1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * VFIO: IOMMU DMA mapping support for Type1 IOMMU
4  *
5  * Copyright (C) 2012 Red Hat, Inc.  All rights reserved.
6  *     Author: Alex Williamson <alex.williamson@redhat.com>
7  *
8  * Derived from original vfio:
9  * Copyright 2010 Cisco Systems, Inc.  All rights reserved.
10  * Author: Tom Lyon, pugs@cisco.com
11  *
12  * We arbitrarily define a Type1 IOMMU as one matching the below code.
13  * It could be called the x86 IOMMU as it's designed for AMD-Vi & Intel
14  * VT-d, but that makes it harder to re-use as theoretically anyone
15  * implementing a similar IOMMU could make use of this.  We expect the
16  * IOMMU to support the IOMMU API and have few to no restrictions around
17  * the IOVA range that can be mapped.  The Type1 IOMMU is currently
18  * optimized for relatively static mappings of a userspace process with
19  * userspace pages pinned into memory.  We also assume devices and IOMMU
20  * domains are PCI based as the IOMMU API is still centered around a
21  * device/bus interface rather than a group interface.
22  */
23 
24 #include <linux/compat.h>
25 #include <linux/device.h>
26 #include <linux/fs.h>
27 #include <linux/highmem.h>
28 #include <linux/iommu.h>
29 #include <linux/module.h>
30 #include <linux/mm.h>
31 #include <linux/kthread.h>
32 #include <linux/rbtree.h>
33 #include <linux/sched/signal.h>
34 #include <linux/sched/mm.h>
35 #include <linux/slab.h>
36 #include <linux/uaccess.h>
37 #include <linux/vfio.h>
38 #include <linux/workqueue.h>
39 #include <linux/notifier.h>
40 #include <linux/irqdomain.h>
41 #include "vfio.h"
42 
43 #define DRIVER_VERSION  "0.2"
44 #define DRIVER_AUTHOR   "Alex Williamson <alex.williamson@redhat.com>"
45 #define DRIVER_DESC     "Type1 IOMMU driver for VFIO"
46 
47 static bool allow_unsafe_interrupts;
48 module_param_named(allow_unsafe_interrupts,
49 		   allow_unsafe_interrupts, bool, S_IRUGO | S_IWUSR);
50 MODULE_PARM_DESC(allow_unsafe_interrupts,
51 		 "Enable VFIO IOMMU support for on platforms without interrupt remapping support.");
52 
53 static bool disable_hugepages;
54 module_param_named(disable_hugepages,
55 		   disable_hugepages, bool, S_IRUGO | S_IWUSR);
56 MODULE_PARM_DESC(disable_hugepages,
57 		 "Disable VFIO IOMMU support for IOMMU hugepages.");
58 
59 static unsigned int dma_entry_limit __read_mostly = U16_MAX;
60 module_param_named(dma_entry_limit, dma_entry_limit, uint, 0644);
61 MODULE_PARM_DESC(dma_entry_limit,
62 		 "Maximum number of user DMA mappings per container (65535).");
63 
64 struct vfio_iommu {
65 	struct list_head	domain_list;
66 	struct list_head	iova_list;
67 	struct mutex		lock;
68 	struct rb_root		dma_list;
69 	struct list_head	device_list;
70 	struct mutex		device_list_lock;
71 	unsigned int		dma_avail;
72 	unsigned int		vaddr_invalid_count;
73 	uint64_t		pgsize_bitmap;
74 	uint64_t		num_non_pinned_groups;
75 	wait_queue_head_t	vaddr_wait;
76 	bool			v2;
77 	bool			nesting;
78 	bool			dirty_page_tracking;
79 	bool			container_open;
80 	struct list_head	emulated_iommu_groups;
81 };
82 
83 struct vfio_domain {
84 	struct iommu_domain	*domain;
85 	struct list_head	next;
86 	struct list_head	group_list;
87 	bool			fgsp : 1;	/* Fine-grained super pages */
88 	bool			enforce_cache_coherency : 1;
89 };
90 
91 struct vfio_dma {
92 	struct rb_node		node;
93 	dma_addr_t		iova;		/* Device address */
94 	unsigned long		vaddr;		/* Process virtual addr */
95 	size_t			size;		/* Map size (bytes) */
96 	int			prot;		/* IOMMU_READ/WRITE */
97 	bool			iommu_mapped;
98 	bool			lock_cap;	/* capable(CAP_IPC_LOCK) */
99 	bool			vaddr_invalid;
100 	struct task_struct	*task;
101 	struct rb_root		pfn_list;	/* Ex-user pinned pfn list */
102 	unsigned long		*bitmap;
103 };
104 
105 struct vfio_batch {
106 	struct page		**pages;	/* for pin_user_pages_remote */
107 	struct page		*fallback_page; /* if pages alloc fails */
108 	int			capacity;	/* length of pages array */
109 	int			size;		/* of batch currently */
110 	int			offset;		/* of next entry in pages */
111 };
112 
113 struct vfio_iommu_group {
114 	struct iommu_group	*iommu_group;
115 	struct list_head	next;
116 	bool			pinned_page_dirty_scope;
117 };
118 
119 struct vfio_iova {
120 	struct list_head	list;
121 	dma_addr_t		start;
122 	dma_addr_t		end;
123 };
124 
125 /*
126  * Guest RAM pinning working set or DMA target
127  */
128 struct vfio_pfn {
129 	struct rb_node		node;
130 	dma_addr_t		iova;		/* Device address */
131 	unsigned long		pfn;		/* Host pfn */
132 	unsigned int		ref_count;
133 };
134 
135 struct vfio_regions {
136 	struct list_head list;
137 	dma_addr_t iova;
138 	phys_addr_t phys;
139 	size_t len;
140 };
141 
142 #define DIRTY_BITMAP_BYTES(n)	(ALIGN(n, BITS_PER_TYPE(u64)) / BITS_PER_BYTE)
143 
144 /*
145  * Input argument of number of bits to bitmap_set() is unsigned integer, which
146  * further casts to signed integer for unaligned multi-bit operation,
147  * __bitmap_set().
148  * Then maximum bitmap size supported is 2^31 bits divided by 2^3 bits/byte,
149  * that is 2^28 (256 MB) which maps to 2^31 * 2^12 = 2^43 (8TB) on 4K page
150  * system.
151  */
152 #define DIRTY_BITMAP_PAGES_MAX	 ((u64)INT_MAX)
153 #define DIRTY_BITMAP_SIZE_MAX	 DIRTY_BITMAP_BYTES(DIRTY_BITMAP_PAGES_MAX)
154 
155 #define WAITED 1
156 
157 static int put_pfn(unsigned long pfn, int prot);
158 
159 static struct vfio_iommu_group*
160 vfio_iommu_find_iommu_group(struct vfio_iommu *iommu,
161 			    struct iommu_group *iommu_group);
162 
163 /*
164  * This code handles mapping and unmapping of user data buffers
165  * into DMA'ble space using the IOMMU
166  */
167 
vfio_find_dma(struct vfio_iommu * iommu,dma_addr_t start,size_t size)168 static struct vfio_dma *vfio_find_dma(struct vfio_iommu *iommu,
169 				      dma_addr_t start, size_t size)
170 {
171 	struct rb_node *node = iommu->dma_list.rb_node;
172 
173 	while (node) {
174 		struct vfio_dma *dma = rb_entry(node, struct vfio_dma, node);
175 
176 		if (start + size <= dma->iova)
177 			node = node->rb_left;
178 		else if (start >= dma->iova + dma->size)
179 			node = node->rb_right;
180 		else
181 			return dma;
182 	}
183 
184 	return NULL;
185 }
186 
vfio_find_dma_first_node(struct vfio_iommu * iommu,dma_addr_t start,u64 size)187 static struct rb_node *vfio_find_dma_first_node(struct vfio_iommu *iommu,
188 						dma_addr_t start, u64 size)
189 {
190 	struct rb_node *res = NULL;
191 	struct rb_node *node = iommu->dma_list.rb_node;
192 	struct vfio_dma *dma_res = NULL;
193 
194 	while (node) {
195 		struct vfio_dma *dma = rb_entry(node, struct vfio_dma, node);
196 
197 		if (start < dma->iova + dma->size) {
198 			res = node;
199 			dma_res = dma;
200 			if (start >= dma->iova)
201 				break;
202 			node = node->rb_left;
203 		} else {
204 			node = node->rb_right;
205 		}
206 	}
207 	if (res && size && dma_res->iova >= start + size)
208 		res = NULL;
209 	return res;
210 }
211 
vfio_link_dma(struct vfio_iommu * iommu,struct vfio_dma * new)212 static void vfio_link_dma(struct vfio_iommu *iommu, struct vfio_dma *new)
213 {
214 	struct rb_node **link = &iommu->dma_list.rb_node, *parent = NULL;
215 	struct vfio_dma *dma;
216 
217 	while (*link) {
218 		parent = *link;
219 		dma = rb_entry(parent, struct vfio_dma, node);
220 
221 		if (new->iova + new->size <= dma->iova)
222 			link = &(*link)->rb_left;
223 		else
224 			link = &(*link)->rb_right;
225 	}
226 
227 	rb_link_node(&new->node, parent, link);
228 	rb_insert_color(&new->node, &iommu->dma_list);
229 }
230 
vfio_unlink_dma(struct vfio_iommu * iommu,struct vfio_dma * old)231 static void vfio_unlink_dma(struct vfio_iommu *iommu, struct vfio_dma *old)
232 {
233 	rb_erase(&old->node, &iommu->dma_list);
234 }
235 
236 
vfio_dma_bitmap_alloc(struct vfio_dma * dma,size_t pgsize)237 static int vfio_dma_bitmap_alloc(struct vfio_dma *dma, size_t pgsize)
238 {
239 	uint64_t npages = dma->size / pgsize;
240 
241 	if (npages > DIRTY_BITMAP_PAGES_MAX)
242 		return -EINVAL;
243 
244 	/*
245 	 * Allocate extra 64 bits that are used to calculate shift required for
246 	 * bitmap_shift_left() to manipulate and club unaligned number of pages
247 	 * in adjacent vfio_dma ranges.
248 	 */
249 	dma->bitmap = kvzalloc(DIRTY_BITMAP_BYTES(npages) + sizeof(u64),
250 			       GFP_KERNEL);
251 	if (!dma->bitmap)
252 		return -ENOMEM;
253 
254 	return 0;
255 }
256 
vfio_dma_bitmap_free(struct vfio_dma * dma)257 static void vfio_dma_bitmap_free(struct vfio_dma *dma)
258 {
259 	kvfree(dma->bitmap);
260 	dma->bitmap = NULL;
261 }
262 
vfio_dma_populate_bitmap(struct vfio_dma * dma,size_t pgsize)263 static void vfio_dma_populate_bitmap(struct vfio_dma *dma, size_t pgsize)
264 {
265 	struct rb_node *p;
266 	unsigned long pgshift = __ffs(pgsize);
267 
268 	for (p = rb_first(&dma->pfn_list); p; p = rb_next(p)) {
269 		struct vfio_pfn *vpfn = rb_entry(p, struct vfio_pfn, node);
270 
271 		bitmap_set(dma->bitmap, (vpfn->iova - dma->iova) >> pgshift, 1);
272 	}
273 }
274 
vfio_iommu_populate_bitmap_full(struct vfio_iommu * iommu)275 static void vfio_iommu_populate_bitmap_full(struct vfio_iommu *iommu)
276 {
277 	struct rb_node *n;
278 	unsigned long pgshift = __ffs(iommu->pgsize_bitmap);
279 
280 	for (n = rb_first(&iommu->dma_list); n; n = rb_next(n)) {
281 		struct vfio_dma *dma = rb_entry(n, struct vfio_dma, node);
282 
283 		bitmap_set(dma->bitmap, 0, dma->size >> pgshift);
284 	}
285 }
286 
vfio_dma_bitmap_alloc_all(struct vfio_iommu * iommu,size_t pgsize)287 static int vfio_dma_bitmap_alloc_all(struct vfio_iommu *iommu, size_t pgsize)
288 {
289 	struct rb_node *n;
290 
291 	for (n = rb_first(&iommu->dma_list); n; n = rb_next(n)) {
292 		struct vfio_dma *dma = rb_entry(n, struct vfio_dma, node);
293 		int ret;
294 
295 		ret = vfio_dma_bitmap_alloc(dma, pgsize);
296 		if (ret) {
297 			struct rb_node *p;
298 
299 			for (p = rb_prev(n); p; p = rb_prev(p)) {
300 				struct vfio_dma *dma = rb_entry(n,
301 							struct vfio_dma, node);
302 
303 				vfio_dma_bitmap_free(dma);
304 			}
305 			return ret;
306 		}
307 		vfio_dma_populate_bitmap(dma, pgsize);
308 	}
309 	return 0;
310 }
311 
vfio_dma_bitmap_free_all(struct vfio_iommu * iommu)312 static void vfio_dma_bitmap_free_all(struct vfio_iommu *iommu)
313 {
314 	struct rb_node *n;
315 
316 	for (n = rb_first(&iommu->dma_list); n; n = rb_next(n)) {
317 		struct vfio_dma *dma = rb_entry(n, struct vfio_dma, node);
318 
319 		vfio_dma_bitmap_free(dma);
320 	}
321 }
322 
323 /*
324  * Helper Functions for host iova-pfn list
325  */
vfio_find_vpfn(struct vfio_dma * dma,dma_addr_t iova)326 static struct vfio_pfn *vfio_find_vpfn(struct vfio_dma *dma, dma_addr_t iova)
327 {
328 	struct vfio_pfn *vpfn;
329 	struct rb_node *node = dma->pfn_list.rb_node;
330 
331 	while (node) {
332 		vpfn = rb_entry(node, struct vfio_pfn, node);
333 
334 		if (iova < vpfn->iova)
335 			node = node->rb_left;
336 		else if (iova > vpfn->iova)
337 			node = node->rb_right;
338 		else
339 			return vpfn;
340 	}
341 	return NULL;
342 }
343 
vfio_link_pfn(struct vfio_dma * dma,struct vfio_pfn * new)344 static void vfio_link_pfn(struct vfio_dma *dma,
345 			  struct vfio_pfn *new)
346 {
347 	struct rb_node **link, *parent = NULL;
348 	struct vfio_pfn *vpfn;
349 
350 	link = &dma->pfn_list.rb_node;
351 	while (*link) {
352 		parent = *link;
353 		vpfn = rb_entry(parent, struct vfio_pfn, node);
354 
355 		if (new->iova < vpfn->iova)
356 			link = &(*link)->rb_left;
357 		else
358 			link = &(*link)->rb_right;
359 	}
360 
361 	rb_link_node(&new->node, parent, link);
362 	rb_insert_color(&new->node, &dma->pfn_list);
363 }
364 
vfio_unlink_pfn(struct vfio_dma * dma,struct vfio_pfn * old)365 static void vfio_unlink_pfn(struct vfio_dma *dma, struct vfio_pfn *old)
366 {
367 	rb_erase(&old->node, &dma->pfn_list);
368 }
369 
vfio_add_to_pfn_list(struct vfio_dma * dma,dma_addr_t iova,unsigned long pfn)370 static int vfio_add_to_pfn_list(struct vfio_dma *dma, dma_addr_t iova,
371 				unsigned long pfn)
372 {
373 	struct vfio_pfn *vpfn;
374 
375 	vpfn = kzalloc(sizeof(*vpfn), GFP_KERNEL);
376 	if (!vpfn)
377 		return -ENOMEM;
378 
379 	vpfn->iova = iova;
380 	vpfn->pfn = pfn;
381 	vpfn->ref_count = 1;
382 	vfio_link_pfn(dma, vpfn);
383 	return 0;
384 }
385 
vfio_remove_from_pfn_list(struct vfio_dma * dma,struct vfio_pfn * vpfn)386 static void vfio_remove_from_pfn_list(struct vfio_dma *dma,
387 				      struct vfio_pfn *vpfn)
388 {
389 	vfio_unlink_pfn(dma, vpfn);
390 	kfree(vpfn);
391 }
392 
vfio_iova_get_vfio_pfn(struct vfio_dma * dma,unsigned long iova)393 static struct vfio_pfn *vfio_iova_get_vfio_pfn(struct vfio_dma *dma,
394 					       unsigned long iova)
395 {
396 	struct vfio_pfn *vpfn = vfio_find_vpfn(dma, iova);
397 
398 	if (vpfn)
399 		vpfn->ref_count++;
400 	return vpfn;
401 }
402 
vfio_iova_put_vfio_pfn(struct vfio_dma * dma,struct vfio_pfn * vpfn)403 static int vfio_iova_put_vfio_pfn(struct vfio_dma *dma, struct vfio_pfn *vpfn)
404 {
405 	int ret = 0;
406 
407 	vpfn->ref_count--;
408 	if (!vpfn->ref_count) {
409 		ret = put_pfn(vpfn->pfn, dma->prot);
410 		vfio_remove_from_pfn_list(dma, vpfn);
411 	}
412 	return ret;
413 }
414 
vfio_lock_acct(struct vfio_dma * dma,long npage,bool async)415 static int vfio_lock_acct(struct vfio_dma *dma, long npage, bool async)
416 {
417 	struct mm_struct *mm;
418 	int ret;
419 
420 	if (!npage)
421 		return 0;
422 
423 	mm = async ? get_task_mm(dma->task) : dma->task->mm;
424 	if (!mm)
425 		return -ESRCH; /* process exited */
426 
427 	ret = mmap_write_lock_killable(mm);
428 	if (!ret) {
429 		ret = __account_locked_vm(mm, abs(npage), npage > 0, dma->task,
430 					  dma->lock_cap);
431 		mmap_write_unlock(mm);
432 	}
433 
434 	if (async)
435 		mmput(mm);
436 
437 	return ret;
438 }
439 
440 /*
441  * Some mappings aren't backed by a struct page, for example an mmap'd
442  * MMIO range for our own or another device.  These use a different
443  * pfn conversion and shouldn't be tracked as locked pages.
