drivers/iommu/iova.c

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This source file includes following definitions.
init_iova_domain
has_iova_flush_queue
free_iova_flush_queue
init_iova_flush_queue
__get_cached_rbnode
__cached_rbnode_insert_update
__cached_rbnode_delete_update
iova_insert_rbtree
__alloc_and_insert_iova_range
alloc_iova_mem
free_iova_mem
iova_cache_get
iova_cache_put
alloc_iova
private_find_iova
private_free_iova
find_iova
__free_iova
free_iova
alloc_iova_fast
free_iova_fast
fq_full
fq_ring_add
fq_ring_free
iova_domain_flush
fq_destroy_all_entries
fq_flush_timeout
queue_iova
put_iova_domain
__is_range_overlap
alloc_and_init_iova
__insert_new_range
__adjust_overlap_range
reserve_iova
copy_reserved_iova
split_and_remove_iova
iova_magazine_alloc
iova_magazine_free
iova_magazine_free_pfns
iova_magazine_full
iova_magazine_empty
iova_magazine_pop
iova_magazine_push
init_iova_rcaches
__iova_rcache_insert
iova_rcache_insert
__iova_rcache_get
iova_rcache_get
free_iova_rcaches
free_cpu_cached_iovas
   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright © 2006-2009, Intel Corporation.
   4  *
   5  * Author: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
   6  */
   7 
   8 #include <linux/iova.h>
   9 #include <linux/module.h>
  10 #include <linux/slab.h>
  11 #include <linux/smp.h>
  12 #include <linux/bitops.h>
  13 #include <linux/cpu.h>
  14 
  15 /* The anchor node sits above the top of the usable address space */
  16 #define IOVA_ANCHOR     ~0UL
  17 
  18 static bool iova_rcache_insert(struct iova_domain *iovad,
  19                                unsigned long pfn,
  20                                unsigned long size);
  21 static unsigned long iova_rcache_get(struct iova_domain *iovad,
  22                                      unsigned long size,
  23                                      unsigned long limit_pfn);
  24 static void init_iova_rcaches(struct iova_domain *iovad);
  25 static void free_iova_rcaches(struct iova_domain *iovad);
  26 static void fq_destroy_all_entries(struct iova_domain *iovad);
  27 static void fq_flush_timeout(struct timer_list *t);
  28 
  29 void
  30 init_iova_domain(struct iova_domain *iovad, unsigned long granule,
  31         unsigned long start_pfn)
  32 {
  33         /*
  34          * IOVA granularity will normally be equal to the smallest
  35          * supported IOMMU page size; both *must* be capable of
  36          * representing individual CPU pages exactly.
  37          */
  38         BUG_ON((granule > PAGE_SIZE) || !is_power_of_2(granule));
  39 
  40         spin_lock_init(&iovad->iova_rbtree_lock);
  41         iovad->rbroot = RB_ROOT;
  42         iovad->cached_node = &iovad->anchor.node;
  43         iovad->cached32_node = &iovad->anchor.node;
  44         iovad->granule = granule;
  45         iovad->start_pfn = start_pfn;
  46         iovad->dma_32bit_pfn = 1UL << (32 - iova_shift(iovad));
  47         iovad->max32_alloc_size = iovad->dma_32bit_pfn;
  48         iovad->flush_cb = NULL;
  49         iovad->fq = NULL;
  50         iovad->anchor.pfn_lo = iovad->anchor.pfn_hi = IOVA_ANCHOR;
  51         rb_link_node(&iovad->anchor.node, NULL, &iovad->rbroot.rb_node);
  52         rb_insert_color(&iovad->anchor.node, &iovad->rbroot);
  53         init_iova_rcaches(iovad);
  54 }
  55 EXPORT_SYMBOL_GPL(init_iova_domain);
  56 
  57 bool has_iova_flush_queue(struct iova_domain *iovad)
  58 {
  59         return !!iovad->fq;
  60 }
  61 
  62 static void free_iova_flush_queue(struct iova_domain *iovad)
  63 {
  64         if (!has_iova_flush_queue(iovad))
  65                 return;
  66 
  67         if (timer_pending(&iovad->fq_timer))
  68                 del_timer(&iovad->fq_timer);
  69 
  70         fq_destroy_all_entries(iovad);
  71 
  72         free_percpu(iovad->fq);
  73 
  74         iovad->fq         = NULL;
  75         iovad->flush_cb   = NULL;
  76         iovad->entry_dtor = NULL;
  77 }
  78 
  79 int init_iova_flush_queue(struct iova_domain *iovad,
  80                           iova_flush_cb flush_cb, iova_entry_dtor entry_dtor)
  81 {
  82         struct iova_fq __percpu *queue;
  83         int cpu;
  84 
  85         atomic64_set(&iovad->fq_flush_start_cnt,  0);
  86         atomic64_set(&iovad->fq_flush_finish_cnt, 0);
  87 
  88         queue = alloc_percpu(struct iova_fq);
  89         if (!queue)
  90                 return -ENOMEM;
  91 
  92         iovad->flush_cb   = flush_cb;
  93         iovad->entry_dtor = entry_dtor;
  94 
  95         for_each_possible_cpu(cpu) {
  96                 struct iova_fq *fq;
  97 
  98                 fq = per_cpu_ptr(queue, cpu);
  99                 fq->head = 0;
 100                 fq->tail = 0;
 101 
 102                 spin_lock_init(&fq->lock);
