linux/drivers/xen/grant-table.c
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   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/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
  74static grant_ref_t **gnttab_list;
  75static unsigned int nr_grant_frames;
  76static int gnttab_free_count;
  77static grant_ref_t gnttab_free_head;
  78static DEFINE_SPINLOCK(gnttab_list_lock);
  79struct grant_frames xen_auto_xlat_grant_frames;
  80static unsigned int xen_gnttab_version;
  81module_param_named(version, xen_gnttab_version, uint, 0);
  82
  83static 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*/
  90struct 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         * Query the status of a grant entry. Ref parameter is reference of
 139         * queried grant entry, return value is the status of queried entry.
 140         * Detailed status(writing/reading) can be gotten from the return value
 141         * by bit operations.
 142         */
 143        int (*query_foreign_access)(grant_ref_t ref);
 144};
 145
 146struct unmap_refs_callback_data {
 147        struct completion completion;
 148        int result;
 149};
 150
 151static const struct gnttab_ops *gnttab_interface;
 152
 153/* This reflects status of grant entries, so act as a global value. */
 154static grant_status_t *grstatus;
 155
 156static struct gnttab_free_callback *gnttab_free_callback_list;
 157
 158static int gnttab_expand(unsigned int req_entries);
 159
 160#define RPP (PAGE_SIZE / sizeof(grant_ref_t))
 161#define SPP (PAGE_SIZE / sizeof(grant_status_t))
 162
 163static inline grant_ref_t *__gnttab_entry(grant_ref_t entry)
 164{
 165        return &gnttab_list[(entry) / RPP][(entry) % RPP];
 166}
 167/* This can be used as an l-value */
 168#define gnttab_entry(entry) (*__gnttab_entry(entry))
 169
 170static int get_free_entries(unsigned count)
 171{
 172        unsigned long flags;
 173        int ref, rc = 0;
 174        grant_ref_t head;
 175
 176        spin_lock_irqsave(&gnttab_list_lock, flags);
 177
 178        if ((gnttab_free_count < count) &&
 179            ((rc = gnttab_expand(count - gnttab_free_count)) < 0)) {
 180                spin_unlock_irqrestore(&gnttab_list_lock, flags);
 181                return rc;
 182        }
 183
 184        ref = head = gnttab_free_head;
 185        gnttab_free_count -= count;
 186        while (count-- > 1)
 187                head = gnttab_entry(head);
 188        gnttab_free_head = gnttab_entry(head);
 189        gnttab_entry(head) = GNTTAB_LIST_END;
 190
 191        spin_unlock_irqrestore(&gnttab_list_lock, flags);
 192
 193        return ref;
 194}
 195
 196static void do_free_callbacks(void)
 197{
 198        struct gnttab_free_callback *callback, *next;
 199
 200        callback = gnttab_free_callback_list;
 201        gnttab_free_callback_list = NULL;
 202
 203        while (callback != NULL) {
 204                next = callback->next;
 205                if (gnttab_free_count >= callback->count) {
 206                        callback->next = NULL;
 207                        callback->fn(callback->arg);
 208                } else {
 209                        callback->next = gnttab_free_callback_list;
 210                        gnttab_free_callback_list = callback;
 211                }
 212                callback = next;
 213        }
 214}
 215
 216static inline void check_free_callbacks(void)
 217{
 218        if (unlikely(gnttab_free_callback_list))
 219                do_free_callbacks();
 220}
 221
 222static void put_free_entry(grant_ref_t ref)
 223{
 224        unsigned long flags;
 225        spin_lock_irqsave(&gnttab_list_lock, flags);
 226        gnttab_entry(ref) = gnttab_free_head;
 227        gnttab_free_head = ref;
 228        gnttab_free_count++;
 229        check_free_callbacks();
 230        spin_unlock_irqrestore(&gnttab_list_lock, flags);
 231}
 232
 233/*
 234 * Following applies to gnttab_update_entry_v1 and gnttab_update_entry_v2.
 235 * Introducing a valid entry into the grant table:
 236 *  1. Write ent->domid.
 237 *  2. Write ent->frame:
 238 *      GTF_permit_access:   Frame to which access is permitted.
 239 *      GTF_accept_transfer: Pseudo-phys frame slot being filled by new
 240 *                           frame, or zero if none.
 241 *  3. Write memory barrier (WMB).
 242 *  4. Write ent->flags, inc. valid type.
 243 */
 244static void gnttab_update_entry_v1(grant_ref_t ref, domid_t domid,
 245                                   unsigned long frame, unsigned flags)
 246{
 247        gnttab_shared.v1[ref].domid = domid;
 248        gnttab_shared.v1[ref].frame = frame;
 249        wmb();
 250        gnttab_shared.v1[ref].flags = flags;
 251}
 252
 253static void gnttab_update_entry_v2(grant_ref_t ref, domid_t domid,
 254                                   unsigned long frame, unsigned int flags)
 255{
 256        gnttab_shared.v2[ref].hdr.domid = domid;
 257        gnttab_shared.v2[ref].full_page.frame = frame;
 258        wmb();  /* Hypervisor concurrent accesses. */
 259        gnttab_shared.v2[ref].hdr.flags = GTF_permit_access | flags;
 260}
 261
 262/*
 263 * Public grant-issuing interface functions
 264 */
 265void gnttab_grant_foreign_access_ref(grant_ref_t ref, domid_t domid,
 266                                     unsigned long frame, int readonly)
 267{
 268        gnttab_interface->update_entry(ref, domid, frame,
 269                           GTF_permit_access | (readonly ? GTF_readonly : 0));
 270}
 271EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access_ref);
 272
 273int gnttab_grant_foreign_access(domid_t domid, unsigned long frame,
 274                                int readonly)
 275{
 276        int ref;
 277
 278        ref = get_free_entries(1);
 279        if (unlikely(ref < 0))
 280                return -ENOSPC;
 281
 282        gnttab_grant_foreign_access_ref(ref, domid, frame, readonly);
 283
 284        return ref;
 285}
 286EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access);
 287
 288static int gnttab_query_foreign_access_v1(grant_ref_t ref)
 289{
 290        return gnttab_shared.v1[ref].flags & (GTF_reading|GTF_writing);
 291}
 292
 293static int gnttab_query_foreign_access_v2(grant_ref_t ref)
 294{
 295        return grstatus[ref] & (GTF_reading|GTF_writing);
 296}
 297
 298int gnttab_query_foreign_access(grant_ref_t ref)
 299{
 300        return gnttab_interface->query_foreign_access(ref);
 301}
 302EXPORT_SYMBOL_GPL(gnttab_query_foreign_access);
 303
 304static int gnttab_end_foreign_access_ref_v1(grant_ref_t ref, int readonly)
 305{
 306        u16 flags, nflags;
 307        u16 *pflags;
 308
 309        pflags = &gnttab_shared.v1[ref].flags;
 310        nflags = *pflags;
 311        do {
 312                flags = nflags;
 313                if (flags & (GTF_reading|GTF_writing))
 314                        return 0;
 315        } while ((nflags = sync_cmpxchg(pflags, flags, 0)) != flags);
 316
 317        return 1;
 318}
 319
 320static int gnttab_end_foreign_access_ref_v2(grant_ref_t ref, int readonly)
 321{
 322        gnttab_shared.v2[ref].hdr.flags = 0;
 323        mb();   /* Concurrent access by hypervisor. */
 324        if (grstatus[ref] & (GTF_reading|GTF_writing)) {
 325                return 0;
 326        } else {
 327                /*
 328                 * The read of grstatus needs to have acquire semantics.
