1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Virtio driver for the paravirtualized IOMMU
4 *
5 * Copyright (C) 2019 Arm Limited
6 */
7
8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9
10 #include <linux/amba/bus.h>
11 #include <linux/delay.h>
12 #include <linux/dma-iommu.h>
13 #include <linux/dma-map-ops.h>
14 #include <linux/freezer.h>
15 #include <linux/interval_tree.h>
16 #include <linux/iommu.h>
17 #include <linux/module.h>
18 #include <linux/of_platform.h>
19 #include <linux/pci.h>
20 #include <linux/platform_device.h>
21 #include <linux/virtio.h>
22 #include <linux/virtio_config.h>
23 #include <linux/virtio_ids.h>
24 #include <linux/wait.h>
25
26 #include <uapi/linux/virtio_iommu.h>
27
28 #define MSI_IOVA_BASE 0x8000000
29 #define MSI_IOVA_LENGTH 0x100000
30
31 #define VIOMMU_REQUEST_VQ 0
32 #define VIOMMU_EVENT_VQ 1
33 #define VIOMMU_NR_VQS 2
34
35 struct viommu_dev {
36 struct iommu_device iommu;
37 struct device *dev;
38 struct virtio_device *vdev;
39
40 struct ida domain_ids;
41
42 struct virtqueue *vqs[VIOMMU_NR_VQS];
43 spinlock_t request_lock;
44 struct list_head requests;
45 void *evts;
46
47 /* Device configuration */
48 struct iommu_domain_geometry geometry;
49 u64 pgsize_bitmap;
50 u32 first_domain;
51 u32 last_domain;
52 /* Supported MAP flags */
53 u32 map_flags;
54 u32 probe_size;
55 };
56
57 struct viommu_mapping {
58 phys_addr_t paddr;
59 struct interval_tree_node iova;
60 u32 flags;
61 };
62
63 struct viommu_domain {
64 struct iommu_domain domain;
65 struct viommu_dev *viommu;
66 struct mutex mutex; /* protects viommu pointer */
67 unsigned int id;
68 u32 map_flags;
69
70 spinlock_t mappings_lock;
71 struct rb_root_cached mappings;
72
73 unsigned long nr_endpoints;
74 bool bypass;
75 };
76
77 struct viommu_endpoint {
78 struct device *dev;
79 struct viommu_dev *viommu;
80 struct viommu_domain *vdomain;
81 struct list_head resv_regions;
82 };
83
84 struct viommu_request {
85 struct list_head list;
86 void *writeback;
87 unsigned int write_offset;
88 unsigned int len;
89 char buf[];
90 };
91
92 #define VIOMMU_FAULT_RESV_MASK 0xffffff00
93
94 struct viommu_event {
95 union {
96 u32 head;
97 struct virtio_iommu_fault fault;
98 };
99 };
100
101 #define to_viommu_domain(domain) \
102 container_of(domain, struct viommu_domain, domain)
103
viommu_get_req_errno(void * buf,size_t len)104 static int viommu_get_req_errno(void *buf, size_t len)
105 {
106 struct virtio_iommu_req_tail *tail = buf + len - sizeof(*tail);
107
108 switch (tail->status) {
109 case VIRTIO_IOMMU_S_OK:
110 return 0;
111 case VIRTIO_IOMMU_S_UNSUPP:
112 return -ENOSYS;
113 case VIRTIO_IOMMU_S_INVAL:
114 return -EINVAL;
115 case VIRTIO_IOMMU_S_RANGE:
116 return -ERANGE;
117 case VIRTIO_IOMMU_S_NOENT:
118 return -ENOENT;
119 case VIRTIO_IOMMU_S_FAULT:
120 return -EFAULT;
121 case VIRTIO_IOMMU_S_NOMEM:
122 return -ENOMEM;
123 case VIRTIO_IOMMU_S_IOERR:
124 case VIRTIO_IOMMU_S_DEVERR:
125 default:
126 return -EIO;
127 }
128 }
129
viommu_set_req_status(void * buf,size_t len,int status)130 static void viommu_set_req_status(void *buf, size_t len, int status)
131 {
132 struct virtio_iommu_req_tail *tail = buf + len - sizeof(*tail);
133
134 tail->status = status;
135 }
136
viommu_get_write_desc_offset(struct viommu_dev * viommu,struct virtio_iommu_req_head * req,size_t len)137 static off_t viommu_get_write_desc_offset(struct viommu_dev *viommu,
138 struct virtio_iommu_req_head *req,
139 size_t len)
140 {
141 size_t tail_size = sizeof(struct virtio_iommu_req_tail);
142
143 if (req->type == VIRTIO_IOMMU_T_PROBE)
144 return len - viommu->probe_size - tail_size;
145
146 return len - tail_size;
147 }
148
149 /*
150 * __viommu_sync_req - Complete all in-flight requests
151 *
152 * Wait for all added requests to complete. When this function returns, all
153 * requests that were in-flight at the time of the call have completed.
