aboutsummaryrefslogtreecommitdiff
path: root/drivers/iommu/iova.c
blob: c5c274ab5c5a034abe91fb1f1f5dcf6380c9315e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
/*
 * Copyright © 2006-2009, Intel Corporation.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
 * Place - Suite 330, Boston, MA 02111-1307 USA.
 *
 * Author: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
 */

#include <linux/iova.h>

void
init_iova_domain(struct iova_domain *iovad, unsigned long pfn_32bit)
{
	spin_lock_init(&iovad->iova_rbtree_lock);
	iovad->rbroot = RB_ROOT;
	iovad->cached32_node = NULL;
	iovad->dma_32bit_pfn = pfn_32bit;
}

static struct rb_node *
__get_cached_rbnode(struct iova_domain *iovad, unsigned long *limit_pfn)
{
	if ((*limit_pfn != iovad->dma_32bit_pfn) ||
		(iovad->cached32_node == NULL))
		return rb_last(&iovad->rbroot);
	else {
		struct rb_node *prev_node = rb_prev(iovad->cached32_node);
		struct iova *curr_iova =
			container_of(iovad->cached32_node, struct iova, node);
		*limit_pfn = curr_iova->pfn_lo - 1;
		return prev_node;
	}
}

static void
__cached_rbnode_insert_update(struct iova_domain *iovad,
	unsigned long limit_pfn, struct iova *new)
{
	if (limit_pfn != iovad->dma_32bit_pfn)
		return;
	iovad->cached32_node = &new->node;
}

static void
__cached_rbnode_delete_update(struct iova_domain *iovad, struct iova *free)
{
	struct iova *cached_iova;
	struct rb_node *curr;

	if (!iovad->cached32_node)
		return;
	curr = iovad->cached32_node;
	cached_iova = container_of(curr, struct iova, node);

	if (free->pfn_lo >= cached_iova->pfn_lo) {
		struct rb_node *node = rb_next(&free->node);
		struct iova *iova = container_of(node, struct iova, node);

		/* only cache if it's below 32bit pfn */
		if (node && iova->pfn_lo < iovad->dma_32bit_pfn)
			iovad->cached32_node = node;
		else
			iovad->cached32_node = NULL;
	}
}

/* Computes the padding size required, to make the
 * the start address naturally aligned on its size
 */
static int
iova_get_pad_size(int size, unsigned int limit_pfn)
{
	unsigned int pad_size = 0;
	unsigned int order = ilog2(size);

	if (order)
		pad_size = (limit_pfn + 1) % (1 << order);

	return pad_size;
}

static int __alloc_and_insert_iova_range(struct iova_domain *iovad,
		unsigned long size, unsigned long limit_pfn,
			struct iova *new, bool size_aligned)
{
	struct rb_node *prev, *curr = NULL;
	unsigned long flags;
	unsigned long saved_pfn;
	unsigned int pad_size = 0;

	/* Walk the tree backwards */
	spin_lock_irqsave(&iovad->iova_rbtree_lock, flags);
	saved_pfn = limit_pfn;
	curr = __get_cached_rbnode(iovad, &limit_pfn);
	prev = curr;
	while (curr) {
		struct iova *curr_iova = container_of(curr, struct iova, node);

		if (limit_pfn < curr_iova->pfn_lo)
			goto move_left;
		else if (limit_pfn < curr_iova->pfn_hi)
			goto adjust_limit_pfn;
		else {
			if (size_aligned)
				pad_size = iova_get_pad_size(size, limit_pfn);
			if ((curr_iova->pfn_hi + size + pad_size) <= limit_pfn)
				break;	/* found a free slot */
		}
adjust_limit_pfn:
		limit_pfn = curr_iova->pfn_lo - 1;
move_left:
		prev = curr;
		curr = rb_prev(curr);
	}

	if (!curr) {
		if (size_aligned)
			pad_size = iova_get_pad_size(size, limit_pfn);
		if ((IOVA_START_PFN + size + pad_size) > limit_pfn) {
			spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
			return -ENOMEM;
		}
	}

	/* pfn_lo will point to size aligned address if size_aligned is set */
	new->pfn_lo = limit_pfn - (size + pad_size) + 1;
	new->pfn_hi = new->pfn_lo + size - 1;

	/* Insert the new_iova into domain rbtree by holding writer lock */
	/* Add new node and rebalance tree. */
	{
		struct rb_node **entry, *parent = NULL;