 103         }
 104 
 105         smp_wmb();
 106 
 107         iovad->fq = queue;
 108 
 109         timer_setup(&iovad->fq_timer, fq_flush_timeout, 0);
 110         atomic_set(&iovad->fq_timer_on, 0);
 111 
 112         return 0;
 113 }
 114 EXPORT_SYMBOL_GPL(init_iova_flush_queue);
 115 
 116 static struct rb_node *
 117 __get_cached_rbnode(struct iova_domain *iovad, unsigned long limit_pfn)
 118 {
 119         if (limit_pfn <= iovad->dma_32bit_pfn)
 120                 return iovad->cached32_node;
 121 
 122         return iovad->cached_node;
 123 }
 124 
 125 static void
 126 __cached_rbnode_insert_update(struct iova_domain *iovad, struct iova *new)
 127 {
 128         if (new->pfn_hi < iovad->dma_32bit_pfn)
 129                 iovad->cached32_node = &new->node;
 130         else
 131                 iovad->cached_node = &new->node;
 132 }
 133 
 134 static void
 135 __cached_rbnode_delete_update(struct iova_domain *iovad, struct iova *free)
 136 {
 137         struct iova *cached_iova;
 138 
 139         cached_iova = rb_entry(iovad->cached32_node, struct iova, node);
 140         if (free == cached_iova ||
 141             (free->pfn_hi < iovad->dma_32bit_pfn &&
 142              free->pfn_lo >= cached_iova->pfn_lo)) {
 143                 iovad->cached32_node = rb_next(&free->node);
 144                 iovad->max32_alloc_size = iovad->dma_32bit_pfn;
 145         }
 146 
 147         cached_iova = rb_entry(iovad->cached_node, struct iova, node);
 148         if (free->pfn_lo >= cached_iova->pfn_lo)
 149                 iovad->cached_node = rb_next(&free->node);
 150 }
 151 
 152 /* Insert the iova into domain rbtree by holding writer lock */
 153 static void
 154 iova_insert_rbtree(struct rb_root *root, struct iova *iova,
 155                    struct rb_node *start)
 156 {
 157         struct rb_node **new, *parent = NULL;
 158 
 159         new = (start) ? &start : &(root->rb_node);
 160         /* Figure out where to put new node */
 161         while (*new) {
 162                 struct iova *this = rb_entry(*new, struct iova, node);
 163 
 164                 parent = *new;
 165 
 166                 if (iova->pfn_lo < this->pfn_lo)
 167                         new = &((*new)->rb_left);
 168                 else if (iova->pfn_lo > this->pfn_lo)
 169                         new = &((*new)->rb_right);
 170                 else {
 171                         WARN_ON(1); /* this should not happen */
 172                         return;
 173                 }
 174         }
 175         /* Add new node and rebalance tree. */
 176         rb_link_node(&iova->node, parent, new);
 177         rb_insert_color(&iova->node, root);
 178 }
 179 
 180 static int __alloc_and_insert_iova_range(struct iova_domain *iovad,
 181                 unsigned long size, unsigned long limit_pfn,
 182                         struct iova *new, bool size_aligned)
 183 {
 184         struct rb_node *curr, *prev;
 185         struct iova *curr_iova;
 186         unsigned long flags;
 187         unsigned long new_pfn;
 188         unsigned long align_mask = ~0UL;
 189 
 190         if (size_aligned)
 191                 align_mask <<= fls_long(size - 1);
 192 
 193         /* Walk the tree backwards */
 194         spin_lock_irqsave(&iovad->iova_rbtree_lock, flags);
 195         if (limit_pfn <= iovad->dma_32bit_pfn &&
 196                         size >= iovad->max32_alloc_size)
 197                 goto iova32_full;
 198 
 199         curr = __get_cached_rbnode(iovad, limit_pfn);
 200         curr_iova = rb_entry(curr, struct iova, node);
 201         do {
 202                 limit_pfn = min(limit_pfn, curr_iova->pfn_lo);
 203                 new_pfn = (limit_pfn - size) & align_mask;
 204                 prev = curr;
 205                 curr = rb_prev(curr);
 206                 curr_iova = rb_entry(curr, struct iova, node);
 207         } while (curr && new_pfn <= curr_iova->pfn_hi);
 208 
 209         if (limit_pfn < size || new_pfn < iovad->start_pfn) {
 210                 iovad->max32_alloc_size = size;
 211                 goto iova32_full;
 212         }
 213 
 214         /* pfn_lo will point to size aligned address if size_aligned is set */
 215         new->pfn_lo = new_pfn;
 216         new->pfn_hi = new->pfn_lo + size - 1;
 217 
 218         /* If we have 'prev', it's a valid place to start the insertion. */
 219         iova_insert_rbtree(&iovad->rbroot, new, prev);
 220         __cached_rbnode_insert_update(iovad, new);
 221 
 222         spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
 223         return 0;
 224 
 225 iova32_full:
 226         spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
 227         return -ENOMEM;
 228 }
 229 
 230 static struct kmem_cache *iova_cache;
