xref: /linux/drivers/vdpa/vdpa_user/iova_domain.c (revision 78c3925c048c752334873f56c3a3d1c9d53e0416) 
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 void vduse_domain_sync_single_for_device(struct vduse_iova_domain *domain,
377 				      dma_addr_t dma_addr, size_t size,
378 				      enum dma_data_direction dir)
379 {
380 	read_lock(&domain->bounce_lock);
381 	if (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL)
382 		vduse_domain_bounce(domain, dma_addr, size, DMA_TO_DEVICE);
383 	read_unlock(&domain->bounce_lock);
384 }
385 
386 void vduse_domain_sync_single_for_cpu(struct vduse_iova_domain *domain,
387 				      dma_addr_t dma_addr, size_t size,
388 				      enum dma_data_direction dir)
389 {
390 	read_lock(&domain->bounce_lock);
391 	if (dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL)
392 		vduse_domain_bounce(domain, dma_addr, size, DMA_FROM_DEVICE);
393 	read_unlock(&domain->bounce_lock);
394 }
395 
396 dma_addr_t vduse_domain_map_page(struct vduse_iova_domain *domain,
397 				 struct page *page, unsigned long offset,
398 				 size_t size, enum dma_data_direction dir,
399 				 unsigned long attrs)
400 {
401 	struct iova_domain *iovad = &domain->stream_iovad;
402 	unsigned long limit = domain->bounce_size - 1;
403 	phys_addr_t pa = page_to_phys(page) + offset;
404 	dma_addr_t iova = vduse_domain_alloc_iova(iovad, size, limit);
405 
406 	if (!iova)
407 		return DMA_MAPPING_ERROR;
408 
409 	if (vduse_domain_init_bounce_map(domain))
410 		goto err;
411 
412 	read_lock(&domain->bounce_lock);
413 	if (vduse_domain_map_bounce_page(domain, (u64)iova, (u64)size, pa))
414 		goto err_unlock;
415 
416 	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC) &&
417 	    (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL))
418 		vduse_domain_bounce(domain, iova, size, DMA_TO_DEVICE);
419 
420 	read_unlock(&domain->bounce_lock);
421 
422 	return iova;
423 err_unlock:
424 	read_unlock(&domain->bounce_lock);
425 err:
426 	vduse_domain_free_iova(iovad, iova, size);
427 	return DMA_MAPPING_ERROR;
428 }
429 
430 void vduse_domain_unmap_page(struct vduse_iova_domain *domain,
431 			     dma_addr_t dma_addr, size_t size,
432 			     enum dma_data_direction dir, unsigned long attrs)
433 {
434 	struct iova_domain *iovad = &domain->stream_iovad;
435 	read_lock(&domain->bounce_lock);
436 	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC) &&
437 	    (dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL))
438 		vduse_domain_bounce(domain, dma_addr, size, DMA_FROM_DEVICE);
439 
440 	vduse_domain_unmap_bounce_page(domain, (u64)dma_addr, (u64)size);
441 	read_unlock(&domain->bounce_lock);
442 	vduse_domain_free_iova(iovad, dma_addr, size);
443 }
444 
445 void *vduse_domain_alloc_coherent(struct vduse_iova_domain *domain,
446 				  size_t size, dma_addr_t *dma_addr,
447 				  gfp_t flag, unsigned long attrs)
448 {
449 	struct iova_domain *iovad = &domain->consistent_iovad;
450 	unsigned long limit = domain->iova_limit;
451 	dma_addr_t iova = vduse_domain_alloc_iova(iovad, size, limit);
452 	void *orig = alloc_pages_exact(size, flag);
453 
454 	if (!iova || !orig)
455 		goto err;
456 
457 	spin_lock(&domain->iotlb_lock);
458 	if (vduse_iotlb_add_range(domain, (u64)iova, (u64)iova + size - 1,
459 				  virt_to_phys(orig), VHOST_MAP_RW,
460 				  domain->file, (u64)iova)) {
461 		spin_unlock(&domain->iotlb_lock);
462 		goto err;
463 	}
464 	spin_unlock(&domain->iotlb_lock);
465 
466 	*dma_addr = iova;
467 
468 	return orig;
469 err:
470 	*dma_addr = DMA_MAPPING_ERROR;
471 	if (orig)
472 		free_pages_exact(orig, size);
473 	if (iova)
474 		vduse_domain_free_iova(iovad, iova, size);
475 
476 	return NULL;
477 }
478 
479 void vduse_domain_free_coherent(struct vduse_iova_domain *domain, size_t size,
480 				void *vaddr, dma_addr_t dma_addr,
481 				unsigned long attrs)
482 {
483 	struct iova_domain *iovad = &domain->consistent_iovad;
484 	struct vhost_iotlb_map *map;
485 	struct vdpa_map_file *map_file;
486 	phys_addr_t pa;
487 
488 	spin_lock(&domain->iotlb_lock);
489 	map = vhost_iotlb_itree_first(domain->iotlb, (u64)dma_addr,
490 				      (u64)dma_addr + size - 1);
491 	if (WARN_ON(!map)) {
492 		spin_unlock(&domain->iotlb_lock);