154 */
__viommu_sync_req(struct viommu_dev * viommu)155 static int __viommu_sync_req(struct viommu_dev *viommu)
156 {
157 unsigned int len;
158 size_t write_len;
159 struct viommu_request *req;
160 struct virtqueue *vq = viommu->vqs[VIOMMU_REQUEST_VQ];
161
162 assert_spin_locked(&viommu->request_lock);
163
164 virtqueue_kick(vq);
165
166 while (!list_empty(&viommu->requests)) {
167 len = 0;
168 req = virtqueue_get_buf(vq, &len);
169 if (!req)
170 continue;
171
172 if (!len)
173 viommu_set_req_status(req->buf, req->len,
174 VIRTIO_IOMMU_S_IOERR);
175
176 write_len = req->len - req->write_offset;
177 if (req->writeback && len == write_len)
178 memcpy(req->writeback, req->buf + req->write_offset,
179 write_len);
180
181 list_del(&req->list);
182 kfree(req);
183 }
184
185 return 0;
186 }
187
viommu_sync_req(struct viommu_dev * viommu)188 static int viommu_sync_req(struct viommu_dev *viommu)
189 {
190 int ret;
191 unsigned long flags;
192
193 spin_lock_irqsave(&viommu->request_lock, flags);
194 ret = __viommu_sync_req(viommu);
195 if (ret)
196 dev_dbg(viommu->dev, "could not sync requests (%d)\n", ret);
197 spin_unlock_irqrestore(&viommu->request_lock, flags);
198
199 return ret;
200 }
201
202 /*
203 * __viommu_add_request - Add one request to the queue
204 * @buf: pointer to the request buffer
205 * @len: length of the request buffer
206 * @writeback: copy data back to the buffer when the request completes.
207 *
208 * Add a request to the queue. Only synchronize the queue if it's already full.
209 * Otherwise don't kick the queue nor wait for requests to complete.
210 *
211 * When @writeback is true, data written by the device, including the request
212 * status, is copied into @buf after the request completes. This is unsafe if
213 * the caller allocates @buf on stack and drops the lock between add_req() and
214 * sync_req().
215 *
216 * Return 0 if the request was successfully added to the queue.
217 */
__viommu_add_req(struct viommu_dev * viommu,void * buf,size_t len,bool writeback)218 static int __viommu_add_req(struct viommu_dev *viommu, void *buf, size_t len,
219 bool writeback)
220 {
221 int ret;
222 off_t write_offset;
223 struct viommu_request *req;
224 struct scatterlist top_sg, bottom_sg;
225 struct scatterlist *sg[2] = { &top_sg, &bottom_sg };
226 struct virtqueue *vq = viommu->vqs[VIOMMU_REQUEST_VQ];
227
228 assert_spin_locked(&viommu->request_lock);
229
230 write_offset = viommu_get_write_desc_offset(viommu, buf, len);
231 if (write_offset <= 0)
232 return -EINVAL;
233
234 req = kzalloc(sizeof(*req) + len, GFP_ATOMIC);
235 if (!req)
236 return -ENOMEM;
237
238 req->len = len;
239 if (writeback) {
240 req->writeback = buf + write_offset;
241 req->write_offset = write_offset;
242 }
243 memcpy(&req->buf, buf, write_offset);
244
245 sg_init_one(&top_sg, req->buf, write_offset);
246 sg_init_one(&bottom_sg, req->buf + write_offset, len - write_offset);
247
248 ret = virtqueue_add_sgs(vq, sg, 1, 1, req, GFP_ATOMIC);
249 if (ret == -ENOSPC) {
250 /* If the queue is full, sync and retry */
251 if (!__viommu_sync_req(viommu))
252 ret = virtqueue_add_sgs(vq, sg, 1, 1, req, GFP_ATOMIC);
253 }
254 if (ret)
255 goto err_free;
256
257 list_add_tail(&req->list, &viommu->requests);
258 return 0;
259
260 err_free:
261 kfree(req);
262 return ret;
263 }
264
viommu_add_req(struct viommu_dev * viommu,void * buf,size_t len)265 static int viommu_add_req(struct viommu_dev *viommu, void *buf, size_t len)
266 {
267 int ret;
268 unsigned long flags;
269
270 spin_lock_irqsave(&viommu->request_lock, flags);
271 ret = __viommu_add_req(viommu, buf, len, false);
272 if (ret)
273 dev_dbg(viommu->dev, "could not add request: %d\n", ret);
274 spin_unlock_irqrestore(&viommu->request_lock, flags);
275
276 return ret;
277 }
278
279 /*
280 * Send a request and wait for it to complete. Return the request status (as an
281 * errno)
282 */
viommu_send_req_sync(struct viommu_dev * viommu,void * buf,size_t len)283 static int viommu_send_req_sync(struct viommu_dev *viommu, void *buf,
284 size_t len)
285 {
286 int ret;
287 unsigned long flags;
288
289 spin_lock_irqsave(&viommu->request_lock, flags);
290
291 ret = __viommu_add_req(viommu, buf, len, true);
292 if (ret) {
293 dev_dbg(viommu->dev, "could not add request (%d)\n", ret);
294 goto out_unlock;
295 }
296
297 ret = __viommu_sync_req(viommu);
298 if (ret) {
299 dev_dbg(viommu->dev, "could not sync requests (%d)\n", ret);
300 /* Fall-through (get the actual request status) */
301 }
302
303 ret = viommu_get_req_errno(buf, len);
304 out_unlock:
305 spin_unlock_irqrestore(&viommu->request_lock, flags);
306 return ret;
307 }
308
309 /*
310 * viommu_add_mapping - add a mapping to the internal tree
311 *
312 * On success, return the new mapping. Otherwise return NULL.
