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/bootmem.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/pgtable.h>
  68 #include <asm/sync_bitops.h>
  69
  70 /* External tools reserve first few grant table entries. */
  71 #define NR_RESERVED_ENTRIES 8
  72 #define GNTTAB_LIST_END 0xffffffff
  73
  74 static grant_ref_t **gnttab_list;
  75 static unsigned int nr_grant_frames;
  76 static int gnttab_free_count;
  77 static grant_ref_t gnttab_free_head;
  78 static DEFINE_SPINLOCK(gnttab_list_lock);
  79 struct grant_frames xen_auto_xlat_grant_frames;
  80 static unsigned int xen_gnttab_version;
  81 module_param_named(version, xen_gnttab_version, uint, 0);
  82
  83 static union {
  84         struct grant_entry_v1 *v1;
  85         union grant_entry_v2 *v2;
  86         void *addr;
  87 } gnttab_shared;
  88
  89 /*This is a structure of function pointers for grant table*/
  90 struct gnttab_ops {
  91         /*
  92          * Version of the grant interface.
  93          */
  94         unsigned int version;
  95         /*
  96          * Grant refs per grant frame.
  97          */
  98         unsigned int grefs_per_grant_frame;
  99         /*
 100          * Mapping a list of frames for storing grant entries. Frames parameter
 101          * is used to store grant table address when grant table being setup,
 102          * nr_gframes is the number of frames to map grant table. Returning
 103          * GNTST_okay means success and negative value means failure.
 104          */
 105         int (*map_frames)(xen_pfn_t *frames, unsigned int nr_gframes);
 106         /*
 107          * Release a list of frames which are mapped in map_frames for grant
 108          * entry status.
 109          */
 110         void (*unmap_frames)(void);
 111         /*
 112          * Introducing a valid entry into the grant table, granting the frame of
 113          * this grant entry to domain for accessing or transfering. Ref
 114          * parameter is reference of this introduced grant entry, domid is id of
 115          * granted domain, frame is the page frame to be granted, and flags is
 116          * status of the grant entry to be updated.
 117          */
 118         void (*update_entry)(grant_ref_t ref, domid_t domid,
 119                              unsigned long frame, unsigned flags);
 120         /*
 121          * Stop granting a grant entry to domain for accessing. Ref parameter is
 122          * reference of a grant entry whose grant access will be stopped,
 123          * readonly is not in use in this function. If the grant entry is
 124          * currently mapped for reading or writing, just return failure(==0)
 125          * directly and don't tear down the grant access. Otherwise, stop grant
 126          * access for this entry and return success(==1).
 127          */
 128         int (*end_foreign_access_ref)(grant_ref_t ref, int readonly);
 129         /*
 130          * Stop granting a grant entry to domain for transfer. Ref parameter is
 131          * reference of a grant entry whose grant transfer will be stopped. If
 132          * tranfer has not started, just reclaim the grant entry and return
 133          * failure(==0). Otherwise, wait for the transfer to complete and then
 134          * return the frame.
 135          */
 136         unsigned long (*end_foreign_transfer_ref)(grant_ref_t ref);
 137         /*
 138          * Read the frame number related to a given grant reference.
 139          */
 140         unsigned long (*read_frame)(grant_ref_t ref);
 141 };
 142
 143 struct unmap_refs_callback_data {
 144         struct completion completion;
 145         int result;
 146 };
 147
 148 static const struct gnttab_ops *gnttab_interface;
 149
 150 /* This reflects status of grant entries, so act as a global value. */
 151 static grant_status_t *grstatus;
 152
 153 static struct gnttab_free_callback *gnttab_free_callback_list;
 154
 155 static int gnttab_expand(unsigned int req_entries);
 156
 157 #define RPP (PAGE_SIZE / sizeof(grant_ref_t))
 158 #define SPP (PAGE_SIZE / sizeof(grant_status_t))
 159
 160 static inline grant_ref_t *__gnttab_entry(grant_ref_t entry)
 161 {
 162         return &gnttab_list[(entry) / RPP][(entry) % RPP];
 163 }
 164 /* This can be used as an l-value */
 165 #define gnttab_entry(entry) (*__gnttab_entry(entry))
 166
 167 static int get_free_entries(unsigned count)
 168 {
 169         unsigned long flags;
 170         int ref, rc = 0;
 171         grant_ref_t head;
 172
 173         spin_lock_irqsave(&gnttab_list_lock, flags);
 174
 175         if ((gnttab_free_count < count) &&
 176             ((rc = gnttab_expand(count - gnttab_free_count)) < 0)) {
 177                 spin_unlock_irqrestore(&gnttab_list_lock, flags);
 178                 return rc;
 179         }
 180
 181         ref = head = gnttab_free_head;
 182         gnttab_free_count -= count;
 183         while (count-- > 1)
 184                 head = gnttab_entry(head);
 185         gnttab_free_head = gnttab_entry(head);
 186         gnttab_entry(head) = GNTTAB_LIST_END;
 187
 188         spin_unlock_irqrestore(&gnttab_list_lock, flags);
 189
 190         return ref;
 191 }
 192
 193 static void do_free_callbacks(void)
 194 {
 195         struct gnttab_free_callback *callback, *next;
 196
 197         callback = gnttab_free_callback_list;
 198         gnttab_free_callback_list = NULL;
 199
 200         while (callback != NULL) {
 201                 next = callback->next;
 202                 if (gnttab_free_count >= callback->count) {
 203                         callback->next = NULL;
 204                         callback->fn(callback->arg);
 205                 } else {
 206                         callback->next = gnttab_free_callback_list;
 207                         gnttab_free_callback_list = callback;
 208                 }
 209                 callback = next;
 210         }
 211 }
 212
 213 static inline void check_free_callbacks(void)
 214 {
 215         if (unlikely(gnttab_free_callback_list))
 216                 do_free_callbacks();
 217 }
 218
 219 static void put_free_entry(grant_ref_t ref)
 220 {
 221         unsigned long flags;
 222         spin_lock_irqsave(&gnttab_list_lock, flags);
 223         gnttab_entry(ref) = gnttab_free_head;
 224         gnttab_free_head = ref;
 225         gnttab_free_count++;
 226         check_free_callbacks();
 227         spin_unlock_irqrestore(&gnttab_list_lock, flags);
 228 }
 229
 230 /*
 231  * Following applies to gnttab_update_entry_v1 and gnttab_update_entry_v2.
 232  * Introducing a valid entry into the grant table:
 233  *  1. Write ent->domid.
 234  *  2. Write ent->frame:
 235  *      GTF_permit_access:   Frame to which access is permitted.
 236  *      GTF_accept_transfer: Pseudo-phys frame slot being filled by new
 237  *                           frame, or zero if none.
 238  *  3. Write memory barrier (WMB).
 239  *  4. Write ent->flags, inc. valid type.
