         if (ret != args->nr_pages) {
1012                 pr_debug("Failed to decrease reservation for DMA buffer\n");
1013                 ret = -EFAULT;
1014                 goto fail;
1015         }
1016
1017         ret = gnttab_pages_set_private(args->nr_pages, args->pages);
1018         if (ret < 0)
1019                 goto fail;
1020
1021         return 0;
1022
1023 fail:
1024         gnttab_dma_free_pages(args);
1025         return ret;
1026 }
1027 EXPORT_SYMBOL_GPL(gnttab_dma_alloc_pages);
1028
1029 /**
1030  * gnttab_dma_free_pages - free DMAable pages
1031  * @args: arguments to the function
1032  */
1033 int gnttab_dma_free_pages(struct gnttab_dma_alloc_args *args)
1034 {
1035         size_t size;
1036         int i, ret;
1037
1038         gnttab_pages_clear_private(args->nr_pages, args->pages);
1039
1040         for (i = 0; i < args->nr_pages; i++)
1041                 args->frames[i] = page_to_xen_pfn(args->pages[i]);
1042
1043         ret = xenmem_reservation_increase(args->nr_pages, args->frames);
1044         if (ret != args->nr_pages) {
1045                 pr_debug("Failed to increase reservation for DMA buffer\n");
1046                 ret = -EFAULT;
1047         } else {
1048                 ret = 0;
1049         }
1050
1051         xenmem_reservation_va_mapping_update(args->nr_pages, args->pages,
1052                                              args->frames);
1053
1054         size = args->nr_pages << PAGE_SHIFT;
1055         if (args->coherent)
1056                 dma_free_coherent(args->dev, size,
1057                                   args->vaddr, args->dev_bus_addr);
1058         else
1059                 dma_free_wc(args->dev, size,
1060                             args->vaddr, args->dev_bus_addr);
1061         return ret;
1062 }
1063 EXPORT_SYMBOL_GPL(gnttab_dma_free_pages);
1064 #endif
1065
1066 /* Handling of paged out grant targets (GNTST_eagain) */
1067 #define MAX_DELAY 256
1068 static inline void
1069 gnttab_retry_eagain_gop(unsigned int cmd, void *gop, int16_t *status,
1070                                                 const char *func)
1071 {
1072         unsigned delay = 1;
1073
1074         do {
1075                 BUG_ON(HYPERVISOR_grant_table_op(cmd, gop, 1));
1076                 if (*status == GNTST_eagain)
1077                         msleep(delay++);
1078         } while ((*status == GNTST_eagain) && (delay < MAX_DELAY));
1079
1080         if (delay >= MAX_DELAY) {
1081                 pr_err("%s: %s eagain grant\n", func, current->comm);
1082                 *status = GNTST_bad_page;
1083         }
1084 }
1085
1086 void gnttab_batch_map(struct gnttab_map_grant_ref *batch, unsigned count)
1087 {
1088         struct gnttab_map_grant_ref *op;
1089
1090         if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, batch, count))
1091                 BUG();
1092         for (op = batch; op < batch + count; op++)
1093                 if (op->status == GNTST_eagain)
1094                         gnttab_retry_eagain_gop(GNTTABOP_map_grant_ref, op,
1095                                                 &op->status, __func__);
1096 }
1097 EXPORT_SYMBOL_GPL(gnttab_batch_map);
1098
1099 void gnttab_batch_copy(struct gnttab_copy *batch, unsigned count)
1100 {
1101         struct gnttab_copy *op;
1102
1103         if (HYPERVISOR_grant_table_op(GNTTABOP_copy, batch, count))
1104                 BUG();
1105         for (op = batch; op < batch + count; op++)
1106                 if (op->status == GNTST_eagain)
1107                         gnttab_retry_eagain_gop(GNTTABOP_copy, op,
1108                                                 &op->status, __func__);
1109 }
1110 EXPORT_SYMBOL_GPL(gnttab_batch_copy);
1111
1112 void gnttab_foreach_grant_in_range(struct page *page,