313 */
viommu_add_mapping(struct viommu_domain * vdomain,u64 iova,u64 end,phys_addr_t paddr,u32 flags)314 static int viommu_add_mapping(struct viommu_domain *vdomain, u64 iova, u64 end,
315 phys_addr_t paddr, u32 flags)
316 {
317 unsigned long irqflags;
318 struct viommu_mapping *mapping;
319
320 mapping = kzalloc(sizeof(*mapping), GFP_ATOMIC);
321 if (!mapping)
322 return -ENOMEM;
323
324 mapping->paddr = paddr;
325 mapping->iova.start = iova;
326 mapping->iova.last = end;
327 mapping->flags = flags;
328
329 spin_lock_irqsave(&vdomain->mappings_lock, irqflags);
330 interval_tree_insert(&mapping->iova, &vdomain->mappings);
331 spin_unlock_irqrestore(&vdomain->mappings_lock, irqflags);
332
333 return 0;
334 }
335
336 /*
337 * viommu_del_mappings - remove mappings from the internal tree
338 *
339 * @vdomain: the domain
340 * @iova: start of the range
341 * @end: end of the range
342 *
343 * On success, returns the number of unmapped bytes
344 */
viommu_del_mappings(struct viommu_domain * vdomain,u64 iova,u64 end)345 static size_t viommu_del_mappings(struct viommu_domain *vdomain,
346 u64 iova, u64 end)
347 {
348 size_t unmapped = 0;
349 unsigned long flags;
350 struct viommu_mapping *mapping = NULL;
351 struct interval_tree_node *node, *next;
352
353 spin_lock_irqsave(&vdomain->mappings_lock, flags);
354 next = interval_tree_iter_first(&vdomain->mappings, iova, end);
355 while (next) {
356 node = next;
357 mapping = container_of(node, struct viommu_mapping, iova);
358 next = interval_tree_iter_next(node, iova, end);
359
360 /* Trying to split a mapping? */
361 if (mapping->iova.start < iova)
362 break;
363
364 /*
365 * Virtio-iommu doesn't allow UNMAP to split a mapping created
366 * with a single MAP request, so remove the full mapping.
367 */
368 unmapped += mapping->iova.last - mapping->iova.start + 1;
369
370 interval_tree_remove(node, &vdomain->mappings);
371 kfree(mapping);
372 }
373 spin_unlock_irqrestore(&vdomain->mappings_lock, flags);
374
375 return unmapped;
376 }
377
378 /*
379 * Fill the domain with identity mappings, skipping the device's reserved
380 * regions.
381 */
viommu_domain_map_identity(struct viommu_endpoint * vdev,struct viommu_domain * vdomain)382 static int viommu_domain_map_identity(struct viommu_endpoint *vdev,
383 struct viommu_domain *vdomain)
384 {
385 int ret;
386 struct iommu_resv_region *resv;
387 u64 iova = vdomain->domain.geometry.aperture_start;
388 u64 limit = vdomain->domain.geometry.aperture_end;
389 u32 flags = VIRTIO_IOMMU_MAP_F_READ | VIRTIO_IOMMU_MAP_F_WRITE;
390 unsigned long granule = 1UL << __ffs(vdomain->domain.pgsize_bitmap);
391
392 iova = ALIGN(iova, granule);
393 limit = ALIGN_DOWN(limit + 1, granule) - 1;
394
395 list_for_each_entry(resv, &vdev->resv_regions, list) {
396 u64 resv_start = ALIGN_DOWN(resv->start, granule);
397 u64 resv_end = ALIGN(resv->start + resv->length, granule) - 1;
398
399 if (resv_end < iova || resv_start > limit)
400 /* No overlap */
401 continue;
402
403 if (resv_start > iova) {
404 ret = viommu_add_mapping(vdomain, iova, resv_start - 1,
405 (phys_addr_t)iova, flags);
406 if (ret)
407 goto err_unmap;
408 }
409
410 if (resv_end >= limit)
411 return 0;
412
413 iova = resv_end + 1;
414 }
415
416 ret = viommu_add_mapping(vdomain, iova, limit, (phys_addr_t)iova,
417 flags);
418 if (ret)
419 goto err_unmap;
420 return 0;
421
422 err_unmap:
423 viommu_del_mappings(vdomain, 0, iova);
424 return ret;
425 }
426
427 /*
428 * viommu_replay_mappings - re-send MAP requests
429 *
430 * When reattaching a domain that was previously detached from all endpoints,
431 * mappings were deleted from the device. Re-create the mappings available in
432 * the internal tree.
