2 * Copyright © 2006-2009, Intel Corporation.
4 * This program is free software; you can redistribute it and/or modify it
5 * under the terms and conditions of the GNU General Public License,
6 * version 2, as published by the Free Software Foundation.
8 * This program is distributed in the hope it will be useful, but WITHOUT
9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
13 * You should have received a copy of the GNU General Public License along with
14 * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
15 * Place - Suite 330, Boston, MA 02111-1307 USA.
17 * Author: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
20 #include <linux/iova.h>
21 #include <linux/slab.h>
23 static struct kmem_cache
*iommu_iova_cache
;
25 int iommu_iova_cache_init(void)
29 iommu_iova_cache
= kmem_cache_create("iommu_iova",
34 if (!iommu_iova_cache
) {
35 pr_err("Couldn't create iova cache\n");
42 void iommu_iova_cache_destroy(void)
44 kmem_cache_destroy(iommu_iova_cache
);
47 struct iova
*alloc_iova_mem(void)
49 return kmem_cache_alloc(iommu_iova_cache
, GFP_ATOMIC
);
52 void free_iova_mem(struct iova
*iova
)
54 kmem_cache_free(iommu_iova_cache
, iova
);
58 init_iova_domain(struct iova_domain
*iovad
, unsigned long granule
,
59 unsigned long start_pfn
, unsigned long pfn_32bit
)
62 * IOVA granularity will normally be equal to the smallest
63 * supported IOMMU page size; both *must* be capable of
64 * representing individual CPU pages exactly.
66 BUG_ON((granule
> PAGE_SIZE
) || !is_power_of_2(granule
));
68 spin_lock_init(&iovad
->iova_rbtree_lock
);
69 iovad
->rbroot
= RB_ROOT
;
70 iovad
->cached32_node
= NULL
;
71 iovad
->granule
= granule
;
72 iovad
->start_pfn
= start_pfn
;
73 iovad
->dma_32bit_pfn
= pfn_32bit
;
76 static struct rb_node
*
77 __get_cached_rbnode(struct iova_domain
*iovad
, unsigned long *limit_pfn
)
79 if ((*limit_pfn
!= iovad
->dma_32bit_pfn
) ||
80 (iovad
->cached32_node
== NULL
))
81 return rb_last(&iovad
->rbroot
);
83 struct rb_node
*prev_node
= rb_prev(iovad
->cached32_node
);
84 struct iova
*curr_iova
=
85 container_of(iovad
->cached32_node
, struct iova
, node
);
86 *limit_pfn
= curr_iova
->pfn_lo
- 1;
92 __cached_rbnode_insert_update(struct iova_domain
*iovad
,
93 unsigned long limit_pfn
, struct iova
*new)
95 if (limit_pfn
!= iovad
->dma_32bit_pfn
)
97 iovad
->cached32_node
= &new->node
;
101 __cached_rbnode_delete_update(struct iova_domain
*iovad
, struct iova
*free
)
103 struct iova
*cached_iova
;
104 struct rb_node
*curr
;
106 if (!iovad
->cached32_node
)
108 curr
= iovad
->cached32_node
;
109 cached_iova
= container_of(curr
, struct iova
, node
);
111 if (free
->pfn_lo
>= cached_iova
->pfn_lo
) {
112 struct rb_node
*node
= rb_next(&free
->node
);
113 struct iova
*iova
= container_of(node
, struct iova
, node
);
115 /* only cache if it's below 32bit pfn */
116 if (node
&& iova
->pfn_lo
< iovad
->dma_32bit_pfn
)
117 iovad
->cached32_node
= node
;
119 iovad
->cached32_node
= NULL
;
123 /* Computes the padding size required, to make the
124 * the start address naturally aligned on its size
127 iova_get_pad_size(int size
, unsigned int limit_pfn
)
129 unsigned int pad_size
= 0;
130 unsigned int order
= ilog2(size
);
133 pad_size
= (limit_pfn
+ 1) % (1 << order
);
138 static int __alloc_and_insert_iova_range(struct iova_domain