 329                 *  On x86, reads already have that, and we just need to
 330                 * protect against compiler reorderings.
 331                 * On other architectures we may need a full barrier.
 332                 */
 333#ifdef CONFIG_X86
 334                barrier();
 335#else
 336                mb();
 337#endif
 338        }
 339
 340        return 1;
 341}
 342
 343static inline int _gnttab_end_foreign_access_ref(grant_ref_t ref, int readonly)
 344{
 345        return gnttab_interface->end_foreign_access_ref(ref, readonly);
 346}
 347
 348int gnttab_end_foreign_access_ref(grant_ref_t ref, int readonly)
 349{
 350        if (_gnttab_end_foreign_access_ref(ref, readonly))
 351                return 1;
 352        pr_warn("WARNING: g.e. %#x still in use!\n", ref);
 353        return 0;
 354}
 355EXPORT_SYMBOL_GPL(gnttab_end_foreign_access_ref);
 356
 357struct deferred_entry {
 358        struct list_head list;
 359        grant_ref_t ref;
 360        bool ro;
 361        uint16_t warn_delay;
 362        struct page *page;
 363};
 364static LIST_HEAD(deferred_list);
 365static void gnttab_handle_deferred(struct timer_list *);
 366static DEFINE_TIMER(deferred_timer, gnttab_handle_deferred);
 367
 368static void gnttab_handle_deferred(struct timer_list *unused)
 369{
 370        unsigned int nr = 10;
 371        struct deferred_entry *first = NULL;
 372        unsigned long flags;
 373
 374        spin_lock_irqsave(&gnttab_list_lock, flags);
 375        while (nr--) {
 376                struct deferred_entry *entry
 377                        = list_first_entry(&deferred_list,
 378                                           struct deferred_entry, list);
 379
 380                if (entry == first)
 381                        break;
 382                list_del(&entry->list);
 383                spin_unlock_irqrestore(&gnttab_list_lock, flags);
 384                if (_gnttab_end_foreign_access_ref(entry->ref, entry->ro)) {
 385                        put_free_entry(entry->ref);
 386                        if (entry->page) {
 387                                pr_debug("freeing g.e. %#x (pfn %#lx)\n",
 388                                         entry->ref, page_to_pfn(entry->page));
 389                                put_page(entry->page);
 390                        } else
 391                                pr_info("freeing g.e. %#x\n", entry->ref);
 392                        kfree(entry);
 393                        entry = NULL;
 394                } else {
 395                        if (!--entry->warn_delay)
 396                                pr_info("g.e. %#x still pending\n", entry->ref);
 397                        if (!first)
 398                                first = entry;
 399                }
 400                spin_lock_irqsave(&gnttab_list_lock, flags);
 401                if (entry)
 402                        list_add_tail(&entry->list, &deferred_list);
 403                else if (list_empty(&deferred_list))
 404                        break;
 405        }
 406        if (!list_empty(&deferred_list) && !timer_pending(&deferred_timer)) {
 407                deferred_timer.expires = jiffies + HZ;
 408                add_timer(&deferred_timer);
 409        }
 410        spin_unlock_irqrestore(&gnttab_list_lock, flags);
 411}
 412
 413static void gnttab_add_deferred(grant_ref_t ref, bool readonly,
 414                                struct page *page)
 415{
 416        struct deferred_entry *entry = kmalloc(sizeof(*entry), GFP_ATOMIC);
 417        const char *what = KERN_WARNING "leaking";
 418
 419        if (entry) {
 420                unsigned long flags;
 421
 422                entry->ref = ref;
 423                entry->ro = readonly;
 424                entry->page = page;
 425                entry->warn_delay = 60;
 426                spin_lock_irqsave(&gnttab_list_lock, flags);
 427                list_add_tail(&entry->list, &deferred_list);
 428                if (!timer_pending(&deferred_timer)) {
 429                        deferred_timer.expires = jiffies + HZ;
 430                        add_timer(&deferred_timer);
 431                }
 432                spin_unlock_irqrestore(&gnttab_list_lock, flags);
 433                what = KERN_DEBUG "deferring";
 434        }
 435        printk("%s g.e. %#x (pfn %#lx)\n",
 436               what, ref, page ? page_to_pfn(page) : -1);
 437}
 438
 439void gnttab_end_foreign_access(grant_ref_t ref, int readonly,
 440                               unsigned long page)
 441{
 442        if (gnttab_end_foreign_access_ref(ref, readonly)) {
 443                put_free_entry(ref);
 444                if (page != 0)
 445                        put_page(virt_to_page(page));
 446        } else
 447                gnttab_add_deferred(ref, readonly,
 448                                    page ? virt_to_page(page) : NULL);
 449}
 450EXPORT_SYMBOL_GPL(gnttab_end_foreign_access);
 451
 452int gnttab_grant_foreign_transfer(domid_t domid, unsigned long pfn)
 453{
 454        int ref;
 455
 456        ref = get_free_entries(1);
 457        if (unlikely(ref < 0))
 458                return -ENOSPC;
 459        gnttab_grant_foreign_transfer_ref(ref, domid, pfn);
 460
 461        return ref;
 462}
 463EXPORT_SYMBOL_GPL(gnttab_grant_foreign_transfer);
 464
 465void gnttab_grant_foreign_transfer_ref(grant_ref_t ref, domid_t domid,
 466                                       unsigned long pfn)
 467{
 468        gnttab_interface->update_entry(ref, domid, pfn, GTF_accept_transfer);
 469}
 470EXPORT_SYMBOL_GPL(gnttab_grant_foreign_transfer_ref);
 471
 472static unsigned long gnttab_end_foreign_transfer_ref_v1(grant_ref_t ref)
 473{
 474        unsigned long frame;
 475        u16           flags;
 476        u16          *pflags;
 477
 478        pflags = &gnttab_shared.v1[ref].flags;
 479
 480        /*
 481         * If a transfer is not even yet started, try to reclaim the grant
 482         * reference and return failure (== 0).