433 */
viommu_replay_mappings(struct viommu_domain * vdomain)434 static int viommu_replay_mappings(struct viommu_domain *vdomain)
435 {
436 int ret = 0;
437 unsigned long flags;
438 struct viommu_mapping *mapping;
439 struct interval_tree_node *node;
440 struct virtio_iommu_req_map map;
441
442 spin_lock_irqsave(&vdomain->mappings_lock, flags);
443 node = interval_tree_iter_first(&vdomain->mappings, 0, -1UL);
444 while (node) {
445 mapping = container_of(node, struct viommu_mapping, iova);
446 map = (struct virtio_iommu_req_map) {
447 .head.type = VIRTIO_IOMMU_T_MAP,
448 .domain = cpu_to_le32(vdomain->id),
449 .virt_start = cpu_to_le64(mapping->iova.start),
450 .virt_end = cpu_to_le64(mapping->iova.last),
451 .phys_start = cpu_to_le64(mapping->paddr),
452 .flags = cpu_to_le32(mapping->flags),
453 };
454
455 ret = viommu_send_req_sync(vdomain->viommu, &map, sizeof(map));
456 if (ret)
457 break;
458
459 node = interval_tree_iter_next(node, 0, -1UL);
460 }
461 spin_unlock_irqrestore(&vdomain->mappings_lock, flags);
462
463 return ret;
464 }
465
viommu_add_resv_mem(struct viommu_endpoint * vdev,struct virtio_iommu_probe_resv_mem * mem,size_t len)466 static int viommu_add_resv_mem(struct viommu_endpoint *vdev,
467 struct virtio_iommu_probe_resv_mem *mem,
468 size_t len)
469 {
470 size_t size;
471 u64 start64, end64;
472 phys_addr_t start, end;
473 struct iommu_resv_region *region = NULL, *next;
474 unsigned long prot = IOMMU_WRITE | IOMMU_NOEXEC | IOMMU_MMIO;
475
476 start = start64 = le64_to_cpu(mem->start);
477 end = end64 = le64_to_cpu(mem->end);
478 size = end64 - start64 + 1;
479
480 /* Catch any overflow, including the unlikely end64 - start64 + 1 = 0 */
481 if (start != start64 || end != end64 || size < end64 - start64)
482 return -EOVERFLOW;
483
484 if (len < sizeof(*mem))
485 return -EINVAL;
486
487 switch (mem->subtype) {
488 default:
489 dev_warn(vdev->dev, "unknown resv mem subtype 0x%x\n",
490 mem->subtype);
491 fallthrough;
492 case VIRTIO_IOMMU_RESV_MEM_T_RESERVED:
493 region = iommu_alloc_resv_region(start, size, 0,
494 IOMMU_RESV_RESERVED);
495 break;
496 case VIRTIO_IOMMU_RESV_MEM_T_MSI:
497 region = iommu_alloc_resv_region(start, size, prot,
498 IOMMU_RESV_MSI);
499 break;
500 }
501 if (!region)
502 return -ENOMEM;
503
504 /* Keep the list sorted */
505 list_for_each_entry(next, &vdev->resv_regions, list) {
506 if (next->start > region->start)
507 break;
508 }
509 list_add_tail(®ion->list, &next->list);
510 return 0;
511 }
512
viommu_probe_endpoint(struct viommu_dev * viommu,struct device * dev)513 static int viommu_probe_endpoint(struct viommu_dev *viommu, struct device *dev)
514 {
515 int ret;
516 u16 type, len;
517 size_t cur = 0;
518 size_t probe_len;
519 struct virtio_iommu_req_probe *probe;
520 struct virtio_iommu_probe_property *prop;
521 struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
522 struct viommu_endpoint *vdev = dev_iommu_priv_get(dev);
523
524 if (!fwspec->num_ids)
525 return -EINVAL;
526
527 probe_len = sizeof(*probe) + viommu->probe_size +
528 sizeof(struct virtio_iommu_req_tail);
529 probe = kzalloc(probe_len, GFP_KERNEL);
530 if (!probe)
531 return -ENOMEM;
532
533 probe->head.type = VIRTIO_IOMMU_T_PROBE;
534 /*
535 * For now, assume that properties of an endpoint that outputs multiple
536 * IDs are consistent. Only probe the first one.