1113                                    unsigned int offset,
1114                                    unsigned int len,
1115                                    xen_grant_fn_t fn,
1116                                    void *data)
1117 {
1118         unsigned int goffset;
1119         unsigned int glen;
1120         unsigned long xen_pfn;
1121
1122         len = min_t(unsigned int, PAGE_SIZE - offset, len);
1123         goffset = xen_offset_in_page(offset);
1124
1125         xen_pfn = page_to_xen_pfn(page) + XEN_PFN_DOWN(offset);
1126
1127         while (len) {
1128                 glen = min_t(unsigned int, XEN_PAGE_SIZE - goffset, len);
1129                 fn(pfn_to_gfn(xen_pfn), goffset, glen, data);
1130
1131                 goffset = 0;
1132                 xen_pfn++;
1133                 len -= glen;
1134         }
1135 }
1136 EXPORT_SYMBOL_GPL(gnttab_foreach_grant_in_range);
1137
1138 void gnttab_foreach_grant(struct page **pages,
1139                           unsigned int nr_grefs,
1140                           xen_grant_fn_t fn,
1141                           void *data)
1142 {
1143         unsigned int goffset = 0;
1144         unsigned long xen_pfn = 0;
1145         unsigned int i;
1146
1147         for (i = 0; i < nr_grefs; i++) {
1148                 if ((i % XEN_PFN_PER_PAGE) == 0) {
1149                         xen_pfn = page_to_xen_pfn(pages[i / XEN_PFN_PER_PAGE]);
1150                         goffset = 0;
1151                 }
1152
1153                 fn(pfn_to_gfn(xen_pfn), goffset, XEN_PAGE_SIZE, data);
1154
1155                 goffset += XEN_PAGE_SIZE;
1156                 xen_pfn++;
1157         }
1158 }
1159
1160 int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
1161                     struct gnttab_map_grant_ref *kmap_ops,
1162                     struct page **pages, unsigned int count)
1163 {
1164         int i, ret;
1165
1166         ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, map_ops, count);
1167         if (ret)
1168                 return ret;
1169
1170         for (i = 0; i < count; i++) {
1171                 switch (map_ops[i].status) {
1172                 case GNTST_okay:
1173                 {
1174                         struct xen_page_foreign *foreign;
1175
1176                         SetPageForeign(pages[i]);
1177                         foreign = xen_page_foreign(pages[i]);
1178                         foreign->domid = map_ops[i].dom;
1179                         foreign->gref = map_ops[i].ref;
1180                         break;
1181                 }
1182
1183                 case GNTST_no_device_space:
1184                         pr_warn_ratelimited("maptrack limit reached, can't map all guest pages\n");
1185                         break;
1186
1187                 case GNTST_eagain:
1188                         /* Retry eagain maps */
1189                         gnttab_retry_eagain_gop(GNTTABOP_map_grant_ref,
1190                                                 map_ops + i,
1191                                                 &map_ops[i].status, __func__);
1192                         /* Test status in next loop iteration. */
1193                         i--;
1194                         break;
1195
1196                 default:
1197                         break;
1198                 }
1199         }
1200
1201         return set_foreign_p2m_mapping(map_ops, kmap_ops, pages, count);
1202 }
1203 EXPORT_SYMBOL_GPL(gnttab_map_refs);
1204
1205 int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
1206                       struct gnttab_unmap_grant_ref *kunmap_ops,
1207                       struct page **pages, unsigned int count)
1208 {
1209         unsigned int i;
1210         int ret;
1211