 240  */
 241 static void gnttab_update_entry_v1(grant_ref_t ref, domid_t domid,
 242                                    unsigned long frame, unsigned flags)
 243 {
 244         gnttab_shared.v1[ref].domid = domid;
 245         gnttab_shared.v1[ref].frame = frame;
 246         wmb();
 247         gnttab_shared.v1[ref].flags = flags;
 248 }
 249
 250 static void gnttab_update_entry_v2(grant_ref_t ref, domid_t domid,
 251                                    unsigned long frame, unsigned int flags)
 252 {
 253         gnttab_shared.v2[ref].hdr.domid = domid;
 254         gnttab_shared.v2[ref].full_page.frame = frame;
 255         wmb();  /* Hypervisor concurrent accesses. */
 256         gnttab_shared.v2[ref].hdr.flags = GTF_permit_access | flags;
 257 }
 258
 259 /*
 260  * Public grant-issuing interface functions
 261  */
 262 void gnttab_grant_foreign_access_ref(grant_ref_t ref, domid_t domid,
 263                                      unsigned long frame, int readonly)
 264 {
 265         gnttab_interface->update_entry(ref, domid, frame,
 266                            GTF_permit_access | (readonly ? GTF_readonly : 0));
 267 }
 268 EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access_ref);
 269
 270 int gnttab_grant_foreign_access(domid_t domid, unsigned long frame,
 271                                 int readonly)
 272 {
 273         int ref;
 274
 275         ref = get_free_entries(1);
 276         if (unlikely(ref < 0))
 277                 return -ENOSPC;
 278
 279         gnttab_grant_foreign_access_ref(ref, domid, frame, readonly);
 280
 281         return ref;
 282 }
 283 EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access);
 284
 285 static int gnttab_end_foreign_access_ref_v1(grant_ref_t ref, int readonly)
 286 {
 287         u16 flags, nflags;
 288         u16 *pflags;
 289
 290         pflags = &gnttab_shared.v1[ref].flags;
 291         nflags = *pflags;
 292         do {
 293                 flags = nflags;
 294                 if (flags & (GTF_reading|GTF_writing))
 295                         return 0;
 296         } while ((nflags = sync_cmpxchg(pflags, flags, 0)) != flags);
 297
 298         return 1;
 299 }
 300
 301 static int gnttab_end_foreign_access_ref_v2(grant_ref_t ref, int readonly)
 302 {
 303         gnttab_shared.v2[ref].hdr.flags = 0;
 304         mb();   /* Concurrent access by hypervisor. */
 305         if (grstatus[ref] & (GTF_reading|GTF_writing)) {
 306                 return 0;
 307         } else {
 308                 /*
 309                  * The read of grstatus needs to have acquire semantics.
 310                  *  On x86, reads already have that, and we just need to
 311                  * protect against compiler reorderings.
 312                  * On other architectures we may need a full barrier.
 313                  */
 314 #ifdef CONFIG_X86
 315                 barrier();
 316 #else
 317                 mb();
 318 #endif
 319         }
 320
 321         return 1;
 322 }
 323
 324 static inline int _gnttab_end_foreign_access_ref(grant_ref_t ref, int readonly)
 325 {
 326         return gnttab_interface->end_foreign_access_ref(ref, readonly);
 327 }
 328
 329 int gnttab_end_foreign_access_ref(grant_ref_t ref, int readonly)
 330 {
 331         if (_gnttab_end_foreign_access_ref(ref, readonly))
 332                 return 1;
 333         pr_warn("WARNING: g.e. %#x still in use!\n", ref);
 334         return 0;
 335 }
 336 EXPORT_SYMBOL_GPL(gnttab_end_foreign_access_ref);
 337
 338 static unsigned long gnttab_read_frame_v1(grant_ref_t ref)
 339 {
 340         return gnttab_shared.v1[ref].frame;
 341 }
 342
 343 static unsigned long gnttab_read_frame_v2(grant_ref_t ref)
 344 {
 345         return gnttab_shared.v2[ref].full_page.frame;
 346 }
 347
 348 struct deferred_entry {
 349         struct list_head list;
 350         grant_ref_t ref;
 351         bool ro;
 352         uint16_t warn_delay;
 353         struct page *page;
 354 };
 355 static LIST_HEAD(deferred_list);
 356 static void gnttab_handle_deferred(struct timer_list *);
 357 static DEFINE_TIMER(deferred_timer, gnttab_handle_deferred);
 358
 359 static void gnttab_handle_deferred(struct timer_list *unused)
 360 {
 361         unsigned int nr = 10;
 362         struct deferred_entry *first = NULL;
 363         unsigned long flags;
 364
 365         spin_lock_irqsave(&gnttab_list_lock, flags);
 366         while (nr--) {
 367                 struct deferred_entry *entry
 368                         = list_first_entry(&deferred_list,
 369                                            struct deferred_entry, list);
 370
 371                 if (entry == first)
 372                         break;
 373                 list_del(&entry->list);
 374                 spin_unlock_irqrestore(&gnttab_list_lock, flags);
 375                 if (_gnttab_end_foreign_access_ref(entry->ref, entry->ro)) {
 376                         put_free_entry(entry->ref);
 377                         pr_debug("freeing g.e. %#x (pfn %#lx)\n",
 378                                  entry->ref, page_to_pfn(entry->page));
 379                         put_page(entry->page);
 380                         kfree(entry);
 381                         entry = NULL;
 382                 } else {
 383                         if (!--entry->warn_delay)
 384                                 pr_info("g.e. %#x still pending\n", entry->ref);
 385                         if (!first)
 386                                 first = entry;
 387                 }
 388                 spin_lock_irqsave(&gnttab_list_lock, flags);
 389                 if (entry)
 390                         list_add_tail(&entry->list, &deferred_list);
 391                 else if (list_empty(&deferred_list))
 392                         break;
 393         }
 394         if (!list_empty(&deferred_list) && !timer_pending(&deferred_timer)) {
 395                 deferred_timer.expires = jiffies + HZ;
 396                 add_timer(&deferred_timer);
 397         }
 398         spin_unlock_irqrestore(&gnttab_list_lock, flags);
 399 }
 400
 401 static void gnttab_add_deferred(grant_ref_t ref, bool readonly,
 402                                 struct page *page)
 403 {
 404         struct deferred_entry *entry;
 405         gfp_t gfp = (in_atomic() || irqs_disabled()) ? GFP_ATOMIC : GFP_KERNEL;
 406         const char *what = KERN_WARNING "leaking";
 407
 408         entry = kmalloc(sizeof(*entry), gfp);
 409         if (!page) {
 410                 unsigned long gfn = gnttab_interface->read_frame(ref);
 411
 412                 page = pfn_to_page(gfn_to_pfn(gfn));
 413                 get_page(page);
 414         }
 415
 416         if (entry) {
 417                 unsigned long flags;
 418
 419                 entry->ref = ref;
 420                 entry->ro = readonly;
 421                 entry->page = page;
 422                 entry->warn_delay = 60;
 423                 spin_lock_irqsave(&gnttab_list_lock, flags);