 483         */
 484        while (!((flags = *pflags) & GTF_transfer_committed)) {
 485                if (sync_cmpxchg(pflags, flags, 0) == flags)
 486                        return 0;
 487                cpu_relax();
 488        }
 489
 490        /* If a transfer is in progress then wait until it is completed. */
 491        while (!(flags & GTF_transfer_completed)) {
 492                flags = *pflags;
 493                cpu_relax();
 494        }
 495
 496        rmb();  /* Read the frame number /after/ reading completion status. */
 497        frame = gnttab_shared.v1[ref].frame;
 498        BUG_ON(frame == 0);
 499
 500        return frame;
 501}
 502
 503static unsigned long gnttab_end_foreign_transfer_ref_v2(grant_ref_t ref)
 504{
 505        unsigned long frame;
 506        u16           flags;
 507        u16          *pflags;
 508
 509        pflags = &gnttab_shared.v2[ref].hdr.flags;
 510
 511        /*
 512         * If a transfer is not even yet started, try to reclaim the grant
 513         * reference and return failure (== 0).
 514         */
 515        while (!((flags = *pflags) & GTF_transfer_committed)) {
 516                if (sync_cmpxchg(pflags, flags, 0) == flags)
 517                        return 0;
 518                cpu_relax();
 519        }
 520
 521        /* If a transfer is in progress then wait until it is completed. */
 522        while (!(flags & GTF_transfer_completed)) {
 523                flags = *pflags;
 524                cpu_relax();
 525        }
 526
 527        rmb();  /* Read the frame number /after/ reading completion status. */
 528        frame = gnttab_shared.v2[ref].full_page.frame;
 529        BUG_ON(frame == 0);
 530
 531        return frame;
 532}
 533
 534unsigned long gnttab_end_foreign_transfer_ref(grant_ref_t ref)
 535{
 536        return gnttab_interface->end_foreign_transfer_ref(ref);
 537}
 538EXPORT_SYMBOL_GPL(gnttab_end_foreign_transfer_ref);
 539
 540unsigned long gnttab_end_foreign_transfer(grant_ref_t ref)
 541{
 542        unsigned long frame = gnttab_end_foreign_transfer_ref(ref);
 543        put_free_entry(ref);
 544        return frame;
 545}
 546EXPORT_SYMBOL_GPL(gnttab_end_foreign_transfer);
 547
 548void gnttab_free_grant_reference(grant_ref_t ref)
 549{
 550        put_free_entry(ref);
 551}
 552EXPORT_SYMBOL_GPL(gnttab_free_grant_reference);
 553
 554void gnttab_free_grant_references(grant_ref_t head)
 555{
 556        grant_ref_t ref;
 557        unsigned long flags;
 558        int count = 1;
 559        if (head == GNTTAB_LIST_END)
 560                return;
 561        spin_lock_irqsave(&gnttab_list_lock, flags);
 562        ref = head;
 563        while (gnttab_entry(ref) != GNTTAB_LIST_END) {
 564                ref = gnttab_entry(ref);
 565                count++;
 566        }
 567        gnttab_entry(ref) = gnttab_free_head;
 568        gnttab_free_head = head;
 569        gnttab_free_count += count;
 570        check_free_callbacks();
 571        spin_unlock_irqrestore(&gnttab_list_lock, flags);
 572}
 573EXPORT_SYMBOL_GPL(gnttab_free_grant_references);
 574
 575int gnttab_alloc_grant_references(u16 count, grant_ref_t *head)
 576{
 577        int h = get_free_entries(count);
 578
 579        if (h < 0)
 580                return -ENOSPC;
 581
 582        *head = h;
 583
 584        return 0;
 585}
 586EXPORT_SYMBOL_GPL(gnttab_alloc_grant_references);
 587
 588int gnttab_empty_grant_references(const grant_ref_t *private_head)
 589{
 590        return (*private_head == GNTTAB_LIST_END);
 591}
 592EXPORT_SYMBOL_GPL(gnttab_empty_grant_references);
 593
 594int gnttab_claim_grant_reference(grant_ref_t *private_head)
 595{
 596        grant_ref_t g = *private_head;
 597        if (unlikely(g == GNTTAB_LIST_END))
 598                return -ENOSPC;
 599        *private_head = gnttab_entry(g);
 600        return g;
 601}
 602EXPORT_SYMBOL_GPL(gnttab_claim_grant_reference);
 603
 604void gnttab_release_grant_reference(grant_ref_t *private_head,
 605                                    grant_ref_t release)
 606{
 607        gnttab_entry(release) = *private_head;
 608        *private_head = release;
 609}
 610EXPORT_SYMBOL_GPL(gnttab_release_grant_reference);
 611
 612void gnttab_request_free_callback(struct gnttab_free_callback *callback,
 613                                  void (*fn)(void *), void *arg, u16 count)
 614{
 615        unsigned long flags;
 616        struct gnttab_free_callback *cb;
 617
 618        spin_lock_irqsave(&gnttab_list_lock, flags);
 619
 620        /* Check if the callback is already on the list */
 621        cb = gnttab_free_callback_list;
 622        while (cb) {
 623                if (cb == callback)
 624                        goto out;
 625                cb = cb->next;
 626        }
 627
 628        callback->fn = fn;
 629        callback->arg = arg;
 630        callback->count = count;
 631        callback->next = gnttab_free_callback_list;
 632        gnttab_free_callback_list = callback;
 633        check_free_callbacks();
 634out:
 635        spin_unlock_irqrestore(&gnttab_list_lock, flags);
 636}
 637EXPORT_SYMBOL_GPL(gnttab_request_free_callback);
 638
 639void gnttab_cancel_free_callback(struct gnttab_free_callback *callback)
 640{
 641        struct gnttab_free_callback **pcb;
 642        unsigned long flags;
 643
 644        spin_lock_irqsave(&gnttab_list_lock, flags);
 645        for (pcb = &gnttab_free_callback_list; *pcb; pcb = &(*pcb)->next) {
 646                if (*pcb == callback) {
 647                        *pcb = callback->next;
 648                        break;
 649                }
 650        }
 651        spin_unlock_irqrestore(&gnttab_list_lock, flags);
 652}
 653EXPORT_SYMBOL_GPL(gnttab_cancel_free_callback);
 654
 655static unsigned int gnttab_frames(unsigned int frames, unsigned int align)
 656{
 657        return (frames * gnttab_interface->grefs_per_grant_frame + align - 1) /
 658               align;
 659}
 660
 661static int grow_gnttab_list(unsigned int more_frames)
 662{
 663        unsigned int new_nr_grant_frames, extra_entries, i;
 664        unsigned int nr_glist_frames, new_nr_glist_frames;
 665        unsigned int grefs_per_frame;
 666
