xref: /linux/drivers/vdpa/vdpa_user/iova_domain.c (revision 6c8c1406) 
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * MMU-based software IOTLB.
4  *
5  * Copyright (C) 2020-2021 Bytedance Inc. and/or its affiliates. All rights reserved.
6  *
7  * Author: Xie Yongji <xieyongji@bytedance.com>
8  *
9  */
10 
11 #include <linux/slab.h>
12 #include <linux/file.h>
13 #include <linux/anon_inodes.h>
14 #include <linux/highmem.h>
15 #include <linux/vmalloc.h>
16 #include <linux/vdpa.h>
17 
18 #include "iova_domain.h"
19 
20 static int vduse_iotlb_add_range(struct vduse_iova_domain *domain,
21 				 u64 start, u64 last,
22 				 u64 addr, unsigned int perm,
23 				 struct file *file, u64 offset)
24 {
25 	struct vdpa_map_file *map_file;
26 	int ret;
27 
28 	map_file = kmalloc(sizeof(*map_file), GFP_ATOMIC);
29 	if (!map_file)
30 		return -ENOMEM;
31 
32 	map_file->file = get_file(file);
33 	map_file->offset = offset;
34 
35 	ret = vhost_iotlb_add_range_ctx(domain->iotlb, start, last,
36 					addr, perm, map_file);
37 	if (ret) {
38 		fput(map_file->file);
39 		kfree(map_file);
40 		return ret;
41 	}
42 	return 0;
43 }
44 
45 static void vduse_iotlb_del_range(struct vduse_iova_domain *domain,
46 				  u64 start, u64 last)
47 {
48 	struct vdpa_map_file *map_file;
49 	struct vhost_iotlb_map *map;
50 
51 	while ((map = vhost_iotlb_itree_first(domain->iotlb, start, last))) {
52 		map_file = (struct vdpa_map_file *)map->opaque;
53 		fput(map_file->file);
54 		kfree(map_file);
55 		vhost_iotlb_map_free(domain->iotlb, map);
56 	}
57 }
58 
59 int vduse_domain_set_map(struct vduse_iova_domain *domain,
60 			 struct vhost_iotlb *iotlb)
61 {
62 	struct vdpa_map_file *map_file;
63 	struct vhost_iotlb_map *map;
64 	u64 start = 0ULL, last = ULLONG_MAX;
65 	int ret;
66 
67 	spin_lock(&domain->iotlb_lock);
68 	vduse_iotlb_del_range(domain, start, last);
69 
70 	for (map = vhost_iotlb_itree_first(iotlb, start, last); map;
71 	     map = vhost_iotlb_itree_next(map, start, last)) {
72 		map_file = (struct vdpa_map_file *)map->opaque;
73 		ret = vduse_iotlb_add_range(domain, map->start, map->last,
74 					    map->addr, map->perm,
75 					    map_file->file,
76 					    map_file->offset);
77 		if (ret)
78 			goto err;
79 	}
80 	spin_unlock(&domain->iotlb_lock);
81 
82 	return 0;
83 err:
84 	vduse_iotlb_del_range(domain, start, last);
85 	spin_unlock(&domain->iotlb_lock);
86 	return ret;
87 }
88 
89 void vduse_domain_clear_map(struct vduse_iova_domain *domain,
90 			    struct vhost_iotlb *iotlb)
91 {
92 	struct vhost_iotlb_map *map;
93 	u64 start = 0ULL, last = ULLONG_MAX;
94 
95 	spin_lock(&domain->iotlb_lock);
96 	for (map = vhost_iotlb_itree_first(iotlb, start, last); map;
97 	     map = vhost_iotlb_itree_next(map, start, last)) {
98 		vduse_iotlb_del_range(domain, map->start, map->last);
99 	}
100 	spin_unlock(&domain->iotlb_lock);
101 }
102 
103 static int vduse_domain_map_bounce_page(struct vduse_iova_domain *domain,