537 */
538 probe->endpoint = cpu_to_le32(fwspec->ids[0]);
539
540 ret = viommu_send_req_sync(viommu, probe, probe_len);
541 if (ret)
542 goto out_free;
543
544 prop = (void *)probe->properties;
545 type = le16_to_cpu(prop->type) & VIRTIO_IOMMU_PROBE_T_MASK;
546
547 while (type != VIRTIO_IOMMU_PROBE_T_NONE &&
548 cur < viommu->probe_size) {
549 len = le16_to_cpu(prop->length) + sizeof(*prop);
550
551 switch (type) {
552 case VIRTIO_IOMMU_PROBE_T_RESV_MEM:
553 ret = viommu_add_resv_mem(vdev, (void *)prop, len);
554 break;
555 default:
556 dev_err(dev, "unknown viommu prop 0x%x\n", type);
557 }
558
559 if (ret)
560 dev_err(dev, "failed to parse viommu prop 0x%x\n", type);
561
562 cur += len;
563 if (cur >= viommu->probe_size)
564 break;
565
566 prop = (void *)probe->properties + cur;
567 type = le16_to_cpu(prop->type) & VIRTIO_IOMMU_PROBE_T_MASK;
568 }
569
570 out_free:
571 kfree(probe);
572 return ret;
573 }
574
viommu_fault_handler(struct viommu_dev * viommu,struct virtio_iommu_fault * fault)575 static int viommu_fault_handler(struct viommu_dev *viommu,
576 struct virtio_iommu_fault *fault)
577 {
578 char *reason_str;
579
580 u8 reason = fault->reason;
581 u32 flags = le32_to_cpu(fault->flags);
582 u32 endpoint = le32_to_cpu(fault->endpoint);
583 u64 address = le64_to_cpu(fault->address);
584
585 switch (reason) {
586 case VIRTIO_IOMMU_FAULT_R_DOMAIN:
587 reason_str = "domain";
588 break;
589 case VIRTIO_IOMMU_FAULT_R_MAPPING:
590 reason_str = "page";
591 break;
592 case VIRTIO_IOMMU_FAULT_R_UNKNOWN:
593 default:
594 reason_str = "unknown";
595 break;
596 }
597
598 /* TODO: find EP by ID and report_iommu_fault */
599 if (flags & VIRTIO_IOMMU_FAULT_F_ADDRESS)
600 dev_err_ratelimited(viommu->dev, "%s fault from EP %u at %#llx [%s%s%s]\n",
601 reason_str, endpoint, address,
602 flags & VIRTIO_IOMMU_FAULT_F_READ ? "R" : "",
603 flags & VIRTIO_IOMMU_FAULT_F_WRITE ? "W" : "",
604 flags & VIRTIO_IOMMU_FAULT_F_EXEC ? "X" : "");
605 else
606 dev_err_ratelimited(viommu->dev, "%s fault from EP %u\n",
607 reason_str, endpoint);
608 return 0;
609 }
610
viommu_event_handler(struct virtqueue * vq)611 static void viommu_event_handler(struct virtqueue *vq)
612 {
613 int ret;
614 unsigned int len;
615 struct scatterlist sg[1];
616 struct viommu_event *evt;
617 struct viommu_dev *viommu = vq->vdev->priv;
618
619 while ((evt = virtqueue_get_buf(vq, &len)) != NULL) {
620 if (len > sizeof(*evt)) {
621 dev_err(viommu->dev,
622 "invalid event buffer (len %u != %zu)\n",
623 len, sizeof(*evt));
624 } else if (!(evt->head & VIOMMU_FAULT_RESV_MASK)) {
625 viommu_fault_handler(viommu, &evt->fault);
626 }
627
628 sg_init_one(sg, evt, sizeof(*evt));
629 ret = virtqueue_add_inbuf(vq, sg, 1, evt, GFP_ATOMIC);
630 if (ret)
631 dev_err(viommu->dev, "could not add event buffer\n");
632 }
633
634 virtqueue_kick(vq);
635 }
636
637 /* IOMMU API */
638
viommu_domain_alloc(unsigned type)639 static struct iommu_domain *viommu_domain_alloc(unsigned type)
640 {
641 struct viommu_domain *vdomain;
642
643 if (type != IOMMU_DOMAIN_UNMANAGED &&
644 type != IOMMU_DOMAIN_DMA &&
645 type != IOMMU_DOMAIN_IDENTITY)
646 return NULL;
647
648 vdomain = kzalloc(sizeof(*vdomain), GFP_KERNEL);
649 if (!vdomain)
650 return NULL;
651
652 mutex_init(&vdomain->mutex);
653 spin_lock_init(&vdomain->mappings_lock);
654 vdomain->mappings = RB_ROOT_CACHED;
655
656 return &vdomain->domain;
657 }
658
viommu_domain_finalise(struct viommu_endpoint * vdev,struct iommu_domain * domain)659 static int viommu_domain_finalise(struct viommu_endpoint *vdev,
660 struct iommu_domain *domain)
661 {
662 int ret;
663 unsigned long viommu_page_size;
664 struct viommu_dev *viommu = vdev->viommu;
665 struct viommu_domain *vdomain = to_viommu_domain(domain);