 667        BUG_ON(gnttab_interface == NULL);
 668        grefs_per_frame = gnttab_interface->grefs_per_grant_frame;
 669
 670        new_nr_grant_frames = nr_grant_frames + more_frames;
 671        extra_entries = more_frames * grefs_per_frame;
 672
 673        nr_glist_frames = gnttab_frames(nr_grant_frames, RPP);
 674        new_nr_glist_frames = gnttab_frames(new_nr_grant_frames, RPP);
 675        for (i = nr_glist_frames; i < new_nr_glist_frames; i++) {
 676                gnttab_list[i] = (grant_ref_t *)__get_free_page(GFP_ATOMIC);
 677                if (!gnttab_list[i])
 678                        goto grow_nomem;
 679        }
 680
 681
 682        for (i = grefs_per_frame * nr_grant_frames;
 683             i < grefs_per_frame * new_nr_grant_frames - 1; i++)
 684                gnttab_entry(i) = i + 1;
 685
 686        gnttab_entry(i) = gnttab_free_head;
 687        gnttab_free_head = grefs_per_frame * nr_grant_frames;
 688        gnttab_free_count += extra_entries;
 689
 690        nr_grant_frames = new_nr_grant_frames;
 691
 692        check_free_callbacks();
 693
 694        return 0;
 695
 696grow_nomem:
 697        while (i-- > nr_glist_frames)
 698                free_page((unsigned long) gnttab_list[i]);
 699        return -ENOMEM;
 700}
 701
 702static unsigned int __max_nr_grant_frames(void)
 703{
 704        struct gnttab_query_size query;
 705        int rc;
 706
 707        query.dom = DOMID_SELF;
 708
 709        rc = HYPERVISOR_grant_table_op(GNTTABOP_query_size, &query, 1);
 710        if ((rc < 0) || (query.status != GNTST_okay))
 711                return 4; /* Legacy max supported number of frames */
 712
 713        return query.max_nr_frames;
 714}
 715
 716unsigned int gnttab_max_grant_frames(void)
 717{
 718        unsigned int xen_max = __max_nr_grant_frames();
 719        static unsigned int boot_max_nr_grant_frames;
 720
 721        /* First time, initialize it properly. */
 722        if (!boot_max_nr_grant_frames)
 723                boot_max_nr_grant_frames = __max_nr_grant_frames();
 724
 725        if (xen_max > boot_max_nr_grant_frames)
 726                return boot_max_nr_grant_frames;
 727        return xen_max;
 728}
 729EXPORT_SYMBOL_GPL(gnttab_max_grant_frames);
 730
 731int gnttab_setup_auto_xlat_frames(phys_addr_t addr)
 732{
 733        xen_pfn_t *pfn;
 734        unsigned int max_nr_gframes = __max_nr_grant_frames();
 735        unsigned int i;
 736        void *vaddr;
 737
 738        if (xen_auto_xlat_grant_frames.count)
 739                return -EINVAL;
 740
 741        vaddr = xen_remap(addr, XEN_PAGE_SIZE * max_nr_gframes);
 742        if (vaddr == NULL) {
 743                pr_warn("Failed to ioremap gnttab share frames (addr=%pa)!\n",
 744                        &addr);
 745                return -ENOMEM;
 746        }
 747        pfn = kcalloc(max_nr_gframes, sizeof(pfn[0]), GFP_KERNEL);
 748        if (!pfn) {
 749                xen_unmap(vaddr);
 750                return -ENOMEM;
 751        }
 752        for (i = 0; i < max_nr_gframes; i++)
 753                pfn[i] = XEN_PFN_DOWN(addr) + i;
 754
 755        xen_auto_xlat_grant_frames.vaddr = vaddr;
 756        xen_auto_xlat_grant_frames.pfn = pfn;
 757        xen_auto_xlat_grant_frames.count = max_nr_gframes;
 758
 759        return 0;
 760}
 761EXPORT_SYMBOL_GPL(gnttab_setup_auto_xlat_frames);
 762
 763void gnttab_free_auto_xlat_frames(void)
 764{
 765        if (!xen_auto_xlat_grant_frames.count)
 766                return;
 767        kfree(xen_auto_xlat_grant_frames.pfn);
 768        xen_unmap(xen_auto_xlat_grant_frames.vaddr);
 769
 770        xen_auto_xlat_grant_frames.pfn = NULL;
 771        xen_auto_xlat_grant_frames.count = 0;
 772        xen_auto_xlat_grant_frames.vaddr = NULL;
 773}
 774EXPORT_SYMBOL_GPL(gnttab_free_auto_xlat_frames);
 775
 776int gnttab_pages_set_private(int nr_pages, struct page **pages)
 777{
 778        int i;
 779
 780        for (i = 0; i < nr_pages; i++) {
 781#if BITS_PER_LONG < 64
 782                struct xen_page_foreign *foreign;
 783
 784                foreign = kzalloc(sizeof(*foreign), GFP_KERNEL);
 785                if (!foreign)
 786                        return -ENOMEM;
 787
 788                set_page_private(pages[i], (unsigned long)foreign);
 789#endif
 790                SetPagePrivate(pages[i]);
 791        }
 792
 793        return 0;
 794}
 795EXPORT_SYMBOL_GPL(gnttab_pages_set_private);
 796
 797/**
 798 * gnttab_alloc_pages - alloc pages suitable for grant mapping into
 799 * @nr_pages: number of pages to alloc
 800 * @pages: returns the pages
 801 */
 802int gnttab_alloc_pages(int nr_pages, struct page **pages)
 803{
 804        int ret;
 805
 806        ret = alloc_xenballooned_pages(nr_pages, pages);
 807        if (ret < 0)
 808                return ret;
 809
 810        ret = gnttab_pages_set_private(nr_pages, pages);
 811        if (ret < 0)
 812                gnttab_free_pages(nr_pages, pages);
 813
 814        return ret;
 815}
 816EXPORT_SYMBOL_GPL(gnttab_alloc_pages);
 817
 818void gnttab_pages_clear_private(int nr_pages, struct page **pages)
 819{
 820        int i;
 821
 822        for (i = 0; i < nr_pages; i++) {
 823                if (PagePrivate(pages[i])) {
 824#if BITS_PER_LONG < 64
 825                        kfree((void *)page_private(pages[i]));
 826#endif
 827                        ClearPagePrivate(pages[i]);
 828                }
 829        }
 830}
 831EXPORT_SYMBOL_GPL(gnttab_pages_clear_private);
 832
 833/**
 834 * gnttab_free_pages - free pages allocated by gnttab_alloc_pages()
 835 * @nr_pages; number of pages to free
 836 * @pages: the pages
 837 */
 838void gnttab_free_pages(int nr_pages, struct page **pages)
 839{
 840        gnttab_pages_clear_private(nr_pages, pages);
 841        free_xenballooned_pages(nr_pages, pages);
 842}
 843EXPORT_SYMBOL_GPL(gnttab_free_pages);
 844
 845#ifdef CONFIG_XEN_GRANT_DMA_ALLOC
 846/**
 847 * gnttab_dma_alloc_pages - alloc DMAable pages suitable for grant mapping into
 848 * @args: arguments to the function
 849 */
 850int gnttab_dma_alloc_pages(struct gnttab_dma_alloc_args *args)
 851{
 852        unsigned long pfn, start_pfn;
 853        size_t size;