 231 static unsigned int iova_cache_users;
 232 static DEFINE_MUTEX(iova_cache_mutex);
 233 
 234 struct iova *alloc_iova_mem(void)
 235 {
 236         return kmem_cache_zalloc(iova_cache, GFP_ATOMIC | __GFP_NOWARN);
 237 }
 238 EXPORT_SYMBOL(alloc_iova_mem);
 239 
 240 void free_iova_mem(struct iova *iova)
 241 {
 242         if (iova->pfn_lo != IOVA_ANCHOR)
 243                 kmem_cache_free(iova_cache, iova);
 244 }
 245 EXPORT_SYMBOL(free_iova_mem);
 246 
 247 int iova_cache_get(void)
 248 {
 249         mutex_lock(&iova_cache_mutex);
 250         if (!iova_cache_users) {
 251                 iova_cache = kmem_cache_create(
 252                         "iommu_iova", sizeof(struct iova), 0,
 253                         SLAB_HWCACHE_ALIGN, NULL);
 254                 if (!iova_cache) {
 255                         mutex_unlock(&iova_cache_mutex);
 256                         printk(KERN_ERR "Couldn't create iova cache\n");
 257                         return -ENOMEM;
 258                 }
 259         }
 260 
 261         iova_cache_users++;
 262         mutex_unlock(&iova_cache_mutex);
 263 
 264         return 0;
 265 }
 266 EXPORT_SYMBOL_GPL(iova_cache_get);
 267 
 268 void iova_cache_put(void)
 269 {
 270         mutex_lock(&iova_cache_mutex);
 271         if (WARN_ON(!iova_cache_users)) {
 272                 mutex_unlock(&iova_cache_mutex);
 273                 return;
 274         }
 275         iova_cache_users--;
 276         if (!iova_cache_users)
 277                 kmem_cache_destroy(iova_cache);
 278         mutex_unlock(&iova_cache_mutex);
 279 }
 280 EXPORT_SYMBOL_GPL(iova_cache_put);
 281 
 282 /**
 283  * alloc_iova - allocates an iova
 284  * @iovad: - iova domain in question
 285  * @size: - size of page frames to allocate
 286  * @limit_pfn: - max limit address
 287  * @size_aligned: - set if size_aligned address range is required
 288  * This function allocates an iova in the range iovad->start_pfn to limit_pfn,
 289  * searching top-down from limit_pfn to iovad->start_pfn. If the size_aligned
 290  * flag is set then the allocated address iova->pfn_lo will be naturally
 291  * aligned on roundup_power_of_two(size).
 292  */
 293 struct iova *
 294 alloc_iova(struct iova_domain *iovad, unsigned long size,
 295         unsigned long limit_pfn,
 296         bool size_aligned)
 297 {
 298         struct iova *new_iova;
 299         int ret;
 300 
 301         new_iova = alloc_iova_mem();
 302         if (!new_iova)
 303                 return NULL;
 304 
 305         ret = __alloc_and_insert_iova_range(iovad, size, limit_pfn + 1,
 306                         new_iova, size_aligned);
 307 
 308         if (ret) {
 309                 free_iova_mem(new_iova);
 310                 return NULL;
 311         }
 312 
 313         return new_iova;
 314 }
 315 EXPORT_SYMBOL_GPL(alloc_iova);
 316 
 317 static struct iova *
 318 private_find_iova(struct iova_domain *iovad, unsigned long pfn)
 319 {
 320         struct rb_node *node = iovad->rbroot.rb_node;
 321 
 322         assert_spin_locked(&iovad->iova_rbtree_lock);
 323 
 324         while (node) {
 325                 struct iova *iova = rb_entry(node, struct iova, node);
 326 
 327                 if (pfn < iova->pfn_lo)
 328                         node = node->rb_left;
 329                 else if (pfn > iova->pfn_hi)
 330                         node = node->rb_right;
 331                 else
 332                         return iova;    /* pfn falls within iova's range */
 333         }
 334 
 335         return NULL;
 336 }
 337 
 338 static void private_free_iova(struct iova_domain *iovad, struct iova *iova)
 339 {
 340         assert_spin_locked(&iovad->iova_rbtree_lock);
 341         __cached_rbnode_delete_update(iovad, iova);
 342         rb_erase(&iova->node, &iovad->rbroot);
 343         free_iova_mem(iova);
 344 }
 345 
 346 /**
 347  * find_iova - finds an iova for a given pfn
 348  * @iovad: - iova domain in question.
 349  * @pfn: - page frame number
 350  * This function finds and returns an iova belonging to the
 351  * given doamin which matches the given pfn.
 352  */
 353 struct iova *find_iova(struct iova_domain *iovad, unsigned long pfn)
 354 {
 355         unsigned long flags;
 356         struct iova *iova;
 357 
 358         /* Take the lock so that no other thread is manipulating the rbtree */
 359         spin_lock_irqsave(&iovad->iova_rbtree_lock, flags);
 360         iova = private_find_iova(iovad, pfn);
 361         spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
 362         return iova;
 363 }
 364 EXPORT_SYMBOL_GPL(find_iova);
 365 
 366 /**
 367  * __free_iova - frees the given iova
 368  * @iovad: iova domain in question.
 369  * @iova: iova in question.