1212         ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap_ops, count);
1213         if (ret)
1214                 return ret;
1215
1216         for (i = 0; i < count; i++)
1217                 ClearPageForeign(pages[i]);
1218
1219         return clear_foreign_p2m_mapping(unmap_ops, kunmap_ops, pages, count);
1220 }
1221 EXPORT_SYMBOL_GPL(gnttab_unmap_refs);
1222
1223 #define GNTTAB_UNMAP_REFS_DELAY 5
1224
1225 static void __gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item);
1226
1227 static void gnttab_unmap_work(struct work_struct *work)
1228 {
1229         struct gntab_unmap_queue_data
1230                 *unmap_data = container_of(work,
1231                                            struct gntab_unmap_queue_data,
1232                                            gnttab_work.work);
1233         if (unmap_data->age != UINT_MAX)
1234                 unmap_data->age++;
1235         __gnttab_unmap_refs_async(unmap_data);
1236 }
1237
1238 static void __gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item)
1239 {
1240         int ret;
1241         int pc;
1242
1243         for (pc = 0; pc < item->count; pc++) {
1244                 if (page_count(item->pages[pc]) > 1) {
1245                         unsigned long delay = GNTTAB_UNMAP_REFS_DELAY * (item->age + 1);
1246                         schedule_delayed_work(&item->gnttab_work,
1247                                               msecs_to_jiffies(delay));
1248                         return;
1249                 }
1250         }
1251
1252         ret = gnttab_unmap_refs(item->unmap_ops, item->kunmap_ops,
1253                                 item->pages, item->count);
1254         item->done(ret, item);
1255 }
1256
1257 void gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item)
1258 {
1259         INIT_DELAYED_WORK(&item->gnttab_work, gnttab_unmap_work);
1260         item->age = 0;
1261
1262         __gnttab_unmap_refs_async(item);
1263 }
1264 EXPORT_SYMBOL_GPL(gnttab_unmap_refs_async);
1265
1266 static void unmap_refs_callback(int result,
1267                 struct gntab_unmap_queue_data *data)
1268 {
1269         struct unmap_refs_callback_data *d = data->data;
1270
1271         d->result = result;
1272         complete(&d->completion);
1273 }
1274
1275 int gnttab_unmap_refs_sync(struct gntab_unmap_queue_data *item)
1276 {
1277         struct unmap_refs_callback_data data;
1278
1279         init_completion(&data.completion);
1280         item->data = &data;
1281         item->done = &unmap_refs_callback;
1282         gnttab_unmap_refs_async(item);
1283         wait_for_completion(&data.completion);
1284
1285         return data.result;
1286 }
1287 EXPORT_SYMBOL_GPL(gnttab_unmap_refs_sync);
1288
1289 static unsigned int nr_status_frames(unsigned int nr_grant_frames)
1290 {
1291         return gnttab_frames(nr_grant_frames, SPP);
1292 }
1293
1294 static int gnttab_map_frames_v1(xen_pfn_t *frames, unsigned int nr_gframes)
1295 {
1296         int rc;
1297
1298         rc = arch_gnttab_map_shared(frames, nr_gframes,
1299                                     gnttab_max_grant_frames(),
1300                                     &gnttab_shared.addr);
1301         BUG_ON(rc);
1302
1303         return 0;
1304 }
1305
1306 static void gnttab_unmap_frames_v1(void)
1307 {
1308         arch_gnttab_unmap(gnttab_shared.addr, nr_grant_frames);
1309 }
1310
1311 static int gnttab_map_frames_v2(xen_pfn_t *frames, unsigned int nr_gframes)
1312 {
1313         uint64_t *sframes;
1314         unsigned int nr_sframes;
1315         struct gnttab_get_status_frames getframes;
1316         int rc;
1317
1318         nr_sframes = nr_status_frames(nr_gframes);
1319
1320         /* No need for kzalloc as it is initialized in following hypercall
1321          * GNTTABOP_get_status_frames.