666
667 viommu_page_size = 1UL << __ffs(viommu->pgsize_bitmap);
668 if (viommu_page_size > PAGE_SIZE) {
669 dev_err(vdev->dev,
670 "granule 0x%lx larger than system page size 0x%lx\n",
671 viommu_page_size, PAGE_SIZE);
672 return -EINVAL;
673 }
674
675 ret = ida_alloc_range(&viommu->domain_ids, viommu->first_domain,
676 viommu->last_domain, GFP_KERNEL);
677 if (ret < 0)
678 return ret;
679
680 vdomain->id = (unsigned int)ret;
681
682 domain->pgsize_bitmap = viommu->pgsize_bitmap;
683 domain->geometry = viommu->geometry;
684
685 vdomain->map_flags = viommu->map_flags;
686 vdomain->viommu = viommu;
687
688 if (domain->type == IOMMU_DOMAIN_IDENTITY) {
689 if (virtio_has_feature(viommu->vdev,
690 VIRTIO_IOMMU_F_BYPASS_CONFIG)) {
691 vdomain->bypass = true;
692 return 0;
693 }
694
695 ret = viommu_domain_map_identity(vdev, vdomain);
696 if (ret) {
697 ida_free(&viommu->domain_ids, vdomain->id);
698 vdomain->viommu = NULL;
699 return -EOPNOTSUPP;
700 }
701 }
702
703 return 0;
704 }
705
viommu_domain_free(struct iommu_domain * domain)706 static void viommu_domain_free(struct iommu_domain *domain)
707 {
708 struct viommu_domain *vdomain = to_viommu_domain(domain);
709
710 /* Free all remaining mappings */
711 viommu_del_mappings(vdomain, 0, ULLONG_MAX);
712
713 if (vdomain->viommu)
714 ida_free(&vdomain->viommu->domain_ids, vdomain->id);
715
716 kfree(vdomain);
717 }
718
viommu_attach_dev(struct iommu_domain * domain,struct device * dev)719 static int viommu_attach_dev(struct iommu_domain *domain, struct device *dev)
720 {
721 int i;
722 int ret = 0;
723 struct virtio_iommu_req_attach req;
724 struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
725 struct viommu_endpoint *vdev = dev_iommu_priv_get(dev);
726 struct viommu_domain *vdomain = to_viommu_domain(domain);
727
728 mutex_lock(&vdomain->mutex);
729 if (!vdomain->viommu) {
730 /*
731 * Properly initialize the domain now that we know which viommu
732 * owns it.
733 */
734 ret = viommu_domain_finalise(vdev, domain);
735 } else if (vdomain->viommu != vdev->viommu) {
736 dev_err(dev, "cannot attach to foreign vIOMMU\n");
737 ret = -EXDEV;
738 }
739 mutex_unlock(&vdomain->mutex);
740
741 if (ret)
742 return ret;
743
744 /*
745 * In the virtio-iommu device, when attaching the endpoint to a new
746 * domain, it is detached from the old one and, if as a result the
747 * old domain isn't attached to any endpoint, all mappings are removed
748 * from the old domain and it is freed.
749 *
750 * In the driver the old domain still exists, and its mappings will be
751 * recreated if it gets reattached to an endpoint. Otherwise it will be
752 * freed explicitly.
753 *
754 * vdev->vdomain is protected by group->mutex
755 */
756 if (vdev->vdomain)
757 vdev->vdomain->nr_endpoints--;
758
759 req = (struct virtio_iommu_req_attach) {
760 .head.type = VIRTIO_IOMMU_T_ATTACH,
761 .domain = cpu_to_le32(vdomain->id),
762 };
763
764 if (vdomain->bypass)
765 req.flags |= cpu_to_le32(VIRTIO_IOMMU_ATTACH_F_BYPASS);
766
767 for (i = 0; i < fwspec->num_ids; i++) {
768 req.endpoint = cpu_to_le32(fwspec->ids[i]);
769
770 ret = viommu_send_req_sync(vdomain->viommu, &req, sizeof(req));
771 if (ret)
772 return ret;
773 }
774
775 if (!vdomain->nr_endpoints) {
776 /*
777 * This endpoint is the first to be attached to the domain.
778 * Replay existing mappings (e.g. SW MSI).
779 */
780 ret = viommu_replay_mappings(vdomain);
781 if (ret)
782 return ret;
783 }
784
785 vdomain->nr_endpoints++;
786 vdev->vdomain = vdomain;
787
788 return 0;
789 }
790
viommu_map(struct iommu_domain * domain,unsigned long iova,phys_addr_t paddr,size_t size,int prot,gfp_t gfp)791 static int viommu_map(struct iommu_domain *domain, unsigned long iova,