*iovad
,
139 unsigned long size
, unsigned long limit_pfn
,
140 struct iova
*new, bool size_aligned
)
142 struct rb_node
*prev
, *curr
= NULL
;
144 unsigned long saved_pfn
;
145 unsigned int pad_size
= 0;
147 /* Walk the tree backwards */
148 spin_lock_irqsave(&iovad
->iova_rbtree_lock
, flags
);
149 saved_pfn
= limit_pfn
;
150 curr
= __get_cached_rbnode(iovad
, &limit_pfn
);
153 struct iova
*curr_iova
= container_of(curr
, struct iova
, node
);
155 if (limit_pfn
< curr_iova
->pfn_lo
)
157 else if (limit_pfn
< curr_iova
->pfn_hi
)
158 goto adjust_limit_pfn
;
161 pad_size
= iova_get_pad_size(size
, limit_pfn
);
162 if ((curr_iova
->pfn_hi
+ size
+ pad_size
) <= limit_pfn
)
163 break; /* found a free slot */
166 limit_pfn
= curr_iova
->pfn_lo
- 1;
169 curr
= rb_prev(curr
);
174 pad_size
= iova_get_pad_size(size
, limit_pfn
);
175 if ((iovad
->start_pfn
+ size
+ pad_size
) > limit_pfn
) {
176 spin_unlock_irqrestore(&iovad
->iova_rbtree_lock
, flags
);
181 /* pfn_lo will point to size aligned address if size_aligned is set */
182 new->pfn_lo
= limit_pfn
- (size
+ pad_size
) + 1;
183 new->pfn_hi
= new->pfn_lo
+ size
- 1;
185 /* Insert the new_iova into domain rbtree by holding writer lock */
186 /* Add new node and rebalance tree. */
188 struct rb_node
**entry
, *parent
= NULL
;
190 /* If we have 'prev', it's a valid place to start the
191 insertion. Otherwise, start from the root. */
195 entry
= &iovad
->rbroot
.rb_node
;
197 /* Figure out where to put new node */
199 struct iova
*this = container_of(*entry
,
203 if (new->pfn_lo
< this->pfn_lo
)
204 entry
= &((*entry
)->rb_left
);
205 else if (new->pfn_lo
> this->pfn_lo
)
206 entry
= &((*entry
)->rb_right
);
208 BUG(); /* this should not happen */
211 /* Add new node and rebalance tree. */
212 rb_link_node(&new->node
, parent
, entry
);
213 rb_insert_color(&new->node
, &iovad
->rbroot
);
215 __cached_rbnode_insert_update(iovad
, saved_pfn
, new);
217 spin_unlock_irqrestore(&iovad
->iova_rbtree_lock
, flags
);
224 iova_insert_rbtree(struct rb_root
*root
, struct iova
*iova
)
226 struct rb_node
**new = &(root
->rb_node
), *parent
= NULL
;
227 /* Figure out where to put new node */
229 struct iova
*this = container_of(*new, struct iova
, node
);
233 if (iova
->pfn_lo
< this->pfn_lo
)
234 new = &((*new)->rb_left
);
235 else if (iova
->pfn_lo
> this->pfn_lo
)
236 new = &((*new)->rb_right
);
238 BUG(); /* this should not happen */
240 /* Add new node and rebalance tree. */
241 rb_link_node(&iova
->node
, parent
, new);
242 rb_insert_color(&iova
->node
, root
);
246 * alloc_iova - allocates an iova
247 * @iovad: - iova domain in question
248 * @size: - size of page frames to allocate
249 * @limit_pfn: - max limit address
250 * @size_aligned: - set if size_aligned address range is required
251 * This function allocates an iova in the range iovad->start_pfn to limit_pfn,
252 * searching top-down from limit_pfn to iovad->start_pfn. If the size_aligned
253 * flag is set then the allocated address iova->pfn_lo will be naturally
254 * aligned on roundup_power_of_two(size).
257 alloc_iova(struct iova_domain
*iovad
, unsigned long size
,
258 unsigned long limit_pfn
,
261 struct iova
*new_iova
;
264 new_iova
= alloc_iova_mem();
268 /* If size aligned is set then round the size to
269 * to next power of two.