104 					 u64 iova, u64 size, u64 paddr)
105 {
106 	struct vduse_bounce_map *map;
107 	u64 last = iova + size - 1;
108 
109 	while (iova <= last) {
110 		map = &domain->bounce_maps[iova >> PAGE_SHIFT];
111 		if (!map->bounce_page) {
112 			map->bounce_page = alloc_page(GFP_ATOMIC);
113 			if (!map->bounce_page)
114 				return -ENOMEM;
115 		}
116 		map->orig_phys = paddr;
117 		paddr += PAGE_SIZE;
118 		iova += PAGE_SIZE;
119 	}
120 	return 0;
121 }
122 
123 static void vduse_domain_unmap_bounce_page(struct vduse_iova_domain *domain,
124 					   u64 iova, u64 size)
125 {
126 	struct vduse_bounce_map *map;
127 	u64 last = iova + size - 1;
128 
129 	while (iova <= last) {
130 		map = &domain->bounce_maps[iova >> PAGE_SHIFT];
131 		map->orig_phys = INVALID_PHYS_ADDR;
132 		iova += PAGE_SIZE;
133 	}
134 }
135 
136 static void do_bounce(phys_addr_t orig, void *addr, size_t size,
137 		      enum dma_data_direction dir)
138 {
139 	unsigned long pfn = PFN_DOWN(orig);
140 	unsigned int offset = offset_in_page(orig);
141 	struct page *page;
142 	unsigned int sz = 0;
143 
144 	while (size) {
145 		sz = min_t(size_t, PAGE_SIZE - offset, size);
146 
147 		page = pfn_to_page(pfn);
148 		if (dir == DMA_TO_DEVICE)
149 			memcpy_from_page(addr, page, offset, sz);
150 		else
151 			memcpy_to_page(page, offset, addr, sz);
152 
153 		size -= sz;
154 		pfn++;
155 		addr += sz;
156 		offset = 0;
157 	}
158 }
159 
160 static void vduse_domain_bounce(struct vduse_iova_domain *domain,
161 				dma_addr_t iova, size_t size,
162 				enum dma_data_direction dir)
163 {
164 	struct vduse_bounce_map *map;
165 	unsigned int offset;
166 	void *addr;
167 	size_t sz;
168 
169 	if (iova >= domain->bounce_size)
170 		return;
171 
172 	while (size) {
173 		map = &domain->bounce_maps[iova >> PAGE_SHIFT];
174 		offset = offset_in_page(iova);
175 		sz = min_t(size_t, PAGE_SIZE - offset, size);
176 
177 		if (WARN_ON(!map->bounce_page ||
178 			    map->orig_phys == INVALID_PHYS_ADDR))
179 			return;
180 
181 		addr = kmap_local_page(map->bounce_page);
182 		do_bounce(map->orig_phys + offset, addr + offset, sz, dir);
183 		kunmap_local(addr);
184 		size -= sz;
185 		iova += sz;
186 	}
187 }
188 
189 static struct page *
190 vduse_domain_get_coherent_page(struct vduse_iova_domain *domain, u64 iova)
191 {
192 	u64 start = iova & PAGE_MASK;
193 	u64 last = start + PAGE_SIZE - 1;
194 	struct vhost_iotlb_map *map;
195 	struct page *page = NULL;
196 
197 	spin_lock(&domain->iotlb_lock);
198 	map = vhost_iotlb_itree_first(domain->iotlb, start, last);
199 	if (!map)
200 		goto out;
201 
202 	page = pfn_to_page((map->addr + iova - map->start) >> PAGE_SHIFT);
203 	get_page(page);
204 out:
205 	spin_unlock(&domain->iotlb_lock);
206 
207 	return page;
208 }
209 
210 static struct page *
211 vduse_domain_get_bounce_page(struct vduse_iova_domain *domain, u64 iova)
212 {
213 	struct vduse_bounce_map *map;