444  * For compound pages, any driver that sets the reserved bit in head
445  * page needs to set the reserved bit in all subpages to be safe.
446  */
is_invalid_reserved_pfn(unsigned long pfn)447 static bool is_invalid_reserved_pfn(unsigned long pfn)
448 {
449 	if (pfn_valid(pfn))
450 		return PageReserved(pfn_to_page(pfn));
451 
452 	return true;
453 }
454 
put_pfn(unsigned long pfn,int prot)455 static int put_pfn(unsigned long pfn, int prot)
456 {
457 	if (!is_invalid_reserved_pfn(pfn)) {
458 		struct page *page = pfn_to_page(pfn);
459 
460 		unpin_user_pages_dirty_lock(&page, 1, prot & IOMMU_WRITE);
461 		return 1;
462 	}
463 	return 0;
464 }
465 
466 #define VFIO_BATCH_MAX_CAPACITY (PAGE_SIZE / sizeof(struct page *))
467 
vfio_batch_init(struct vfio_batch * batch)468 static void vfio_batch_init(struct vfio_batch *batch)
469 {
470 	batch->size = 0;
471 	batch->offset = 0;
472 
473 	if (unlikely(disable_hugepages))
474 		goto fallback;
475 
476 	batch->pages = (struct page **) __get_free_page(GFP_KERNEL);
477 	if (!batch->pages)
478 		goto fallback;
479 
480 	batch->capacity = VFIO_BATCH_MAX_CAPACITY;
481 	return;
482 
483 fallback:
484 	batch->pages = &batch->fallback_page;
485 	batch->capacity = 1;
486 }
487 
vfio_batch_unpin(struct vfio_batch * batch,struct vfio_dma * dma)488 static void vfio_batch_unpin(struct vfio_batch *batch, struct vfio_dma *dma)
489 {
490 	while (batch->size) {
491 		unsigned long pfn = page_to_pfn(batch->pages[batch->offset]);
492 
493 		put_pfn(pfn, dma->prot);
494 		batch->offset++;
495 		batch->size--;
496 	}
497 }
498 
vfio_batch_fini(struct vfio_batch * batch)499 static void vfio_batch_fini(struct vfio_batch *batch)
500 {
501 	if (batch->capacity == VFIO_BATCH_MAX_CAPACITY)
502 		free_page((unsigned long)batch->pages);
503 }
504 
follow_fault_pfn(struct vm_area_struct * vma,struct mm_struct * mm,unsigned long vaddr,unsigned long * pfn,bool write_fault)505 static int follow_fault_pfn(struct vm_area_struct *vma, struct mm_struct *mm,
506 			    unsigned long vaddr, unsigned long *pfn,
507 			    bool write_fault)
508 {
509 	pte_t *ptep;
510 	spinlock_t *ptl;
511 	int ret;
512 
513 	ret = follow_pte(vma->vm_mm, vaddr, &ptep, &ptl);
514 	if (ret) {
515 		bool unlocked = false;
516 
517 		ret = fixup_user_fault(mm, vaddr,
518 				       FAULT_FLAG_REMOTE |
519 				       (write_fault ?  FAULT_FLAG_WRITE : 0),
520 				       &unlocked);
521 		if (unlocked)
522 			return -EAGAIN;
523 
524 		if (ret)
525 			return ret;
526 
527 		ret = follow_pte(vma->vm_mm, vaddr, &ptep, &ptl);
528 		if (ret)
529 			return ret;
530 	}
531 
532 	if (write_fault && !pte_write(*ptep))
533 		ret = -EFAULT;
534 	else
535 		*pfn = pte_pfn(*ptep);
536 
537 	pte_unmap_unlock(ptep, ptl);
538 	return ret;
539 }
540 
541 /*
542  * Returns the positive number of pfns successfully obtained or a negative
543  * error code.
544  */
vaddr_get_pfns(struct mm_struct * mm,unsigned long vaddr,long npages,int prot,unsigned long * pfn,struct page ** pages)545 static int vaddr_get_pfns(struct mm_struct *mm, unsigned long vaddr,
546 			  long npages, int prot, unsigned long *pfn,
547 			  struct page **pages)
548 {
549 	struct vm_area_struct *vma;
550 	unsigned int flags = 0;
551 	int ret;
552 
553 	if (prot & IOMMU_WRITE)
554 		flags |= FOLL_WRITE;
555 
556 	mmap_read_lock(mm);
557 	ret = pin_user_pages_remote(mm, vaddr, npages, flags | FOLL_LONGTERM,
558 				    pages, NULL, NULL);
559 	if (ret > 0) {
560 		int i;
561 
562 		/*
563 		 * The zero page is always resident, we don't need to pin it
564 		 * and it falls into our invalid/reserved test so we don't
565 		 * unpin in put_pfn().  Unpin all zero pages in the batch here.
566 		 */
567 		for (i = 0 ; i < ret; i++) {
568 			if (unlikely(is_zero_pfn(page_to_pfn(pages[i]))))
569 				unpin_user_page(pages[i]);
570 		}
571 
572 		*pfn = page_to_pfn(pages[0]);
573 		goto done;
574 	}
575 
576 	vaddr = untagged_addr(vaddr);
577 
578 retry:
579 	vma = vma_lookup(mm, vaddr);
580 
581 	if (vma && vma->vm_flags & VM_PFNMAP) {
582 		ret = follow_fault_pfn(vma, mm, vaddr, pfn, prot & IOMMU_WRITE);
583 		if (ret == -EAGAIN)
584 			goto retry;
585 
586 		if (!ret) {
587 			if (is_invalid_reserved_pfn(*pfn))
588 				ret = 1;
589 			else
590 				ret = -EFAULT;
591 		}
592 	}
593 done:
594 	mmap_read_unlock(mm);
595 	return ret;
596 }
597 
vfio_wait(struct vfio_iommu * iommu)598 static int vfio_wait(struct vfio_iommu *iommu)
599 {
600 	DEFINE_WAIT(wait);
601 
602 	prepare_to_wait(&iommu->vaddr_wait, &wait, TASK_KILLABLE);
603 	mutex_unlock(&iommu->lock);
604 	schedule();
605 	mutex_lock(&iommu->lock);
606 	finish_wait(&iommu->vaddr_wait, &wait);
607 	if (kthread_should_stop() || !iommu->container_open ||
608 	    fatal_signal_pending(current)) {
609 		return -EFAULT;
610 	}
611 	return WAITED;
612 }
613 
614 /*
615  * Find dma struct and wait for its vaddr to be valid.  iommu lock is dropped
616  * if the task waits, but is re-locked on return.  Return result in *dma_p.
617  * Return 0 on success with no waiting, WAITED on success if waited, and -errno
618  * on error.
619  */
vfio_find_dma_valid(struct vfio_iommu * iommu,dma_addr_t start,size_t size,struct vfio_dma ** dma_p)620 static int vfio_find_dma_valid(struct vfio_iommu *iommu, dma_addr_t start,
621 			       size_t size, struct vfio_dma **dma_p)
622 {
623 	int ret = 0;
624 
625 	do {
626 		*dma_p = vfio_find_dma(iommu, start, size);
627 		if (!*dma_p)
628 			return -EINVAL;
629 		else if (!(*dma_p)->vaddr_invalid)
630 			return ret;
631 		else
632 			ret = vfio_wait(iommu);
633 	} while (ret == WAITED);
634 
635 	return ret;
636 }
637 
638 /*
639  * Wait for all vaddr in the dma_list to become valid.  iommu lock is dropped
640  * if the task waits, but is re-locked on return.  Return 0 on success with no
641  * waiting, WAITED on success if waited, and -errno on error.
642  */
vfio_wait_all_valid(struct vfio_iommu * iommu)643 static int vfio_wait_all_valid(struct vfio_iommu *iommu)
644 {
645 	int ret = 0;
646 
647 	while (iommu->vaddr_invalid_count && ret >= 0)
648 		ret = vfio_wait(iommu);
649 
650 	return ret;
651 }
652 
653 /*
654  * Attempt to pin pages.  We really don't want to track all the pfns and
655  * the iommu can only map chunks of consecutive pfns anyway, so get the
656  * first page and all consecutive pages with the same locking.
657  */
vfio_pin_pages_remote(struct vfio_dma * dma,unsigned long vaddr,long npage,unsigned long * pfn_base,unsigned long limit,struct vfio_batch * batch)658 static long vfio_pin_pages_remote(struct vfio_dma *dma, unsigned long vaddr,
659 				  long npage, unsigned long *pfn_base,
660 				  unsigned long limit, struct vfio_batch *batch)
661 {
662 	unsigned long pfn;
663 	struct mm_struct *mm = current->mm;
664 	long ret, pinned = 0, lock_acct = 0;
665 	bool rsvd;
666 	dma_addr_t iova = vaddr - dma->vaddr + dma->iova;
667 
668 	/* This code path is only user initiated */
669 	if (!mm)
670 		return -ENODEV;
671 
672 	if (batch->size) {
673 		/* Leftover pages in batch from an earlier call. */
674 		*pfn_base = page_to_pfn(batch->pages[batch->offset]);
675 		pfn = *pfn_base;
676 		rsvd = is_invalid_reserved_pfn(*pfn_base);
677 	} else {
678 		*pfn_base = 0;
679 	}
680 
681 	while (npage) {
682 		if (!batch->size) {
683 			/* Empty batch, so refill it. */
684 			long req_pages = min_t(long, npage, batch->capacity);
685 
686 			ret = vaddr_get_pfns(mm, vaddr, req_pages, dma->prot,
687 					     &pfn, batch->pages);
688 			if (ret < 0)
689 				goto unpin_out;
690 
691 			batch->size = ret;
692 			batch->offset = 0;
693 
694 			if (!*pfn_base) {
695 				*pfn_base = pfn;
696 				rsvd = is_invalid_reserved_pfn(*pfn_base);
697 			}
698 		}
699 
700 		/*
701 		 * pfn is preset for the first iteration of this inner loop and
702 		 * updated at the end to handle a VM_PFNMAP pfn.  In that case,
703 		 * batch->pages isn't valid (there's no struct page), so allow
704 		 * batch->pages to be touched only when there's more than one
705 		 * pfn to check, which guarantees the pfns are from a
706 		 * !VM_PFNMAP vma.
707 		 */
708 		while (true) {
709 			if (pfn != *pfn_base + pinned ||
710 			    rsvd != is_invalid_reserved_pfn(pfn))
711 				goto out;
712 
713 			/*
714 			 * Reserved pages aren't counted against the user,
715 			 * externally pinned pages are already counted against
716 			 * the user.
717 			 */
718 			if (!rsvd && !vfio_find_vpfn(dma, iova)) {
719 				if (!dma->lock_cap &&
720 				    mm->locked_vm + lock_acct + 1 > limit) {
721 					pr_warn("%s: RLIMIT_MEMLOCK (%ld) exceeded\n",
722 						__func__, limit << PAGE_SHIFT);
723 					ret = -ENOMEM;
724 					goto unpin_out;
725 				}
726 				lock_acct++;
727 			}
728 
729 			pinned++;
730 			npage--;
731 			vaddr += PAGE_SIZE;
732 			iova += PAGE_SIZE;
733 			batch->offset++;
734 			batch->size--;
735 
736 			if (!batch->size)
737 				break;
738 
739 			pfn = page_to_pfn(batch->pages[batch->offset]);
740 		}
741 
742 		if (unlikely(disable_hugepages))
743 			break;
744 	}
745 
746 out:
747 	ret = vfio_lock_acct(dma, lock_acct, false);
748 
749 unpin_out:
750 	if (batch->size == 1 && !batch->offset) {
751 		/* May be a VM_PFNMAP pfn, which the batch can't remember. */
752 		put_pfn(pfn, dma->prot);
753 		batch->size = 0;
754 	}
755 
756 	if (ret < 0) {
757 		if (pinned && !rsvd) {
758 			for (pfn = *pfn_base ; pinned ; pfn++, pinned--)
759 				put_pfn(pfn, dma->prot);
760 		}
761 		vfio_batch_unpin(batch, dma);
762 
763 		return ret;
764 	}
765 
766 	return pinned;
767 }
768 
vfio_unpin_pages_remote(struct vfio_dma * dma,dma_addr_t iova,unsigned long pfn,long npage,bool do_accounting)769 static long vfio_unpin_pages_remote(struct vfio_dma *dma, dma_addr_t iova,
770 				    unsigned long pfn, long npage,
771 				    bool do_accounting)
772 {
773 	long unlocked = 0, locked = 0;
774 	long i;
775 
776 	for (i = 0; i < npage; i++, iova += PAGE_SIZE) {
777 		if (put_pfn(pfn++, dma->prot)) {
778 			unlocked++;
779 			if (vfio_find_vpfn(dma, iova))
780 				locked++;
781 		}
782 	}
783 
784 	if (do_accounting)
785 		vfio_lock_acct(dma, locked - unlocked, true);
786 
787 	return unlocked;
788 }
789 
vfio_pin_page_external(struct vfio_dma * dma,unsigned long vaddr,unsigned long * pfn_base,bool do_accounting)790 static int vfio_pin_page_external(struct vfio_dma *dma, unsigned long vaddr,
791 				  unsigned long *pfn_base, bool do_accounting)
792 {
793 	struct page *pages[1];
794 	struct mm_struct *mm;
795 	int ret;
796 
797 	mm = get_task_mm(dma->task);
798 	if (!mm)
799 		return -ENODEV;
800 
801 	ret = vaddr_get_pfns(mm, vaddr, 1, dma->prot, pfn_base, pages);
802 	if (ret != 1)
803 		goto out;
804 
805 	ret = 0;
806 
807 	if (do_accounting && !is_invalid_reserved_pfn(*pfn_base)) {
808 		ret = vfio_lock_acct(dma, 1, true);
809 		if (ret) {
810 			put_pfn(*pfn_base, dma->prot);
811 			if (ret == -ENOMEM)
812 				pr_warn("%s: Task %s (%d) RLIMIT_MEMLOCK "
813 					"(%ld) exceeded\n", __func__,
814 					dma->task->comm, task_pid_nr(dma->task),
815 					task_rlimit(dma->task, RLIMIT_MEMLOCK));
816 		}
817 	}
818 
819 out:
820 	mmput(mm);
821 	return ret;
822 }
823 
vfio_unpin_page_external(struct vfio_dma * dma,dma_addr_t iova,bool do_accounting)824 static int vfio_unpin_page_external(struct vfio_dma *dma, dma_addr_t iova,
825 				    bool do_accounting)
826 {
827 	int unlocked;
828 	struct vfio_pfn *vpfn = vfio_find_vpfn(dma, iova);
829 
830 	if (!vpfn)
831 		return 0;
832 
833 	unlocked = vfio_iova_put_vfio_pfn(dma, vpfn);
834 
835 	if (do_accounting)
836 		vfio_lock_acct(dma, -unlocked, true);
837 
838 	return unlocked;
839 }
840 
vfio_iommu_type1_pin_pages(void * iommu_data,struct iommu_group * iommu_group,dma_addr_t user_iova,int npage,int prot,struct page ** pages)841 static int vfio_iommu_type1_pin_pages(void *iommu_data,
842 				      struct iommu_group *iommu_group,
843 				      dma_addr_t user_iova,
844 				      int npage, int prot,
845 				      struct page **pages)
846 {
847 	struct vfio_iommu *iommu = iommu_data;
848 	struct vfio_iommu_group *group;
849 	int i, j, ret;
850 	unsigned long remote_vaddr;
851 	struct vfio_dma *dma;
852 	bool do_accounting;
853 	dma_addr_t iova;
854 
855 	if (!iommu || !pages)
856 		return -EINVAL;
857 
858 	/* Supported for v2 version only */
859 	if (!iommu->v2)
860 		return -EACCES;
861 
862 	mutex_lock(&iommu->lock);
863 
864 	/*
865 	 * Wait for all necessary vaddr's to be valid so they can be used in
866 	 * the main loop without dropping the lock, to avoid racing vs unmap.