 424                 list_add_tail(&entry->list, &deferred_list);
 425                 if (!timer_pending(&deferred_timer)) {
 426                         deferred_timer.expires = jiffies + HZ;
 427                         add_timer(&deferred_timer);
 428                 }
 429                 spin_unlock_irqrestore(&gnttab_list_lock, flags);
 430                 what = KERN_DEBUG "deferring";
 431         }
 432         printk("%s g.e. %#x (pfn %#lx)\n",
 433                what, ref, page ? page_to_pfn(page) : -1);
 434 }
 435
 436 int gnttab_try_end_foreign_access(grant_ref_t ref)
 437 {
 438         int ret = _gnttab_end_foreign_access_ref(ref, 0);
 439
 440         if (ret)
 441                 put_free_entry(ref);
 442
 443         return ret;
 444 }
 445 EXPORT_SYMBOL_GPL(gnttab_try_end_foreign_access);
 446
 447 void gnttab_end_foreign_access(grant_ref_t ref, int readonly,
 448                                unsigned long page)
 449 {
 450         if (gnttab_try_end_foreign_access(ref)) {
 451                 if (page != 0)
 452                         put_page(virt_to_page(page));
 453         } else
 454                 gnttab_add_deferred(ref, readonly,
 455                                     page ? virt_to_page(page) : NULL);
 456 }
 457 EXPORT_SYMBOL_GPL(gnttab_end_foreign_access);
 458
 459 int gnttab_grant_foreign_transfer(domid_t domid, unsigned long pfn)
 460 {
 461         int ref;
 462
 463         ref = get_free_entries(1);
 464         if (unlikely(ref < 0))
 465                 return -ENOSPC;
 466         gnttab_grant_foreign_transfer_ref(ref, domid, pfn);
 467
 468         return ref;
 469 }
 470 EXPORT_SYMBOL_GPL(gnttab_grant_foreign_transfer);
 471
 472 void gnttab_grant_foreign_transfer_ref(grant_ref_t ref, domid_t domid,
 473                                        unsigned long pfn)
 474 {
 475         gnttab_interface->update_entry(ref, domid, pfn, GTF_accept_transfer);
 476 }
 477 EXPORT_SYMBOL_GPL(gnttab_grant_foreign_transfer_ref);
 478
 479 static unsigned long gnttab_end_foreign_transfer_ref_v1(grant_ref_t ref)
 480 {
 481         unsigned long frame;
 482         u16           flags;
 483         u16          *pflags;
 484
 485         pflags = &gnttab_shared.v1[ref].flags;
 486
 487         /*
 488          * If a transfer is not even yet started, try to reclaim the grant
 489          * reference and return failure (== 0).
 490          */
 491         while (!((flags = *pflags) & GTF_transfer_committed)) {
 492                 if (sync_cmpxchg(pflags, flags, 0) == flags)
 493                         return 0;
 494                 cpu_relax();
 495         }
 496
 497         /* If a transfer is in progress then wait until it is completed. */
 498         while (!(flags & GTF_transfer_completed)) {
 499                 flags = *pflags;
 500                 cpu_relax();
 501         }
 502
 503         rmb();  /* Read the frame number /after/ reading completion status. */
 504         frame = gnttab_shared.v1[ref].frame;
 505         BUG_ON(frame == 0);
 506
 507         return frame;
 508 }
 509
 510 static unsigned long gnttab_end_foreign_transfer_ref_v2(grant_ref_t ref)
 511 {
 512         unsigned long frame;
 513         u16           flags;
 514         u16          *pflags;
 515
 516         pflags = &gnttab_shared.v2[ref].hdr.flags;
 517
 518         /*
 519          * If a transfer is not even yet started, try to reclaim the grant
 520          * reference and return failure (== 0).
 521          */
 522         while (!((flags = *pflags) & GTF_transfer_committed)) {
 523                 if (sync_cmpxchg(pflags, flags, 0) == flags)
 524                         return 0;
 525                 cpu_relax();
 526         }
 527
 528         /* If a transfer is in progress then wait until it is completed. */
 529         while (!(flags & GTF_transfer_completed)) {
 530                 flags = *pflags;
 531                 cpu_relax();
 532         }
 533
 534         rmb();  /* Read the frame number /after/ reading completion status. */
 535         frame = gnttab_shared.v2[ref].full_page.frame;
 536         BUG_ON(frame == 0);
 537
 538         return frame;
 539 }
 540
 541 unsigned long gnttab_end_foreign_transfer_ref(grant_ref_t ref)
 542 {
 543         return gnttab_interface->end_foreign_transfer_ref(ref);
 544 }
 545 EXPORT_SYMBOL_GPL(gnttab_end_foreign_transfer_ref);
 546
 547 unsigned long gnttab_end_foreign_transfer(grant_ref_t ref)
 548 {
 549         unsigned long frame = gnttab_end_foreign_transfer_ref(ref);
 550         put_free_entry(ref);
 551         return frame;
 552 }
 553 EXPORT_SYMBOL_GPL(gnttab_end_foreign_transfer);
 554
 555 void gnttab_free_grant_reference(grant_ref_t ref)
 556 {
 557         put_free_entry(ref);
 558 }
 559 EXPORT_SYMBOL_GPL(gnttab_free_grant_reference);
 560
 561 void gnttab_free_grant_references(grant_ref_t head)
 562 {
 563         grant_ref_t ref;
 564         unsigned long flags;
 565         int count = 1;
 566         if (head == GNTTAB_LIST_END)
 567                 return;
 568         spin_lock_irqsave(&gnttab_list_lock, flags);
 569         ref = head;
 570         while (gnttab_entry(ref) != GNTTAB_LIST_END) {
 571                 ref = gnttab_entry(ref);
 572                 count++;
 573         }
 574         gnttab_entry(ref) = gnttab_free_head;
 575         gnttab_free_head = head;
 576         gnttab_free_count += count;
 577         check_free_callbacks();
 578         spin_unlock_irqrestore(&gnttab_list_lock, flags);
 579 }
 580 EXPORT_SYMBOL_GPL(gnttab_free_grant_references);
 581
 582 int gnttab_alloc_grant_references(u16 count, grant_ref_t *head)
 583 {
 584         int h = get_free_entries(count);
 585
 586         if (h < 0)
 587                 return -ENOSPC;
 588
 589         *head = h;
 590
 591         return 0;
 592 }
 593 EXPORT_SYMBOL_GPL(gnttab_alloc_grant_references);
 594
 595 int gnttab_empty_grant_references(const grant_ref_t *private_head)
 596 {
 597         return (*private_head == GNTTAB_LIST_END);
 598 }
 599 EXPORT_SYMBOL_GPL(gnttab_empty_grant_references);
 600
 601 int gnttab_claim_grant_reference(grant_ref_t *private_head)
 602 {
 603         grant_ref_t g = *private_head;
 604         if (unlikely(g == GNTTAB_LIST_END))
 605                 return -ENOSPC;
 606         *private_head = gnttab_entry(g);
 607         return g;
 608 }
 609 EXPORT_SYMBOL_GPL(gnttab_claim_grant_reference);
 610
 611 void gnttab_release_grant_reference(grant_ref_t *private_head,
 612                                     grant_ref_t release)
 613 {
 614         gnttab_entry(release) = *private_head;
 615         *private_head = release;
 616 }
 617 EXPORT_SYMBOL_GPL(gnttab_release_grant_reference);
 618
 619 void gnttab_request_free_callback(struct gnttab_free_callback *callback,
 620                                   void (*fn)(void *), void *arg, u16 count)
 621 {
 622         unsigned long flags;