214 	struct page *page = NULL;
215 
216 	read_lock(&domain->bounce_lock);
217 	map = &domain->bounce_maps[iova >> PAGE_SHIFT];
218 	if (domain->user_bounce_pages || !map->bounce_page)
219 		goto out;
220 
221 	page = map->bounce_page;
222 	get_page(page);
223 out:
224 	read_unlock(&domain->bounce_lock);
225 
226 	return page;
227 }
228 
229 static void
230 vduse_domain_free_kernel_bounce_pages(struct vduse_iova_domain *domain)
231 {
232 	struct vduse_bounce_map *map;
233 	unsigned long pfn, bounce_pfns;
234 
235 	bounce_pfns = domain->bounce_size >> PAGE_SHIFT;
236 
237 	for (pfn = 0; pfn < bounce_pfns; pfn++) {
238 		map = &domain->bounce_maps[pfn];
239 		if (WARN_ON(map->orig_phys != INVALID_PHYS_ADDR))
240 			continue;
241 
242 		if (!map->bounce_page)
243 			continue;
244 
245 		__free_page(map->bounce_page);
246 		map->bounce_page = NULL;
247 	}
248 }
249 
250 int vduse_domain_add_user_bounce_pages(struct vduse_iova_domain *domain,
251 				       struct page **pages, int count)
252 {
253 	struct vduse_bounce_map *map;
254 	int i, ret;
255 
256 	/* Now we don't support partial mapping */
257 	if (count != (domain->bounce_size >> PAGE_SHIFT))
258 		return -EINVAL;
259 
260 	write_lock(&domain->bounce_lock);
261 	ret = -EEXIST;
262 	if (domain->user_bounce_pages)
263 		goto out;
264 
265 	for (i = 0; i < count; i++) {
266 		map = &domain->bounce_maps[i];
267 		if (map->bounce_page) {
268 			/* Copy kernel page to user page if it's in use */
269 			if (map->orig_phys != INVALID_PHYS_ADDR)
270 				memcpy_to_page(pages[i], 0,
271 					       page_address(map->bounce_page),
272 					       PAGE_SIZE);
273 			__free_page(map->bounce_page);
274 		}
275 		map->bounce_page = pages[i];
276 		get_page(pages[i]);
277 	}
278 	domain->user_bounce_pages = true;
279 	ret = 0;
280 out:
281 	write_unlock(&domain->bounce_lock);
282 
283 	return ret;
284 }
285 
286 void vduse_domain_remove_user_bounce_pages(struct vduse_iova_domain *domain)
287 {
288 	struct vduse_bounce_map *map;
289 	unsigned long i, count;
290 
291 	write_lock(&domain->bounce_lock);
292 	if (!domain->user_bounce_pages)
293 		goto out;
294 
295 	count = domain->bounce_size >> PAGE_SHIFT;
296 	for (i = 0; i < count; i++) {
297 		struct page *page = NULL;
298 
299 		map = &domain->bounce_maps[i];
300 		if (WARN_ON(!map->bounce_page))
301 			continue;
302 
303 		/* Copy user page to kernel page if it's in use */
304 		if (map->orig_phys != INVALID_PHYS_ADDR) {
305 			page = alloc_page(GFP_ATOMIC | __GFP_NOFAIL);
306 			memcpy_from_page(page_address(page),
307 					 map->bounce_page, 0, PAGE_SIZE);
308 		}
309 		put_page(map->bounce_page);
310 		map->bounce_page = page;
311 	}
312 	domain->user_bounce_pages = false;
313 out:
314 	write_unlock(&domain->bounce_lock);
315 }
316 
317 void vduse_domain_reset_bounce_map(struct vduse_iova_domain *domain)
318 {
319 	if (!domain->bounce_map)
320 		return;
321 
322 	spin_lock(&domain->iotlb_lock);