867 	 */
868 again:
869 	if (iommu->vaddr_invalid_count) {
870 		for (i = 0; i < npage; i++) {
871 			iova = user_iova + PAGE_SIZE * i;
872 			ret = vfio_find_dma_valid(iommu, iova, PAGE_SIZE, &dma);
873 			if (ret < 0)
874 				goto pin_done;
875 			if (ret == WAITED)
876 				goto again;
877 		}
878 	}
879 
880 	/* Fail if no dma_umap notifier is registered */
881 	if (list_empty(&iommu->device_list)) {
882 		ret = -EINVAL;
883 		goto pin_done;
884 	}
885 
886 	/*
887 	 * If iommu capable domain exist in the container then all pages are
888 	 * already pinned and accounted. Accounting should be done if there is no
889 	 * iommu capable domain in the container.
890 	 */
891 	do_accounting = list_empty(&iommu->domain_list);
892 
893 	for (i = 0; i < npage; i++) {
894 		unsigned long phys_pfn;
895 		struct vfio_pfn *vpfn;
896 
897 		iova = user_iova + PAGE_SIZE * i;
898 		dma = vfio_find_dma(iommu, iova, PAGE_SIZE);
899 		if (!dma) {
900 			ret = -EINVAL;
901 			goto pin_unwind;
902 		}
903 
904 		if ((dma->prot & prot) != prot) {
905 			ret = -EPERM;
906 			goto pin_unwind;
907 		}
908 
909 		vpfn = vfio_iova_get_vfio_pfn(dma, iova);
910 		if (vpfn) {
911 			pages[i] = pfn_to_page(vpfn->pfn);
912 			continue;
913 		}
914 
915 		remote_vaddr = dma->vaddr + (iova - dma->iova);
916 		ret = vfio_pin_page_external(dma, remote_vaddr, &phys_pfn,
917 					     do_accounting);
918 		if (ret)
919 			goto pin_unwind;
920 
921 		ret = vfio_add_to_pfn_list(dma, iova, phys_pfn);
922 		if (ret) {
923 			if (put_pfn(phys_pfn, dma->prot) && do_accounting)
924 				vfio_lock_acct(dma, -1, true);
925 			goto pin_unwind;
926 		}
927 
928 		pages[i] = pfn_to_page(phys_pfn);
929 
930 		if (iommu->dirty_page_tracking) {
931 			unsigned long pgshift = __ffs(iommu->pgsize_bitmap);
932 
933 			/*
934 			 * Bitmap populated with the smallest supported page
935 			 * size
936 			 */
937 			bitmap_set(dma->bitmap,
938 				   (iova - dma->iova) >> pgshift, 1);
939 		}
940 	}
941 	ret = i;
942 
943 	group = vfio_iommu_find_iommu_group(iommu, iommu_group);
944 	if (!group->pinned_page_dirty_scope) {
945 		group->pinned_page_dirty_scope = true;
946 		iommu->num_non_pinned_groups--;
947 	}
948 
949 	goto pin_done;
950 
951 pin_unwind:
952 	pages[i] = NULL;
953 	for (j = 0; j < i; j++) {
954 		dma_addr_t iova;
955 
956 		iova = user_iova + PAGE_SIZE * j;
957 		dma = vfio_find_dma(iommu, iova, PAGE_SIZE);
958 		vfio_unpin_page_external(dma, iova, do_accounting);
959 		pages[j] = NULL;
960 	}
961 pin_done:
962 	mutex_unlock(&iommu->lock);
963 	return ret;
964 }
965 
vfio_iommu_type1_unpin_pages(void * iommu_data,dma_addr_t user_iova,int npage)966 static void vfio_iommu_type1_unpin_pages(void *iommu_data,
967 					 dma_addr_t user_iova, int npage)
968 {
969 	struct vfio_iommu *iommu = iommu_data;
970 	bool do_accounting;
971 	int i;
972 
973 	/* Supported for v2 version only */
974 	if (WARN_ON(!iommu->v2))
975 		return;
976 
977 	mutex_lock(&iommu->lock);
978 
979 	do_accounting = list_empty(&iommu->domain_list);
980 	for (i = 0; i < npage; i++) {
981 		dma_addr_t iova = user_iova + PAGE_SIZE * i;
982 		struct vfio_dma *dma;
983 
984 		dma = vfio_find_dma(iommu, iova, PAGE_SIZE);
985 		if (!dma)
986 			break;
987 
988 		vfio_unpin_page_external(dma, iova, do_accounting);
989 	}
990 
991 	mutex_unlock(&iommu->lock);
992 
993 	WARN_ON(i != npage);
994 }
995 
vfio_sync_unpin(struct vfio_dma * dma,struct vfio_domain * domain,struct list_head * regions,struct iommu_iotlb_gather * iotlb_gather)996 static long vfio_sync_unpin(struct vfio_dma *dma, struct vfio_domain *domain,
997 			    struct list_head *regions,
998 			    struct iommu_iotlb_gather *iotlb_gather)
999 {
1000 	long unlocked = 0;
1001 	struct vfio_regions *entry, *next;
1002 
1003 	iommu_iotlb_sync(domain->domain, iotlb_gather);
1004 
1005 	list_for_each_entry_safe(entry, next, regions, list) {
1006 		unlocked += vfio_unpin_pages_remote(dma,
1007 						    entry->iova,
1008 						    entry->phys >> PAGE_SHIFT,
1009 						    entry->len >> PAGE_SHIFT,
1010 						    false);
1011 		list_del(&entry->list);
1012 		kfree(entry);
1013 	}
1014 
1015 	cond_resched();
1016 
1017 	return unlocked;
1018 }
1019 
1020 /*
1021  * Generally, VFIO needs to unpin remote pages after each IOTLB flush.
1022  * Therefore, when using IOTLB flush sync interface, VFIO need to keep track
1023  * of these regions (currently using a list).
1024  *
1025  * This value specifies maximum number of regions for each IOTLB flush sync.
1026  */
1027 #define VFIO_IOMMU_TLB_SYNC_MAX		512
1028 
unmap_unpin_fast(struct vfio_domain * domain,struct vfio_dma * dma,dma_addr_t * iova,size_t len,phys_addr_t phys,long * unlocked,struct list_head * unmapped_list,int * unmapped_cnt,struct iommu_iotlb_gather * iotlb_gather)1029 static size_t unmap_unpin_fast(struct vfio_domain *domain,
1030 			       struct vfio_dma *dma, dma_addr_t *iova,
1031 			       size_t len, phys_addr_t phys, long *unlocked,
1032 			       struct list_head *unmapped_list,
1033 			       int *unmapped_cnt,
1034 			       struct iommu_iotlb_gather *iotlb_gather)
1035 {
1036 	size_t unmapped = 0;
1037 	struct vfio_regions *entry = kzalloc(sizeof(*entry), GFP_KERNEL);
1038 
1039 	if (entry) {
1040 		unmapped = iommu_unmap_fast(domain->domain, *iova, len,
1041 					    iotlb_gather);
1042 
1043 		if (!unmapped) {
1044 			kfree(entry);
1045 		} else {
1046 			entry->iova = *iova;
1047 			entry->phys = phys;
1048 			entry->len  = unmapped;
1049 			list_add_tail(&entry->list, unmapped_list);
1050 
1051 			*iova += unmapped;
1052 			(*unmapped_cnt)++;
1053 		}
1054 	}
1055 
1056 	/*
1057 	 * Sync if the number of fast-unmap regions hits the limit
1058 	 * or in case of errors.
1059 	 */
1060 	if (*unmapped_cnt >= VFIO_IOMMU_TLB_SYNC_MAX || !unmapped) {
1061 		*unlocked += vfio_sync_unpin(dma, domain, unmapped_list,
1062 					     iotlb_gather);
1063 		*unmapped_cnt = 0;
1064 	}
1065 
1066 	return unmapped;
1067 }
1068 
unmap_unpin_slow(struct vfio_domain * domain,struct vfio_dma * dma,dma_addr_t * iova,size_t len,phys_addr_t phys,long * unlocked)1069 static size_t unmap_unpin_slow(struct vfio_domain *domain,
1070 			       struct vfio_dma *dma, dma_addr_t *iova,
1071 			       size_t len, phys_addr_t phys,
1072 			       long *unlocked)
1073 {
1074 	size_t unmapped = iommu_unmap(domain->domain, *iova, len);
1075 
1076 	if (unmapped) {
1077 		*unlocked += vfio_unpin_pages_remote(dma, *iova,
1078 						     phys >> PAGE_SHIFT,
1079 						     unmapped >> PAGE_SHIFT,
1080 						     false);
1081 		*iova += unmapped;
1082 		cond_resched();
1083 	}
1084 	return unmapped;
1085 }
1086 
vfio_unmap_unpin(struct vfio_iommu * iommu,struct vfio_dma * dma,bool do_accounting)1087 static long vfio_unmap_unpin(struct vfio_iommu *iommu, struct vfio_dma *dma,
1088 			     bool do_accounting)
1089 {
1090 	dma_addr_t iova = dma->iova, end = dma->iova + dma->size;
1091 	struct vfio_domain *domain, *d;
1092 	LIST_HEAD(unmapped_region_list);
1093 	struct iommu_iotlb_gather iotlb_gather;
1094 	int unmapped_region_cnt = 0;
1095 	long unlocked = 0;
1096 
1097 	if (!dma->size)
1098 		return 0;
1099 
1100 	if (list_empty(&iommu->domain_list))
1101 		return 0;
1102 
1103 	/*
1104 	 * We use the IOMMU to track the physical addresses, otherwise we'd
1105 	 * need a much more complicated tracking system.  Unfortunately that
1106 	 * means we need to use one of the iommu domains to figure out the
1107 	 * pfns to unpin.  The rest need to be unmapped in advance so we have
1108 	 * no iommu translations remaining when the pages are unpinned.
1109 	 */
1110 	domain = d = list_first_entry(&iommu->domain_list,
1111 				      struct vfio_domain, next);
1112 
1113 	list_for_each_entry_continue(d, &iommu->domain_list, next) {
1114 		iommu_unmap(d->domain, dma->iova, dma->size);
1115 		cond_resched();
1116 	}
1117 
1118 	iommu_iotlb_gather_init(&iotlb_gather);
1119 	while (iova < end) {
1120 		size_t unmapped, len;
1121 		phys_addr_t phys, next;
1122 
1123 		phys = iommu_iova_to_phys(domain->domain, iova);
1124 		if (WARN_ON(!phys)) {
1125 			iova += PAGE_SIZE;
1126 			continue;
1127 		}
1128 
1129 		/*
1130 		 * To optimize for fewer iommu_unmap() calls, each of which
1131 		 * may require hardware cache flushing, try to find the
1132 		 * largest contiguous physical memory chunk to unmap.
1133 		 */
1134 		for (len = PAGE_SIZE;
1135 		     !domain->fgsp && iova + len < end; len += PAGE_SIZE) {
1136 			next = iommu_iova_to_phys(domain->domain, iova + len);
1137 			if (next != phys + len)
1138 				break;
1139 		}
1140 
1141 		/*
1142 		 * First, try to use fast unmap/unpin. In case of failure,
1143 		 * switch to slow unmap/unpin path.
1144 		 */
1145 		unmapped = unmap_unpin_fast(domain, dma, &iova, len, phys,
1146 					    &unlocked, &unmapped_region_list,
1147 					    &unmapped_region_cnt,
1148 					    &iotlb_gather);
1149 		if (!unmapped) {
1150 			unmapped = unmap_unpin_slow(domain, dma, &iova, len,
1151 						    phys, &unlocked);
1152 			if (WARN_ON(!unmapped))
1153 				break;
1154 		}
1155 	}
1156 
1157 	dma->iommu_mapped = false;
1158 
1159 	if (unmapped_region_cnt) {
1160 		unlocked += vfio_sync_unpin(dma, domain, &unmapped_region_list,
1161 					    &iotlb_gather);
1162 	}
1163 
1164 	if (do_accounting) {
1165 		vfio_lock_acct(dma, -unlocked, true);
1166 		return 0;
1167 	}
1168 	return unlocked;
1169 }
1170 
vfio_remove_dma(struct vfio_iommu * iommu,struct vfio_dma * dma)1171 static void vfio_remove_dma(struct vfio_iommu *iommu, struct vfio_dma *dma)
1172 {
1173 	WARN_ON(!RB_EMPTY_ROOT(&dma->pfn_list));
1174 	vfio_unmap_unpin(iommu, dma, true);
1175 	vfio_unlink_dma(iommu, dma);
1176 	put_task_struct(dma->task);
1177 	vfio_dma_bitmap_free(dma);
1178 	if (dma->vaddr_invalid) {
1179 		iommu->vaddr_invalid_count--;
1180 		wake_up_all(&iommu->vaddr_wait);
1181 	}
1182 	kfree(dma);
1183 	iommu->dma_avail++;
1184 }
1185 
vfio_update_pgsize_bitmap(struct vfio_iommu * iommu)1186 static void vfio_update_pgsize_bitmap(struct vfio_iommu *iommu)
1187 {
1188 	struct vfio_domain *domain;
1189 
1190 	iommu->pgsize_bitmap = ULONG_MAX;
1191 
1192 	list_for_each_entry(domain, &iommu->domain_list, next)
1193 		iommu->pgsize_bitmap &= domain->domain->pgsize_bitmap;
1194 
1195 	/*
1196 	 * In case the IOMMU supports page sizes smaller than PAGE_SIZE
1197 	 * we pretend PAGE_SIZE is supported and hide sub-PAGE_SIZE sizes.
1198 	 * That way the user will be able to map/unmap buffers whose size/
1199 	 * start address is aligned with PAGE_SIZE. Pinning code uses that
1200 	 * granularity while iommu driver can use the sub-PAGE_SIZE size
1201 	 * to map the buffer.
1202 	 */
1203 	if (iommu->pgsize_bitmap & ~PAGE_MASK) {
1204 		iommu->pgsize_bitmap &= PAGE_MASK;
1205 		iommu->pgsize_bitmap |= PAGE_SIZE;
1206 	}
1207 }
1208 
update_user_bitmap(u64 __user * bitmap,struct vfio_iommu * iommu,struct vfio_dma * dma,dma_addr_t base_iova,size_t pgsize)1209 static int update_user_bitmap(u64 __user *bitmap, struct vfio_iommu *iommu,
1210 			      struct vfio_dma *dma, dma_addr_t base_iova,
1211 			      size_t pgsize)
1212 {
1213 	unsigned long pgshift = __ffs(pgsize);
1214 	unsigned long nbits = dma->size >> pgshift;
1215 	unsigned long bit_offset = (dma->iova - base_iova) >> pgshift;
1216 	unsigned long copy_offset = bit_offset / BITS_PER_LONG;
1217 	unsigned long shift = bit_offset % BITS_PER_LONG;
1218 	unsigned long leftover;
1219 
1220 	/*
1221 	 * mark all pages dirty if any IOMMU capable device is not able
1222 	 * to report dirty pages and all pages are pinned and mapped.