792 phys_addr_t paddr, size_t size, int prot, gfp_t gfp)
793 {
794 int ret;
795 u32 flags;
796 u64 end = iova + size - 1;
797 struct virtio_iommu_req_map map;
798 struct viommu_domain *vdomain = to_viommu_domain(domain);
799
800 flags = (prot & IOMMU_READ ? VIRTIO_IOMMU_MAP_F_READ : 0) |
801 (prot & IOMMU_WRITE ? VIRTIO_IOMMU_MAP_F_WRITE : 0) |
802 (prot & IOMMU_MMIO ? VIRTIO_IOMMU_MAP_F_MMIO : 0);
803
804 if (flags & ~vdomain->map_flags)
805 return -EINVAL;
806
807 ret = viommu_add_mapping(vdomain, iova, end, paddr, flags);
808 if (ret)
809 return ret;
810
811 map = (struct virtio_iommu_req_map) {
812 .head.type = VIRTIO_IOMMU_T_MAP,
813 .domain = cpu_to_le32(vdomain->id),
814 .virt_start = cpu_to_le64(iova),
815 .phys_start = cpu_to_le64(paddr),
816 .virt_end = cpu_to_le64(end),
817 .flags = cpu_to_le32(flags),
818 };
819
820 if (!vdomain->nr_endpoints)
821 return 0;
822
823 ret = viommu_send_req_sync(vdomain->viommu, &map, sizeof(map));
824 if (ret)
825 viommu_del_mappings(vdomain, iova, end);
826
827 return ret;
828 }
829
viommu_unmap(struct iommu_domain * domain,unsigned long iova,size_t size,struct iommu_iotlb_gather * gather)830 static size_t viommu_unmap(struct iommu_domain *domain, unsigned long iova,
831 size_t size, struct iommu_iotlb_gather *gather)
832 {
833 int ret = 0;
834 size_t unmapped;
835 struct virtio_iommu_req_unmap unmap;
836 struct viommu_domain *vdomain = to_viommu_domain(domain);
837
838 unmapped = viommu_del_mappings(vdomain, iova, iova + size - 1);
839 if (unmapped < size)
840 return 0;
841
842 /* Device already removed all mappings after detach. */
843 if (!vdomain->nr_endpoints)
844 return unmapped;
845
846 unmap = (struct virtio_iommu_req_unmap) {
847 .head.type = VIRTIO_IOMMU_T_UNMAP,
848 .domain = cpu_to_le32(vdomain->id),
849 .virt_start = cpu_to_le64(iova),
850 .virt_end = cpu_to_le64(iova + unmapped - 1),
851 };
852
853 ret = viommu_add_req(vdomain->viommu, &unmap, sizeof(unmap));
854 return ret ? 0 : unmapped;
855 }
856
viommu_iova_to_phys(struct iommu_domain * domain,dma_addr_t iova)857 static phys_addr_t viommu_iova_to_phys(struct iommu_domain *domain,
858 dma_addr_t iova)
859 {
860 u64 paddr = 0;
861 unsigned long flags;
862 struct viommu_mapping *mapping;
863 struct interval_tree_node *node;
864 struct viommu_domain *vdomain = to_viommu_domain(domain);
865
866 spin_lock_irqsave(&vdomain->mappings_lock, flags);
867 node = interval_tree_iter_first(&vdomain->mappings, iova, iova);
868 if (node) {
869 mapping = container_of(node, struct viommu_mapping, iova);
870 paddr = mapping->paddr + (iova - mapping->iova.start);
871 }
872 spin_unlock_irqrestore(&vdomain->mappings_lock, flags);
873
874 return paddr;
875 }
876
viommu_iotlb_sync(struct iommu_domain * domain,struct iommu_iotlb_gather * gather)877 static void viommu_iotlb_sync(struct iommu_domain *domain,
878 struct iommu_iotlb_gather *gather)
879 {
880 struct viommu_domain *vdomain = to_viommu_domain(domain);
881
882 viommu_sync_req(vdomain->viommu);
883 }
884
viommu_get_resv_regions(struct device * dev,struct list_head * head)885 static void viommu_get_resv_regions(struct device *dev, struct list_head *head)
886 {
887 struct iommu_resv_region *entry, *new_entry, *msi = NULL;
888 struct viommu_endpoint *vdev = dev_iommu_priv_get(dev);
889 int prot = IOMMU_WRITE | IOMMU_NOEXEC | IOMMU_MMIO;
890
891 list_for_each_entry(entry, &vdev->resv_regions, list) {
892 if (entry->type == IOMMU_RESV_MSI)
893 msi = entry;
894
895 new_entry = kmemdup(entry, sizeof(*entry), GFP_KERNEL);
896 if (!new_entry)
897 return;
898 list_add_tail(&new_entry->list, head);
899 }
900
901 /*
902 * If the device didn't register any bypass MSI window, add a
903 * software-mapped region.