1322          */
1323         sframes = kmalloc_array(nr_sframes, sizeof(uint64_t), GFP_ATOMIC);
1324         if (!sframes)
1325                 return -ENOMEM;
1326
1327         getframes.dom        = DOMID_SELF;
1328         getframes.nr_frames  = nr_sframes;
1329         set_xen_guest_handle(getframes.frame_list, sframes);
1330
1331         rc = HYPERVISOR_grant_table_op(GNTTABOP_get_status_frames,
1332                                        &getframes, 1);
1333         if (rc == -ENOSYS) {
1334                 kfree(sframes);
1335                 return -ENOSYS;
1336         }
1337
1338         BUG_ON(rc || getframes.status);
1339
1340         rc = arch_gnttab_map_status(sframes, nr_sframes,
1341                                     nr_status_frames(gnttab_max_grant_frames()),
1342                                     &grstatus);
1343         BUG_ON(rc);
1344         kfree(sframes);
1345
1346         rc = arch_gnttab_map_shared(frames, nr_gframes,
1347                                     gnttab_max_grant_frames(),
1348                                     &gnttab_shared.addr);
1349         BUG_ON(rc);
1350
1351         return 0;
1352 }
1353
1354 static void gnttab_unmap_frames_v2(void)
1355 {
1356         arch_gnttab_unmap(gnttab_shared.addr, nr_grant_frames);
1357         arch_gnttab_unmap(grstatus, nr_status_frames(nr_grant_frames));
1358 }
1359
1360 static int gnttab_map(unsigned int start_idx, unsigned int end_idx)
1361 {
1362         struct gnttab_setup_table setup;
1363         xen_pfn_t *frames;
1364         unsigned int nr_gframes = end_idx + 1;
1365         int rc;
1366
1367         if (xen_feature(XENFEAT_auto_translated_physmap)) {
1368                 struct xen_add_to_physmap xatp;
1369                 unsigned int i = end_idx;
1370                 rc = 0;
1371                 BUG_ON(xen_auto_xlat_grant_frames.count < nr_gframes);
1372                 /*
1373                  * Loop backwards, so that the first hypercall has the largest
1374                  * index, ensuring that the table will grow only once.
1375                  */
1376                 do {
1377                         xatp.domid = DOMID_SELF;
1378                         xatp.idx = i;
1379                         xatp.space = XENMAPSPACE_grant_table;
1380                         xatp.gpfn = xen_auto_xlat_grant_frames.pfn[i];
1381                         rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp);
1382                         if (rc != 0) {
1383                                 pr_warn("grant table add_to_physmap failed, err=%d\n",
1384                                         rc);
1385                                 break;
1386                         }
1387                 } while (i-- > start_idx);
1388
1389                 return rc;
1390         }
1391
1392         /* No need for kzalloc as it is initialized in following hypercall
1393          * GNTTABOP_setup_table.
1394          */
1395         frames = kmalloc_array(nr_gframes, sizeof(unsigned long), GFP_ATOMIC);
1396         if (!frames)
1397                 return -ENOMEM;
1398
1399         setup.dom        = DOMID_SELF;
1400         setup.nr_frames  = nr_gframes;
1401         set_xen_guest_handle(setup.frame_list, frames);
1402
1403         rc = HYPERVISOR_grant_table_op(GNTTABOP_setup_table, &setup, 1);
1404         if (rc == -ENOSYS) {
1405                 kfree(frames);
1406                 return -ENOSYS;
1407         }
1408
1409         BUG_ON(rc || setup.status);
1410
1411         rc = gnttab_interface->map_frames(frames, nr_gframes);
1412
1413         kfree(frames);
1414
1415         return rc;
1416 }
1417
1418 static const struct gnttab_ops gnttab_v1_ops = {
1419         .version                        = 1,
1420         .grefs_per_grant_frame          = XEN_PAGE_SIZE /