1223 	 */
1224 	if (iommu->num_non_pinned_groups && dma->iommu_mapped)
1225 		bitmap_set(dma->bitmap, 0, nbits);
1226 
1227 	if (shift) {
1228 		bitmap_shift_left(dma->bitmap, dma->bitmap, shift,
1229 				  nbits + shift);
1230 
1231 		if (copy_from_user(&leftover,
1232 				   (void __user *)(bitmap + copy_offset),
1233 				   sizeof(leftover)))
1234 			return -EFAULT;
1235 
1236 		bitmap_or(dma->bitmap, dma->bitmap, &leftover, shift);
1237 	}
1238 
1239 	if (copy_to_user((void __user *)(bitmap + copy_offset), dma->bitmap,
1240 			 DIRTY_BITMAP_BYTES(nbits + shift)))
1241 		return -EFAULT;
1242 
1243 	return 0;
1244 }
1245 
vfio_iova_dirty_bitmap(u64 __user * bitmap,struct vfio_iommu * iommu,dma_addr_t iova,size_t size,size_t pgsize)1246 static int vfio_iova_dirty_bitmap(u64 __user *bitmap, struct vfio_iommu *iommu,
1247 				  dma_addr_t iova, size_t size, size_t pgsize)
1248 {
1249 	struct vfio_dma *dma;
1250 	struct rb_node *n;
1251 	unsigned long pgshift = __ffs(pgsize);
1252 	int ret;
1253 
1254 	/*
1255 	 * GET_BITMAP request must fully cover vfio_dma mappings.  Multiple
1256 	 * vfio_dma mappings may be clubbed by specifying large ranges, but
1257 	 * there must not be any previous mappings bisected by the range.
1258 	 * An error will be returned if these conditions are not met.
1259 	 */
1260 	dma = vfio_find_dma(iommu, iova, 1);
1261 	if (dma && dma->iova != iova)
1262 		return -EINVAL;
1263 
1264 	dma = vfio_find_dma(iommu, iova + size - 1, 0);
1265 	if (dma && dma->iova + dma->size != iova + size)
1266 		return -EINVAL;
1267 
1268 	for (n = rb_first(&iommu->dma_list); n; n = rb_next(n)) {
1269 		struct vfio_dma *dma = rb_entry(n, struct vfio_dma, node);
1270 
1271 		if (dma->iova < iova)
1272 			continue;
1273 
1274 		if (dma->iova > iova + size - 1)
1275 			break;
1276 
1277 		ret = update_user_bitmap(bitmap, iommu, dma, iova, pgsize);
1278 		if (ret)
1279 			return ret;
1280 
1281 		/*
1282 		 * Re-populate bitmap to include all pinned pages which are
1283 		 * considered as dirty but exclude pages which are unpinned and
1284 		 * pages which are marked dirty by vfio_dma_rw()
1285 		 */
1286 		bitmap_clear(dma->bitmap, 0, dma->size >> pgshift);
1287 		vfio_dma_populate_bitmap(dma, pgsize);
1288 	}
1289 	return 0;
1290 }
1291 
verify_bitmap_size(uint64_t npages,uint64_t bitmap_size)1292 static int verify_bitmap_size(uint64_t npages, uint64_t bitmap_size)
1293 {
1294 	if (!npages || !bitmap_size || (bitmap_size > DIRTY_BITMAP_SIZE_MAX) ||
1295 	    (bitmap_size < DIRTY_BITMAP_BYTES(npages)))
1296 		return -EINVAL;
1297 
1298 	return 0;
1299 }
1300 
1301 /*
1302  * Notify VFIO drivers using vfio_register_emulated_iommu_dev() to invalidate
1303  * and unmap iovas within the range we're about to unmap. Drivers MUST unpin
1304  * pages in response to an invalidation.
1305  */
vfio_notify_dma_unmap(struct vfio_iommu * iommu,struct vfio_dma * dma)1306 static void vfio_notify_dma_unmap(struct vfio_iommu *iommu,
1307 				  struct vfio_dma *dma)
1308 {
1309 	struct vfio_device *device;
1310 
1311 	if (list_empty(&iommu->device_list))
1312 		return;
1313 
1314 	/*
1315 	 * The device is expected to call vfio_unpin_pages() for any IOVA it has
1316 	 * pinned within the range. Since vfio_unpin_pages() will eventually
1317 	 * call back down to this code and try to obtain the iommu->lock we must
1318 	 * drop it.
1319 	 */
1320 	mutex_lock(&iommu->device_list_lock);
1321 	mutex_unlock(&iommu->lock);
1322 
1323 	list_for_each_entry(device, &iommu->device_list, iommu_entry)
1324 		device->ops->dma_unmap(device, dma->iova, dma->size);
1325 
1326 	mutex_unlock(&iommu->device_list_lock);
1327 	mutex_lock(&iommu->lock);
1328 }
1329 
vfio_dma_do_unmap(struct vfio_iommu * iommu,struct vfio_iommu_type1_dma_unmap * unmap,struct vfio_bitmap * bitmap)1330 static int vfio_dma_do_unmap(struct vfio_iommu *iommu,
1331 			     struct vfio_iommu_type1_dma_unmap *unmap,
1332 			     struct vfio_bitmap *bitmap)
1333 {
1334 	struct vfio_dma *dma, *dma_last = NULL;
1335 	size_t unmapped = 0, pgsize;
1336 	int ret = -EINVAL, retries = 0;
1337 	unsigned long pgshift;
1338 	dma_addr_t iova = unmap->iova;
1339 	u64 size = unmap->size;
1340 	bool unmap_all = unmap->flags & VFIO_DMA_UNMAP_FLAG_ALL;
1341 	bool invalidate_vaddr = unmap->flags & VFIO_DMA_UNMAP_FLAG_VADDR;
1342 	struct rb_node *n, *first_n;
1343 
1344 	mutex_lock(&iommu->lock);
1345 
1346 	pgshift = __ffs(iommu->pgsize_bitmap);
1347 	pgsize = (size_t)1 << pgshift;
1348 
1349 	if (iova & (pgsize - 1))
1350 		goto unlock;
1351 
1352 	if (unmap_all) {
1353 		if (iova || size)
1354 			goto unlock;
1355 		size = U64_MAX;
1356 	} else if (!size || size & (pgsize - 1) ||
1357 		   iova + size - 1 < iova || size > SIZE_MAX) {
1358 		goto unlock;
1359 	}
1360 
1361 	/* When dirty tracking is enabled, allow only min supported pgsize */
1362 	if ((unmap->flags & VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP) &&
1363 	    (!iommu->dirty_page_tracking || (bitmap->pgsize != pgsize))) {
1364 		goto unlock;
1365 	}
1366 
1367 	WARN_ON((pgsize - 1) & PAGE_MASK);
1368 again:
1369 	/*
1370 	 * vfio-iommu-type1 (v1) - User mappings were coalesced together to
1371 	 * avoid tracking individual mappings.  This means that the granularity
1372 	 * of the original mapping was lost and the user was allowed to attempt
1373 	 * to unmap any range.  Depending on the contiguousness of physical
1374 	 * memory and page sizes supported by the IOMMU, arbitrary unmaps may
1375 	 * or may not have worked.  We only guaranteed unmap granularity
1376 	 * matching the original mapping; even though it was untracked here,
1377 	 * the original mappings are reflected in IOMMU mappings.  This
1378 	 * resulted in a couple unusual behaviors.  First, if a range is not
1379 	 * able to be unmapped, ex. a set of 4k pages that was mapped as a
1380 	 * 2M hugepage into the IOMMU, the unmap ioctl returns success but with
1381 	 * a zero sized unmap.  Also, if an unmap request overlaps the first
1382 	 * address of a hugepage, the IOMMU will unmap the entire hugepage.
1383 	 * This also returns success and the returned unmap size reflects the
1384 	 * actual size unmapped.
1385 	 *
1386 	 * We attempt to maintain compatibility with this "v1" interface, but
1387 	 * we take control out of the hands of the IOMMU.  Therefore, an unmap
1388 	 * request offset from the beginning of the original mapping will
1389 	 * return success with zero sized unmap.  And an unmap request covering
1390 	 * the first iova of mapping will unmap the entire range.
1391 	 *
1392 	 * The v2 version of this interface intends to be more deterministic.
1393 	 * Unmap requests must fully cover previous mappings.  Multiple
1394 	 * mappings may still be unmaped by specifying large ranges, but there
1395 	 * must not be any previous mappings bisected by the range.  An error
1396 	 * will be returned if these conditions are not met.  The v2 interface
1397 	 * will only return success and a size of zero if there were no
1398 	 * mappings within the range.
1399 	 */
1400 	if (iommu->v2 && !unmap_all) {
1401 		dma = vfio_find_dma(iommu, iova, 1);
1402 		if (dma && dma->iova != iova)
1403 			goto unlock;
1404 
1405 		dma = vfio_find_dma(iommu, iova + size - 1, 0);
1406 		if (dma && dma->iova + dma->size != iova + size)
1407 			goto unlock;
1408 	}
1409 
1410 	ret = 0;
1411 	n = first_n = vfio_find_dma_first_node(iommu, iova, size);
1412 
1413 	while (n) {
1414 		dma = rb_entry(n, struct vfio_dma, node);
1415 		if (dma->iova >= iova + size)
1416 			break;
1417 
1418 		if (!iommu->v2 && iova > dma->iova)
1419 			break;
1420 
1421 		if (invalidate_vaddr) {
1422 			if (dma->vaddr_invalid) {
1423 				struct rb_node *last_n = n;
1424 
1425 				for (n = first_n; n != last_n; n = rb_next(n)) {
1426 					dma = rb_entry(n,
1427 						       struct vfio_dma, node);
1428 					dma->vaddr_invalid = false;
1429 					iommu->vaddr_invalid_count--;
1430 				}
1431 				ret = -EINVAL;
1432 				unmapped = 0;
1433 				break;
1434 			}
1435 			dma->vaddr_invalid = true;
1436 			iommu->vaddr_invalid_count++;
1437 			unmapped += dma->size;
1438 			n = rb_next(n);
1439 			continue;
1440 		}
1441 
1442 		if (!RB_EMPTY_ROOT(&dma->pfn_list)) {
1443 			if (dma_last == dma) {
1444 				BUG_ON(++retries > 10);
1445 			} else {
1446 				dma_last = dma;
1447 				retries = 0;
1448 			}
1449 
1450 			vfio_notify_dma_unmap(iommu, dma);
1451 			goto again;
1452 		}
1453 
1454 		if (unmap->flags & VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP) {
1455 			ret = update_user_bitmap(bitmap->data, iommu, dma,
1456 						 iova, pgsize);
1457 			if (ret)
1458 				break;
1459 		}
1460 
1461 		unmapped += dma->size;
1462 		n = rb_next(n);
1463 		vfio_remove_dma(iommu, dma);
1464 	}
1465 
1466 unlock:
1467 	mutex_unlock(&iommu->lock);
1468 
1469 	/* Report how much was unmapped */
1470 	unmap->size = unmapped;
1471 
1472 	return ret;
1473 }
1474 
vfio_iommu_map(struct vfio_iommu * iommu,dma_addr_t iova,unsigned long pfn,long npage,int prot)1475 static int vfio_iommu_map(struct vfio_iommu *iommu, dma_addr_t iova,
1476 			  unsigned long pfn, long npage, int prot)
1477 {
1478 	struct vfio_domain *d;
1479 	int ret;
1480 
1481 	list_for_each_entry(d, &iommu->domain_list, next) {
1482 		ret = iommu_map(d->domain, iova, (phys_addr_t)pfn << PAGE_SHIFT,
1483 				npage << PAGE_SHIFT, prot | IOMMU_CACHE);
1484 		if (ret)
1485 			goto unwind;
1486 
1487 		cond_resched();
1488 	}
1489 
1490 	return 0;
1491 
1492 unwind:
1493 	list_for_each_entry_continue_reverse(d, &iommu->domain_list, next) {
1494 		iommu_unmap(d->domain, iova, npage << PAGE_SHIFT);
1495 		cond_resched();
1496 	}
1497 
1498 	return ret;
1499 }
1500 
vfio_pin_map_dma(struct vfio_iommu * iommu,struct vfio_dma * dma,size_t map_size)1501 static int vfio_pin_map_dma(struct vfio_iommu *iommu, struct vfio_dma *dma,
1502 			    size_t map_size)
1503 {
1504 	dma_addr_t iova = dma->iova;
1505 	unsigned long vaddr = dma->vaddr;
1506 	struct vfio_batch batch;
1507 	size_t size = map_size;
1508 	long npage;
1509 	unsigned long pfn, limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
1510 	int ret = 0;
1511 
1512 	vfio_batch_init(&batch);
1513 
1514 	while (size) {
1515 		/* Pin a contiguous chunk of memory */
1516 		npage = vfio_pin_pages_remote(dma, vaddr + dma->size,
1517 					      size >> PAGE_SHIFT, &pfn, limit,
1518 					      &batch);
1519 		if (npage <= 0) {
1520 			WARN_ON(!npage);
1521 			ret = (int)npage;
1522 			break;
1523 		}
1524 
1525 		/* Map it! */
1526 		ret = vfio_iommu_map(iommu, iova + dma->size, pfn, npage,
1527 				     dma->prot);
1528 		if (ret) {
1529 			vfio_unpin_pages_remote(dma, iova + dma->size, pfn,
1530 						npage, true);
1531 			vfio_batch_unpin(&batch, dma);
1532 			break;
1533 		}
1534 
1535 		size -= npage << PAGE_SHIFT;
1536 		dma->size += npage << PAGE_SHIFT;
1537 	}
1538 
1539 	vfio_batch_fini(&batch);
1540 	dma->iommu_mapped = true;
1541 
1542 	if (ret)
1543 		vfio_remove_dma(iommu, dma);
1544 
1545 	return ret;
1546 }
1547 
1548 /*
1549  * Check dma map request is within a valid iova range
1550  */
vfio_iommu_iova_dma_valid(struct vfio_iommu * iommu,dma_addr_t start,dma_addr_t end)1551 static bool vfio_iommu_iova_dma_valid(struct vfio_iommu *iommu,
1552 				      dma_addr_t start, dma_addr_t end)
1553 {
1554 	struct list_head *iova = &iommu->iova_list;
1555 	struct vfio_iova *node;
1556 
1557 	list_for_each_entry(node, iova, list) {
1558 		if (start >= node->start && end <= node->end)
1559 			return true;
1560 	}
1561 
1562 	/*
1563 	 * Check for list_empty() as well since a container with
1564 	 * a single mdev device will have an empty list.
1565 	 */
1566 	return list_empty(iova);
1567 }
1568 
vfio_dma_do_map(struct vfio_iommu * iommu,struct vfio_iommu_type1_dma_map * map)1569 static int vfio_dma_do_map(struct vfio_iommu *iommu,
1570 			   struct vfio_iommu_type1_dma_map *map)
1571 {
1572 	bool set_vaddr = map->flags & VFIO_DMA_MAP_FLAG_VADDR;
1573 	dma_addr_t iova = map->iova;
1574 	unsigned long vaddr = map->vaddr;
1575 	size_t size = map->size;
1576 	int ret = 0, prot = 0;
1577 	size_t pgsize;
1578 	struct vfio_dma *dma;
1579 
1580 	/* Verify that none of our __u64 fields overflow */
1581 	if (map->size != size || map->vaddr != vaddr || map->iova != iova)
1582 		return -EINVAL;
1583 
1584 	/* READ/WRITE from device perspective */
1585 	if (map->flags & VFIO_DMA_MAP_FLAG_WRITE)
1586 		prot |= IOMMU_WRITE;
1587 	if (map->flags & VFIO_DMA_MAP_FLAG_READ)
1588 		prot |= IOMMU_READ;
1589 
1590 	if ((prot && set_vaddr) || (!prot && !set_vaddr))
1591 		return -EINVAL;
1592 
1593 	mutex_lock(&iommu->lock);
1594 
1595 	pgsize = (size_t)1 << __ffs(iommu->pgsize_bitmap);
1596 
1597 	WARN_ON((pgsize - 1) & PAGE_MASK);
1598 
1599 	if (!size || (size | iova | vaddr) & (pgsize - 1)) {
1600 		ret = -EINVAL;
1601 		goto out_unlock;
1602 	}
1603 
1604 	/* Don't allow IOVA or virtual address wrap */
1605 	if (iova + size - 1 < iova || vaddr + size - 1 < vaddr) {
1606 		ret = -EINVAL;
1607 		goto out_unlock;
1608 	}
1609 
1610 	dma = vfio_find_dma(iommu, iova, size);
1611 	if (set_vaddr) {
1612 		if (!dma) {
1613 			ret = -ENOENT;
1614 		} else if (!dma->vaddr_invalid || dma->iova != iova ||
1615 			   dma->size != size) {
1616 			ret = -EINVAL;
1617 		} else {
1618 			dma->vaddr = vaddr;
1619 			dma->vaddr_invalid = false;
1620 			iommu->vaddr_invalid_count--;
1621 			wake_up_all(&iommu->vaddr_wait);
1622 		}
1623 		goto out_unlock;
1624 	} else if (dma) {
1625 		ret = -EEXIST;
1626 		goto out_unlock;
1627 	}
1628 
1629 	if (!iommu->dma_avail) {
1630 		ret = -ENOSPC;
1631 		goto out_unlock;
1632 	}
1633 
1634 	if (!vfio_iommu_iova_dma_valid(iommu, iova, iova + size - 1)) {
1635 		ret = -EINVAL;
1636 		goto out_unlock;
1637 	}
1638 
1639 	dma = kzalloc(sizeof(*dma), GFP_KERNEL);
1640 	if (!dma) {
1641 		ret = -ENOMEM;
1642 		goto out_unlock;
1643 	}
1644 
1645 	iommu->dma_avail--;
1646 	dma->iova = iova;
1647 	dma->vaddr = vaddr;
1648 	dma->prot = prot;
1649 
1650 	/*
1651 	 * We need to be able to both add to a task's locked memory and test
1652 	 * against the locked memory limit and we need to be able to do both
1653 	 * outside of this call path as pinning can be asynchronous via the
1654 	 * external interfaces for mdev devices.  RLIMIT_MEMLOCK requires a
1655 	 * task_struct and VM locked pages requires an mm_struct, however
1656 	 * holding an indefinite mm reference is not recommended, therefore we
1657 	 * only hold a reference to a task.  We could hold a reference to
1658 	 * current, however QEMU uses this call path through vCPU threads,
1659 	 * which can be killed resulting in a NULL mm and failure in the unmap
1660 	 * path when called via a different thread.  Avoid this problem by
1661 	 * using the group_leader as threads within the same group require
1662 	 * both CLONE_THREAD and CLONE_VM and will therefore use the same
1663 	 * mm_struct.