 623         struct gnttab_free_callback *cb;
 624
 625         spin_lock_irqsave(&gnttab_list_lock, flags);
 626
 627         /* Check if the callback is already on the list */
 628         cb = gnttab_free_callback_list;
 629         while (cb) {
 630                 if (cb == callback)
 631                         goto out;
 632                 cb = cb->next;
 633         }
 634
 635         callback->fn = fn;
 636         callback->arg = arg;
 637         callback->count = count;
 638         callback->next = gnttab_free_callback_list;
 639         gnttab_free_callback_list = callback;
 640         check_free_callbacks();
 641 out:
 642         spin_unlock_irqrestore(&gnttab_list_lock, flags);
 643 }
 644 EXPORT_SYMBOL_GPL(gnttab_request_free_callback);
 645
 646 void gnttab_cancel_free_callback(struct gnttab_free_callback *callback)
 647 {
 648         struct gnttab_free_callback **pcb;
 649         unsigned long flags;
 650
 651         spin_lock_irqsave(&gnttab_list_lock, flags);
 652         for (pcb = &gnttab_free_callback_list; *pcb; pcb = &(*pcb)->next) {
 653                 if (*pcb == callback) {
 654                         *pcb = callback->next;
 655                         break;
 656                 }
 657         }
 658         spin_unlock_irqrestore(&gnttab_list_lock, flags);
 659 }
 660 EXPORT_SYMBOL_GPL(gnttab_cancel_free_callback);
 661
 662 static unsigned int gnttab_frames(unsigned int frames, unsigned int align)
 663 {
 664         return (frames * gnttab_interface->grefs_per_grant_frame + align - 1) /
 665                align;
 666 }
 667
 668 static int grow_gnttab_list(unsigned int more_frames)
 669 {
 670         unsigned int new_nr_grant_frames, extra_entries, i;
 671         unsigned int nr_glist_frames, new_nr_glist_frames;
 672         unsigned int grefs_per_frame;
 673
 674         BUG_ON(gnttab_interface == NULL);
 675         grefs_per_frame = gnttab_interface->grefs_per_grant_frame;
 676
 677         new_nr_grant_frames = nr_grant_frames + more_frames;
 678         extra_entries = more_frames * grefs_per_frame;
 679
 680         nr_glist_frames = gnttab_frames(nr_grant_frames, RPP);
 681         new_nr_glist_frames = gnttab_frames(new_nr_grant_frames, RPP);
 682         for (i = nr_glist_frames; i < new_nr_glist_frames; i++) {
 683                 gnttab_list[i] = (grant_ref_t *)__get_free_page(GFP_ATOMIC);
 684                 if (!gnttab_list[i])
 685                         goto grow_nomem;
 686         }
 687
 688
 689         for (i = grefs_per_frame * nr_grant_frames;
 690              i < grefs_per_frame * new_nr_grant_frames - 1; i++)
 691                 gnttab_entry(i) = i + 1;
 692
 693         gnttab_entry(i) = gnttab_free_head;
 694         gnttab_free_head = grefs_per_frame * nr_grant_frames;
 695         gnttab_free_count += extra_entries;
 696
 697         nr_grant_frames = new_nr_grant_frames;
 698
 699         check_free_callbacks();
 700
 701         return 0;
 702
 703 grow_nomem:
 704         while (i-- > nr_glist_frames)
 705                 free_page((unsigned long) gnttab_list[i]);
 706         return -ENOMEM;
 707 }
 708
 709 static unsigned int __max_nr_grant_frames(void)
 710 {
 711         struct gnttab_query_size query;
 712         int rc;
 713
 714         query.dom = DOMID_SELF;
 715
 716         rc = HYPERVISOR_grant_table_op(GNTTABOP_query_size, &query, 1);
 717         if ((rc < 0) || (query.status != GNTST_okay))
 718                 return 4; /* Legacy max supported number of frames */
 719
 720         return query.max_nr_frames;
 721 }
 722
 723 unsigned int gnttab_max_grant_frames(void)
 724 {
 725         unsigned int xen_max = __max_nr_grant_frames();
 726         static unsigned int boot_max_nr_grant_frames;
 727
 728         /* First time, initialize it properly. */
 729         if (!boot_max_nr_grant_frames)
 730                 boot_max_nr_grant_frames = __max_nr_grant_frames();
 731
 732         if (xen_max > boot_max_nr_grant_frames)
 733                 return boot_max_nr_grant_frames;
 734         return xen_max;
 735 }
 736 EXPORT_SYMBOL_GPL(gnttab_max_grant_frames);
 737
 738 int gnttab_setup_auto_xlat_frames(phys_addr_t addr)
 739 {
 740         xen_pfn_t *pfn;
 741         unsigned int max_nr_gframes = __max_nr_grant_frames();
 742         unsigned int i;
 743         void *vaddr;
 744
 745         if (xen_auto_xlat_grant_frames.count)
 746                 return -EINVAL;
 747
 748         vaddr = xen_remap(addr, XEN_PAGE_SIZE * max_nr_gframes);
 749         if (vaddr == NULL) {
 750                 pr_warn("Failed to ioremap gnttab share frames (addr=%pa)!\n",
 751                         &addr);
 752                 return -ENOMEM;
 753         }
 754         pfn = kcalloc(max_nr_gframes, sizeof(pfn[0]), GFP_KERNEL);
 755         if (!pfn) {
 756                 xen_unmap(vaddr);
 757                 return -ENOMEM;
 758         }
 759         for (i = 0; i < max_nr_gframes; i++)
 760                 pfn[i] = XEN_PFN_DOWN(addr) + i;
 761
 762         xen_auto_xlat_grant_frames.vaddr = vaddr;
 763         xen_auto_xlat_grant_frames.pfn = pfn;
 764         xen_auto_xlat_grant_frames.count = max_nr_gframes;
 765
 766         return 0;
 767 }
 768 EXPORT_SYMBOL_GPL(gnttab_setup_auto_xlat_frames);
 769
 770 void gnttab_free_auto_xlat_frames(void)
 771 {
 772         if (!xen_auto_xlat_grant_frames.count)
 773                 return;
 774         kfree(xen_auto_xlat_grant_frames.pfn);
 775         xen_unmap(xen_auto_xlat_grant_frames.vaddr);
 776
 777         xen_auto_xlat_grant_frames.pfn = NULL;
 778         xen_auto_xlat_grant_frames.count = 0;
 779         xen_auto_xlat_grant_frames.vaddr = NULL;
 780 }
 781 EXPORT_SYMBOL_GPL(gnttab_free_auto_xlat_frames);
 782
 783 int gnttab_pages_set_private(int nr_pages, struct page **pages)
 784 {
 785         int i;
 786
 787         for (i = 0; i < nr_pages; i++) {
 788 #if BITS_PER_LONG < 64
 789                 struct xen_page_foreign *foreign;
 790
 791                 foreign = kzalloc(sizeof(*foreign), GFP_KERNEL);
 792                 if (!foreign)
 793                         return -ENOMEM;
 794
 795                 set_page_private(pages[i], (unsigned long)foreign);
 796 #endif
 797                 SetPagePrivate(pages[i]);
 798         }
 799
 800         return 0;
 801 }
 802 EXPORT_SYMBOL_GPL(gnttab_pages_set_private);
 803
 804 /**
 805  * gnttab_alloc_pages - alloc pages suitable for grant mapping into
 806  * @nr_pages: number of pages to alloc
 807  * @pages: returns the pages
 808  */
 809 int gnttab_alloc_pages(int nr_pages, struct page **pages)
 810 {
 811         int ret;
 812
 813         ret = alloc_xenballooned_pages(nr_pages, pages);
 814         if (ret < 0)
 815                 return ret;
 816
 817         ret = gnttab_pages_set_private(nr_pages, pages);
 818         if (ret < 0)
 819                 gnttab_free_pages(nr_pages, pages);
 820
 821         return ret;
 822 }