323 	if (!domain->bounce_map)
324 		goto unlock;
325 
326 	vduse_iotlb_del_range(domain, 0, domain->bounce_size - 1);
327 	domain->bounce_map = 0;
328 unlock:
329 	spin_unlock(&domain->iotlb_lock);
330 }
331 
332 static int vduse_domain_init_bounce_map(struct vduse_iova_domain *domain)
333 {
334 	int ret = 0;
335 
336 	if (domain->bounce_map)
337 		return 0;
338 
339 	spin_lock(&domain->iotlb_lock);
340 	if (domain->bounce_map)
341 		goto unlock;
342 
343 	ret = vduse_iotlb_add_range(domain, 0, domain->bounce_size - 1,
344 				    0, VHOST_MAP_RW, domain->file, 0);
345 	if (ret)
346 		goto unlock;
347 
348 	domain->bounce_map = 1;
349 unlock:
350 	spin_unlock(&domain->iotlb_lock);
351 	return ret;
352 }
353 
354 static dma_addr_t
355 vduse_domain_alloc_iova(struct iova_domain *iovad,
356 			unsigned long size, unsigned long limit)
357 {
358 	unsigned long shift = iova_shift(iovad);
359 	unsigned long iova_len = iova_align(iovad, size) >> shift;
360 	unsigned long iova_pfn;
361 
362 	iova_pfn = alloc_iova_fast(iovad, iova_len, limit >> shift, true);
363 
364 	return (dma_addr_t)iova_pfn << shift;
365 }
366 
367 static void vduse_domain_free_iova(struct iova_domain *iovad,
368 				   dma_addr_t iova, size_t size)
369 {
370 	unsigned long shift = iova_shift(iovad);
371 	unsigned long iova_len = iova_align(iovad, size) >> shift;
372 
373 	free_iova_fast(iovad, iova >> shift, iova_len);
374 }
375 
376 dma_addr_t vduse_domain_map_page(struct vduse_iova_domain *domain,
377 				 struct page *page, unsigned long offset,
378 				 size_t size, enum dma_data_direction dir,
379 				 unsigned long attrs)
380 {
381 	struct iova_domain *iovad = &domain->stream_iovad;
382 	unsigned long limit = domain->bounce_size - 1;
383 	phys_addr_t pa = page_to_phys(page) + offset;
384 	dma_addr_t iova = vduse_domain_alloc_iova(iovad, size, limit);
385 
386 	if (!iova)
387 		return DMA_MAPPING_ERROR;
388 
389 	if (vduse_domain_init_bounce_map(domain))
390 		goto err;
391 
392 	read_lock(&domain->bounce_lock);
393 	if (vduse_domain_map_bounce_page(domain, (u64)iova, (u64)size, pa))
394 		goto err_unlock;
395 
396 	if (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL)
397 		vduse_domain_bounce(domain, iova, size, DMA_TO_DEVICE);
398 
399 	read_unlock(&domain->bounce_lock);
400 
401 	return iova;
402 err_unlock:
403 	read_unlock(&domain->bounce_lock);
404 err:
405 	vduse_domain_free_iova(iovad, iova, size);
406 	return DMA_MAPPING_ERROR;
407 }
408 
409 void vduse_domain_unmap_page(struct vduse_iova_domain *domain,
410 			     dma_addr_t dma_addr, size_t size,
411 			     enum dma_data_direction dir, unsigned long attrs)
412 {
413 	struct iova_domain *iovad = &domain->stream_iovad;
414 
415 	read_lock(&domain->bounce_lock);
416 	if (dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL)
417 		vduse_domain_bounce(domain, dma_addr, size, DMA_FROM_DEVICE);
418 
419 	vduse_domain_unmap_bounce_page(domain, (u64)dma_addr, (u64)size);