1664 	 *
1665 	 * Previously we also used the task for testing CAP_IPC_LOCK at the
1666 	 * time of pinning and accounting, however has_capability() makes use
1667 	 * of real_cred, a copy-on-write field, so we can't guarantee that it
1668 	 * matches group_leader, or in fact that it might not change by the
1669 	 * time it's evaluated.  If a process were to call MAP_DMA with
1670 	 * CAP_IPC_LOCK but later drop it, it doesn't make sense that they
1671 	 * possibly see different results for an iommu_mapped vfio_dma vs
1672 	 * externally mapped.  Therefore track CAP_IPC_LOCK in vfio_dma at the
1673 	 * time of calling MAP_DMA.
1674 	 */
1675 	get_task_struct(current->group_leader);
1676 	dma->task = current->group_leader;
1677 	dma->lock_cap = capable(CAP_IPC_LOCK);
1678 
1679 	dma->pfn_list = RB_ROOT;
1680 
1681 	/* Insert zero-sized and grow as we map chunks of it */
1682 	vfio_link_dma(iommu, dma);
1683 
1684 	/* Don't pin and map if container doesn't contain IOMMU capable domain*/
1685 	if (list_empty(&iommu->domain_list))
1686 		dma->size = size;
1687 	else
1688 		ret = vfio_pin_map_dma(iommu, dma, size);
1689 
1690 	if (!ret && iommu->dirty_page_tracking) {
1691 		ret = vfio_dma_bitmap_alloc(dma, pgsize);
1692 		if (ret)
1693 			vfio_remove_dma(iommu, dma);
1694 	}
1695 
1696 out_unlock:
1697 	mutex_unlock(&iommu->lock);
1698 	return ret;
1699 }
1700 
vfio_iommu_replay(struct vfio_iommu * iommu,struct vfio_domain * domain)1701 static int vfio_iommu_replay(struct vfio_iommu *iommu,
1702 			     struct vfio_domain *domain)
1703 {
1704 	struct vfio_batch batch;
1705 	struct vfio_domain *d = NULL;
1706 	struct rb_node *n;
1707 	unsigned long limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
1708 	int ret;
1709 
1710 	ret = vfio_wait_all_valid(iommu);
1711 	if (ret < 0)
1712 		return ret;
1713 
1714 	/* Arbitrarily pick the first domain in the list for lookups */
1715 	if (!list_empty(&iommu->domain_list))
1716 		d = list_first_entry(&iommu->domain_list,
1717 				     struct vfio_domain, next);
1718 
1719 	vfio_batch_init(&batch);
1720 
1721 	n = rb_first(&iommu->dma_list);
1722 
1723 	for (; n; n = rb_next(n)) {
1724 		struct vfio_dma *dma;
1725 		dma_addr_t iova;
1726 
1727 		dma = rb_entry(n, struct vfio_dma, node);
1728 		iova = dma->iova;
1729 
1730 		while (iova < dma->iova + dma->size) {
1731 			phys_addr_t phys;
1732 			size_t size;
1733 
1734 			if (dma->iommu_mapped) {
1735 				phys_addr_t p;
1736 				dma_addr_t i;
1737 
1738 				if (WARN_ON(!d)) { /* mapped w/o a domain?! */
1739 					ret = -EINVAL;
1740 					goto unwind;
1741 				}
1742 
1743 				phys = iommu_iova_to_phys(d->domain, iova);
1744 
1745 				if (WARN_ON(!phys)) {
1746 					iova += PAGE_SIZE;
1747 					continue;
1748 				}
1749 
1750 				size = PAGE_SIZE;
1751 				p = phys + size;
1752 				i = iova + size;
1753 				while (i < dma->iova + dma->size &&
1754 				       p == iommu_iova_to_phys(d->domain, i)) {
1755 					size += PAGE_SIZE;
1756 					p += PAGE_SIZE;
1757 					i += PAGE_SIZE;
1758 				}
1759 			} else {
1760 				unsigned long pfn;
1761 				unsigned long vaddr = dma->vaddr +
1762 						     (iova - dma->iova);
1763 				size_t n = dma->iova + dma->size - iova;
1764 				long npage;
1765 
1766 				npage = vfio_pin_pages_remote(dma, vaddr,
1767 							      n >> PAGE_SHIFT,
1768 							      &pfn, limit,
1769 							      &batch);
1770 				if (npage <= 0) {
1771 					WARN_ON(!npage);
1772 					ret = (int)npage;
1773 					goto unwind;
1774 				}
1775 
1776 				phys = pfn << PAGE_SHIFT;
1777 				size = npage << PAGE_SHIFT;
1778 			}
1779 
1780 			ret = iommu_map(domain->domain, iova, phys,
1781 					size, dma->prot | IOMMU_CACHE);
1782 			if (ret) {
1783 				if (!dma->iommu_mapped) {
1784 					vfio_unpin_pages_remote(dma, iova,
1785 							phys >> PAGE_SHIFT,
1786 							size >> PAGE_SHIFT,
1787 							true);
1788 					vfio_batch_unpin(&batch, dma);
1789 				}
1790 				goto unwind;
1791 			}
1792 
1793 			iova += size;
1794 		}
1795 	}
1796 
1797 	/* All dmas are now mapped, defer to second tree walk for unwind */
1798 	for (n = rb_first(&iommu->dma_list); n; n = rb_next(n)) {
1799 		struct vfio_dma *dma = rb_entry(n, struct vfio_dma, node);
1800 
1801 		dma->iommu_mapped = true;
1802 	}
1803 
1804 	vfio_batch_fini(&batch);
1805 	return 0;
1806 
1807 unwind:
1808 	for (; n; n = rb_prev(n)) {
1809 		struct vfio_dma *dma = rb_entry(n, struct vfio_dma, node);
1810 		dma_addr_t iova;
1811 
1812 		if (dma->iommu_mapped) {
1813 			iommu_unmap(domain->domain, dma->iova, dma->size);
1814 			continue;
1815 		}
1816 
1817 		iova = dma->iova;
1818 		while (iova < dma->iova + dma->size) {
1819 			phys_addr_t phys, p;
1820 			size_t size;
1821 			dma_addr_t i;
1822 
1823 			phys = iommu_iova_to_phys(domain->domain, iova);
1824 			if (!phys) {
1825 				iova += PAGE_SIZE;
1826 				continue;
1827 			}
1828 
1829 			size = PAGE_SIZE;
1830 			p = phys + size;
1831 			i = iova + size;
1832 			while (i < dma->iova + dma->size &&
1833 			       p == iommu_iova_to_phys(domain->domain, i)) {
1834 				size += PAGE_SIZE;
1835 				p += PAGE_SIZE;
1836 				i += PAGE_SIZE;
1837 			}
1838 
1839 			iommu_unmap(domain->domain, iova, size);
1840 			vfio_unpin_pages_remote(dma, iova, phys >> PAGE_SHIFT,
1841 						size >> PAGE_SHIFT, true);
1842 		}
1843 	}
1844 
1845 	vfio_batch_fini(&batch);
1846 	return ret;
1847 }
1848 
1849 /*
1850  * We change our unmap behavior slightly depending on whether the IOMMU
1851  * supports fine-grained superpages.  IOMMUs like AMD-Vi will use a superpage
1852  * for practically any contiguous power-of-two mapping we give it.  This means
1853  * we don't need to look for contiguous chunks ourselves to make unmapping
1854  * more efficient.  On IOMMUs with coarse-grained super pages, like Intel VT-d
1855  * with discrete 2M/1G/512G/1T superpages, identifying contiguous chunks
1856  * significantly boosts non-hugetlbfs mappings and doesn't seem to hurt when
1857  * hugetlbfs is in use.
1858  */
vfio_test_domain_fgsp(struct vfio_domain * domain)1859 static void vfio_test_domain_fgsp(struct vfio_domain *domain)
1860 {
1861 	struct page *pages;
1862 	int ret, order = get_order(PAGE_SIZE * 2);
1863 
1864 	pages = alloc_pages(GFP_KERNEL | __GFP_ZERO, order);
1865 	if (!pages)
1866 		return;
1867 
1868 	ret = iommu_map(domain->domain, 0, page_to_phys(pages), PAGE_SIZE * 2,
1869 			IOMMU_READ | IOMMU_WRITE | IOMMU_CACHE);
1870 	if (!ret) {
1871 		size_t unmapped = iommu_unmap(domain->domain, 0, PAGE_SIZE);
1872 
1873 		if (unmapped == PAGE_SIZE)
1874 			iommu_unmap(domain->domain, PAGE_SIZE, PAGE_SIZE);
1875 		else
1876 			domain->fgsp = true;
1877 	}
1878 
1879 	__free_pages(pages, order);
1880 }
1881 
find_iommu_group(struct vfio_domain * domain,struct iommu_group * iommu_group)1882 static struct vfio_iommu_group *find_iommu_group(struct vfio_domain *domain,
1883 						 struct iommu_group *iommu_group)
1884 {
1885 	struct vfio_iommu_group *g;
1886 
1887 	list_for_each_entry(g, &domain->group_list, next) {
1888 		if (g->iommu_group == iommu_group)
1889 			return g;
1890 	}
1891 
1892 	return NULL;
1893 }
1894 
1895 static struct vfio_iommu_group*
vfio_iommu_find_iommu_group(struct vfio_iommu * iommu,struct iommu_group * iommu_group)1896 vfio_iommu_find_iommu_group(struct vfio_iommu *iommu,
1897 			    struct iommu_group *iommu_group)
1898 {
1899 	struct vfio_iommu_group *group;
1900 	struct vfio_domain *domain;
1901 
1902 	list_for_each_entry(domain, &iommu->domain_list, next) {
1903 		group = find_iommu_group(domain, iommu_group);
1904 		if (group)
1905 			return group;
1906 	}
1907 
1908 	list_for_each_entry(group, &iommu->emulated_iommu_groups, next)
1909 		if (group->iommu_group == iommu_group)
1910 			return group;
1911 	return NULL;
1912 }
1913 
vfio_iommu_has_sw_msi(struct list_head * group_resv_regions,phys_addr_t * base)1914 static bool vfio_iommu_has_sw_msi(struct list_head *group_resv_regions,
1915 				  phys_addr_t *base)
1916 {
1917 	struct iommu_resv_region *region;
1918 	bool ret = false;
1919 
1920 	list_for_each_entry(region, group_resv_regions, list) {
1921 		/*
1922 		 * The presence of any 'real' MSI regions should take
1923 		 * precedence over the software-managed one if the
1924 		 * IOMMU driver happens to advertise both types.
1925 		 */
1926 		if (region->type == IOMMU_RESV_MSI) {
1927 			ret = false;
1928 			break;
1929 		}
1930 
1931 		if (region->type == IOMMU_RESV_SW_MSI) {
1932 			*base = region->start;
1933 			ret = true;
1934 		}
1935 	}
1936 
1937 	return ret;
1938 }
1939 
1940 /*
1941  * This is a helper function to insert an address range to iova list.
1942  * The list is initially created with a single entry corresponding to
1943  * the IOMMU domain geometry to which the device group is attached.
1944  * The list aperture gets modified when a new domain is added to the
1945  * container if the new aperture doesn't conflict with the current one
1946  * or with any existing dma mappings. The list is also modified to
1947  * exclude any reserved regions associated with the device group.
1948  */
vfio_iommu_iova_insert(struct list_head * head,dma_addr_t start,dma_addr_t end)1949 static int vfio_iommu_iova_insert(struct list_head *head,
1950 				  dma_addr_t start, dma_addr_t end)
1951 {
1952 	struct vfio_iova *region;
1953 
1954 	region = kmalloc(sizeof(*region), GFP_KERNEL);
1955 	if (!region)
1956 		return -ENOMEM;
1957 
1958 	INIT_LIST_HEAD(&region->list);
1959 	region->start = start;
1960 	region->end = end;
1961 
1962 	list_add_tail(&region->list, head);
1963 	return 0;
1964 }
1965 
1966 /*
1967  * Check the new iommu aperture conflicts with existing aper or with any
1968  * existing dma mappings.
1969  */
vfio_iommu_aper_conflict(struct vfio_iommu * iommu,dma_addr_t start,dma_addr_t end)1970 static bool vfio_iommu_aper_conflict(struct vfio_iommu *iommu,
1971 				     dma_addr_t start, dma_addr_t end)
1972 {
1973 	struct vfio_iova *first, *last;
1974 	struct list_head *iova = &iommu->iova_list;
1975 
1976 	if (list_empty(iova))
1977 		return false;
1978 
1979 	/* Disjoint sets, return conflict */
1980 	first = list_first_entry(iova, struct vfio_iova, list);
1981 	last = list_last_entry(iova, struct vfio_iova, list);
1982 	if (start > last->end || end < first->start)
1983 		return true;
1984 
1985 	/* Check for any existing dma mappings below the new start */
1986 	if (start > first->start) {
1987 		if (vfio_find_dma(iommu, first->start, start - first->start))
1988 			return true;
1989 	}
1990 
1991 	/* Check for any existing dma mappings beyond the new end */
1992 	if (end < last->end) {
1993 		if (vfio_find_dma(iommu, end + 1, last->end - end))
1994 			return true;
1995 	}
1996 
1997 	return false;
1998 }
1999 
2000 /*
2001  * Resize iommu iova aperture window. This is called only if the new
2002  * aperture has no conflict with existing aperture and dma mappings.
2003  */
vfio_iommu_aper_resize(struct list_head * iova,dma_addr_t start,dma_addr_t end)2004 static int vfio_iommu_aper_resize(struct list_head *iova,
2005 				  dma_addr_t start, dma_addr_t end)
2006 {
2007 	struct vfio_iova *node, *next;
2008 
2009 	if (list_empty(iova))
2010 		return vfio_iommu_iova_insert(iova, start, end);
2011 
2012 	/* Adjust iova list start */
2013 	list_for_each_entry_safe(node, next, iova, list) {
2014 		if (start < node->start)
2015 			break;
2016 		if (start >= node->start && start < node->end) {
2017 			node->start = start;
2018 			break;
2019 		}
2020 		/* Delete nodes before new start */
2021 		list_del(&node->list);
2022 		kfree(node);
2023 	}
2024 
2025 	/* Adjust iova list end */
2026 	list_for_each_entry_safe(node, next, iova, list) {
2027 		if (end > node->end)
2028 			continue;
2029 		if (end > node->start && end <= node->end) {
2030 			node->end = end;
2031 			continue;
2032 		}
2033 		/* Delete nodes after new end */
2034 		list_del(&node->list);
2035 		kfree(node);
2036 	}
2037 
2038 	return 0;
2039 }
2040 
2041 /*
2042  * Check reserved region conflicts with existing dma mappings
2043  */
vfio_iommu_resv_conflict(struct vfio_iommu * iommu,struct list_head * resv_regions)2044 static bool vfio_iommu_resv_conflict(struct vfio_iommu *iommu,
2045 				     struct list_head *resv_regions)
2046 {
2047 	struct iommu_resv_region *region;
2048 
2049 	/* Check for conflict with existing dma mappings */
2050 	list_for_each_entry(region, resv_regions, list) {
2051 		if (region->type == IOMMU_RESV_DIRECT_RELAXABLE)
2052 			continue;
2053 
2054 		if (vfio_find_dma(iommu, region->start, region->length))
2055 			return true;
2056 	}
2057 
2058 	return false;
2059 }
2060 
2061 /*
2062  * Check iova region overlap with  reserved regions and
2063  * exclude them from the iommu iova range
2064  */
vfio_iommu_resv_exclude(struct list_head * iova,struct list_head * resv_regions)2065 static int vfio_iommu_resv_exclude(struct list_head *iova,
2066 				   struct list_head *resv_regions)
2067 {
2068 	struct iommu_resv_region *resv;
2069 	struct vfio_iova *n, *next;
2070 
2071 	list_for_each_entry(resv, resv_regions, list) {
2072 		phys_addr_t start, end;
2073 
2074 		if (resv->type == IOMMU_RESV_DIRECT_RELAXABLE)
2075 			continue;
2076 
2077 		start = resv->start;
2078 		end = resv->start + resv->length - 1;
2079 
2080 		list_for_each_entry_safe(n, next, iova, list) {
2081 			int ret = 0;
2082 
2083 			/* No overlap */
2084 			if (start > n->end || end < n->start)
2085 				continue;
2086 			/*
2087 			 * Insert a new node if current node overlaps with the
2088 			 * reserve region to exclude that from valid iova range.