 823 EXPORT_SYMBOL_GPL(gnttab_alloc_pages);
 824
 825 void gnttab_pages_clear_private(int nr_pages, struct page **pages)
 826 {
 827         int i;
 828
 829         for (i = 0; i < nr_pages; i++) {
 830                 if (PagePrivate(pages[i])) {
 831 #if BITS_PER_LONG < 64
 832                         kfree((void *)page_private(pages[i]));
 833 #endif
 834                         ClearPagePrivate(pages[i]);
 835                 }
 836         }
 837 }
 838 EXPORT_SYMBOL_GPL(gnttab_pages_clear_private);
 839
 840 /**
 841  * gnttab_free_pages - free pages allocated by gnttab_alloc_pages()
 842  * @nr_pages; number of pages to free
 843  * @pages: the pages
 844  */
 845 void gnttab_free_pages(int nr_pages, struct page **pages)
 846 {
 847         gnttab_pages_clear_private(nr_pages, pages);
 848         free_xenballooned_pages(nr_pages, pages);
 849 }
 850 EXPORT_SYMBOL_GPL(gnttab_free_pages);
 851
 852 #ifdef CONFIG_XEN_GRANT_DMA_ALLOC
 853 /**
 854  * gnttab_dma_alloc_pages - alloc DMAable pages suitable for grant mapping into
 855  * @args: arguments to the function
 856  */
 857 int gnttab_dma_alloc_pages(struct gnttab_dma_alloc_args *args)
 858 {
 859         unsigned long pfn, start_pfn;
 860         size_t size;
 861         int i, ret;
 862
 863         size = args->nr_pages << PAGE_SHIFT;
 864         if (args->coherent)
 865                 args->vaddr = dma_alloc_coherent(args->dev, size,
 866                                                  &args->dev_bus_addr,
 867                                                  GFP_KERNEL | __GFP_NOWARN);
 868         else
 869                 args->vaddr = dma_alloc_wc(args->dev, size,
 870                                            &args->dev_bus_addr,
 871                                            GFP_KERNEL | __GFP_NOWARN);
 872         if (!args->vaddr) {
 873                 pr_debug("Failed to allocate DMA buffer of size %zu\n", size);
 874                 return -ENOMEM;
 875         }
 876
 877         start_pfn = __phys_to_pfn(args->dev_bus_addr);
 878         for (pfn = start_pfn, i = 0; pfn < start_pfn + args->nr_pages;
 879                         pfn++, i++) {
 880                 struct page *page = pfn_to_page(pfn);
 881
 882                 args->pages[i] = page;
 883                 args->frames[i] = xen_page_to_gfn(page);
 884                 xenmem_reservation_scrub_page(page);
 885         }
 886
 887         xenmem_reservation_va_mapping_reset(args->nr_pages, args->pages);
 888
 889         ret = xenmem_reservation_decrease(args->nr_pages, args->frames);
 890         if (ret != args->nr_pages) {
 891                 pr_debug("Failed to decrease reservation for DMA buffer\n");
 892                 ret = -EFAULT;
 893                 goto fail;
 894         }
 895
 896         ret = gnttab_pages_set_private(args->nr_pages, args->pages);
 897         if (ret < 0)
 898                 goto fail;
 899
 900         return 0;
 901
 902 fail:
 903         gnttab_dma_free_pages(args);
 904         return ret;
 905 }
 906 EXPORT_SYMBOL_GPL(gnttab_dma_alloc_pages);
 907
 908 /**
 909  * gnttab_dma_free_pages - free DMAable pages
 910  * @args: arguments to the function
 911  */
 912 int gnttab_dma_free_pages(struct gnttab_dma_alloc_args *args)
 913 {
 914         size_t size;
 915         int i, ret;
 916
 917         gnttab_pages_clear_private(args->nr_pages, args->pages);
 918
 919         for (i = 0; i < args->nr_pages; i++)
 920                 args->frames[i] = page_to_xen_pfn(args->pages[i]);
 921
 922         ret = xenmem_reservation_increase(args->nr_pages, args->frames);
 923         if (ret != args->nr_pages) {
 924                 pr_debug("Failed to increase reservation for DMA buffer\n");
 925                 ret = -EFAULT;
 926         } else {
 927                 ret = 0;
 928         }
 929
 930         xenmem_reservation_va_mapping_update(args->nr_pages, args->pages,
 931                                              args->frames);
 932
 933         size = args->nr_pages << PAGE_SHIFT;
 934         if (args->coherent)
 935                 dma_free_coherent(args->dev, size,
 936                                   args->vaddr, args->dev_bus_addr);
 937         else
 938                 dma_free_wc(args->dev, size,
 939                             args->vaddr, args->dev_bus_addr);
 940         return ret;
 941 }
 942 EXPORT_SYMBOL_GPL(gnttab_dma_free_pages);
 943 #endif
 944
 945 /* Handling of paged out grant targets (GNTST_eagain) */
 946 #define MAX_DELAY 256
 947 static inline void
 948 gnttab_retry_eagain_gop(unsigned int cmd, void *gop, int16_t *status,
 949                                                 const char *func)
 950 {
 951         unsigned delay = 1;
 952
 953         do {
 954                 BUG_ON(HYPERVISOR_grant_table_op(cmd, gop, 1));
 955                 if (*status == GNTST_eagain)
 956                         msleep(delay++);
 957         } while ((*status == GNTST_eagain) && (delay < MAX_DELAY));
 958
 959         if (delay >= MAX_DELAY) {
 960                 pr_err("%s: %s eagain grant\n", func, current->comm);
 961                 *status = GNTST_bad_page;
 962         }
 963 }
 964
 965 void gnttab_batch_map(struct gnttab_map_grant_ref *batch, unsigned count)
 966 {
 967         struct gnttab_map_grant_ref *op;
 968
 969         if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, batch, count))
 970                 BUG();
 971         for (op = batch; op < batch + count; op++)
 972                 if (op->status == GNTST_eagain)
 973                         gnttab_retry_eagain_gop(GNTTABOP_map_grant_ref, op,
 974                                                 &op->status, __func__);
 975 }
 976 EXPORT_SYMBOL_GPL(gnttab_batch_map);
 977
 978 void gnttab_batch_copy(struct gnttab_copy *batch, unsigned count)
 979 {
 980         struct gnttab_copy *op;
 981
 982         if (HYPERVISOR_grant_table_op(GNTTABOP_copy, batch, count))
 983                 BUG();
 984         for (op = batch; op < batch + count; op++)
 985                 if (op->status == GNTST_eagain)
 986                         gnttab_retry_eagain_gop(GNTTABOP_copy, op,
 987                                                 &op->status, __func__);
 988 }
 989 EXPORT_SYMBOL_GPL(gnttab_batch_copy);
 990
 991 void gnttab_foreach_grant_in_range(struct page *page,
 992                                    unsigned int offset,
 993                                    unsigned int len,
 994                                    xen_grant_fn_t fn,
 995                                    void *data)
 996 {
 997         unsigned int goffset;
 998         unsigned int glen;
 999         unsigned long xen_pfn;
1000
1001         len = min_t(unsigned int, PAGE_SIZE - offset, len);
1002         goffset = xen_offset_in_page(offset);
1003
1004         xen_pfn = page_to_xen_pfn(page) + XEN_PFN_DOWN(offset);
1005
1006         while (len) {
1007                 glen = min_t(unsigned int, XEN_PAGE_SIZE - goffset, len);