1421                                           sizeof(struct grant_entry_v1),
1422         .map_frames                     = gnttab_map_frames_v1,
1423         .unmap_frames                   = gnttab_unmap_frames_v1,
1424         .update_entry                   = gnttab_update_entry_v1,
1425         .end_foreign_access_ref         = gnttab_end_foreign_access_ref_v1,
1426         .end_foreign_transfer_ref       = gnttab_end_foreign_transfer_ref_v1,
1427         .read_frame                     = gnttab_read_frame_v1,
1428 };
1429
1430 static const struct gnttab_ops gnttab_v2_ops = {
1431         .version                        = 2,
1432         .grefs_per_grant_frame          = XEN_PAGE_SIZE /
1433                                           sizeof(union grant_entry_v2),
1434         .map_frames                     = gnttab_map_frames_v2,
1435         .unmap_frames                   = gnttab_unmap_frames_v2,
1436         .update_entry                   = gnttab_update_entry_v2,
1437         .end_foreign_access_ref         = gnttab_end_foreign_access_ref_v2,
1438         .end_foreign_transfer_ref       = gnttab_end_foreign_transfer_ref_v2,
1439         .read_frame                     = gnttab_read_frame_v2,
1440 };
1441
1442 static bool gnttab_need_v2(void)
1443 {
1444 #ifdef CONFIG_X86
1445         uint32_t base, width;
1446
1447         if (xen_pv_domain()) {
1448                 base = xen_cpuid_base();
1449                 if (cpuid_eax(base) < 5)
1450                         return false;   /* Information not available, use V1. */
1451                 width = cpuid_ebx(base + 5) &
1452                         XEN_CPUID_MACHINE_ADDRESS_WIDTH_MASK;
1453                 return width > 32 + PAGE_SHIFT;
1454         }
1455 #endif
1456         return !!(max_possible_pfn >> 32);
1457 }
1458
1459 static void gnttab_request_version(void)
1460 {
1461         long rc;
1462         struct gnttab_set_version gsv;
1463
1464         if (gnttab_need_v2())
1465                 gsv.version = 2;
1466         else
1467                 gsv.version = 1;
1468
1469         /* Boot parameter overrides automatic selection. */
1470         if (xen_gnttab_version >= 1 && xen_gnttab_version <= 2)
1471                 gsv.version = xen_gnttab_version;
1472
1473         rc = HYPERVISOR_grant_table_op(GNTTABOP_set_version, &gsv, 1);
1474         if (rc == 0 && gsv.version == 2)
1475                 gnttab_interface = &gnttab_v2_ops;
1476         else
1477                 gnttab_interface = &gnttab_v1_ops;
1478         pr_info("Grant tables using version %d layout\n",
1479                 gnttab_interface->version);
1480 }
1481
1482 static int gnttab_setup(void)
1483 {
1484         unsigned int max_nr_gframes;
1485
1486         max_nr_gframes = gnttab_max_grant_frames();
1487         if (max_nr_gframes < nr_grant_frames)
1488                 return -ENOSYS;
1489
1490         if (xen_feature(XENFEAT_auto_translated_physmap) && gnttab_shared.addr == NULL) {
1491                 gnttab_shared.addr = xen_auto_xlat_grant_frames.vaddr;
1492                 if (gnttab_shared.addr == NULL) {
1493                         pr_warn("gnttab share frames is not mapped!\n");
1494                         return -ENOMEM;
1495                 }
1496         }
1497         return gnttab_map(0, nr_grant_frames - 1);
1498 }
1499
1500 int gnttab_resume(void)
1501 {
1502         gnttab_request_version();
1503         return gnttab_setup();
1504 }
1505
1506 int gnttab_suspend(void)
1507 {
1508         if (!xen_feature(XENFEAT_auto_translated_physmap))
1509                 gnttab_interface->unmap_frames();
1510         return 0;
1511 }
1512
1513 static int gnttab_expand(unsigned int req_entries)
1514 {
1515         int rc;
1516         unsigned int cur, extra;