 370  * Frees the given iova belonging to the giving domain
 371  */
 372 void
 373 __free_iova(struct iova_domain *iovad, struct iova *iova)
 374 {
 375         unsigned long flags;
 376 
 377         spin_lock_irqsave(&iovad->iova_rbtree_lock, flags);
 378         private_free_iova(iovad, iova);
 379         spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
 380 }
 381 EXPORT_SYMBOL_GPL(__free_iova);
 382 
 383 /**
 384  * free_iova - finds and frees the iova for a given pfn
 385  * @iovad: - iova domain in question.
 386  * @pfn: - pfn that is allocated previously
 387  * This functions finds an iova for a given pfn and then
 388  * frees the iova from that domain.
 389  */
 390 void
 391 free_iova(struct iova_domain *iovad, unsigned long pfn)
 392 {
 393         struct iova *iova = find_iova(iovad, pfn);
 394 
 395         if (iova)
 396                 __free_iova(iovad, iova);
 397 
 398 }
 399 EXPORT_SYMBOL_GPL(free_iova);
 400 
 401 /**
 402  * alloc_iova_fast - allocates an iova from rcache
 403  * @iovad: - iova domain in question
 404  * @size: - size of page frames to allocate
 405  * @limit_pfn: - max limit address
 406  * @flush_rcache: - set to flush rcache on regular allocation failure
 407  * This function tries to satisfy an iova allocation from the rcache,
 408  * and falls back to regular allocation on failure. If regular allocation
 409  * fails too and the flush_rcache flag is set then the rcache will be flushed.
 410 */
 411 unsigned long
 412 alloc_iova_fast(struct iova_domain *iovad, unsigned long size,
 413                 unsigned long limit_pfn, bool flush_rcache)
 414 {
 415         unsigned long iova_pfn;
 416         struct iova *new_iova;
 417 
 418         iova_pfn = iova_rcache_get(iovad, size, limit_pfn + 1);
 419         if (iova_pfn)
 420                 return iova_pfn;
 421 
 422 retry:
 423         new_iova = alloc_iova(iovad, size, limit_pfn, true);
 424         if (!new_iova) {
 425                 unsigned int cpu;
 426 
 427                 if (!flush_rcache)
 428                         return 0;
 429 
 430                 /* Try replenishing IOVAs by flushing rcache. */
 431                 flush_rcache = false;
 432                 for_each_online_cpu(cpu)
 433                         free_cpu_cached_iovas(cpu, iovad);
 434                 goto retry;
 435         }
 436 
 437         return new_iova->pfn_lo;
 438 }
 439 EXPORT_SYMBOL_GPL(alloc_iova_fast);
 440 
 441 /**
 442  * free_iova_fast - free iova pfn range into rcache
 443  * @iovad: - iova domain in question.
 444  * @pfn: - pfn that is allocated previously
 445  * @size: - # of pages in range
 446  * This functions frees an iova range by trying to put it into the rcache,
 447  * falling back to regular iova deallocation via free_iova() if this fails.
 448  */
 449 void
 450 free_iova_fast(struct iova_domain *iovad, unsigned long pfn, unsigned long size)
 451 {
 452         if (iova_rcache_insert(iovad, pfn, size))
 453                 return;
 454 
 455         free_iova(iovad, pfn);
 456 }
 457 EXPORT_SYMBOL_GPL(free_iova_fast);
 458 
 459 #define fq_ring_for_each(i, fq) \
 460         for ((i) = (fq)->head; (i) != (fq)->tail; (i) = ((i) + 1) % IOVA_FQ_SIZE)
 461 
 462 static inline bool fq_full(struct iova_fq *fq)
 463 {
 464         assert_spin_locked(&fq->lock);
 465         return (((fq->tail + 1) % IOVA_FQ_SIZE) == fq->head);
 466 }
 467 
 468 static inline unsigned fq_ring_add(struct iova_fq *fq)
 469 {
 470         unsigned idx = fq->tail;
 471 
 472         assert_spin_locked(&fq->lock);
 473 
 474         fq->tail = (idx + 1) % IOVA_FQ_SIZE;
 475 
 476         return idx;
 477 }
 478 
 479 static void fq_ring_free(struct iova_domain *iovad, struct iova_fq *fq)
 480 {
 481         u64 counter = atomic64_read(&iovad->fq_flush_finish_cnt);
 482         unsigned idx;
 483 
 484         assert_spin_locked(&fq->lock);
 485 
 486         fq_ring_for_each(idx, fq) {
 487 
 488                 if (fq->entries[idx].counter >= counter)
 489                         break;
 490 
 491                 if (iovad->entry_dtor)
 492                         iovad->entry_dtor(fq->entries[idx].data);
 493 
 494                 free_iova_fast(iovad,
 495                                fq->entries[idx].iova_pfn,
 496                                fq->entries[idx].pages);
 497 
 498                 fq->head = (fq->head + 1) % IOVA_FQ_SIZE;
 499         }
 500 }
 501 
 502 static void iova_domain_flush(struct iova_domain *iovad)
 503 {
 504         atomic64_inc(&iovad->fq_flush_start_cnt);
 505         iovad->flush_cb(iovad);
 506         atomic64_inc(&iovad->fq_flush_finish_cnt);
 507 }
 508 
 509 static void fq_destroy_all_entries(struct iova_domain *iovad)
 510 {
 511         int cpu;
 512 
 513         /*
 514          * This code runs when the iova_domain is being detroyed, so don't
 515          * bother to free iovas, just call the entry_dtor on all remaining
 516          * entries.