272 size
= __roundup_pow_of_two(size
);
274 ret
= __alloc_and_insert_iova_range(iovad
, size
, limit_pfn
,
275 new_iova
, size_aligned
);
278 free_iova_mem(new_iova
);
286 * find_iova - find's an iova for a given pfn
287 * @iovad: - iova domain in question.
288 * @pfn: - page frame number
289 * This function finds and returns an iova belonging to the
290 * given doamin which matches the given pfn.
292 struct iova
*find_iova(struct iova_domain
*iovad
, unsigned long pfn
)
295 struct rb_node
*node
;
297 /* Take the lock so that no other thread is manipulating the rbtree */
298 spin_lock_irqsave(&iovad
->iova_rbtree_lock
, flags
);
299 node
= iovad
->rbroot
.rb_node
;
301 struct iova
*iova
= container_of(node
, struct iova
, node
);
303 /* If pfn falls within iova's range, return iova */
304 if ((pfn
>= iova
->pfn_lo
) && (pfn
<= iova
->pfn_hi
)) {
305 spin_unlock_irqrestore(&iovad
->iova_rbtree_lock
, flags
);
306 /* We are not holding the lock while this iova
307 * is referenced by the caller as the same thread
308 * which called this function also calls __free_iova()
309 * and it is by design that only one thread can possibly
310 * reference a particular iova and hence no conflict.
315 if (pfn
< iova
->pfn_lo
)
316 node
= node
->rb_left
;
317 else if (pfn
> iova
->pfn_lo
)
318 node
= node
->rb_right
;
321 spin_unlock_irqrestore(&iovad
->iova_rbtree_lock
, flags
);
326 * __free_iova - frees the given iova
327 * @iovad: iova domain in question.
328 * @iova: iova in question.
329 * Frees the given iova belonging to the giving domain
332 __free_iova(struct iova_domain
*iovad
, struct iova
*iova
)
336 spin_lock_irqsave(&iovad
->iova_rbtree_lock
, flags
);
337 __cached_rbnode_delete_update(iovad
, iova
);
338 rb_erase(&iova
->node
, &iovad
->rbroot
);
339 spin_unlock_irqrestore(&iovad
->iova_rbtree_lock
, flags
);
344 * free_iova - finds and frees the iova for a given pfn
345 * @iovad: - iova domain in question.
346 * @pfn: - pfn that is allocated previously
347 * This functions finds an iova for a given pfn and then
348 * frees the iova from that domain.
351 free_iova(struct iova_domain
*iovad
, unsigned long pfn
)
353 struct iova
*iova
= find_iova(iovad
, pfn
);
356 __free_iova(iovad
, iova
);
361 * put_iova_domain - destroys the iova doamin
362 * @iovad: - iova domain in question.
363 * All the iova's in that domain are destroyed.
365 void put_iova_domain(struct iova_domain
*iovad
)
367 struct rb_node
*node
;
370 spin_lock_irqsave(&iovad
->iova_rbtree_lock
, flags
);
371 node
= rb_first(&iovad
->rbroot
);
373 struct iova
*iova
= container_of(node
, struct iova
, node
);
375 rb_erase(node
, &iovad
->rbroot
);
377 node
= rb_first(&iovad
->rbroot
);
379 spin_unlock_irqrestore(&iovad
->iova_rbtree_lock
, flags
);
383 __is_range_overlap(struct rb_node
*node
,
384 unsigned long pfn_lo
, unsigned long pfn_hi
)
386 struct iova
*iova
= container_of(node
, struct iova
, node
);
388 if ((pfn_lo
<= iova
->pfn_hi
) && (pfn_hi
>= iova
->pfn_lo
))
393 static inline struct iova
*
394 alloc_and_init_iova(unsigned long pfn_lo
, unsigned long pfn_hi
)
398 iova
= alloc_iova_mem();
400 iova
->pfn_lo
= pfn_lo
;
401 iova
->pfn_hi
= pfn_hi
;
408 __insert_new_range(struct iova_domain
*iovad
,
409 unsigned long pfn_lo
, unsigned long pfn_hi
)
413 iova
= alloc_and_init_iova(pfn_lo
, pfn_hi
);
415 iova_insert_rbtree(&iovad
->rbroot
, iova
);
421 __adjust_overlap_range(struct iova
*iova
,
422 unsigned long *pfn_lo
, unsigned long *pfn_hi
)
424 if (*pfn_lo
< iova
->pfn_lo
)
425 iova
->pfn_lo
= *pfn_lo
;
426 if (*pfn_hi
> iova
->pfn_hi
)
427 *pfn_lo
= iova
->pfn_hi
+ 1;
431 * reserve_iova - reserves an iova in the given range
432 * @iovad: - iova domain pointer
433 * @pfn_lo: - lower page frame address
434 * @pfn_hi:- higher pfn adderss
435 * This function allocates reserves the address range from pfn_lo to pfn_hi so
436 * that this address is not dished out as part of alloc_iova.