1008                 fn(pfn_to_gfn(xen_pfn), goffset, glen, data);
1009
1010                 goffset = 0;
1011                 xen_pfn++;
1012                 len -= glen;
1013         }
1014 }
1015 EXPORT_SYMBOL_GPL(gnttab_foreach_grant_in_range);
1016
1017 void gnttab_foreach_grant(struct page **pages,
1018                           unsigned int nr_grefs,
1019                           xen_grant_fn_t fn,
1020                           void *data)
1021 {
1022         unsigned int goffset = 0;
1023         unsigned long xen_pfn = 0;
1024         unsigned int i;
1025
1026         for (i = 0; i < nr_grefs; i++) {
1027                 if ((i % XEN_PFN_PER_PAGE) == 0) {
1028                         xen_pfn = page_to_xen_pfn(pages[i / XEN_PFN_PER_PAGE]);
1029                         goffset = 0;
1030                 }
1031
1032                 fn(pfn_to_gfn(xen_pfn), goffset, XEN_PAGE_SIZE, data);
1033
1034                 goffset += XEN_PAGE_SIZE;
1035                 xen_pfn++;
1036         }
1037 }
1038
1039 int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
1040                     struct gnttab_map_grant_ref *kmap_ops,
1041                     struct page **pages, unsigned int count)
1042 {
1043         int i, ret;
1044
1045         ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, map_ops, count);
1046         if (ret)
1047                 return ret;
1048
1049         for (i = 0; i < count; i++) {
1050                 switch (map_ops[i].status) {
1051                 case GNTST_okay:
1052                 {
1053                         struct xen_page_foreign *foreign;
1054
1055                         SetPageForeign(pages[i]);
1056                         foreign = xen_page_foreign(pages[i]);
1057                         foreign->domid = map_ops[i].dom;
1058                         foreign->gref = map_ops[i].ref;
1059                         break;
1060                 }
1061
1062                 case GNTST_no_device_space:
1063                         pr_warn_ratelimited("maptrack limit reached, can't map all guest pages\n");
1064                         break;
1065
1066                 case GNTST_eagain:
1067                         /* Retry eagain maps */
1068                         gnttab_retry_eagain_gop(GNTTABOP_map_grant_ref,
1069                                                 map_ops + i,
1070                                                 &map_ops[i].status, __func__);
1071                         /* Test status in next loop iteration. */
1072                         i--;
1073                         break;
1074
1075                 default:
1076                         break;
1077                 }
1078         }
1079
1080         return set_foreign_p2m_mapping(map_ops, kmap_ops, pages, count);
1081 }
1082 EXPORT_SYMBOL_GPL(gnttab_map_refs);
1083
1084 int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
1085                       struct gnttab_unmap_grant_ref *kunmap_ops,
1086                       struct page **pages, unsigned int count)
1087 {
1088         unsigned int i;
1089         int ret;
1090
1091         ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap_ops, count);
1092         if (ret)
1093                 return ret;
1094
1095         for (i = 0; i < count; i++)
1096                 ClearPageForeign(pages[i]);
1097
1098         return clear_foreign_p2m_mapping(unmap_ops, kunmap_ops, pages, count);
1099 }
1100 EXPORT_SYMBOL_GPL(gnttab_unmap_refs);
1101
1102 #define GNTTAB_UNMAP_REFS_DELAY 5
1103
1104 static void __gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item);
1105
1106 static void gnttab_unmap_work(struct work_struct *work)
1107 {
1108         struct gntab_unmap_queue_data
1109                 *unmap_data = container_of(work,
1110                                            struct gntab_unmap_queue_data,
1111                                            gnttab_work.work);
1112         if (unmap_data->age != UINT_MAX)
1113                 unmap_data->age++;
1114         __gnttab_unmap_refs_async(unmap_data);
1115 }
1116
1117 static void __gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item)
1118 {
1119         int ret;
1120         int pc;
1121
1122         for (pc = 0; pc < item->count; pc++) {
1123                 if (page_count(item->pages[pc]) > 1) {
1124                         unsigned long delay = GNTTAB_UNMAP_REFS_DELAY * (item->age + 1);
1125                         schedule_delayed_work(&item->gnttab_work,
1126                                               msecs_to_jiffies(delay));
1127                         return;
1128                 }
1129         }
1130
1131         ret = gnttab_unmap_refs(item->unmap_ops, item->kunmap_ops,
1132                                 item->pages, item->count);
1133         item->done(ret, item);
1134 }
1135
1136 void gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item)
1137 {
1138         INIT_DELAYED_WORK(&item->gnttab_work, gnttab_unmap_work);
1139         item->age = 0;
1140
1141         __gnttab_unmap_refs_async(item);
1142 }
1143 EXPORT_SYMBOL_GPL(gnttab_unmap_refs_async);
1144
1145 static void unmap_refs_callback(int result,
1146                 struct gntab_unmap_queue_data *data)
1147 {
1148         struct unmap_refs_callback_data *d = data->data;
1149
1150         d->result = result;
1151         complete(&d->completion);
1152 }
1153
1154 int gnttab_unmap_refs_sync(struct gntab_unmap_queue_data *item)
1155 {
1156         struct unmap_refs_callback_data data;
1157
1158         init_completion(&data.completion);
1159         item->data = &data;
1160         item->done = &unmap_refs_callback;
1161         gnttab_unmap_refs_async(item);
1162         wait_for_completion(&data.completion);
1163
1164         return data.result;
1165 }
1166 EXPORT_SYMBOL_GPL(gnttab_unmap_refs_sync);
1167
1168 static unsigned int nr_status_frames(unsigned int nr_grant_frames)
1169 {
1170         BUG_ON(gnttab_interface == NULL);
1171         return gnttab_frames(nr_grant_frames, SPP);
1172 }
1173
1174 static int gnttab_map_frames_v1(xen_pfn_t *frames, unsigned int nr_gframes)
1175 {
1176         int rc;
1177
1178         rc = arch_gnttab_map_shared(frames, nr_gframes,
1179                                     gnttab_max_grant_frames(),
1180                                     &gnttab_shared.addr);
1181         BUG_ON(rc);
1182
1183         return 0;
1184 }
1185
1186 static void gnttab_unmap_frames_v1(void)
1187 {
1188         arch_gnttab_unmap(gnttab_shared.addr, nr_grant_frames);
1189 }
1190
1191 static int gnttab_map_frames_v2(xen_pfn_t *frames, unsigned int nr_gframes)
1192 {
1193         uint64_t *sframes;
1194         unsigned int nr_sframes;
1195         struct gnttab_get_status_frames getframes;
1196         int rc;
1197
1198         nr_sframes = nr_status_frames(nr_gframes);
1199
1200         /* No need for kzalloc as it is initialized in following hypercall
1201          * GNTTABOP_get_status_frames.