2089 			 * Note that, new node is inserted before the current
2090 			 * node and finally the current node is deleted keeping
2091 			 * the list updated and sorted.
2092 			 */
2093 			if (start > n->start)
2094 				ret = vfio_iommu_iova_insert(&n->list, n->start,
2095 							     start - 1);
2096 			if (!ret && end < n->end)
2097 				ret = vfio_iommu_iova_insert(&n->list, end + 1,
2098 							     n->end);
2099 			if (ret)
2100 				return ret;
2101 
2102 			list_del(&n->list);
2103 			kfree(n);
2104 		}
2105 	}
2106 
2107 	if (list_empty(iova))
2108 		return -EINVAL;
2109 
2110 	return 0;
2111 }
2112 
vfio_iommu_resv_free(struct list_head * resv_regions)2113 static void vfio_iommu_resv_free(struct list_head *resv_regions)
2114 {
2115 	struct iommu_resv_region *n, *next;
2116 
2117 	list_for_each_entry_safe(n, next, resv_regions, list) {
2118 		list_del(&n->list);
2119 		kfree(n);
2120 	}
2121 }
2122 
vfio_iommu_iova_free(struct list_head * iova)2123 static void vfio_iommu_iova_free(struct list_head *iova)
2124 {
2125 	struct vfio_iova *n, *next;
2126 
2127 	list_for_each_entry_safe(n, next, iova, list) {
2128 		list_del(&n->list);
2129 		kfree(n);
2130 	}
2131 }
2132 
vfio_iommu_iova_get_copy(struct vfio_iommu * iommu,struct list_head * iova_copy)2133 static int vfio_iommu_iova_get_copy(struct vfio_iommu *iommu,
2134 				    struct list_head *iova_copy)
2135 {
2136 	struct list_head *iova = &iommu->iova_list;
2137 	struct vfio_iova *n;
2138 	int ret;
2139 
2140 	list_for_each_entry(n, iova, list) {
2141 		ret = vfio_iommu_iova_insert(iova_copy, n->start, n->end);
2142 		if (ret)
2143 			goto out_free;
2144 	}
2145 
2146 	return 0;
2147 
2148 out_free:
2149 	vfio_iommu_iova_free(iova_copy);
2150 	return ret;
2151 }
2152 
vfio_iommu_iova_insert_copy(struct vfio_iommu * iommu,struct list_head * iova_copy)2153 static void vfio_iommu_iova_insert_copy(struct vfio_iommu *iommu,
2154 					struct list_head *iova_copy)
2155 {
2156 	struct list_head *iova = &iommu->iova_list;
2157 
2158 	vfio_iommu_iova_free(iova);
2159 
2160 	list_splice_tail(iova_copy, iova);
2161 }
2162 
2163 /* Redundantly walks non-present capabilities to simplify caller */
vfio_iommu_device_capable(struct device * dev,void * data)2164 static int vfio_iommu_device_capable(struct device *dev, void *data)
2165 {
2166 	return device_iommu_capable(dev, (enum iommu_cap)data);
2167 }
2168 
vfio_iommu_domain_alloc(struct device * dev,void * data)2169 static int vfio_iommu_domain_alloc(struct device *dev, void *data)
2170 {
2171 	struct iommu_domain **domain = data;
2172 
2173 	*domain = iommu_domain_alloc(dev->bus);
2174 	return 1; /* Don't iterate */
2175 }
2176 
vfio_iommu_type1_attach_group(void * iommu_data,struct iommu_group * iommu_group,enum vfio_group_type type)2177 static int vfio_iommu_type1_attach_group(void *iommu_data,
2178 		struct iommu_group *iommu_group, enum vfio_group_type type)
2179 {
2180 	struct vfio_iommu *iommu = iommu_data;
2181 	struct vfio_iommu_group *group;
2182 	struct vfio_domain *domain, *d;
2183 	bool resv_msi, msi_remap;
2184 	phys_addr_t resv_msi_base = 0;
2185 	struct iommu_domain_geometry *geo;
2186 	LIST_HEAD(iova_copy);
2187 	LIST_HEAD(group_resv_regions);
2188 	int ret = -EINVAL;
2189 
2190 	mutex_lock(&iommu->lock);
2191 
2192 	/* Check for duplicates */
2193 	if (vfio_iommu_find_iommu_group(iommu, iommu_group))
2194 		goto out_unlock;
2195 
2196 	ret = -ENOMEM;
2197 	group = kzalloc(sizeof(*group), GFP_KERNEL);
2198 	if (!group)
2199 		goto out_unlock;
2200 	group->iommu_group = iommu_group;
2201 
2202 	if (type == VFIO_EMULATED_IOMMU) {
2203 		list_add(&group->next, &iommu->emulated_iommu_groups);
2204 		/*
2205 		 * An emulated IOMMU group cannot dirty memory directly, it can
2206 		 * only use interfaces that provide dirty tracking.
2207 		 * The iommu scope can only be promoted with the addition of a
2208 		 * dirty tracking group.
2209 		 */
2210 		group->pinned_page_dirty_scope = true;
2211 		ret = 0;
2212 		goto out_unlock;
2213 	}
2214 
2215 	ret = -ENOMEM;
2216 	domain = kzalloc(sizeof(*domain), GFP_KERNEL);
2217 	if (!domain)
2218 		goto out_free_group;
2219 
2220 	/*
2221 	 * Going via the iommu_group iterator avoids races, and trivially gives
2222 	 * us a representative device for the IOMMU API call. We don't actually
2223 	 * want to iterate beyond the first device (if any).
2224 	 */
2225 	ret = -EIO;
2226 	iommu_group_for_each_dev(iommu_group, &domain->domain,
2227 				 vfio_iommu_domain_alloc);
2228 	if (!domain->domain)
2229 		goto out_free_domain;
2230 
2231 	if (iommu->nesting) {
2232 		ret = iommu_enable_nesting(domain->domain);
2233 		if (ret)
2234 			goto out_domain;
2235 	}
2236 
2237 	ret = iommu_attach_group(domain->domain, group->iommu_group);
2238 	if (ret)
2239 		goto out_domain;
2240 
2241 	/* Get aperture info */
2242 	geo = &domain->domain->geometry;
2243 	if (vfio_iommu_aper_conflict(iommu, geo->aperture_start,
2244 				     geo->aperture_end)) {
2245 		ret = -EINVAL;
2246 		goto out_detach;
2247 	}
2248 
2249 	ret = iommu_get_group_resv_regions(iommu_group, &group_resv_regions);
2250 	if (ret)
2251 		goto out_detach;
2252 
2253 	if (vfio_iommu_resv_conflict(iommu, &group_resv_regions)) {
2254 		ret = -EINVAL;
2255 		goto out_detach;
2256 	}
2257 
2258 	/*
2259 	 * We don't want to work on the original iova list as the list
2260 	 * gets modified and in case of failure we have to retain the
2261 	 * original list. Get a copy here.
2262 	 */
2263 	ret = vfio_iommu_iova_get_copy(iommu, &iova_copy);
2264 	if (ret)
2265 		goto out_detach;
2266 
2267 	ret = vfio_iommu_aper_resize(&iova_copy, geo->aperture_start,
2268 				     geo->aperture_end);
2269 	if (ret)
2270 		goto out_detach;
2271 
2272 	ret = vfio_iommu_resv_exclude(&iova_copy, &group_resv_regions);
2273 	if (ret)
2274 		goto out_detach;
2275 
2276 	resv_msi = vfio_iommu_has_sw_msi(&group_resv_regions, &resv_msi_base);
2277 
2278 	INIT_LIST_HEAD(&domain->group_list);
2279 	list_add(&group->next, &domain->group_list);
2280 
2281 	msi_remap = irq_domain_check_msi_remap() ||
2282 		    iommu_group_for_each_dev(iommu_group, (void *)IOMMU_CAP_INTR_REMAP,
2283 					     vfio_iommu_device_capable);
2284 
2285 	if (!allow_unsafe_interrupts && !msi_remap) {
2286 		pr_warn("%s: No interrupt remapping support.  Use the module param \"allow_unsafe_interrupts\" to enable VFIO IOMMU support on this platform\n",
2287 		       __func__);
2288 		ret = -EPERM;
2289 		goto out_detach;
2290 	}
2291 
2292 	/*
2293 	 * If the IOMMU can block non-coherent operations (ie PCIe TLPs with
2294 	 * no-snoop set) then VFIO always turns this feature on because on Intel
2295 	 * platforms it optimizes KVM to disable wbinvd emulation.
2296 	 */
2297 	if (domain->domain->ops->enforce_cache_coherency)
2298 		domain->enforce_cache_coherency =
2299 			domain->domain->ops->enforce_cache_coherency(
2300 				domain->domain);
2301 
2302 	/*
2303 	 * Try to match an existing compatible domain.  We don't want to
2304 	 * preclude an IOMMU driver supporting multiple bus_types and being
2305 	 * able to include different bus_types in the same IOMMU domain, so
2306 	 * we test whether the domains use the same iommu_ops rather than
2307 	 * testing if they're on the same bus_type.
2308 	 */
2309 	list_for_each_entry(d, &iommu->domain_list, next) {
2310 		if (d->domain->ops == domain->domain->ops &&
2311 		    d->enforce_cache_coherency ==
2312 			    domain->enforce_cache_coherency) {
2313 			iommu_detach_group(domain->domain, group->iommu_group);
2314 			if (!iommu_attach_group(d->domain,
2315 						group->iommu_group)) {
2316 				list_add(&group->next, &d->group_list);
2317 				iommu_domain_free(domain->domain);
2318 				kfree(domain);
2319 				goto done;
2320 			}
2321 
2322 			ret = iommu_attach_group(domain->domain,
2323 						 group->iommu_group);
2324 			if (ret)
2325 				goto out_domain;
2326 		}
2327 	}
2328 
2329 	vfio_test_domain_fgsp(domain);
2330 
2331 	/* replay mappings on new domains */
2332 	ret = vfio_iommu_replay(iommu, domain);
2333 	if (ret)
2334 		goto out_detach;
2335 
2336 	if (resv_msi) {
2337 		ret = iommu_get_msi_cookie(domain->domain, resv_msi_base);
2338 		if (ret && ret != -ENODEV)
2339 			goto out_detach;
2340 	}
2341 
2342 	list_add(&domain->next, &iommu->domain_list);
2343 	vfio_update_pgsize_bitmap(iommu);
2344 done:
2345 	/* Delete the old one and insert new iova list */
2346 	vfio_iommu_iova_insert_copy(iommu, &iova_copy);
2347 
2348 	/*
2349 	 * An iommu backed group can dirty memory directly and therefore
2350 	 * demotes the iommu scope until it declares itself dirty tracking
2351 	 * capable via the page pinning interface.
2352 	 */
2353 	iommu->num_non_pinned_groups++;
2354 	mutex_unlock(&iommu->lock);
2355 	vfio_iommu_resv_free(&group_resv_regions);
2356 
2357 	return 0;
2358 
2359 out_detach:
2360 	iommu_detach_group(domain->domain, group->iommu_group);
2361 out_domain:
2362 	iommu_domain_free(domain->domain);
2363 	vfio_iommu_iova_free(&iova_copy);
2364 	vfio_iommu_resv_free(&group_resv_regions);
2365 out_free_domain:
2366 	kfree(domain);
2367 out_free_group:
2368 	kfree(group);
2369 out_unlock:
2370 	mutex_unlock(&iommu->lock);
2371 	return ret;
2372 }
2373 
vfio_iommu_unmap_unpin_all(struct vfio_iommu * iommu)2374 static void vfio_iommu_unmap_unpin_all(struct vfio_iommu *iommu)
2375 {
2376 	struct rb_node *node;
2377 
2378 	while ((node = rb_first(&iommu->dma_list)))
2379 		vfio_remove_dma(iommu, rb_entry(node, struct vfio_dma, node));
2380 }
2381 
vfio_iommu_unmap_unpin_reaccount(struct vfio_iommu * iommu)2382 static void vfio_iommu_unmap_unpin_reaccount(struct vfio_iommu *iommu)
2383 {
2384 	struct rb_node *n, *p;
2385 
2386 	n = rb_first(&iommu->dma_list);
2387 	for (; n; n = rb_next(n)) {
2388 		struct vfio_dma *dma;
2389 		long locked = 0, unlocked = 0;
2390 
2391 		dma = rb_entry(n, struct vfio_dma, node);
2392 		unlocked += vfio_unmap_unpin(iommu, dma, false);
2393 		p = rb_first(&dma->pfn_list);
2394 		for (; p; p = rb_next(p)) {
2395 			struct vfio_pfn *vpfn = rb_entry(p, struct vfio_pfn,
2396 							 node);
2397 
2398 			if (!is_invalid_reserved_pfn(vpfn->pfn))
2399 				locked++;
2400 		}
2401 		vfio_lock_acct(dma, locked - unlocked, true);
2402 	}
2403 }
2404 
2405 /*
2406  * Called when a domain is removed in detach. It is possible that
2407  * the removed domain decided the iova aperture window. Modify the
2408  * iova aperture with the smallest window among existing domains.
2409  */
vfio_iommu_aper_expand(struct vfio_iommu * iommu,struct list_head * iova_copy)2410 static void vfio_iommu_aper_expand(struct vfio_iommu *iommu,
2411 				   struct list_head *iova_copy)
2412 {
2413 	struct vfio_domain *domain;
2414 	struct vfio_iova *node;
2415 	dma_addr_t start = 0;
2416 	dma_addr_t end = (dma_addr_t)~0;
2417 
2418 	if (list_empty(iova_copy))
2419 		return;
2420 
2421 	list_for_each_entry(domain, &iommu->domain_list, next) {
2422 		struct iommu_domain_geometry *geo = &domain->domain->geometry;
2423 
2424 		if (geo->aperture_start > start)
2425 			start = geo->aperture_start;
2426 		if (geo->aperture_end < end)
2427 			end = geo->aperture_end;
2428 	}
2429 
2430 	/* Modify aperture limits. The new aper is either same or bigger */
2431 	node = list_first_entry(iova_copy, struct vfio_iova, list);
2432 	node->start = start;
2433 	node = list_last_entry(iova_copy, struct vfio_iova, list);
2434 	node->end = end;
2435 }
2436 
2437 /*
2438  * Called when a group is detached. The reserved regions for that
2439  * group can be part of valid iova now. But since reserved regions
2440  * may be duplicated among groups, populate the iova valid regions
2441  * list again.