493 		return;
494 	}
495 	map_file = (struct vdpa_map_file *)map->opaque;
496 	fput(map_file->file);
497 	kfree(map_file);
498 	pa = map->addr;
499 	vhost_iotlb_map_free(domain->iotlb, map);
500 	spin_unlock(&domain->iotlb_lock);
501 
502 	vduse_domain_free_iova(iovad, dma_addr, size);
503 	free_pages_exact(phys_to_virt(pa), size);
504 }
505 
506 static vm_fault_t vduse_domain_mmap_fault(struct vm_fault *vmf)
507 {
508 	struct vduse_iova_domain *domain = vmf->vma->vm_private_data;
509 	unsigned long iova = vmf->pgoff << PAGE_SHIFT;
510 	struct page *page;
511 
512 	if (!domain)
513 		return VM_FAULT_SIGBUS;
514 
515 	if (iova < domain->bounce_size)
516 		page = vduse_domain_get_bounce_page(domain, iova);
517 	else
518 		page = vduse_domain_get_coherent_page(domain, iova);
519 
520 	if (!page)
521 		return VM_FAULT_SIGBUS;
522 
523 	vmf->page = page;
524 
525 	return 0;
526 }
527 
528 static const struct vm_operations_struct vduse_domain_mmap_ops = {
529 	.fault = vduse_domain_mmap_fault,
530 };
531 
532 static int vduse_domain_mmap(struct file *file, struct vm_area_struct *vma)
533 {
534 	struct vduse_iova_domain *domain = file->private_data;
535 
536 	vm_flags_set(vma, VM_DONTDUMP | VM_DONTEXPAND);
537 	vma->vm_private_data = domain;
538 	vma->vm_ops = &vduse_domain_mmap_ops;
539 
540 	return 0;
541 }
542 
543 static int vduse_domain_release(struct inode *inode, struct file *file)
544 {
545 	struct vduse_iova_domain *domain = file->private_data;
546 
547 	spin_lock(&domain->iotlb_lock);
548 	vduse_iotlb_del_range(domain, 0, ULLONG_MAX);
549 	vduse_domain_remove_user_bounce_pages(domain);
550 	vduse_domain_free_kernel_bounce_pages(domain);
551 	spin_unlock(&domain->iotlb_lock);
552 	put_iova_domain(&domain->stream_iovad);
553 	put_iova_domain(&domain->consistent_iovad);
554 	vhost_iotlb_free(domain->iotlb);
555 	vfree(domain->bounce_maps);
556 	kfree(domain);
557 
558 	return 0;
559 }
560 
561 static const struct file_operations vduse_domain_fops = {
562 	.owner = THIS_MODULE,
563 	.mmap = vduse_domain_mmap,
564 	.release = vduse_domain_release,
565 };
566 
567 void vduse_domain_destroy(struct vduse_iova_domain *domain)
568 {
569 	fput(domain->file);
570 }
571 
572 struct vduse_iova_domain *
573 vduse_domain_create(unsigned long iova_limit, size_t bounce_size)
574 {
575 	struct vduse_iova_domain *domain;
576 	struct file *file;
577 	struct vduse_bounce_map *map;
578 	unsigned long pfn, bounce_pfns;
579 	int ret;
580 
581 	bounce_pfns = PAGE_ALIGN(bounce_size) >> PAGE_SHIFT;
582 	if (iova_limit <= bounce_size)
583 		return NULL;
584 
585 	domain = kzalloc(sizeof(*domain), GFP_KERNEL);
586 	if (!domain)
587 		return NULL;
588 
589 	domain->iotlb = vhost_iotlb_alloc(0, 0);
590 	if (!domain->iotlb)
591 		goto err_iotlb;
592 
593 	domain->iova_limit = iova_limit;
594 	domain->bounce_size = PAGE_ALIGN(bounce_size);
595 	domain->bounce_maps = vzalloc(bounce_pfns *
596 				sizeof(struct vduse_bounce_map));
597 	if (!domain->bounce_maps)
598 		goto err_map;
599 
600 	for (pfn = 0; pfn < bounce_pfns; pfn++) {
601 		map = &domain->bounce_maps[pfn];
602 		map->orig_phys = INVALID_PHYS_ADDR;
603 	}
604 	file = anon_inode_getfile("[vduse-domain]", &vduse_domain_fops,
605 				domain, O_RDWR);
606 	if (IS_ERR(file))
607 		goto err_file;
608 
609 	domain->file = file;
610 	rwlock_init(&domain->bounce_lock);
611 	spin_lock_init(&domain->iotlb_lock);
612 	init_iova_domain(&domain->stream_iovad,
613 			PAGE_SIZE, IOVA_START_PFN);
614 	ret = iova_domain_init_rcaches(&domain->stream_iovad);
615 	if (ret)
616 		goto err_iovad_stream;
617 	init_iova_domain(&domain->consistent_iovad,
618 			PAGE_SIZE, bounce_pfns);
619 	ret = iova_domain_init_rcaches(&domain->consistent_iovad);
620 	if (ret)
621 		goto err_iovad_consistent;
622 
623 	return domain;
624 err_iovad_consistent:
625 	put_iova_domain(&domain->stream_iovad);
626 err_iovad_stream:
627 	fput(file);
628 err_file:
629 	vfree(domain->bounce_maps);
630 err_map:
631 	vhost_iotlb_free(domain->iotlb);
632 err_iotlb:
633 	kfree(domain);
634 	return NULL;
635 }
636 
637 int vduse_domain_init(void)
638 {
639 	return iova_cache_get();
640 }
641 
642 void vduse_domain_exit(void)
643 {
644 	iova_cache_put();
645 }
646