 517          */
 518         if (!iovad->entry_dtor)
 519                 return;
 520 
 521         for_each_possible_cpu(cpu) {
 522                 struct iova_fq *fq = per_cpu_ptr(iovad->fq, cpu);
 523                 int idx;
 524 
 525                 fq_ring_for_each(idx, fq)
 526                         iovad->entry_dtor(fq->entries[idx].data);
 527         }
 528 }
 529 
 530 static void fq_flush_timeout(struct timer_list *t)
 531 {
 532         struct iova_domain *iovad = from_timer(iovad, t, fq_timer);
 533         int cpu;
 534 
 535         atomic_set(&iovad->fq_timer_on, 0);
 536         iova_domain_flush(iovad);
 537 
 538         for_each_possible_cpu(cpu) {
 539                 unsigned long flags;
 540                 struct iova_fq *fq;
 541 
 542                 fq = per_cpu_ptr(iovad->fq, cpu);
 543                 spin_lock_irqsave(&fq->lock, flags);
 544                 fq_ring_free(iovad, fq);
 545                 spin_unlock_irqrestore(&fq->lock, flags);
 546         }
 547 }
 548 
 549 void queue_iova(struct iova_domain *iovad,
 550                 unsigned long pfn, unsigned long pages,
 551                 unsigned long data)
 552 {
 553         struct iova_fq *fq = raw_cpu_ptr(iovad->fq);
 554         unsigned long flags;
 555         unsigned idx;
 556 
 557         spin_lock_irqsave(&fq->lock, flags);
 558 
 559         /*
 560          * First remove all entries from the flush queue that have already been
 561          * flushed out on another CPU. This makes the fq_full() check below less
 562          * likely to be true.
 563          */
 564         fq_ring_free(iovad, fq);
 565 
 566         if (fq_full(fq)) {
 567                 iova_domain_flush(iovad);
 568                 fq_ring_free(iovad, fq);
 569         }
 570 
 571         idx = fq_ring_add(fq);
 572 
 573         fq->entries[idx].iova_pfn = pfn;
 574         fq->entries[idx].pages    = pages;
 575         fq->entries[idx].data     = data;
 576         fq->entries[idx].counter  = atomic64_read(&iovad->fq_flush_start_cnt);
 577 
 578         spin_unlock_irqrestore(&fq->lock, flags);
 579 
 580         /* Avoid false sharing as much as possible. */
 581         if (!atomic_read(&iovad->fq_timer_on) &&
 582             !atomic_cmpxchg(&iovad->fq_timer_on, 0, 1))
 583                 mod_timer(&iovad->fq_timer,
 584                           jiffies + msecs_to_jiffies(IOVA_FQ_TIMEOUT));
 585 }
 586 EXPORT_SYMBOL_GPL(queue_iova);
 587 
 588 /**
 589  * put_iova_domain - destroys the iova doamin
 590  * @iovad: - iova domain in question.
 591  * All the iova's in that domain are destroyed.
 592  */
 593 void put_iova_domain(struct iova_domain *iovad)
 594 {
 595         struct iova *iova, *tmp;
 596 
 597         free_iova_flush_queue(iovad);
 598         free_iova_rcaches(iovad);
 599         rbtree_postorder_for_each_entry_safe(iova, tmp, &iovad->rbroot, node)
 600                 free_iova_mem(iova);
 601 }
 602 EXPORT_SYMBOL_GPL(put_iova_domain);
 603 
 604 static int
 605 __is_range_overlap(struct rb_node *node,
 606         unsigned long pfn_lo, unsigned long pfn_hi)
 607 {
 608         struct iova *iova = rb_entry(node, struct iova, node);
 609 
 610         if ((pfn_lo <= iova->pfn_hi) && (pfn_hi >= iova->pfn_lo))
 611                 return 1;
 612         return 0;
 613 }
 614 
 615 static inline struct iova *
 616 alloc_and_init_iova(unsigned long pfn_lo, unsigned long pfn_hi)
 617 {
 618         struct iova *iova;
 619 
 620         iova = alloc_iova_mem();
 621         if (iova) {
 622                 iova->pfn_lo = pfn_lo;
 623                 iova->pfn_hi = pfn_hi;
 624         }
 625 
 626         return iova;
 627 }
 628 
 629 static struct iova *
 630 __insert_new_range(struct iova_domain *iovad,
 631         unsigned long pfn_lo, unsigned long pfn_hi)
 632 {
 633         struct iova *iova;
 634 
 635         iova = alloc_and_init_iova(pfn_lo, pfn_hi);
 636         if (iova)
 637                 iova_insert_rbtree(&iovad->rbroot, iova, NULL);
 638 
 639         return iova;
 640 }
 641 
 642 static void
 643 __adjust_overlap_range(struct iova *iova,
 644         unsigned long *pfn_lo, unsigned long *pfn_hi)
 645 {
 646         if (*pfn_lo < iova->pfn_lo)
 647                 iova->pfn_lo = *pfn_lo;
 648         if (*pfn_hi > iova->pfn_hi)
 649                 *pfn_lo = iova->pfn_hi + 1;
 650 }
 651 
 652 /**
 653  * reserve_iova - reserves an iova in the given range
 654  * @iovad: - iova domain pointer
 655  * @pfn_lo: - lower page frame address
 656  * @pfn_hi:- higher pfn adderss
 657  * This function allocates reserves the address range from pfn_lo to pfn_hi so
 658  * that this address is not dished out as part of alloc_iova.
