drivers/xen/grant-table.c

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This source file includes following definitions.
__gnttab_entry
get_free_entries
do_free_callbacks
check_free_callbacks
put_free_entry
gnttab_update_entry_v1
gnttab_update_entry_v2
gnttab_grant_foreign_access_ref
gnttab_grant_foreign_access
gnttab_query_foreign_access_v1
gnttab_query_foreign_access_v2
gnttab_query_foreign_access
gnttab_end_foreign_access_ref_v1
gnttab_end_foreign_access_ref_v2
_gnttab_end_foreign_access_ref
gnttab_end_foreign_access_ref
gnttab_handle_deferred
gnttab_add_deferred
gnttab_end_foreign_access
gnttab_grant_foreign_transfer
gnttab_grant_foreign_transfer_ref
gnttab_end_foreign_transfer_ref_v1
gnttab_end_foreign_transfer_ref_v2
gnttab_end_foreign_transfer_ref
gnttab_end_foreign_transfer
gnttab_free_grant_reference
gnttab_free_grant_references
gnttab_alloc_grant_references
gnttab_empty_grant_references
gnttab_claim_grant_reference
gnttab_release_grant_reference
gnttab_request_free_callback
gnttab_cancel_free_callback
gnttab_frames
grow_gnttab_list
__max_nr_grant_frames
gnttab_max_grant_frames
gnttab_setup_auto_xlat_frames
gnttab_free_auto_xlat_frames
gnttab_pages_set_private
gnttab_alloc_pages
gnttab_pages_clear_private
gnttab_free_pages
gnttab_dma_alloc_pages
gnttab_dma_free_pages
gnttab_retry_eagain_gop
gnttab_batch_map
gnttab_batch_copy
gnttab_foreach_grant_in_range
gnttab_foreach_grant
gnttab_map_refs
gnttab_unmap_refs
gnttab_unmap_work
__gnttab_unmap_refs_async
gnttab_unmap_refs_async
unmap_refs_callback
gnttab_unmap_refs_sync
nr_status_frames
gnttab_map_frames_v1
gnttab_unmap_frames_v1
gnttab_map_frames_v2
gnttab_unmap_frames_v2
gnttab_map
gnttab_need_v2
gnttab_request_version
gnttab_setup
gnttab_resume
gnttab_suspend
gnttab_expand
gnttab_init
__gnttab_init
   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 
  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          * 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 
 146 struct unmap_refs_callback_data {
 147         struct completion completion;
 148         int result;
 149 };
 150 
 151 static const struct gnttab_ops *gnttab_interface;
 152 
 153 /* This reflects status of grant entries, so act as a global value. */
 154 static grant_status_t *grstatus;
 155 
 156 static struct gnttab_free_callback *gnttab_free_callback_list;
 157 
 158 static 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 
 163 static 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 
 170 static 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 
 196 static 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 
 216 static inline void check_free_callbacks(void)
 217 {
 218         if (unlikely(gnttab_free_callback_list))
 219                 do_free_callbacks();
 220 }
 221 
 222 static 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  */
 244 static 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 
 253 static 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  */
 265 void 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 }
 271 EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access_ref);
 272 
 273 int 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 }
 286 EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access);
 287 
 288 static int gnttab_query_foreign_access_v1(grant_ref_t ref)
 289 {
 290         return gnttab_shared.v1[ref].flags & (GTF_reading|GTF_writing);
 291 }
 292 
 293 static int gnttab_query_foreign_access_v2(grant_ref_t ref)
 294 {
 295         return grstatus[ref] & (GTF_reading|GTF_writing);
 296 }
 297 
 298 int gnttab_query_foreign_access(grant_ref_t ref)
 299 {
 300         return gnttab_interface->query_foreign_access(ref);
 301 }
 302 EXPORT_SYMBOL_GPL(gnttab_query_foreign_access);
 303 
 304 static 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 
 320 static 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 
 343 static 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 
 348 int 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 }
 355 EXPORT_SYMBOL_GPL(gnttab_end_foreign_access_ref);
 356 
 357 struct 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 };
 364 static LIST_HEAD(deferred_list);
 365 static void gnttab_handle_deferred(struct timer_list *);
 366 static DEFINE_TIMER(deferred_timer, gnttab_handle_deferred);
 367 
 368 static 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 
 413 static 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 
 439 void 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 }
 450 EXPORT_SYMBOL_GPL(gnttab_end_foreign_access);
 451 
 452 int 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 }
 463 EXPORT_SYMBOL_GPL(gnttab_grant_foreign_transfer);
 464 
 465 void 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 }
 470 EXPORT_SYMBOL_GPL(gnttab_grant_foreign_transfer_ref);
 471 
 472 static 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 
 503 static 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 
 534 unsigned long gnttab_end_foreign_transfer_ref(grant_ref_t ref)
 535 {
 536         return gnttab_interface->end_foreign_transfer_ref(ref);
 537 }
 538 EXPORT_SYMBOL_GPL(gnttab_end_foreign_transfer_ref);
 539 
 540 unsigned 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 }
 546 EXPORT_SYMBOL_GPL(gnttab_end_foreign_transfer);
 547 
 548 void gnttab_free_grant_reference(grant_ref_t ref)
 549 {
 550         put_free_entry(ref);
 551 }
 552 EXPORT_SYMBOL_GPL(gnttab_free_grant_reference);
 553 
 554 void 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 }