1517
1518         cur = nr_grant_frames;
1519         extra = ((req_entries + gnttab_interface->grefs_per_grant_frame - 1) /
1520                  gnttab_interface->grefs_per_grant_frame);
1521         if (cur + extra > gnttab_max_grant_frames()) {
1522                 pr_warn_ratelimited("xen/grant-table: max_grant_frames reached"
1523                                     " cur=%u extra=%u limit=%u"
1524                                     " gnttab_free_count=%u req_entries=%u\n",
1525                                     cur, extra, gnttab_max_grant_frames(),
1526                                     gnttab_free_count, req_entries);
1527                 return -ENOSPC;
1528         }
1529
1530         rc = gnttab_map(cur, cur + extra - 1);
1531         if (rc == 0)
1532                 rc = grow_gnttab_list(extra);
1533
1534         return rc;
1535 }
1536
1537 int gnttab_init(void)
1538 {
1539         int i;
1540         unsigned long max_nr_grant_frames;
1541         unsigned int max_nr_glist_frames, nr_glist_frames;
1542         unsigned int nr_init_grefs;
1543         int ret;
1544
1545         gnttab_request_version();
1546         max_nr_grant_frames = gnttab_max_grant_frames();
1547         nr_grant_frames = 1;
1548
1549         /* Determine the maximum number of frames required for the
1550          * grant reference free list on the current hypervisor.
1551          */
1552         max_nr_glist_frames = (max_nr_grant_frames *
1553                                gnttab_interface->grefs_per_grant_frame / RPP);
1554
1555         gnttab_list = kmalloc_array(max_nr_glist_frames,
1556                                     sizeof(grant_ref_t *),
1557                                     GFP_KERNEL);
1558         if (gnttab_list == NULL)
1559                 return -ENOMEM;
1560
1561         nr_glist_frames = gnttab_frames(nr_grant_frames, RPP);
1562         for (i = 0; i < nr_glist_frames; i++) {
1563                 gnttab_list[i] = (grant_ref_t *)__get_free_page(GFP_KERNEL);
1564                 if (gnttab_list[i] == NULL) {
1565                         ret = -ENOMEM;
1566                         goto ini_nomem;
1567                 }
1568         }
1569
1570         ret = arch_gnttab_init(max_nr_grant_frames,
1571                                nr_status_frames(max_nr_grant_frames));
1572         if (ret < 0)
1573                 goto ini_nomem;
1574
1575         if (gnttab_setup() < 0) {
1576                 ret = -ENODEV;
1577                 goto ini_nomem;
1578         }
1579
1580         nr_init_grefs = nr_grant_frames *
1581                         gnttab_interface->grefs_per_grant_frame;
1582
1583         for (i = NR_RESERVED_ENTRIES; i < nr_init_grefs - 1; i++)
1584                 gnttab_entry(i) = i + 1;
1585
1586         gnttab_entry(nr_init_grefs - 1) = GNTTAB_LIST_END;
1587         gnttab_free_count = nr_init_grefs - NR_RESERVED_ENTRIES;
1588         gnttab_free_head  = NR_RESERVED_ENTRIES;
1589
1590         printk("Grant table initialized\n");
1591         return 0;
1592
1593  ini_nomem:
1594         for (i--; i >= 0; i--)
1595                 free_page((unsigned long)gnttab_list[i]);
1596         kfree(gnttab_list);
1597         return ret;
1598 }
1599 EXPORT_SYMBOL_GPL(gnttab_init);
1600
1601 static int __gnttab_init(void)
1602 {
1603         if (!xen_domain())
1604                 return -ENODEV;
1605
1606         /* Delay grant-table initialization in the PV on HVM case */
1607         if (xen_hvm_domain() && !xen_pvh_domain())
1608                 return 0;
1609
1610         return gnttab_init();
1611 }
1612 /* Starts after core_initcall so that xen_pvh_gnttab_setup can be called
1613  * beforehand to initialize xen_auto_xlat_grant_frames. */
1614 core_initcall_sync(__gnttab_init);