 659  */
 660 struct iova *
 661 reserve_iova(struct iova_domain *iovad,
 662         unsigned long pfn_lo, unsigned long pfn_hi)
 663 {
 664         struct rb_node *node;
 665         unsigned long flags;
 666         struct iova *iova;
 667         unsigned int overlap = 0;
 668 
 669         /* Don't allow nonsensical pfns */
 670         if (WARN_ON((pfn_hi | pfn_lo) > (ULLONG_MAX >> iova_shift(iovad))))
 671                 return NULL;
 672 
 673         spin_lock_irqsave(&iovad->iova_rbtree_lock, flags);
 674         for (node = rb_first(&iovad->rbroot); node; node = rb_next(node)) {
 675                 if (__is_range_overlap(node, pfn_lo, pfn_hi)) {
 676                         iova = rb_entry(node, struct iova, node);
 677                         __adjust_overlap_range(iova, &pfn_lo, &pfn_hi);
 678                         if ((pfn_lo >= iova->pfn_lo) &&
 679                                 (pfn_hi <= iova->pfn_hi))
 680                                 goto finish;
 681                         overlap = 1;
 682 
 683                 } else if (overlap)
 684                                 break;
 685         }
 686 
 687         /* We are here either because this is the first reserver node
 688          * or need to insert remaining non overlap addr range
 689          */
 690         iova = __insert_new_range(iovad, pfn_lo, pfn_hi);
 691 finish:
 692 
 693         spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
 694         return iova;
 695 }
 696 EXPORT_SYMBOL_GPL(reserve_iova);
 697 
 698 /**
 699  * copy_reserved_iova - copies the reserved between domains
 700  * @from: - source doamin from where to copy
 701  * @to: - destination domin where to copy
 702  * This function copies reserved iova's from one doamin to
 703  * other.
 704  */
 705 void
 706 copy_reserved_iova(struct iova_domain *from, struct iova_domain *to)
 707 {
 708         unsigned long flags;
 709         struct rb_node *node;
 710 
 711         spin_lock_irqsave(&from->iova_rbtree_lock, flags);
 712         for (node = rb_first(&from->rbroot); node; node = rb_next(node)) {
 713                 struct iova *iova = rb_entry(node, struct iova, node);
 714                 struct iova *new_iova;
 715 
 716                 if (iova->pfn_lo == IOVA_ANCHOR)
 717                         continue;
 718 
 719                 new_iova = reserve_iova(to, iova->pfn_lo, iova->pfn_hi);
 720                 if (!new_iova)
 721                         printk(KERN_ERR "Reserve iova range %lx@%lx failed\n",
 722                                 iova->pfn_lo, iova->pfn_lo);
 723         }
 724         spin_unlock_irqrestore(&from->iova_rbtree_lock, flags);
 725 }
 726 EXPORT_SYMBOL_GPL(copy_reserved_iova);
 727 
 728 struct iova *
 729 split_and_remove_iova(struct iova_domain *iovad, struct iova *iova,
 730                       unsigned long pfn_lo, unsigned long pfn_hi)
 731 {
 732         unsigned long flags;
 733         struct iova *prev = NULL, *next = NULL;
 734 
 735         spin_lock_irqsave(&iovad->iova_rbtree_lock, flags);
 736         if (iova->pfn_lo < pfn_lo) {
 737                 prev = alloc_and_init_iova(iova->pfn_lo, pfn_lo - 1);
 738                 if (prev == NULL)
 739                         goto error;
 740         }
 741         if (iova->pfn_hi > pfn_hi) {
 742                 next = alloc_and_init_iova(pfn_hi + 1, iova->pfn_hi);
 743                 if (next == NULL)
 744                         goto error;
 745         }
 746 
 747         __cached_rbnode_delete_update(iovad, iova);
 748         rb_erase(&iova->node, &iovad->rbroot);
 749 
 750         if (prev) {
 751                 iova_insert_rbtree(&iovad->rbroot, prev, NULL);
 752                 iova->pfn_lo = pfn_lo;
 753         }
 754         if (next) {
 755                 iova_insert_rbtree(&iovad->rbroot, next, NULL);
 756                 iova->pfn_hi = pfn_hi;
 757         }
 758         spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
 759 
 760         return iova;
 761 
 762 error:
 763         spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
 764         if (prev)
 765                 free_iova_mem(prev);
 766         return NULL;
 767 }
 768 
 769 /*
 770  * Magazine caches for IOVA ranges.  For an introduction to magazines,
 771  * see the USENIX 2001 paper "Magazines and Vmem: Extending the Slab
 772  * Allocator to Many CPUs and Arbitrary Resources" by Bonwick and Adams.
 773  * For simplicity, we use a static magazine size and don't implement the
 774  * dynamic size tuning described in the paper.