 573 EXPORT_SYMBOL_GPL(gnttab_free_grant_references);
 574 
 575 int 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 }
 586 EXPORT_SYMBOL_GPL(gnttab_alloc_grant_references);
 587 
 588 int gnttab_empty_grant_references(const grant_ref_t *private_head)
 589 {
 590         return (*private_head == GNTTAB_LIST_END);
 591 }
 592 EXPORT_SYMBOL_GPL(gnttab_empty_grant_references);
 593 
 594 int 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 }
 602 EXPORT_SYMBOL_GPL(gnttab_claim_grant_reference);
 603 
 604 void 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 }
 610 EXPORT_SYMBOL_GPL(gnttab_release_grant_reference);
 611 
 612 void 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();
 634 out:
 635         spin_unlock_irqrestore(&gnttab_list_lock, flags);
 636 }
 637 EXPORT_SYMBOL_GPL(gnttab_request_free_callback);
 638 
 639 void 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 }
 653 EXPORT_SYMBOL_GPL(gnttab_cancel_free_callback);
 654 
 655 static 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 
 661 static 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 
 696 grow_nomem:
 697         while (i-- > nr_glist_frames)
 698                 free_page((unsigned long) gnttab_list[i]);
 699         return -ENOMEM;
 700 }
 701 
 702 static 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 
 716 unsigned 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 }
 729 EXPORT_SYMBOL_GPL(gnttab_max_grant_frames);
 730 
 731 int 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 }
 761 EXPORT_SYMBOL_GPL(gnttab_setup_auto_xlat_frames);
 762 
 763 void 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 }
 774 EXPORT_SYMBOL_GPL(gnttab_free_auto_xlat_frames);
 775 
 776 int 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 }
 795 EXPORT_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  */
 802 int 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 }
 816 EXPORT_SYMBOL_GPL(gnttab_alloc_pages);
 817 
 818 void 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 }
 831 EXPORT_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  */
 838 void 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 }
 843 EXPORT_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  */
 850 int 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 
 895 fail:
 896         gnttab_dma_free_pages(args);
 897         return ret;
 898 }
 899 EXPORT_SYMBOL_GPL(gnttab_dma_alloc_pages);
 900 
 901 /**
 902  * gnttab_dma_free_pages - free DMAable pages
 903  * @args: arguments to the function
 904  */
 905 int 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 }
 935 EXPORT_SYMBOL_GPL(gnttab_dma_free_pages);
 936 #endif
 937 
 938 /* Handling of paged out grant targets (GNTST_eagain) */
 939 #define MAX_DELAY 256
 940 static inline void
 941 gnttab_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 
 958 void 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 }
 969 EXPORT_SYMBOL_GPL(gnttab_batch_map);
 970 
 971 void 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 }
 982 EXPORT_SYMBOL_GPL(gnttab_batch_copy);
 983 
 984 void 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 }
1008 EXPORT_SYMBOL_GPL(gnttab_foreach_grant_in_range);
1009 
1010 void 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 
1032 int 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 }
1075 EXPORT_SYMBOL_GPL(gnttab_map_refs);
1076 
1077 int 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 }
1093 EXPORT_SYMBOL_GPL(gnttab_unmap_refs);
1094 
1095 #define GNTTAB_UNMAP_REFS_DELAY 5
1096 
1097 static void __gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item);
1098 
1099 static 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 
1110 static 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 
1129 void 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 }
1136 EXPORT_SYMBOL_GPL(gnttab_unmap_refs_async);
1137 
1138 static 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 
1147 int 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 }
1159 EXPORT_SYMBOL_GPL(gnttab_unmap_refs_sync);
1160 
1161 static 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 
1167 static 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 
1179 static void gnttab_unmap_frames_v1(void)
1180 {
1181         arch_gnttab_unmap(gnttab_shared.addr, nr_grant_frames);
1182 }
1183 
1184 static 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 
1227 static 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 
1233 static 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 
1291 static 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 
1303 static 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 
1315 static 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 
1332 static 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 
1355 static 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 
1373 int gnttab_resume(void)
1374 {
1375         gnttab_request_version();
1376         return gnttab_setup();
1377 }
1378 
1379 int gnttab_suspend(void)
1380 {
1381         if (!xen_feature(XENFEAT_auto_translated_physmap))
1382                 gnttab_interface->unmap_frames();
1383         return 0;
1384 }
1385 
1386 static 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 
1411 int 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 }
1474 EXPORT_SYMBOL_GPL(gnttab_init);
1475 
1476 static 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. */
1489 core_initcall_sync(__gnttab_init);
/* [<][>][^][v][top][bottom][index][help] */
root/drivers/xen/grant-table.c

DEFINITIONS