2442  */
vfio_iommu_resv_refresh(struct vfio_iommu * iommu,struct list_head * iova_copy)2443 static int vfio_iommu_resv_refresh(struct vfio_iommu *iommu,
2444 				   struct list_head *iova_copy)
2445 {
2446 	struct vfio_domain *d;
2447 	struct vfio_iommu_group *g;
2448 	struct vfio_iova *node;
2449 	dma_addr_t start, end;
2450 	LIST_HEAD(resv_regions);
2451 	int ret;
2452 
2453 	if (list_empty(iova_copy))
2454 		return -EINVAL;
2455 
2456 	list_for_each_entry(d, &iommu->domain_list, next) {
2457 		list_for_each_entry(g, &d->group_list, next) {
2458 			ret = iommu_get_group_resv_regions(g->iommu_group,
2459 							   &resv_regions);
2460 			if (ret)
2461 				goto done;
2462 		}
2463 	}
2464 
2465 	node = list_first_entry(iova_copy, struct vfio_iova, list);
2466 	start = node->start;
2467 	node = list_last_entry(iova_copy, struct vfio_iova, list);
2468 	end = node->end;
2469 
2470 	/* purge the iova list and create new one */
2471 	vfio_iommu_iova_free(iova_copy);
2472 
2473 	ret = vfio_iommu_aper_resize(iova_copy, start, end);
2474 	if (ret)
2475 		goto done;
2476 
2477 	/* Exclude current reserved regions from iova ranges */
2478 	ret = vfio_iommu_resv_exclude(iova_copy, &resv_regions);
2479 done:
2480 	vfio_iommu_resv_free(&resv_regions);
2481 	return ret;
2482 }
2483 
vfio_iommu_type1_detach_group(void * iommu_data,struct iommu_group * iommu_group)2484 static void vfio_iommu_type1_detach_group(void *iommu_data,
2485 					  struct iommu_group *iommu_group)
2486 {
2487 	struct vfio_iommu *iommu = iommu_data;
2488 	struct vfio_domain *domain;
2489 	struct vfio_iommu_group *group;
2490 	bool update_dirty_scope = false;
2491 	LIST_HEAD(iova_copy);
2492 
2493 	mutex_lock(&iommu->lock);
2494 	list_for_each_entry(group, &iommu->emulated_iommu_groups, next) {
2495 		if (group->iommu_group != iommu_group)
2496 			continue;
2497 		update_dirty_scope = !group->pinned_page_dirty_scope;
2498 		list_del(&group->next);
2499 		kfree(group);
2500 
2501 		if (list_empty(&iommu->emulated_iommu_groups) &&
2502 		    list_empty(&iommu->domain_list)) {
2503 			WARN_ON(!list_empty(&iommu->device_list));
2504 			vfio_iommu_unmap_unpin_all(iommu);
2505 		}
2506 		goto detach_group_done;
2507 	}
2508 
2509 	/*
2510 	 * Get a copy of iova list. This will be used to update
2511 	 * and to replace the current one later. Please note that
2512 	 * we will leave the original list as it is if update fails.
2513 	 */
2514 	vfio_iommu_iova_get_copy(iommu, &iova_copy);
2515 
2516 	list_for_each_entry(domain, &iommu->domain_list, next) {
2517 		group = find_iommu_group(domain, iommu_group);
2518 		if (!group)
2519 			continue;
2520 
2521 		iommu_detach_group(domain->domain, group->iommu_group);
2522 		update_dirty_scope = !group->pinned_page_dirty_scope;
2523 		list_del(&group->next);
2524 		kfree(group);
2525 		/*
2526 		 * Group ownership provides privilege, if the group list is
2527 		 * empty, the domain goes away. If it's the last domain with
2528 		 * iommu and external domain doesn't exist, then all the
2529 		 * mappings go away too. If it's the last domain with iommu and
2530 		 * external domain exist, update accounting
2531 		 */
2532 		if (list_empty(&domain->group_list)) {
2533 			if (list_is_singular(&iommu->domain_list)) {
2534 				if (list_empty(&iommu->emulated_iommu_groups)) {
2535 					WARN_ON(!list_empty(
2536 						&iommu->device_list));
2537 					vfio_iommu_unmap_unpin_all(iommu);
2538 				} else {
2539 					vfio_iommu_unmap_unpin_reaccount(iommu);
2540 				}
2541 			}
2542 			iommu_domain_free(domain->domain);
2543 			list_del(&domain->next);
2544 			kfree(domain);
2545 			vfio_iommu_aper_expand(iommu, &iova_copy);
2546 			vfio_update_pgsize_bitmap(iommu);
2547 		}
2548 		break;
2549 	}
2550 
2551 	if (!vfio_iommu_resv_refresh(iommu, &iova_copy))
2552 		vfio_iommu_iova_insert_copy(iommu, &iova_copy);
2553 	else
2554 		vfio_iommu_iova_free(&iova_copy);
2555 
2556 detach_group_done:
2557 	/*
2558 	 * Removal of a group without dirty tracking may allow the iommu scope
2559 	 * to be promoted.
2560 	 */
2561 	if (update_dirty_scope) {
2562 		iommu->num_non_pinned_groups--;
2563 		if (iommu->dirty_page_tracking)
2564 			vfio_iommu_populate_bitmap_full(iommu);
2565 	}
2566 	mutex_unlock(&iommu->lock);
2567 }
2568 
vfio_iommu_type1_open(unsigned long arg)2569 static void *vfio_iommu_type1_open(unsigned long arg)
2570 {
2571 	struct vfio_iommu *iommu;
2572 
2573 	iommu = kzalloc(sizeof(*iommu), GFP_KERNEL);
2574 	if (!iommu)
2575 		return ERR_PTR(-ENOMEM);
2576 
2577 	switch (arg) {
2578 	case VFIO_TYPE1_IOMMU:
2579 		break;
2580 	case VFIO_TYPE1_NESTING_IOMMU:
2581 		iommu->nesting = true;
2582 		fallthrough;
2583 	case VFIO_TYPE1v2_IOMMU:
2584 		iommu->v2 = true;
2585 		break;
2586 	default:
2587 		kfree(iommu);
2588 		return ERR_PTR(-EINVAL);
2589 	}
2590 
2591 	INIT_LIST_HEAD(&iommu->domain_list);
2592 	INIT_LIST_HEAD(&iommu->iova_list);
2593 	iommu->dma_list = RB_ROOT;
2594 	iommu->dma_avail = dma_entry_limit;
2595 	iommu->container_open = true;
2596 	mutex_init(&iommu->lock);
2597 	mutex_init(&iommu->device_list_lock);
2598 	INIT_LIST_HEAD(&iommu->device_list);
2599 	init_waitqueue_head(&iommu->vaddr_wait);
2600 	iommu->pgsize_bitmap = PAGE_MASK;
2601 	INIT_LIST_HEAD(&iommu->emulated_iommu_groups);
2602 
2603 	return iommu;
2604 }
2605 
vfio_release_domain(struct vfio_domain * domain)2606 static void vfio_release_domain(struct vfio_domain *domain)
2607 {
2608 	struct vfio_iommu_group *group, *group_tmp;
2609 
2610 	list_for_each_entry_safe(group, group_tmp,
2611 				 &domain->group_list, next) {
2612 		iommu_detach_group(domain->domain, group->iommu_group);
2613 		list_del(&group->next);
2614 		kfree(group);
2615 	}
2616 
2617 	iommu_domain_free(domain->domain);
2618 }
2619 
vfio_iommu_type1_release(void * iommu_data)2620 static void vfio_iommu_type1_release(void *iommu_data)
2621 {
2622 	struct vfio_iommu *iommu = iommu_data;
2623 	struct vfio_domain *domain, *domain_tmp;
2624 	struct vfio_iommu_group *group, *next_group;
2625 
2626 	list_for_each_entry_safe(group, next_group,
2627 			&iommu->emulated_iommu_groups, next) {
2628 		list_del(&group->next);
2629 		kfree(group);
2630 	}
2631 
2632 	vfio_iommu_unmap_unpin_all(iommu);
2633 
2634 	list_for_each_entry_safe(domain, domain_tmp,
2635 				 &iommu->domain_list, next) {
2636 		vfio_release_domain(domain);
2637 		list_del(&domain->next);
2638 		kfree(domain);
2639 	}
2640 
2641 	vfio_iommu_iova_free(&iommu->iova_list);
2642 
2643 	kfree(iommu);
2644 }
2645 
vfio_domains_have_enforce_cache_coherency(struct vfio_iommu * iommu)2646 static int vfio_domains_have_enforce_cache_coherency(struct vfio_iommu *iommu)
2647 {
2648 	struct vfio_domain *domain;
2649 	int ret = 1;
2650 
2651 	mutex_lock(&iommu->lock);
2652 	list_for_each_entry(domain, &iommu->domain_list, next) {
2653 		if (!(domain->enforce_cache_coherency)) {
2654 			ret = 0;
2655 			break;
2656 		}
2657 	}
2658 	mutex_unlock(&iommu->lock);
2659 
2660 	return ret;
2661 }
2662 
vfio_iommu_type1_check_extension(struct vfio_iommu * iommu,unsigned long arg)2663 static int vfio_iommu_type1_check_extension(struct vfio_iommu *iommu,
2664 					    unsigned long arg)
2665 {
2666 	switch (arg) {
2667 	case VFIO_TYPE1_IOMMU:
2668 	case VFIO_TYPE1v2_IOMMU:
2669 	case VFIO_TYPE1_NESTING_IOMMU:
2670 	case VFIO_UNMAP_ALL:
2671 	case VFIO_UPDATE_VADDR:
2672 		return 1;
2673 	case VFIO_DMA_CC_IOMMU:
2674 		if (!iommu)
2675 			return 0;
2676 		return vfio_domains_have_enforce_cache_coherency(iommu);
2677 	default:
2678 		return 0;
2679 	}
2680 }
2681 
vfio_iommu_iova_add_cap(struct vfio_info_cap * caps,struct vfio_iommu_type1_info_cap_iova_range * cap_iovas,size_t size)2682 static int vfio_iommu_iova_add_cap(struct vfio_info_cap *caps,
2683 		 struct vfio_iommu_type1_info_cap_iova_range *cap_iovas,
2684 		 size_t size)
2685 {
2686 	struct vfio_info_cap_header *header;
2687 	struct vfio_iommu_type1_info_cap_iova_range *iova_cap;
2688 
2689 	header = vfio_info_cap_add(caps, size,
2690 				   VFIO_IOMMU_TYPE1_INFO_CAP_IOVA_RANGE, 1);
2691 	if (IS_ERR(header))
2692 		return PTR_ERR(header);
2693 
2694 	iova_cap = container_of(header,
2695 				struct vfio_iommu_type1_info_cap_iova_range,
2696 				header);
2697 	iova_cap->nr_iovas = cap_iovas->nr_iovas;
2698 	memcpy(iova_cap->iova_ranges, cap_iovas->iova_ranges,
2699 	       cap_iovas->nr_iovas * sizeof(*cap_iovas->iova_ranges));
2700 	return 0;
2701 }
2702 
vfio_iommu_iova_build_caps(struct vfio_iommu * iommu,struct vfio_info_cap * caps)2703 static int vfio_iommu_iova_build_caps(struct vfio_iommu *iommu,
2704 				      struct vfio_info_cap *caps)
2705 {
2706 	struct vfio_iommu_type1_info_cap_iova_range *cap_iovas;
2707 	struct vfio_iova *iova;
2708 	size_t size;
2709 	int iovas = 0, i = 0, ret;
2710 
2711 	list_for_each_entry(iova, &iommu->iova_list, list)
2712 		iovas++;
2713 
2714 	if (!iovas) {
2715 		/*
2716 		 * Return 0 as a container with a single mdev device
2717 		 * will have an empty list
2718 		 */
2719 		return 0;
2720 	}
2721 
2722 	size = struct_size(cap_iovas, iova_ranges, iovas);
2723 
2724 	cap_iovas = kzalloc(size, GFP_KERNEL);
2725 	if (!cap_iovas)
2726 		return -ENOMEM;
2727 
2728 	cap_iovas->nr_iovas = iovas;
2729 
2730 	list_for_each_entry(iova, &iommu->iova_list, list) {
2731 		cap_iovas->iova_ranges[i].start = iova->start;
2732 		cap_iovas->iova_ranges[i].end = iova->end;
2733 		i++;
2734 	}
2735 
2736 	ret = vfio_iommu_iova_add_cap(caps, cap_iovas, size);
2737 
2738 	kfree(cap_iovas);
2739 	return ret;
2740 }
2741 
vfio_iommu_migration_build_caps(struct vfio_iommu * iommu,struct vfio_info_cap * caps)2742 static int vfio_iommu_migration_build_caps(struct vfio_iommu *iommu,
2743 					   struct vfio_info_cap *caps)
2744 {
2745 	struct vfio_iommu_type1_info_cap_migration cap_mig;
2746 
2747 	cap_mig.header.id = VFIO_IOMMU_TYPE1_INFO_CAP_MIGRATION;
2748 	cap_mig.header.version = 1;
2749 
2750 	cap_mig.flags = 0;
2751 	/* support minimum pgsize */
2752 	cap_mig.pgsize_bitmap = (size_t)1 << __ffs(iommu->pgsize_bitmap);
2753 	cap_mig.max_dirty_bitmap_size = DIRTY_BITMAP_SIZE_MAX;
2754 
2755 	return vfio_info_add_capability(caps, &cap_mig.header, sizeof(cap_mig));
2756 }
2757 
vfio_iommu_dma_avail_build_caps(struct vfio_iommu * iommu,struct vfio_info_cap * caps)2758 static int vfio_iommu_dma_avail_build_caps(struct vfio_iommu *iommu,
2759 					   struct vfio_info_cap *caps)
2760 {
2761 	struct vfio_iommu_type1_info_dma_avail cap_dma_avail;
2762 
2763 	cap_dma_avail.header.id = VFIO_IOMMU_TYPE1_INFO_DMA_AVAIL;
2764 	cap_dma_avail.header.version = 1;
2765 
2766 	cap_dma_avail.avail = iommu->dma_avail;
2767 
2768 	return vfio_info_add_capability(caps, &cap_dma_avail.header,
2769 					sizeof(cap_dma_avail));
2770 }
2771 
vfio_iommu_type1_get_info(struct vfio_iommu * iommu,unsigned long arg)2772 static int vfio_iommu_type1_get_info(struct vfio_iommu *iommu,
2773 				     unsigned long arg)
2774 {
2775 	struct vfio_iommu_type1_info info;
2776 	unsigned long minsz;
2777 	struct vfio_info_cap caps = { .buf = NULL, .size = 0 };
2778 	unsigned long capsz;
2779 	int ret;
2780 
2781 	minsz = offsetofend(struct vfio_iommu_type1_info, iova_pgsizes);
2782 
2783 	/* For backward compatibility, cannot require this */
2784 	capsz = offsetofend(struct vfio_iommu_type1_info, cap_offset);
2785 
2786 	if (copy_from_user(&info, (void __user *)arg, minsz))
2787 		return -EFAULT;
2788 
2789 	if (info.argsz < minsz)
2790 		return -EINVAL;
2791 
2792 	if (info.argsz >= capsz) {
2793 		minsz = capsz;
2794 		info.cap_offset = 0; /* output, no-recopy necessary */
2795 	}
2796 
2797 	mutex_lock(&iommu->lock);
2798 	info.flags = VFIO_IOMMU_INFO_PGSIZES;
2799 
2800 	info.iova_pgsizes = iommu->pgsize_bitmap;
2801 
2802 	ret = vfio_iommu_migration_build_caps(iommu, &caps);
2803 
2804 	if (!ret)
2805 		ret = vfio_iommu_dma_avail_build_caps(iommu, &caps);
2806 
2807 	if (!ret)
2808 		ret = vfio_iommu_iova_build_caps(iommu, &caps);
2809 
2810 	mutex_unlock(&iommu->lock);
2811 
2812 	if (ret)
2813 		return ret;
2814 
2815 	if (caps.size) {
2816 		info.flags |= VFIO_IOMMU_INFO_CAPS;
2817 
2818 		if (info.argsz < sizeof(info) + caps.size) {
2819 			info.argsz = sizeof(info) + caps.size;
2820 		} else {
2821 			vfio_info_cap_shift(&caps, sizeof(info));
2822 			if (copy_to_user((void __user *)arg +
2823 					sizeof(info), caps.buf,
2824 					caps.size)) {
2825 				kfree(caps.buf);
2826 				return -EFAULT;
2827 			}
2828 			info.cap_offset = sizeof(info);
2829 		}
2830 
2831 		kfree(caps.buf);
2832 	}
2833 
2834 	return copy_to_user((void __user *)arg, &info, minsz) ?