 854        int i, ret;
 855
 856        size = args->nr_pages << PAGE_SHIFT;
 857        if (args->coherent)
 858                args->vaddr = dma_alloc_coherent(args->dev, size,
 859                                                 &args->dev_bus_addr,
 860                                                 GFP_KERNEL | __GFP_NOWARN);
 861        else
 862                args->vaddr = dma_alloc_wc(args->dev, size,
 863                                           &args->dev_bus_addr,
 864                                           GFP_KERNEL | __GFP_NOWARN);
 865        if (!args->vaddr) {
 866                pr_debug("Failed to allocate DMA buffer of size %zu\n", size);
 867                return -ENOMEM;
 868        }
 869
 870        start_pfn = __phys_to_pfn(args->dev_bus_addr);
 871        for (pfn = start_pfn, i = 0; pfn < start_pfn + args->nr_pages;
 872                        pfn++, i++) {
 873                struct page *page = pfn_to_page(pfn);
 874
 875                args->pages[i] = page;
 876                args->frames[i] = xen_page_to_gfn(page);
 877                xenmem_reservation_scrub_page(page);
 878        }
 879
 880        xenmem_reservation_va_mapping_reset(args->nr_pages, args->pages);
 881
 882        ret = xenmem_reservation_decrease(args->nr_pages, args->frames);
 883        if (ret != args->nr_pages) {
 884                pr_debug("Failed to decrease reservation for DMA buffer\n");
 885                ret = -EFAULT;
 886                goto fail;
 887        }
 888
 889        ret = gnttab_pages_set_private(args->nr_pages, args->pages);
 890        if (ret < 0)
 891                goto fail;
 892
 893        return 0;
 894
 895fail:
 896        gnttab_dma_free_pages(args);
 897        return ret;
 898}
 899EXPORT_SYMBOL_GPL(gnttab_dma_alloc_pages);
 900
 901/**
 902 * gnttab_dma_free_pages - free DMAable pages
 903 * @args: arguments to the function
 904 */
 905int gnttab_dma_free_pages(struct gnttab_dma_alloc_args *args)
 906{
 907        size_t size;
 908        int i, ret;
 909
 910        gnttab_pages_clear_private(args->nr_pages, args->pages);
 911
 912        for (i = 0; i < args->nr_pages; i++)
 913                args->frames[i] = page_to_xen_pfn(args->pages[i]);
 914
 915        ret = xenmem_reservation_increase(args->nr_pages, args->frames);
 916        if (ret != args->nr_pages) {
 917                pr_debug("Failed to increase reservation for DMA buffer\n");
 918                ret = -EFAULT;
 919        } else {
 920                ret = 0;
 921        }
 922
 923        xenmem_reservation_va_mapping_update(args->nr_pages, args->pages,
 924                                             args->frames);
 925
 926        size = args->nr_pages << PAGE_SHIFT;
 927        if (args->coherent)
 928                dma_free_coherent(args->dev, size,
 929                                  args->vaddr, args->dev_bus_addr);
 930        else
 931                dma_free_wc(args->dev, size,
 932                            args->vaddr, args->dev_bus_addr);
 933        return ret;
 934}
 935EXPORT_SYMBOL_GPL(gnttab_dma_free_pages);
 936#endif
 937
 938/* Handling of paged out grant targets (GNTST_eagain) */
 939#define MAX_DELAY 256
 940static inline void
 941gnttab_retry_eagain_gop(unsigned int cmd, void *gop, int16_t *status,
 942                                                const char *func)
 943{
 944        unsigned delay = 1;
 945
 946        do {
 947                BUG_ON(HYPERVISOR_grant_table_op(cmd, gop, 1));
 948                if (*status == GNTST_eagain)
 949                        msleep(delay++);
 950        } while ((*status == GNTST_eagain) && (delay < MAX_DELAY));
 951
 952        if (delay >= MAX_DELAY) {
 953                pr_err("%s: %s eagain grant\n", func, current->comm);
 954                *status = GNTST_bad_page;
 955        }
 956}
 957
 958void gnttab_batch_map(struct gnttab_map_grant_ref *batch, unsigned count)
 959{
 960        struct gnttab_map_grant_ref *op;
 961
 962        if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, batch, count))
 963                BUG();
 964        for (op = batch; op < batch + count; op++)
 965                if (op->status == GNTST_eagain)
 966                        gnttab_retry_eagain_gop(GNTTABOP_map_grant_ref, op,
 967                                                &op->status, __func__);
 968}
 969EXPORT_SYMBOL_GPL(gnttab_batch_map);
 970
 971void gnttab_batch_copy(struct gnttab_copy *batch, unsigned count)
 972{
 973        struct gnttab_copy *op;
 974
 975        if (HYPERVISOR_grant_table_op(GNTTABOP_copy, batch, count))
 976                BUG();
 977        for (op = batch; op < batch + count; op++)
 978                if (op->status == GNTST_eagain)
 979                        gnttab_retry_eagain_gop(GNTTABOP_copy, op,
 980                                                &op->status, __func__);
 981}
 982EXPORT_SYMBOL_GPL(gnttab_batch_copy);
 983
 984void gnttab_foreach_grant_in_range(struct page *page,
 985                                   unsigned int offset,
 986                                   unsigned int len,
 987                                   xen_grant_fn_t fn,
 988                                   void *data)
 989{
 990        unsigned int goffset;
 991        unsigned int glen;
 992        unsigned long xen_pfn;
 993
 994        len = min_t(unsigned int, PAGE_SIZE - offset, len);
 995        goffset = xen_offset_in_page(offset);
 996
 997        xen_pfn = page_to_xen_pfn(page) + XEN_PFN_DOWN(offset);
 998
 999        while (len) {
1000                glen = min_t(unsigned int, XEN_PAGE_SIZE - goffset, len);
1001                fn(pfn_to_gfn(xen_pfn), goffset, glen, data);
1002
1003                goffset = 0;
1004                xen_pfn++;
1005                len -= glen;
1006        }
1007}
1008EXPORT_SYMBOL_GPL(gnttab_foreach_grant_in_range);
1009
1010void gnttab_foreach_grant(struct page **pages,
1011                          unsigned int nr_grefs,
1012                          xen_grant_fn_t fn,
1013                          void *data)
1014{
1015        unsigned int goffset = 0;
1016        unsigned long xen_pfn = 0;
1017        unsigned int i;
1018