		/* If we have 'prev', it's a valid place to start the
		   insertion. Otherwise, start from the root. */
		if (prev)
			entry = &prev;
		else
			entry = &iovad->rbroot.rb_node;

		/* Figure out where to put new node */
		while (*entry) {
			struct iova *this = container_of(*entry,
							struct iova, node);
			parent = *entry;

			if (new->pfn_lo < this->pfn_lo)
				entry = &((*entry)->rb_left);
			else if (new->pfn_lo > this->pfn_lo)
				entry = &((*entry)->rb_right);
			else
				BUG(); /* this should not happen */
		}

		/* Add new node and rebalance tree. */
		rb_link_node(&new->node, parent, entry);
		rb_insert_color(&new->node, &iovad->rbroot);
	}
	__cached_rbnode_insert_update(iovad, saved_pfn, new);

	spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);


	return 0;
}

static void
iova_insert_rbtree(struct rb_root *root, struct iova *iova)
{
	struct rb_node **new = &(root->rb_node), *parent = NULL;
	/* Figure out where to put new node */
	while (*new) {
		struct iova *this = container_of(*new, struct iova, node);
		parent = *new;

		if (iova->pfn_lo < this->pfn_lo)
			new = &((*new)->rb_left);
		else if (iova->pfn_lo > this->pfn_lo)
			new = &((*new)->rb_right);
		else
			BUG(); /* this should not happen */
	}
	/* Add new node and rebalance tree. */
	rb_link_node(&iova->node, parent, new);
	rb_insert_color(&iova->node, root);
}

/**
 * alloc_iova - allocates an iova
 * @iovad - iova domain in question
 * @size - size of page frames to allocate
 * @limit_pfn - max limit address
 * @size_aligned - set if size_aligned address range is required
 * This function allocates an iova in the range limit_pfn to IOVA_START_PFN
 * looking from limit_pfn instead from IOVA_START_PFN. If the size_aligned
 * flag is set then the allocated address iova->pfn_lo will be naturally
 * aligned on roundup_power_of_two(size).
 */
struct iova *
alloc_iova(struct iova_domain *iovad, unsigned long size,
	unsigned long limit_pfn,
	bool size_aligned)
{
	struct iova *new_iova;
	int ret;

	new_iova = alloc_iova_mem();
	if (!new_iova)
		return NULL;

	/* If size aligned is set then round the size to
	 * to next power of two.
	 */
	if (size_aligned)
		size = __roundup_pow_of_two(size);

	ret = __alloc_and_insert_iova_range(iovad, size, limit_pfn,
			new_iova, size_aligned);

	if (ret) {
		free_iova_mem(new_iova);
		return NULL;
	}

	return new_iova;
}

/**
 * find_iova - find's an iova for a given pfn
 * @iovad - iova domain in question.
 * pfn - page frame number
 * This function finds and returns an iova belonging to the
 * given doamin which matches the given pfn.
 */
struct iova *find_iova(struct iova_domain *iovad, unsigned long pfn)
{
	unsigned long flags;
	struct rb_node *node;

	/* Take the lock so that no other thread is manipulating the rbtree */
	spin_lock_irqsave(&iovad->iova_rbtree_lock, flags);
	node = iovad->rbroot.rb_node;
	while (node) {
		struct iova *iova = container_of(node, struct iova, node);

		/* If pfn falls within iova's range, return iova */
		if ((pfn >= iova->pfn_lo) && (pfn <= iova->pfn_hi)) {
			spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
			/* We are not holding the lock while this iova
			 * is referenced by the caller as the same thread
			 * which called this function also calls __free_iova()
			 * and it is by desing that only one thread can possibly
			 * reference a particular iova and hence no conflict.
			 */
			return iova;
		}

		if (pfn < iova->pfn_lo)
			node = node->rb_left;
		else if (pfn > iova->pfn_lo)
			node = node->rb_right;
	}

	spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
	return NULL;
}

/**
 * __free_iova - frees the given iova
 * @iovad: iova domain in question.
 * @iova: iova in question.
 * Frees the given iova belonging to the giving domain
 */
void
__free_iova(struct iova_domain *iovad, struct iova *iova)
{
	unsigned long flags;

	spin_lock_irqsave(&iovad->iova_rbtree_lock, flags);
	__cached_rbnode_delete_update(iovad, iova);
	rb_erase(&iova->node, &iovad->rbroot);
	spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
	free_iova_mem(iova);
}