2835 			-EFAULT : 0;
2836 }
2837 
vfio_iommu_type1_map_dma(struct vfio_iommu * iommu,unsigned long arg)2838 static int vfio_iommu_type1_map_dma(struct vfio_iommu *iommu,
2839 				    unsigned long arg)
2840 {
2841 	struct vfio_iommu_type1_dma_map map;
2842 	unsigned long minsz;
2843 	uint32_t mask = VFIO_DMA_MAP_FLAG_READ | VFIO_DMA_MAP_FLAG_WRITE |
2844 			VFIO_DMA_MAP_FLAG_VADDR;
2845 
2846 	minsz = offsetofend(struct vfio_iommu_type1_dma_map, size);
2847 
2848 	if (copy_from_user(&map, (void __user *)arg, minsz))
2849 		return -EFAULT;
2850 
2851 	if (map.argsz < minsz || map.flags & ~mask)
2852 		return -EINVAL;
2853 
2854 	return vfio_dma_do_map(iommu, &map);
2855 }
2856 
vfio_iommu_type1_unmap_dma(struct vfio_iommu * iommu,unsigned long arg)2857 static int vfio_iommu_type1_unmap_dma(struct vfio_iommu *iommu,
2858 				      unsigned long arg)
2859 {
2860 	struct vfio_iommu_type1_dma_unmap unmap;
2861 	struct vfio_bitmap bitmap = { 0 };
2862 	uint32_t mask = VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP |
2863 			VFIO_DMA_UNMAP_FLAG_VADDR |
2864 			VFIO_DMA_UNMAP_FLAG_ALL;
2865 	unsigned long minsz;
2866 	int ret;
2867 
2868 	minsz = offsetofend(struct vfio_iommu_type1_dma_unmap, size);
2869 
2870 	if (copy_from_user(&unmap, (void __user *)arg, minsz))
2871 		return -EFAULT;
2872 
2873 	if (unmap.argsz < minsz || unmap.flags & ~mask)
2874 		return -EINVAL;
2875 
2876 	if ((unmap.flags & VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP) &&
2877 	    (unmap.flags & (VFIO_DMA_UNMAP_FLAG_ALL |
2878 			    VFIO_DMA_UNMAP_FLAG_VADDR)))
2879 		return -EINVAL;
2880 
2881 	if (unmap.flags & VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP) {
2882 		unsigned long pgshift;
2883 
2884 		if (unmap.argsz < (minsz + sizeof(bitmap)))
2885 			return -EINVAL;
2886 
2887 		if (copy_from_user(&bitmap,
2888 				   (void __user *)(arg + minsz),
2889 				   sizeof(bitmap)))
2890 			return -EFAULT;
2891 
2892 		if (!access_ok((void __user *)bitmap.data, bitmap.size))
2893 			return -EINVAL;
2894 
2895 		pgshift = __ffs(bitmap.pgsize);
2896 		ret = verify_bitmap_size(unmap.size >> pgshift,
2897 					 bitmap.size);
2898 		if (ret)
2899 			return ret;
2900 	}
2901 
2902 	ret = vfio_dma_do_unmap(iommu, &unmap, &bitmap);
2903 	if (ret)
2904 		return ret;
2905 
2906 	return copy_to_user((void __user *)arg, &unmap, minsz) ?
2907 			-EFAULT : 0;
2908 }
2909 
vfio_iommu_type1_dirty_pages(struct vfio_iommu * iommu,unsigned long arg)2910 static int vfio_iommu_type1_dirty_pages(struct vfio_iommu *iommu,
2911 					unsigned long arg)
2912 {
2913 	struct vfio_iommu_type1_dirty_bitmap dirty;
2914 	uint32_t mask = VFIO_IOMMU_DIRTY_PAGES_FLAG_START |
2915 			VFIO_IOMMU_DIRTY_PAGES_FLAG_STOP |
2916 			VFIO_IOMMU_DIRTY_PAGES_FLAG_GET_BITMAP;
2917 	unsigned long minsz;
2918 	int ret = 0;
2919 
2920 	if (!iommu->v2)
2921 		return -EACCES;
2922 
2923 	minsz = offsetofend(struct vfio_iommu_type1_dirty_bitmap, flags);
2924 
2925 	if (copy_from_user(&dirty, (void __user *)arg, minsz))
2926 		return -EFAULT;
2927 
2928 	if (dirty.argsz < minsz || dirty.flags & ~mask)
2929 		return -EINVAL;
2930 
2931 	/* only one flag should be set at a time */
2932 	if (__ffs(dirty.flags) != __fls(dirty.flags))
2933 		return -EINVAL;
2934 
2935 	if (dirty.flags & VFIO_IOMMU_DIRTY_PAGES_FLAG_START) {
2936 		size_t pgsize;
2937 
2938 		mutex_lock(&iommu->lock);
2939 		pgsize = 1 << __ffs(iommu->pgsize_bitmap);
2940 		if (!iommu->dirty_page_tracking) {
2941 			ret = vfio_dma_bitmap_alloc_all(iommu, pgsize);
2942 			if (!ret)
2943 				iommu->dirty_page_tracking = true;
2944 		}
2945 		mutex_unlock(&iommu->lock);
2946 		return ret;
2947 	} else if (dirty.flags & VFIO_IOMMU_DIRTY_PAGES_FLAG_STOP) {
2948 		mutex_lock(&iommu->lock);
2949 		if (iommu->dirty_page_tracking) {
2950 			iommu->dirty_page_tracking = false;
2951 			vfio_dma_bitmap_free_all(iommu);
2952 		}
2953 		mutex_unlock(&iommu->lock);
2954 		return 0;
2955 	} else if (dirty.flags & VFIO_IOMMU_DIRTY_PAGES_FLAG_GET_BITMAP) {
2956 		struct vfio_iommu_type1_dirty_bitmap_get range;
2957 		unsigned long pgshift;
2958 		size_t data_size = dirty.argsz - minsz;
2959 		size_t iommu_pgsize;
2960 
2961 		if (!data_size || data_size < sizeof(range))
2962 			return -EINVAL;
2963 
2964 		if (copy_from_user(&range, (void __user *)(arg + minsz),
2965 				   sizeof(range)))
2966 			return -EFAULT;
2967 
2968 		if (range.iova + range.size < range.iova)
2969 			return -EINVAL;
2970 		if (!access_ok((void __user *)range.bitmap.data,
2971 			       range.bitmap.size))
2972 			return -EINVAL;
2973 
2974 		pgshift = __ffs(range.bitmap.pgsize);
2975 		ret = verify_bitmap_size(range.size >> pgshift,
2976 					 range.bitmap.size);
2977 		if (ret)
2978 			return ret;
2979 
2980 		mutex_lock(&iommu->lock);
2981 
2982 		iommu_pgsize = (size_t)1 << __ffs(iommu->pgsize_bitmap);
2983 
2984 		/* allow only smallest supported pgsize */
2985 		if (range.bitmap.pgsize != iommu_pgsize) {
2986 			ret = -EINVAL;
2987 			goto out_unlock;
2988 		}
2989 		if (range.iova & (iommu_pgsize - 1)) {
2990 			ret = -EINVAL;
2991 			goto out_unlock;
2992 		}
2993 		if (!range.size || range.size & (iommu_pgsize - 1)) {
2994 			ret = -EINVAL;
2995 			goto out_unlock;
2996 		}
2997 
2998 		if (iommu->dirty_page_tracking)
2999 			ret = vfio_iova_dirty_bitmap(range.bitmap.data,
3000 						     iommu, range.iova,
3001 						     range.size,
3002 						     range.bitmap.pgsize);
3003 		else
3004 			ret = -EINVAL;
3005 out_unlock:
3006 		mutex_unlock(&iommu->lock);
3007 
3008 		return ret;
3009 	}
3010 
3011 	return -EINVAL;
3012 }
3013 
vfio_iommu_type1_ioctl(void * iommu_data,unsigned int cmd,unsigned long arg)3014 static long vfio_iommu_type1_ioctl(void *iommu_data,
3015 				   unsigned int cmd, unsigned long arg)
3016 {
3017 	struct vfio_iommu *iommu = iommu_data;
3018 
3019 	switch (cmd) {
3020 	case VFIO_CHECK_EXTENSION:
3021 		return vfio_iommu_type1_check_extension(iommu, arg);
3022 	case VFIO_IOMMU_GET_INFO:
3023 		return vfio_iommu_type1_get_info(iommu, arg);
3024 	case VFIO_IOMMU_MAP_DMA:
3025 		return vfio_iommu_type1_map_dma(iommu, arg);
3026 	case VFIO_IOMMU_UNMAP_DMA:
3027 		return vfio_iommu_type1_unmap_dma(iommu, arg);
3028 	case VFIO_IOMMU_DIRTY_PAGES:
3029 		return vfio_iommu_type1_dirty_pages(iommu, arg);
3030 	default:
3031 		return -ENOTTY;
3032 	}
3033 }
3034 
vfio_iommu_type1_register_device(void * iommu_data,struct vfio_device * vdev)3035 static void vfio_iommu_type1_register_device(void *iommu_data,
3036 					     struct vfio_device *vdev)
3037 {
3038 	struct vfio_iommu *iommu = iommu_data;
3039 
3040 	if (!vdev->ops->dma_unmap)
3041 		return;
3042 
3043 	/*
3044 	 * list_empty(&iommu->device_list) is tested under the iommu->lock while
3045 	 * iteration for dma_unmap must be done under the device_list_lock.
3046 	 * Holding both locks here allows avoiding the device_list_lock in
3047 	 * several fast paths. See vfio_notify_dma_unmap()
3048 	 */
3049 	mutex_lock(&iommu->lock);
3050 	mutex_lock(&iommu->device_list_lock);
3051 	list_add(&vdev->iommu_entry, &iommu->device_list);
3052 	mutex_unlock(&iommu->device_list_lock);
3053 	mutex_unlock(&iommu->lock);
3054 }
3055 
vfio_iommu_type1_unregister_device(void * iommu_data,struct vfio_device * vdev)3056 static void vfio_iommu_type1_unregister_device(void *iommu_data,
3057 					       struct vfio_device *vdev)
3058 {
3059 	struct vfio_iommu *iommu = iommu_data;
3060 
3061 	if (!vdev->ops->dma_unmap)
3062 		return;
3063 
3064 	mutex_lock(&iommu->lock);
3065 	mutex_lock(&iommu->device_list_lock);
3066 	list_del(&vdev->iommu_entry);
3067 	mutex_unlock(&iommu->device_list_lock);
3068 	mutex_unlock(&iommu->lock);
3069 }
3070 
vfio_iommu_type1_dma_rw_chunk(struct vfio_iommu * iommu,dma_addr_t user_iova,void * data,size_t count,bool write,size_t * copied)3071 static int vfio_iommu_type1_dma_rw_chunk(struct vfio_iommu *iommu,
3072 					 dma_addr_t user_iova, void *data,
3073 					 size_t count, bool write,
3074 					 size_t *copied)
3075 {
3076 	struct mm_struct *mm;
3077 	unsigned long vaddr;
3078 	struct vfio_dma *dma;
3079 	bool kthread = current->mm == NULL;
3080 	size_t offset;
3081 	int ret;
3082 
3083 	*copied = 0;
3084 
3085 	ret = vfio_find_dma_valid(iommu, user_iova, 1, &dma);
3086 	if (ret < 0)
3087 		return ret;
3088 
3089 	if ((write && !(dma->prot & IOMMU_WRITE)) ||
3090 			!(dma->prot & IOMMU_READ))
3091 		return -EPERM;
3092 
3093 	mm = get_task_mm(dma->task);
3094 
3095 	if (!mm)
3096 		return -EPERM;
3097 
3098 	if (kthread)
3099 		kthread_use_mm(mm);
3100 	else if (current->mm != mm)
3101 		goto out;
3102 
3103 	offset = user_iova - dma->iova;
3104 
3105 	if (count > dma->size - offset)
3106 		count = dma->size - offset;
3107 
3108 	vaddr = dma->vaddr + offset;
3109 
3110 	if (write) {
3111 		*copied = copy_to_user((void __user *)vaddr, data,
3112 					 count) ? 0 : count;
3113 		if (*copied && iommu->dirty_page_tracking) {
3114 			unsigned long pgshift = __ffs(iommu->pgsize_bitmap);
3115 			/*
3116 			 * Bitmap populated with the smallest supported page
3117 			 * size
3118 			 */
3119 			bitmap_set(dma->bitmap, offset >> pgshift,
3120 				   ((offset + *copied - 1) >> pgshift) -
3121 				   (offset >> pgshift) + 1);
3122 		}
3123 	} else
3124 		*copied = copy_from_user(data, (void __user *)vaddr,
3125 					   count) ? 0 : count;
3126 	if (kthread)
3127 		kthread_unuse_mm(mm);
3128 out:
3129 	mmput(mm);
3130 	return *copied ? 0 : -EFAULT;
3131 }
3132 
vfio_iommu_type1_dma_rw(void * iommu_data,dma_addr_t user_iova,void * data,size_t count,bool write)3133 static int vfio_iommu_type1_dma_rw(void *iommu_data, dma_addr_t user_iova,
3134 				   void *data, size_t count, bool write)
3135 {
3136 	struct vfio_iommu *iommu = iommu_data;
3137 	int ret = 0;
3138 	size_t done;
3139 
3140 	mutex_lock(&iommu->lock);
3141 	while (count > 0) {
3142 		ret = vfio_iommu_type1_dma_rw_chunk(iommu, user_iova, data,
3143 						    count, write, &done);
3144 		if (ret)
3145 			break;
3146 
3147 		count -= done;
3148 		data += done;
3149 		user_iova += done;
3150 	}
3151 
3152 	mutex_unlock(&iommu->lock);
3153 	return ret;
3154 }
3155 
3156 static struct iommu_domain *
vfio_iommu_type1_group_iommu_domain(void * iommu_data,struct iommu_group * iommu_group)3157 vfio_iommu_type1_group_iommu_domain(void *iommu_data,
3158 				    struct iommu_group *iommu_group)
3159 {
3160 	struct iommu_domain *domain = ERR_PTR(-ENODEV);
3161 	struct vfio_iommu *iommu = iommu_data;
3162 	struct vfio_domain *d;
3163 
3164 	if (!iommu || !iommu_group)
3165 		return ERR_PTR(-EINVAL);
3166 
3167 	mutex_lock(&iommu->lock);
3168 	list_for_each_entry(d, &iommu->domain_list, next) {
3169 		if (find_iommu_group(d, iommu_group)) {
3170 			domain = d->domain;
3171 			break;
3172 		}
3173 	}
3174 	mutex_unlock(&iommu->lock);
3175 
3176 	return domain;
3177 }
3178 
vfio_iommu_type1_notify(void * iommu_data,enum vfio_iommu_notify_type event)3179 static void vfio_iommu_type1_notify(void *iommu_data,
3180 				    enum vfio_iommu_notify_type event)
3181 {
3182 	struct vfio_iommu *iommu = iommu_data;
3183 
3184 	if (event != VFIO_IOMMU_CONTAINER_CLOSE)
3185 		return;
3186 	mutex_lock(&iommu->lock);
3187 	iommu->container_open = false;
3188 	mutex_unlock(&iommu->lock);
3189 	wake_up_all(&iommu->vaddr_wait);
3190 }
3191 
3192 static const struct vfio_iommu_driver_ops vfio_iommu_driver_ops_type1 = {
3193 	.name			= "vfio-iommu-type1",
3194 	.owner			= THIS_MODULE,
3195 	.open			= vfio_iommu_type1_open,
3196 	.release		= vfio_iommu_type1_release,
3197 	.ioctl			= vfio_iommu_type1_ioctl,
3198 	.attach_group		= vfio_iommu_type1_attach_group,
3199 	.detach_group		= vfio_iommu_type1_detach_group,
3200 	.pin_pages		= vfio_iommu_type1_pin_pages,
3201 	.unpin_pages		= vfio_iommu_type1_unpin_pages,
3202 	.register_device	= vfio_iommu_type1_register_device,
3203 	.unregister_device	= vfio_iommu_type1_unregister_device,
3204 	.dma_rw			= vfio_iommu_type1_dma_rw,
3205 	.group_iommu_domain	= vfio_iommu_type1_group_iommu_domain,
3206 	.notify			= vfio_iommu_type1_notify,
3207 };
3208 
vfio_iommu_type1_init(void)3209 static int __init vfio_iommu_type1_init(void)
3210 {
3211 	return vfio_register_iommu_driver(&vfio_iommu_driver_ops_type1);
3212 }
3213 
vfio_iommu_type1_cleanup(void)3214 static void __exit vfio_iommu_type1_cleanup(void)
3215 {
3216 	vfio_unregister_iommu_driver(&vfio_iommu_driver_ops_type1);
3217 }
3218 
3219 module_init(vfio_iommu_type1_init);
3220 module_exit(vfio_iommu_type1_cleanup);
3221 
3222 MODULE_VERSION(DRIVER_VERSION);
3223 MODULE_LICENSE("GPL v2");
3224 MODULE_AUTHOR(DRIVER_AUTHOR);
3225 MODULE_DESCRIPTION(DRIVER_DESC);
3226