 775  */
 776 
 777 #define IOVA_MAG_SIZE 128
 778 
 779 struct iova_magazine {
 780         unsigned long size;
 781         unsigned long pfns[IOVA_MAG_SIZE];
 782 };
 783 
 784 struct iova_cpu_rcache {
 785         spinlock_t lock;
 786         struct iova_magazine *loaded;
 787         struct iova_magazine *prev;
 788 };
 789 
 790 static struct iova_magazine *iova_magazine_alloc(gfp_t flags)
 791 {
 792         return kzalloc(sizeof(struct iova_magazine), flags);
 793 }
 794 
 795 static void iova_magazine_free(struct iova_magazine *mag)
 796 {
 797         kfree(mag);
 798 }
 799 
 800 static void
 801 iova_magazine_free_pfns(struct iova_magazine *mag, struct iova_domain *iovad)
 802 {
 803         unsigned long flags;
 804         int i;
 805 
 806         if (!mag)
 807                 return;
 808 
 809         spin_lock_irqsave(&iovad->iova_rbtree_lock, flags);
 810 
 811         for (i = 0 ; i < mag->size; ++i) {
 812                 struct iova *iova = private_find_iova(iovad, mag->pfns[i]);
 813 
 814                 BUG_ON(!iova);
 815                 private_free_iova(iovad, iova);
 816         }
 817 
 818         spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
 819 
 820         mag->size = 0;
 821 }
 822 
 823 static bool iova_magazine_full(struct iova_magazine *mag)
 824 {
 825         return (mag && mag->size == IOVA_MAG_SIZE);
 826 }
 827 
 828 static bool iova_magazine_empty(struct iova_magazine *mag)
 829 {
 830         return (!mag || mag->size == 0);
 831 }
 832 
 833 static unsigned long iova_magazine_pop(struct iova_magazine *mag,
 834                                        unsigned long limit_pfn)
 835 {
 836         int i;
 837         unsigned long pfn;
 838 
 839         BUG_ON(iova_magazine_empty(mag));
 840 
 841         /* Only fall back to the rbtree if we have no suitable pfns at all */
 842         for (i = mag->size - 1; mag->pfns[i] > limit_pfn; i--)
 843                 if (i == 0)
 844                         return 0;
 845 
 846         /* Swap it to pop it */
 847         pfn = mag->pfns[i];
 848         mag->pfns[i] = mag->pfns[--mag->size];
 849 
 850         return pfn;
 851 }
 852 
 853 static void iova_magazine_push(struct iova_magazine *mag, unsigned long pfn)
 854 {
 855         BUG_ON(iova_magazine_full(mag));
 856 
 857         mag->pfns[mag->size++] = pfn;
 858 }
 859 
 860 static void init_iova_rcaches(struct iova_domain *iovad)
 861 {
 862         struct iova_cpu_rcache *cpu_rcache;
 863         struct iova_rcache *rcache;
 864         unsigned int cpu;
 865         int i;
 866 
 867         for (i = 0; i < IOVA_RANGE_CACHE_MAX_SIZE; ++i) {
 868                 rcache = &iovad->rcaches[i];
 869                 spin_lock_init(&rcache->lock);
 870                 rcache->depot_size = 0;
 871                 rcache->cpu_rcaches = __alloc_percpu(sizeof(*cpu_rcache), cache_line_size());
 872                 if (WARN_ON(!rcache->cpu_rcaches))
 873                         continue;
 874                 for_each_possible_cpu(cpu) {
 875                         cpu_rcache = per_cpu_ptr(rcache->cpu_rcaches, cpu);
 876                         spin_lock_init(&cpu_rcache->lock);
 877                         cpu_rcache->loaded = iova_magazine_alloc(GFP_KERNEL);
 878                         cpu_rcache->prev = iova_magazine_alloc(GFP_KERNEL);
 879                 }
 880         }
 881 }
 882 
 883 /*
 884  * Try inserting IOVA range starting with 'iova_pfn' into 'rcache', and
 885  * return true on success.  Can fail if rcache is full and we can't free
 886  * space, and free_iova() (our only caller) will then return the IOVA
 887  * range to the rbtree instead.
 888  */
 889 static bool __iova_rcache_insert(struct iova_domain *iovad,
 890                                  struct iova_rcache *rcache,
 891                                  unsigned long iova_pfn)
 892 {
 893         struct iova_magazine *mag_to_free = NULL;
 894         struct iova_cpu_rcache *cpu_rcache;
 895         bool can_insert = false;
 896         unsigned long flags;
 897 
 898         cpu_rcache = raw_cpu_ptr(rcache->cpu_rcaches);
 899         spin_lock_irqsave(&cpu_rcache->lock, flags);
 900 
 901         if (!iova_magazine_full(cpu_rcache->loaded)) {
 902                 can_insert = true;
 903         } else if (!iova_magazine_full(cpu_rcache->prev)) {
 904                 swap(cpu_rcache->prev, cpu_rcache->loaded);
 905                 can_insert = true;
 906         } else {
 907                 struct iova_magazine *new_mag = iova_magazine_alloc(GFP_ATOMIC);
 908 
 909                 if (new_mag) {
 910                         spin_lock(&rcache->lock);
 911                         if (rcache->depot_size < MAX_GLOBAL_MAGS) {
 912                                 rcache->depot[rcache->depot_size++] =
 913                                                 cpu_rcache->loaded;
 914                         } else {
 915                                 mag_to_free = cpu_rcache->loaded;
 916                         }
 917                         spin_unlock(&rcache->lock);
 918 
 919                         cpu_rcache->loaded = new_mag;
 920                         can_insert = true;
 921                 }
 922         }
 923 
 924         if (can_insert)
 925                 iova_magazine_push(cpu_rcache->loaded, iova_pfn);
 926 
 927         spin_unlock_irqrestore(&cpu_rcache->lock, flags);
 928 
 929         if (mag_to_free) {
 930                 iova_magazine_free_pfns(mag_to_free, iovad);
 931                 iova_magazine_free(mag_to_free);
 932         }
 933 
 934         return can_insert;
 935 }
 936 
 937 static bool iova_rcache_insert(struct iova_domain *iovad, unsigned long pfn,
 938                                unsigned long size)
 939 {
 940         unsigned int log_size = order_base_2(size);
 941 
 942         if (log_size >= IOVA_RANGE_CACHE_MAX_SIZE)
 943                 return false;
 944 
 945         return __iova_rcache_insert(iovad, &iovad->rcaches[log_size], pfn);
 946 }
 947 
 948 /*
 949  * Caller wants to allocate a new IOVA range from 'rcache'.  If we can
 950  * satisfy the request, return a matching non-NULL range and remove
 951  * it from the 'rcache'.