1019        for (i = 0; i < nr_grefs; i++) {
1020                if ((i % XEN_PFN_PER_PAGE) == 0) {
1021                        xen_pfn = page_to_xen_pfn(pages[i / XEN_PFN_PER_PAGE]);
1022                        goffset = 0;
1023                }
1024
1025                fn(pfn_to_gfn(xen_pfn), goffset, XEN_PAGE_SIZE, data);
1026
1027                goffset += XEN_PAGE_SIZE;
1028                xen_pfn++;
1029        }
1030}
1031
1032int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
1033                    struct gnttab_map_grant_ref *kmap_ops,
1034                    struct page **pages, unsigned int count)
1035{
1036        int i, ret;
1037
1038        ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, map_ops, count);
1039        if (ret)
1040                return ret;
1041
1042        for (i = 0; i < count; i++) {
1043                switch (map_ops[i].status) {
1044                case GNTST_okay:
1045                {
1046                        struct xen_page_foreign *foreign;
1047
1048                        SetPageForeign(pages[i]);
1049                        foreign = xen_page_foreign(pages[i]);
1050                        foreign->domid = map_ops[i].dom;
1051                        foreign->gref = map_ops[i].ref;
1052                        break;
1053                }
1054
1055                case GNTST_no_device_space:
1056                        pr_warn_ratelimited("maptrack limit reached, can't map all guest pages\n");
1057                        break;
1058
1059                case GNTST_eagain:
1060                        /* Retry eagain maps */
1061                        gnttab_retry_eagain_gop(GNTTABOP_map_grant_ref,
1062                                                map_ops + i,
1063                                                &map_ops[i].status, __func__);
1064                        /* Test status in next loop iteration. */
1065                        i--;
1066                        break;
1067
1068                default:
1069                        break;
1070                }
1071        }
1072
1073        return set_foreign_p2m_mapping(map_ops, kmap_ops, pages, count);
1074}
1075EXPORT_SYMBOL_GPL(gnttab_map_refs);
1076
1077int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
1078                      struct gnttab_unmap_grant_ref *kunmap_ops,
1079                      struct page **pages, unsigned int count)
1080{
1081        unsigned int i;
1082        int ret;
1083
1084        ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap_ops, count);
1085        if (ret)
1086                return ret;
1087
1088        for (i = 0; i < count; i++)
1089                ClearPageForeign(pages[i]);
1090
1091        return clear_foreign_p2m_mapping(unmap_ops, kunmap_ops, pages, count);
1092}
1093EXPORT_SYMBOL_GPL(gnttab_unmap_refs);
1094
1095#define GNTTAB_UNMAP_REFS_DELAY 5
1096
1097static void __gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item);
1098
1099static void gnttab_unmap_work(struct work_struct *work)
1100{
1101        struct gntab_unmap_queue_data
1102                *unmap_data = container_of(work, 
1103                                           struct gntab_unmap_queue_data,
1104                                           gnttab_work.work);
1105        if (unmap_data->age != UINT_MAX)
1106                unmap_data->age++;
1107        __gnttab_unmap_refs_async(unmap_data);
1108}
1109
1110static void __gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item)
1111{
1112        int ret;
1113        int pc;
1114
1115        for (pc = 0; pc < item->count; pc++) {
1116                if (page_count(item->pages[pc]) > 1) {
1117                        unsigned long delay = GNTTAB_UNMAP_REFS_DELAY * (item->age + 1);
1118                        schedule_delayed_work(&item->gnttab_work,
1119                                              msecs_to_jiffies(delay));
1120                        return;
1121                }
1122        }
1123
1124        ret = gnttab_unmap_refs(item->unmap_ops, item->kunmap_ops,
1125                                item->pages, item->count);
1126        item->done(ret, item);
1127}
1128
1129void gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item)
1130{
1131        INIT_DELAYED_WORK(&item->gnttab_work, gnttab_unmap_work);
1132        item->age = 0;
1133
1134        __gnttab_unmap_refs_async(item);
1135}
1136EXPORT_SYMBOL_GPL(gnttab_unmap_refs_async);
1137
1138static void unmap_refs_callback(int result,
1139                struct gntab_unmap_queue_data *data)
1140{
1141        struct unmap_refs_callback_data *d = data->data;
1142
1143        d->result = result;
1144        complete(&d->completion);
1145}
1146
1147int gnttab_unmap_refs_sync(struct gntab_unmap_queue_data *item)
1148{
1149        struct unmap_refs_callback_data data;
1150
1151        init_completion(&data.completion);
1152        item->data = &data;
1153        item->done = &unmap_refs_callback;
1154        gnttab_unmap_refs_async(item);
1155        wait_for_completion(&data.completion);
1156
1157        return data.result;
1158}
1159EXPORT_SYMBOL_GPL(gnttab_unmap_refs_sync);
1160
1161static unsigned int nr_status_frames(unsigned int nr_grant_frames)
1162{
1163        BUG_ON(gnttab_interface == NULL);
1164        return gnttab_frames(nr_grant_frames, SPP);
1165}
1166
1167static int gnttab_map_frames_v1(xen_pfn_t *frames, unsigned int nr_gframes)
1168{
1169        int rc;
1170
1171        rc = arch_gnttab_map_shared(frames, nr_gframes,
1172                                    gnttab_max_grant_frames(),
1173                                    &gnttab_shared.addr);
1174        BUG_ON(rc);
1175
1176        return 0;
1177}
1178
1179static void gnttab_unmap_frames_v1(void)
1180{
1181        arch_gnttab_unmap(gnttab_shared.addr, nr_grant_frames);
1182}
1183
1184static int gnttab_map_frames_v2(xen_pfn_t *frames, unsigned int nr_gframes)
1185{
1186        uint64_t *sframes;
1187        unsigned int nr_sframes;
1188        struct gnttab_get_status_frames getframes;
1189        int rc;
1190
1191        nr_sframes = nr_status_frames(nr_gframes);
1192
1193        /* No need for kzalloc as it is initialized in following hypercall
1194         * GNTTABOP_get_status_frames.