1202          */
1203         sframes = kmalloc_array(nr_sframes, sizeof(uint64_t), GFP_ATOMIC);
1204         if (!sframes)
1205                 return -ENOMEM;
1206
1207         getframes.dom        = DOMID_SELF;
1208         getframes.nr_frames  = nr_sframes;
1209         set_xen_guest_handle(getframes.frame_list, sframes);
1210
1211         rc = HYPERVISOR_grant_table_op(GNTTABOP_get_status_frames,
1212                                        &getframes, 1);
1213         if (rc == -ENOSYS) {
1214                 kfree(sframes);
1215                 return -ENOSYS;
1216         }
1217
1218         BUG_ON(rc || getframes.status);
1219
1220         rc = arch_gnttab_map_status(sframes, nr_sframes,
1221                                     nr_status_frames(gnttab_max_grant_frames()),
1222                                     &grstatus);
1223         BUG_ON(rc);
1224         kfree(sframes);
1225
1226         rc = arch_gnttab_map_shared(frames, nr_gframes,
1227                                     gnttab_max_grant_frames(),
1228                                     &gnttab_shared.addr);
1229         BUG_ON(rc);
1230
1231         return 0;
1232 }
1233
1234 static void gnttab_unmap_frames_v2(void)
1235 {
1236         arch_gnttab_unmap(gnttab_shared.addr, nr_grant_frames);
1237         arch_gnttab_unmap(grstatus, nr_status_frames(nr_grant_frames));
1238 }
1239
1240 static int gnttab_map(unsigned int start_idx, unsigned int end_idx)
1241 {
1242         struct gnttab_setup_table setup;
1243         xen_pfn_t *frames;
1244         unsigned int nr_gframes = end_idx + 1;
1245         int rc;
1246
1247         if (xen_feature(XENFEAT_auto_translated_physmap)) {
1248                 struct xen_add_to_physmap xatp;
1249                 unsigned int i = end_idx;
1250                 rc = 0;
1251                 BUG_ON(xen_auto_xlat_grant_frames.count < nr_gframes);
1252                 /*
1253                  * Loop backwards, so that the first hypercall has the largest
1254                  * index, ensuring that the table will grow only once.
1255                  */
1256                 do {
1257                         xatp.domid = DOMID_SELF;
1258                         xatp.idx = i;
1259                         xatp.space = XENMAPSPACE_grant_table;
1260                         xatp.gpfn = xen_auto_xlat_grant_frames.pfn[i];
1261                         rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp);
1262                         if (rc != 0) {
1263                                 pr_warn("grant table add_to_physmap failed, err=%d\n",
1264                                         rc);
1265                                 break;
1266                         }
1267                 } while (i-- > start_idx);
1268
1269                 return rc;
1270         }
1271
1272         /* No need for kzalloc as it is initialized in following hypercall
1273          * GNTTABOP_setup_table.
1274          */
1275         frames = kmalloc_array(nr_gframes, sizeof(unsigned long), GFP_ATOMIC);
1276         if (!frames)
1277                 return -ENOMEM;
1278
1279         setup.dom        = DOMID_SELF;
1280         setup.nr_frames  = nr_gframes;
1281         set_xen_guest_handle(setup.frame_list, frames);
1282
1283         rc = HYPERVISOR_grant_table_op(GNTTABOP_setup_table, &setup, 1);
1284         if (rc == -ENOSYS) {
1285                 kfree(frames);
1286                 return -ENOSYS;
1287         }
1288
1289         BUG_ON(rc || setup.status);
1290
1291         rc = gnttab_interface->map_frames(frames, nr_gframes);
1292
1293         kfree(frames);
1294
1295         return rc;
1296 }
1297
1298 static const struct gnttab_ops gnttab_v1_ops = {
1299         .version                        = 1,
1300         .grefs_per_grant_frame          = XEN_PAGE_SIZE /
1301                                           sizeof(struct grant_entry_v1),
1302         .map_frames                     = gnttab_map_frames_v1,
1303         .unmap_frames                   = gnttab_unmap_frames_v1,
1304         .update_entry                   = gnttab_update_entry_v1,
1305         .end_foreign_access_ref         = gnttab_end_foreign_access_ref_v1,
1306         .end_foreign_transfer_ref       = gnttab_end_foreign_transfer_ref_v1,
1307         .read_frame                     = gnttab_read_frame_v1,
1308 };
1309
1310 static const struct gnttab_ops gnttab_v2_ops = {
1311         .version                        = 2,
1312         .grefs_per_grant_frame          = XEN_PAGE_SIZE /
1313                                           sizeof(union grant_entry_v2),
1314         .map_frames                     = gnttab_map_frames_v2,
1315         .unmap_frames                   = gnttab_unmap_frames_v2,
1316         .update_entry                   = gnttab_update_entry_v2,
1317         .end_foreign_access_ref         = gnttab_end_foreign_access_ref_v2,
1318         .end_foreign_transfer_ref       = gnttab_end_foreign_transfer_ref_v2,
1319         .read_frame                     = gnttab_read_frame_v2,
1320 };
1321
1322 static bool gnttab_need_v2(void)
1323 {
1324 #ifdef CONFIG_X86
1325         uint32_t base, width;
1326
1327         if (xen_pv_domain()) {
1328                 base = xen_cpuid_base();
1329                 if (cpuid_eax(base) < 5)
1330                         return false;   /* Information not available, use V1. */
1331                 width = cpuid_ebx(base + 5) &
1332                         XEN_CPUID_MACHINE_ADDRESS_WIDTH_MASK;
1333                 return width > 32 + PAGE_SHIFT;
1334         }
1335 #endif
1336         return !!(max_possible_pfn >> 32);
1337 }
1338
1339 static void gnttab_request_version(void)
1340 {
1341         long rc;
1342         struct gnttab_set_version gsv;
1343
1344         if (gnttab_need_v2())