 952  */
 953 static unsigned long __iova_rcache_get(struct iova_rcache *rcache,
 954                                        unsigned long limit_pfn)
 955 {
 956         struct iova_cpu_rcache *cpu_rcache;
 957         unsigned long iova_pfn = 0;
 958         bool has_pfn = false;
 959         unsigned long flags;
 960 
 961         cpu_rcache = raw_cpu_ptr(rcache->cpu_rcaches);
 962         spin_lock_irqsave(&cpu_rcache->lock, flags);
 963 
 964         if (!iova_magazine_empty(cpu_rcache->loaded)) {
 965                 has_pfn = true;
 966         } else if (!iova_magazine_empty(cpu_rcache->prev)) {
 967                 swap(cpu_rcache->prev, cpu_rcache->loaded);
 968                 has_pfn = true;
 969         } else {
 970                 spin_lock(&rcache->lock);
 971                 if (rcache->depot_size > 0) {
 972                         iova_magazine_free(cpu_rcache->loaded);
 973                         cpu_rcache->loaded = rcache->depot[--rcache->depot_size];
 974                         has_pfn = true;
 975                 }
 976                 spin_unlock(&rcache->lock);
 977         }
 978 
 979         if (has_pfn)
 980                 iova_pfn = iova_magazine_pop(cpu_rcache->loaded, limit_pfn);
 981 
 982         spin_unlock_irqrestore(&cpu_rcache->lock, flags);
 983 
 984         return iova_pfn;
 985 }
 986 
 987 /*
 988  * Try to satisfy IOVA allocation range from rcache.  Fail if requested
 989  * size is too big or the DMA limit we are given isn't satisfied by the
 990  * top element in the magazine.
 991  */
 992 static unsigned long iova_rcache_get(struct iova_domain *iovad,
 993                                      unsigned long size,
 994                                      unsigned long limit_pfn)
 995 {
 996         unsigned int log_size = order_base_2(size);
 997 
 998         if (log_size >= IOVA_RANGE_CACHE_MAX_SIZE)
 999                 return 0;
1000 
1001         return __iova_rcache_get(&iovad->rcaches[log_size], limit_pfn - size);
1002 }
1003 
1004 /*
1005  * free rcache data structures.
1006  */
1007 static void free_iova_rcaches(struct iova_domain *iovad)
1008 {
1009         struct iova_rcache *rcache;
1010         struct iova_cpu_rcache *cpu_rcache;
1011         unsigned int cpu;
1012         int i, j;
1013 
1014         for (i = 0; i < IOVA_RANGE_CACHE_MAX_SIZE; ++i) {
1015                 rcache = &iovad->rcaches[i];
1016                 for_each_possible_cpu(cpu) {
1017                         cpu_rcache = per_cpu_ptr(rcache->cpu_rcaches, cpu);
1018                         iova_magazine_free(cpu_rcache->loaded);
1019                         iova_magazine_free(cpu_rcache->prev);
1020                 }
1021                 free_percpu(rcache->cpu_rcaches);
1022                 for (j = 0; j < rcache->depot_size; ++j)
1023                         iova_magazine_free(rcache->depot[j]);
1024         }
1025 }
1026 
1027 /*
1028  * free all the IOVA ranges cached by a cpu (used when cpu is unplugged)
1029  */
1030 void free_cpu_cached_iovas(unsigned int cpu, struct iova_domain *iovad)
1031 {
1032         struct iova_cpu_rcache *cpu_rcache;
1033         struct iova_rcache *rcache;
1034         unsigned long flags;
1035         int i;
1036 
1037         for (i = 0; i < IOVA_RANGE_CACHE_MAX_SIZE; ++i) {
1038                 rcache = &iovad->rcaches[i];
1039                 cpu_rcache = per_cpu_ptr(rcache->cpu_rcaches, cpu);
1040                 spin_lock_irqsave(&cpu_rcache->lock, flags);
1041                 iova_magazine_free_pfns(cpu_rcache->loaded, iovad);
1042                 iova_magazine_free_pfns(cpu_rcache->prev, iovad);
1043                 spin_unlock_irqrestore(&cpu_rcache->lock, flags);
1044         }
1045 }
1046 
1047 MODULE_AUTHOR("Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>");
1048 MODULE_LICENSE("GPL");
/* [<][>][^][v][top][bottom][index][help] */
root/drivers/iommu/iova.c

DEFINITIONS