420 	read_unlock(&domain->bounce_lock);
421 	vduse_domain_free_iova(iovad, dma_addr, size);
422 }
423 
424 void *vduse_domain_alloc_coherent(struct vduse_iova_domain *domain,
425 				  size_t size, dma_addr_t *dma_addr,
426 				  gfp_t flag, unsigned long attrs)
427 {
428 	struct iova_domain *iovad = &domain->consistent_iovad;
429 	unsigned long limit = domain->iova_limit;
430 	dma_addr_t iova = vduse_domain_alloc_iova(iovad, size, limit);
431 	void *orig = alloc_pages_exact(size, flag);
432 
433 	if (!iova || !orig)
434 		goto err;
435 
436 	spin_lock(&domain->iotlb_lock);
437 	if (vduse_iotlb_add_range(domain, (u64)iova, (u64)iova + size - 1,
438 				  virt_to_phys(orig), VHOST_MAP_RW,
439 				  domain->file, (u64)iova)) {
440 		spin_unlock(&domain->iotlb_lock);
441 		goto err;
442 	}
443 	spin_unlock(&domain->iotlb_lock);
444 
445 	*dma_addr = iova;
446 
447 	return orig;
448 err:
449 	*dma_addr = DMA_MAPPING_ERROR;
450 	if (orig)
451 		free_pages_exact(orig, size);
452 	if (iova)
453 		vduse_domain_free_iova(iovad, iova, size);
454 
455 	return NULL;
456 }
457 
458 void vduse_domain_free_coherent(struct vduse_iova_domain *domain, size_t size,
459 				void *vaddr, dma_addr_t dma_addr,
460 				unsigned long attrs)
461 {
462 	struct iova_domain *iovad = &domain->consistent_iovad;
463 	struct vhost_iotlb_map *map;
464 	struct vdpa_map_file *map_file;
465 	phys_addr_t pa;
466 
467 	spin_lock(&domain->iotlb_lock);
468 	map = vhost_iotlb_itree_first(domain->iotlb, (u64)dma_addr,
469 				      (u64)dma_addr + size - 1);
470 	if (WARN_ON(!map)) {
471 		spin_unlock(&domain->iotlb_lock);
472 		return;
473 	}
474 	map_file = (struct vdpa_map_file *)map->opaque;
475 	fput(map_file->file);
476 	kfree(map_file);
477 	pa = map->addr;
478 	vhost_iotlb_map_free(domain->iotlb, map);
479 	spin_unlock(&domain->iotlb_lock);
480 
481 	vduse_domain_free_iova(iovad, dma_addr, size);
482 	free_pages_exact(phys_to_virt(pa), size);
483 }
484 
485 static vm_fault_t vduse_domain_mmap_fault(struct vm_fault *vmf)
486 {
487 	struct vduse_iova_domain *domain = vmf->vma->vm_private_data;
488 	unsigned long iova = vmf->pgoff << PAGE_SHIFT;
489 	struct page *page;
490 
491 	if (!domain)
492 		return VM_FAULT_SIGBUS;
493 
494 	if (iova < domain->bounce_size)
495 		page = vduse_domain_get_bounce_page(domain, iova);
496 	else
497 		page = vduse_domain_get_coherent_page(domain, iova);
498 
499 	if (!page)
500 		return VM_FAULT_SIGBUS;
501 
502 	vmf->page = page;
503 
504 	return 0;
505 }
506 
507 static const struct vm_operations_struct vduse_domain_mmap_ops = {
508 	.fault = vduse_domain_mmap_fault,
509 };
510 
511 static int vduse_domain_mmap(struct file *file, struct vm_area_struct *vma)
512 {
513 	struct vduse_iova_domain *domain = file->private_data;
514 
515 	vma->vm_flags |= VM_DONTDUMP | VM_DONTEXPAND;
516 	vma->vm_private_data = domain;
517 	vma->vm_ops = &vduse_domain_mmap_ops;