/**
 * free_iova - finds and frees the iova for a given pfn
 * @iovad: - iova domain in question.
 * @pfn: - pfn that is allocated previously
 * This functions finds an iova for a given pfn and then
 * frees the iova from that domain.
 */
void
free_iova(struct iova_domain *iovad, unsigned long pfn)
{
	struct iova *iova = find_iova(iovad, pfn);
	if (iova)
		__free_iova(iovad, iova);

}

/**
 * put_iova_domain - destroys the iova doamin
 * @iovad: - iova domain in question.
 * All the iova's in that domain are destroyed.
 */
void put_iova_domain(struct iova_domain *iovad)
{
	struct rb_node *node;
	unsigned long flags;

	spin_lock_irqsave(&iovad->iova_rbtree_lock, flags);
	node = rb_first(&iovad->rbroot);
	while (node) {
		struct iova *iova = container_of(node, struct iova, node);
		rb_erase(node, &iovad->rbroot);
		free_iova_mem(iova);
		node = rb_first(&iovad->rbroot);
	}
	spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
}

static int
__is_range_overlap(struct rb_node *node,
	unsigned long pfn_lo, unsigned long pfn_hi)
{
	struct iova *iova = container_of(node, struct iova, node);

	if ((pfn_lo <= iova->pfn_hi) && (pfn_hi >= iova->pfn_lo))
		return 1;
	return 0;
}

static struct iova *
__insert_new_range(struct iova_domain *iovad,
	unsigned long pfn_lo, unsigned long pfn_hi)
{
	struct iova *iova;

	iova = alloc_iova_mem();
	if (!iova)
		return iova;

	iova->pfn_hi = pfn_hi;
	iova->pfn_lo = pfn_lo;
	iova_insert_rbtree(&iovad->rbroot, iova);
	return iova;
}

static void
__adjust_overlap_range(struct iova *iova,
	unsigned long *pfn_lo, unsigned long *pfn_hi)
{
	if (*pfn_lo < iova->pfn_lo)
		iova->pfn_lo = *pfn_lo;
	if (*pfn_hi > iova->pfn_hi)
		*pfn_lo = iova->pfn_hi + 1;
}

/**
 * reserve_iova - reserves an iova in the given range
 * @iovad: - iova domain pointer
 * @pfn_lo: - lower page frame address
 * @pfn_hi:- higher pfn adderss
 * This function allocates reserves the address range from pfn_lo to pfn_hi so
 * that this address is not dished out as part of alloc_iova.
 */
struct iova *
reserve_iova(struct iova_domain *iovad,
	unsigned long pfn_lo, unsigned long pfn_hi)
{
	struct rb_node *node;
	unsigned long flags;
	struct iova *iova;
	unsigned int overlap = 0;

	spin_lock_irqsave(&iovad->iova_rbtree_lock, flags);
	for (node = rb_first(&iovad->rbroot); node; node = rb_next(node)) {
		if (__is_range_overlap(node, pfn_lo, pfn_hi)) {
			iova = container_of(node, struct iova, node);
			__adjust_overlap_range(iova, &pfn_lo, &pfn_hi);
			if ((pfn_lo >= iova->pfn_lo) &&
				(pfn_hi <= iova->pfn_hi))
				goto finish;
			overlap = 1;

		} else if (overlap)
				break;
	}

	/* We are here either because this is the first reserver node
	 * or need to insert remaining non overlap addr range
	 */
	iova = __insert_new_range(iovad, pfn_lo, pfn_hi);
finish:

	spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
	return iova;
}

/**
 * copy_reserved_iova - copies the reserved between domains
 * @from: - source doamin from where to copy
 * @to: - destination domin where to copy
 * This function copies reserved iova's from one doamin to
 * other.
 */
void
copy_reserved_iova(struct iova_domain *from, struct iova_domain *to)
{
	unsigned long flags;
	struct rb_node *node;

	spin_lock_irqsave(&from->iova_rbtree_lock, flags);
	for (node = rb_first(&from->rbroot); node; node = rb_next(node)) {
		struct iova *iova = container_of(node, struct iova, node);
		struct iova *new_iova;
		new_iova = reserve_iova(to, iova->pfn_lo, iova->pfn_hi);
		if (!new_iova)
			printk(KERN_ERR "Reserve iova range %lx@%lx failed\n",
				iova->pfn_lo, iova->pfn_lo);
	}
	spin_unlock_irqrestore(&from->iova_rbtree_lock, flags);
}