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

source code of linux/drivers/iommu/iova.c