518 
519 	return 0;
520 }
521 
522 static int vduse_domain_release(struct inode *inode, struct file *file)
523 {
524 	struct vduse_iova_domain *domain = file->private_data;
525 
526 	spin_lock(&domain->iotlb_lock);
527 	vduse_iotlb_del_range(domain, 0, ULLONG_MAX);
528 	vduse_domain_remove_user_bounce_pages(domain);
529 	vduse_domain_free_kernel_bounce_pages(domain);
530 	spin_unlock(&domain->iotlb_lock);
531 	put_iova_domain(&domain->stream_iovad);
532 	put_iova_domain(&domain->consistent_iovad);
533 	vhost_iotlb_free(domain->iotlb);
534 	vfree(domain->bounce_maps);
535 	kfree(domain);
536 
537 	return 0;
538 }
539 
540 static const struct file_operations vduse_domain_fops = {
541 	.owner = THIS_MODULE,
542 	.mmap = vduse_domain_mmap,
543 	.release = vduse_domain_release,
544 };
545 
546 void vduse_domain_destroy(struct vduse_iova_domain *domain)
547 {
548 	fput(domain->file);
549 }
550 
551 struct vduse_iova_domain *
552 vduse_domain_create(unsigned long iova_limit, size_t bounce_size)
553 {
554 	struct vduse_iova_domain *domain;
555 	struct file *file;
556 	struct vduse_bounce_map *map;
557 	unsigned long pfn, bounce_pfns;
558 	int ret;
559 
560 	bounce_pfns = PAGE_ALIGN(bounce_size) >> PAGE_SHIFT;
561 	if (iova_limit <= bounce_size)
562 		return NULL;
563 
564 	domain = kzalloc(sizeof(*domain), GFP_KERNEL);
565 	if (!domain)
566 		return NULL;
567 
568 	domain->iotlb = vhost_iotlb_alloc(0, 0);
569 	if (!domain->iotlb)
570 		goto err_iotlb;
571 
572 	domain->iova_limit = iova_limit;
573 	domain->bounce_size = PAGE_ALIGN(bounce_size);
574 	domain->bounce_maps = vzalloc(bounce_pfns *
575 				sizeof(struct vduse_bounce_map));
576 	if (!domain->bounce_maps)
577 		goto err_map;
578 
579 	for (pfn = 0; pfn < bounce_pfns; pfn++) {
580 		map = &domain->bounce_maps[pfn];
581 		map->orig_phys = INVALID_PHYS_ADDR;
582 	}
583 	file = anon_inode_getfile("[vduse-domain]", &vduse_domain_fops,
584 				domain, O_RDWR);
585 	if (IS_ERR(file))
586 		goto err_file;
587 
588 	domain->file = file;
589 	rwlock_init(&domain->bounce_lock);
590 	spin_lock_init(&domain->iotlb_lock);
591 	init_iova_domain(&domain->stream_iovad,
592 			PAGE_SIZE, IOVA_START_PFN);
593 	ret = iova_domain_init_rcaches(&domain->stream_iovad);
594 	if (ret)
595 		goto err_iovad_stream;
596 	init_iova_domain(&domain->consistent_iovad,
597 			PAGE_SIZE, bounce_pfns);
598 	ret = iova_domain_init_rcaches(&domain->consistent_iovad);
599 	if (ret)
600 		goto err_iovad_consistent;
601 
602 	return domain;
603 err_iovad_consistent:
604 	put_iova_domain(&domain->stream_iovad);
605 err_iovad_stream:
606 	fput(file);
607 err_file:
608 	vfree(domain->bounce_maps);
609 err_map:
610 	vhost_iotlb_free(domain->iotlb);
611 err_iotlb:
612 	kfree(domain);
613 	return NULL;
614 }
615 
616 int vduse_domain_init(void)
617 {
618 	return iova_cache_get();
619 }
620 
621 void vduse_domain_exit(void)
622 {
623 	iova_cache_put();
624 }
625