1345                 gsv.version = 2;
1346         else
1347                 gsv.version = 1;
1348
1349         /* Boot parameter overrides automatic selection. */
1350         if (xen_gnttab_version >= 1 && xen_gnttab_version <= 2)
1351                 gsv.version = xen_gnttab_version;
1352
1353         rc = HYPERVISOR_grant_table_op(GNTTABOP_set_version, &gsv, 1);
1354         if (rc == 0 && gsv.version == 2)
1355                 gnttab_interface = &gnttab_v2_ops;
1356         else
1357                 gnttab_interface = &gnttab_v1_ops;
1358         pr_info("Grant tables using version %d layout\n",
1359                 gnttab_interface->version);
1360 }
1361
1362 static int gnttab_setup(void)
1363 {
1364         unsigned int max_nr_gframes;
1365
1366         max_nr_gframes = gnttab_max_grant_frames();
1367         if (max_nr_gframes < nr_grant_frames)
1368                 return -ENOSYS;
1369
1370         if (xen_feature(XENFEAT_auto_translated_physmap) && gnttab_shared.addr == NULL) {
1371                 gnttab_shared.addr = xen_auto_xlat_grant_frames.vaddr;
1372                 if (gnttab_shared.addr == NULL) {
1373                         pr_warn("gnttab share frames (addr=0x%08lx) is not mapped!\n",
1374                                 (unsigned long)xen_auto_xlat_grant_frames.vaddr);
1375                         return -ENOMEM;
1376                 }
1377         }
1378         return gnttab_map(0, nr_grant_frames - 1);
1379 }
1380
1381 int gnttab_resume(void)
1382 {
1383         gnttab_request_version();
1384         return gnttab_setup();
1385 }
1386
1387 int gnttab_suspend(void)
1388 {
1389         if (!xen_feature(XENFEAT_auto_translated_physmap))
1390                 gnttab_interface->unmap_frames();
1391         return 0;
1392 }
1393
1394 static int gnttab_expand(unsigned int req_entries)
1395 {
1396         int rc;
1397         unsigned int cur, extra;
1398
1399         BUG_ON(gnttab_interface == NULL);
1400         cur = nr_grant_frames;
1401         extra = ((req_entries + gnttab_interface->grefs_per_grant_frame - 1) /
1402                  gnttab_interface->grefs_per_grant_frame);
1403         if (cur + extra > gnttab_max_grant_frames()) {
1404                 pr_warn_ratelimited("xen/grant-table: max_grant_frames reached"
1405                                     " cur=%u extra=%u limit=%u"
1406                                     " gnttab_free_count=%u req_entries=%u\n",
1407                                     cur, extra, gnttab_max_grant_frames(),
1408                                     gnttab_free_count, req_entries);
1409                 return -ENOSPC;
1410         }
1411
1412         rc = gnttab_map(cur, cur + extra - 1);
1413         if (rc == 0)
1414                 rc = grow_gnttab_list(extra);
1415
1416         return rc;
1417 }
1418
1419 int gnttab_init(void)
1420 {
1421         int i;
1422         unsigned long max_nr_grant_frames;
1423         unsigned int max_nr_glist_frames, nr_glist_frames;
1424         unsigned int nr_init_grefs;
1425         int ret;
1426
1427         gnttab_request_version();
1428         max_nr_grant_frames = gnttab_max_grant_frames();
1429         nr_grant_frames = 1;
1430
1431         /* Determine the maximum number of frames required for the
1432          * grant reference free list on the current hypervisor.
1433          */
1434         BUG_ON(gnttab_interface == NULL);
1435         max_nr_glist_frames = (max_nr_grant_frames *
1436                                gnttab_interface->grefs_per_grant_frame / RPP);
1437
1438         gnttab_list = kmalloc_array(max_nr_glist_frames,
1439                                     sizeof(grant_ref_t *),
1440                                     GFP_KERNEL);
1441         if (gnttab_list == NULL)
1442                 return -ENOMEM;
1443
1444         nr_glist_frames = gnttab_frames(nr_grant_frames, RPP);
1445         for (i = 0; i < nr_glist_frames; i++) {
1446                 gnttab_list[i] = (grant_ref_t *)__get_free_page(GFP_KERNEL);
1447                 if (gnttab_list[i] == NULL) {
1448                         ret = -ENOMEM;
1449                         goto ini_nomem;
1450                 }
1451         }
1452
1453         ret = arch_gnttab_init(max_nr_grant_frames,
1454                                nr_status_frames(max_nr_grant_frames));
1455         if (ret < 0)
1456                 goto ini_nomem;
1457
1458         if (gnttab_setup() < 0) {
1459                 ret = -ENODEV;
1460                 goto ini_nomem;
1461         }
1462
1463         nr_init_grefs = nr_grant_frames *
1464                         gnttab_interface->grefs_per_grant_frame;
1465
1466         for (i = NR_RESERVED_ENTRIES; i < nr_init_grefs - 1; i++)
1467                 gnttab_entry(i) = i + 1;
1468
1469         gnttab_entry(nr_init_grefs - 1) = GNTTAB_LIST_END;
1470         gnttab_free_count = nr_init_grefs - NR_RESERVED_ENTRIES;
1471         gnttab_free_head  = NR_RESERVED_ENTRIES;
1472
1473         printk("Grant table initialized\n");
1474         return 0;
1475
1476  ini_nomem:
1477         for (i--; i >= 0; i--)
1478                 free_page((unsigned long)gnttab_list[i]);
1479         kfree(gnttab_list);
1480         return ret;
1481 }
1482 EXPORT_SYMBOL_GPL(gnttab_init);
1483
1484 static int __gnttab_init(void)
1485 {
1486         if (!xen_domain())
1487                 return -ENODEV;
1488
1489         /* Delay grant-table initialization in the PV on HVM case */
1490         if (xen_hvm_domain() && !xen_pvh_domain())
1491                 return 0;
1492
1493         return gnttab_init();
1494 }
1495 /* Starts after core_initcall so that xen_pvh_gnttab_setup can be called
1496  * beforehand to initialize xen_auto_xlat_grant_frames. */
1497 core_initcall_sync(__gnttab_init);