1195         */
1196        sframes = kmalloc_array(nr_sframes, sizeof(uint64_t), GFP_ATOMIC);
1197        if (!sframes)
1198                return -ENOMEM;
1199
1200        getframes.dom        = DOMID_SELF;
1201        getframes.nr_frames  = nr_sframes;
1202        set_xen_guest_handle(getframes.frame_list, sframes);
1203
1204        rc = HYPERVISOR_grant_table_op(GNTTABOP_get_status_frames,
1205                                       &getframes, 1);
1206        if (rc == -ENOSYS) {
1207                kfree(sframes);
1208                return -ENOSYS;
1209        }
1210
1211        BUG_ON(rc || getframes.status);
1212
1213        rc = arch_gnttab_map_status(sframes, nr_sframes,
1214                                    nr_status_frames(gnttab_max_grant_frames()),
1215                                    &grstatus);
1216        BUG_ON(rc);
1217        kfree(sframes);
1218
1219        rc = arch_gnttab_map_shared(frames, nr_gframes,
1220                                    gnttab_max_grant_frames(),
1221                                    &gnttab_shared.addr);
1222        BUG_ON(rc);
1223
1224        return 0;
1225}
1226
1227static void gnttab_unmap_frames_v2(void)
1228{
1229        arch_gnttab_unmap(gnttab_shared.addr, nr_grant_frames);
1230        arch_gnttab_unmap(grstatus, nr_status_frames(nr_grant_frames));
1231}
1232
1233static int gnttab_map(unsigned int start_idx, unsigned int end_idx)
1234{
1235        struct gnttab_setup_table setup;
1236        xen_pfn_t *frames;
1237        unsigned int nr_gframes = end_idx + 1;
1238        int rc;
1239
1240        if (xen_feature(XENFEAT_auto_translated_physmap)) {
1241                struct xen_add_to_physmap xatp;
1242                unsigned int i = end_idx;
1243                rc = 0;
1244                BUG_ON(xen_auto_xlat_grant_frames.count < nr_gframes);
1245                /*
1246                 * Loop backwards, so that the first hypercall has the largest
1247                 * index, ensuring that the table will grow only once.
1248                 */
1249                do {
1250                        xatp.domid = DOMID_SELF;
1251                        xatp.idx = i;
1252                        xatp.space = XENMAPSPACE_grant_table;
1253                        xatp.gpfn = xen_auto_xlat_grant_frames.pfn[i];
1254                        rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp);
1255                        if (rc != 0) {
1256                                pr_warn("grant table add_to_physmap failed, err=%d\n",
1257                                        rc);
1258                                break;
1259                        }
1260                } while (i-- > start_idx);
1261
1262                return rc;
1263        }
1264
1265        /* No need for kzalloc as it is initialized in following hypercall
1266         * GNTTABOP_setup_table.
1267         */
1268        frames = kmalloc_array(nr_gframes, sizeof(unsigned long), GFP_ATOMIC);
1269        if (!frames)
1270                return -ENOMEM;
1271
1272        setup.dom        = DOMID_SELF;
1273        setup.nr_frames  = nr_gframes;
1274        set_xen_guest_handle(setup.frame_list, frames);
1275
1276        rc = HYPERVISOR_grant_table_op(GNTTABOP_setup_table, &setup, 1);
1277        if (rc == -ENOSYS) {
1278                kfree(frames);
1279                return -ENOSYS;
1280        }
1281
1282        BUG_ON(rc || setup.status);
1283
1284        rc = gnttab_interface->map_frames(frames, nr_gframes);
1285
1286        kfree(frames);
1287
1288        return rc;
1289}
1290
1291static const struct gnttab_ops gnttab_v1_ops = {
1292        .version                        = 1,
1293        .grefs_per_grant_frame          = XEN_PAGE_SIZE /
1294                                          sizeof(struct grant_entry_v1),
1295        .map_frames                     = gnttab_map_frames_v1,
1296        .unmap_frames                   = gnttab_unmap_frames_v1,
1297        .update_entry                   = gnttab_update_entry_v1,
1298        .end_foreign_access_ref         = gnttab_end_foreign_access_ref_v1,
1299        .end_foreign_transfer_ref       = gnttab_end_foreign_transfer_ref_v1,
1300        .query_foreign_access           = gnttab_query_foreign_access_v1,
1301};
1302
1303static const struct gnttab_ops gnttab_v2_ops = {
1304        .version                        = 2,
1305        .grefs_per_grant_frame          = XEN_PAGE_SIZE /
1306                                          sizeof(union grant_entry_v2),
1307        .map_frames                     = gnttab_map_frames_v2,
1308        .unmap_frames                   = gnttab_unmap_frames_v2,
1309        .update_entry                   = gnttab_update_entry_v2,
1310        .end_foreign_access_ref         = gnttab_end_foreign_access_ref_v2,
1311        .end_foreign_transfer_ref       = gnttab_end_foreign_transfer_ref_v2,
1312        .query_foreign_access           = gnttab_query_foreign_access_v2,
1313};
1314
1315static bool gnttab_need_v2(void)
1316{
1317#ifdef CONFIG_X86
1318        uint32_t base, width;
1319
1320        if (xen_pv_domain()) {
1321                base = xen_cpuid_base();
1322                if (cpuid_eax(base) < 5)
1323                        return false;   /* Information not available, use V1. */
1324                width = cpuid_ebx(base + 5) &
1325                        XEN_CPUID_MACHINE_ADDRESS_WIDTH_MASK;
1326                return width > 32 + PAGE_SHIFT;
1327        }
1328#endif
1329        return !!(max_possible_pfn >> 32);
1330}
1331
1332static void gnttab_request_version(void)
1333{
1334        long rc;