439 reserve_iova(struct iova_domain
*iovad
,
440 unsigned long pfn_lo
, unsigned long pfn_hi
)
442 struct rb_node
*node
;
445 unsigned int overlap
= 0;
447 spin_lock_irqsave(&iovad
->iova_rbtree_lock
, flags
);
448 for (node
= rb_first(&iovad
->rbroot
); node
; node
= rb_next(node
)) {
449 if (__is_range_overlap(node
, pfn_lo
, pfn_hi
)) {
450 iova
= container_of(node
, struct iova
, node
);
451 __adjust_overlap_range(iova
, &pfn_lo
, &pfn_hi
);
452 if ((pfn_lo
>= iova
->pfn_lo
) &&
453 (pfn_hi
<= iova
->pfn_hi
))
461 /* We are here either because this is the first reserver node
462 * or need to insert remaining non overlap addr range
464 iova
= __insert_new_range(iovad
, pfn_lo
, pfn_hi
);
467 spin_unlock_irqrestore(&iovad
->iova_rbtree_lock
, flags
);
472 * copy_reserved_iova - copies the reserved between domains
473 * @from: - source doamin from where to copy
474 * @to: - destination domin where to copy
475 * This function copies reserved iova's from one doamin to
479 copy_reserved_iova(struct iova_domain
*from
, struct iova_domain
*to
)
482 struct rb_node
*node
;
484 spin_lock_irqsave(&from
->iova_rbtree_lock
, flags
);
485 for (node
= rb_first(&from
->rbroot
); node
; node
= rb_next(node
)) {
486 struct iova
*iova
= container_of(node
, struct iova
, node
);
487 struct iova
*new_iova
;
489 new_iova
= reserve_iova(to
, iova
->pfn_lo
, iova
->pfn_hi
);
491 printk(KERN_ERR
"Reserve iova range %lx@%lx failed\n",
492 iova
->pfn_lo
, iova
->pfn_lo
);
494 spin_unlock_irqrestore(&from
->iova_rbtree_lock
, flags
);
498 split_and_remove_iova(struct iova_domain
*iovad
, struct iova
*iova
,
499 unsigned long pfn_lo
, unsigned long pfn_hi
)
502 struct iova
*prev
= NULL
, *next
= NULL
;
504 spin_lock_irqsave(&iovad
->iova_rbtree_lock
, flags
);
505 if (iova
->pfn_lo
< pfn_lo
) {
506 prev
= alloc_and_init_iova(iova
->pfn_lo
, pfn_lo
- 1);
510 if (iova
->pfn_hi
> pfn_hi
) {
511 next
= alloc_and_init_iova(pfn_hi
+ 1, iova
->pfn_hi
);
516 __cached_rbnode_delete_update(iovad
, iova
);
517 rb_erase(&iova
->node
, &iovad
->rbroot
);
520 iova_insert_rbtree(&iovad
->rbroot
, prev
);
521 iova
->pfn_lo
= pfn_lo
;
524 iova_insert_rbtree(&iovad
->rbroot
, next
);
525 iova
->pfn_hi
= pfn_hi
;
527 spin_unlock_irqrestore(&iovad
->iova_rbtree_lock
, flags
);
532 spin_unlock_irqrestore(&iovad
->iova_rbtree_lock
, flags
);
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