1335        struct gnttab_set_version gsv;
1336
1337        if (gnttab_need_v2())
1338                gsv.version = 2;
1339        else
1340                gsv.version = 1;
1341
1342        /* Boot parameter overrides automatic selection. */
1343        if (xen_gnttab_version >= 1 && xen_gnttab_version <= 2)
1344                gsv.version = xen_gnttab_version;
1345
1346        rc = HYPERVISOR_grant_table_op(GNTTABOP_set_version, &gsv, 1);
1347        if (rc == 0 && gsv.version == 2)
1348                gnttab_interface = &gnttab_v2_ops;
1349        else
1350                gnttab_interface = &gnttab_v1_ops;
1351        pr_info("Grant tables using version %d layout\n",
1352                gnttab_interface->version);
1353}
1354
1355static int gnttab_setup(void)
1356{
1357        unsigned int max_nr_gframes;
1358
1359        max_nr_gframes = gnttab_max_grant_frames();
1360        if (max_nr_gframes < nr_grant_frames)
1361                return -ENOSYS;
1362
1363        if (xen_feature(XENFEAT_auto_translated_physmap) && gnttab_shared.addr == NULL) {
1364                gnttab_shared.addr = xen_auto_xlat_grant_frames.vaddr;
1365                if (gnttab_shared.addr == NULL) {
1366                        pr_warn("gnttab share frames is not mapped!\n");
1367                        return -ENOMEM;
1368                }
1369        }
1370        return gnttab_map(0, nr_grant_frames - 1);
1371}
1372
1373int gnttab_resume(void)
1374{
1375        gnttab_request_version();
1376        return gnttab_setup();
1377}
1378
1379int gnttab_suspend(void)
1380{
1381        if (!xen_feature(XENFEAT_auto_translated_physmap))
1382                gnttab_interface->unmap_frames();
1383        return 0;
1384}
1385
1386static int gnttab_expand(unsigned int req_entries)
1387{
1388        int rc;
1389        unsigned int cur, extra;
1390
1391        BUG_ON(gnttab_interface == NULL);
1392        cur = nr_grant_frames;
1393        extra = ((req_entries + gnttab_interface->grefs_per_grant_frame - 1) /
1394                 gnttab_interface->grefs_per_grant_frame);
1395        if (cur + extra > gnttab_max_grant_frames()) {
1396                pr_warn_ratelimited("xen/grant-table: max_grant_frames reached"
1397                                    " cur=%u extra=%u limit=%u"
1398                                    " gnttab_free_count=%u req_entries=%u\n",
1399                                    cur, extra, gnttab_max_grant_frames(),
1400                                    gnttab_free_count, req_entries);
1401                return -ENOSPC;
1402        }
1403
1404        rc = gnttab_map(cur, cur + extra - 1);
1405        if (rc == 0)
1406                rc = grow_gnttab_list(extra);
1407
1408        return rc;
1409}
1410
1411int gnttab_init(void)
1412{
1413        int i;
1414        unsigned long max_nr_grant_frames;
1415        unsigned int max_nr_glist_frames, nr_glist_frames;
1416        unsigned int nr_init_grefs;
1417        int ret;
1418
1419        gnttab_request_version();
1420        max_nr_grant_frames = gnttab_max_grant_frames();
1421        nr_grant_frames = 1;
1422
1423        /* Determine the maximum number of frames required for the
1424         * grant reference free list on the current hypervisor.
1425         */
1426        BUG_ON(gnttab_interface == NULL);
1427        max_nr_glist_frames = (max_nr_grant_frames *
1428                               gnttab_interface->grefs_per_grant_frame / RPP);
1429
1430        gnttab_list = kmalloc_array(max_nr_glist_frames,
1431                                    sizeof(grant_ref_t *),
1432                                    GFP_KERNEL);
1433        if (gnttab_list == NULL)
1434                return -ENOMEM;
1435
1436        nr_glist_frames = gnttab_frames(nr_grant_frames, RPP);
1437        for (i = 0; i < nr_glist_frames; i++) {
1438                gnttab_list[i] = (grant_ref_t *)__get_free_page(GFP_KERNEL);
1439                if (gnttab_list[i] == NULL) {
1440                        ret = -ENOMEM;
1441                        goto ini_nomem;
1442                }
1443        }
1444
1445        ret = arch_gnttab_init(max_nr_grant_frames,
1446                               nr_status_frames(max_nr_grant_frames));
1447        if (ret < 0)
1448                goto ini_nomem;
1449
1450        if (gnttab_setup() < 0) {
1451                ret = -ENODEV;
1452                goto ini_nomem;
1453        }
1454
1455        nr_init_grefs = nr_grant_frames *
1456                        gnttab_interface->grefs_per_grant_frame;
1457
1458        for (i = NR_RESERVED_ENTRIES; i < nr_init_grefs - 1; i++)
1459                gnttab_entry(i) = i + 1;
1460
1461        gnttab_entry(nr_init_grefs - 1) = GNTTAB_LIST_END;
1462        gnttab_free_count = nr_init_grefs - NR_RESERVED_ENTRIES;
1463        gnttab_free_head  = NR_RESERVED_ENTRIES;
1464
1465        printk("Grant table initialized\n");
1466        return 0;
1467
1468 ini_nomem:
1469        for (i--; i >= 0; i--)
1470                free_page((unsigned long)gnttab_list[i]);
1471        kfree(gnttab_list);
1472        return ret;
1473}
1474EXPORT_SYMBOL_GPL(gnttab_init);
1475
1476static int __gnttab_init(void)
1477{
1478        if (!xen_domain())
1479                return -ENODEV;
1480
1481        /* Delay grant-table initialization in the PV on HVM case */
1482        if (xen_hvm_domain() && !xen_pvh_domain())
1483                return 0;
1484
1485        return gnttab_init();
1486}
1487/* Starts after core_initcall so that xen_pvh_gnttab_setup can be called
1488 * beforehand to initialize xen_auto_xlat_grant_frames. */
1489core_initcall_sync(__gnttab_init);
1490