904 */
905 if (!msi) {
906 msi = iommu_alloc_resv_region(MSI_IOVA_BASE, MSI_IOVA_LENGTH,
907 prot, IOMMU_RESV_SW_MSI);
908 if (!msi)
909 return;
910
911 list_add_tail(&msi->list, head);
912 }
913
914 iommu_dma_get_resv_regions(dev, head);
915 }
916
917 static struct iommu_ops viommu_ops;
918 static struct virtio_driver virtio_iommu_drv;
919
viommu_match_node(struct device * dev,const void * data)920 static int viommu_match_node(struct device *dev, const void *data)
921 {
922 return dev->parent->fwnode == data;
923 }
924
viommu_get_by_fwnode(struct fwnode_handle * fwnode)925 static struct viommu_dev *viommu_get_by_fwnode(struct fwnode_handle *fwnode)
926 {
927 struct device *dev = driver_find_device(&virtio_iommu_drv.driver, NULL,
928 fwnode, viommu_match_node);
929 put_device(dev);
930
931 return dev ? dev_to_virtio(dev)->priv : NULL;
932 }
933
viommu_probe_device(struct device * dev)934 static struct iommu_device *viommu_probe_device(struct device *dev)
935 {
936 int ret;
937 struct viommu_endpoint *vdev;
938 struct viommu_dev *viommu = NULL;
939 struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
940
941 if (!fwspec || fwspec->ops != &viommu_ops)
942 return ERR_PTR(-ENODEV);
943
944 viommu = viommu_get_by_fwnode(fwspec->iommu_fwnode);
945 if (!viommu)
946 return ERR_PTR(-ENODEV);
947
948 vdev = kzalloc(sizeof(*vdev), GFP_KERNEL);
949 if (!vdev)
950 return ERR_PTR(-ENOMEM);
951
952 vdev->dev = dev;
953 vdev->viommu = viommu;
954 INIT_LIST_HEAD(&vdev->resv_regions);
955 dev_iommu_priv_set(dev, vdev);
956
957 if (viommu->probe_size) {
958 /* Get additional information for this endpoint */
959 ret = viommu_probe_endpoint(viommu, dev);
960 if (ret)
961 goto err_free_dev;
962 }
963
964 return &viommu->iommu;
965
966 err_free_dev:
967 generic_iommu_put_resv_regions(dev, &vdev->resv_regions);
968 kfree(vdev);
969
970 return ERR_PTR(ret);
971 }
972
viommu_probe_finalize(struct device * dev)973 static void viommu_probe_finalize(struct device *dev)
974 {
975 #ifndef CONFIG_ARCH_HAS_SETUP_DMA_OPS
976 /* First clear the DMA ops in case we're switching from a DMA domain */
977 set_dma_ops(dev, NULL);
978 iommu_setup_dma_ops(dev, 0, U64_MAX);
979 #endif
980 }
981
viommu_release_device(struct device * dev)982 static void viommu_release_device(struct device *dev)
983 {
984 struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
985 struct viommu_endpoint *vdev;
986
987 if (!fwspec || fwspec->ops != &viommu_ops)
988 return;
989
990 vdev = dev_iommu_priv_get(dev);
991
992 generic_iommu_put_resv_regions(dev, &vdev->resv_regions);
993 kfree(vdev);
994 }
995
viommu_device_group(struct device * dev)996 static struct iommu_group *viommu_device_group(struct device *dev)
997 {
998 if (dev_is_pci(dev))
999 return pci_device_group(dev);
1000 else
1001 return generic_device_group(dev);
1002 }
1003
viommu_of_xlate(struct device * dev,struct of_phandle_args * args)1004 static int viommu_of_xlate(struct device *dev, struct of_phandle_args *args)
1005 {
1006 return iommu_fwspec_add_ids(dev, args->args, 1);
1007 }
1008
viommu_capable(enum iommu_cap cap)1009 static bool viommu_capable(enum iommu_cap cap)
1010 {
1011 switch (cap) {
1012 case IOMMU_CAP_CACHE_COHERENCY:
1013 return true;
1014 default:
1015 return false;
1016 }
1017 }
1018
1019 static struct iommu_ops viommu_ops = {
1020 .capable = viommu_capable,
1021 .domain_alloc = viommu_domain_alloc,
1022 .probe_device = viommu_probe_device,
1023 .probe_finalize = viommu_probe_finalize,
1024 .release_device = viommu_release_device,
1025 .device_group = viommu_device_group,
1026 .get_resv_regions = viommu_get_resv_regions,
1027 .put_resv_regions = generic_iommu_put_resv_regions,
1028 .of_xlate = viommu_of_xlate,
1029 .owner = THIS_MODULE,
1030 .default_domain_ops = &(const struct iommu_domain_ops) {
1031 .attach_dev = viommu_attach_dev,
1032 .map = viommu_map,
1033 .unmap = viommu_unmap,
1034 .iova_to_phys = viommu_iova_to_phys,
1035 .iotlb_sync = viommu_iotlb_sync,
1036 .free = viommu_domain_free,
1037 }
1038 };
1039
viommu_init_vqs(struct viommu_dev * viommu)1040 static int viommu_init_vqs(struct viommu_dev *viommu)
1041 {
1042 struct virtio_device *vdev = dev_to_virtio(viommu->dev);
1043 const char *names[] = { "request", "event" };
1044 vq_callback_t *callbacks[] = {
1045 NULL, /* No async requests */
1046 viommu_event_handler,
1047 };
1048
1049 return virtio_find_vqs(vdev, VIOMMU_NR_VQS, viommu->vqs, callbacks,
1050 names, NULL);
1051 }
1052
viommu_fill_evtq(struct viommu_dev * viommu)1053 static int viommu_fill_evtq(struct viommu_dev *viommu)
1054 {
1055 int i, ret;
1056 struct scatterlist sg[1];
1057 struct viommu_event *evts;
1058 struct virtqueue *vq = viommu->vqs[VIOMMU_EVENT_VQ];
1059 size_t nr_evts = vq->num_free;
1060
1061 viommu->evts = evts = devm_kmalloc_array(viommu->dev, nr_evts,
1062 sizeof(*evts), GFP_KERNEL);
1063 if (!evts)
1064 return -ENOMEM;
1065
1066 for (i = 0; i < nr_evts; i++) {
1067 sg_init_one(sg, &evts[i], sizeof(*evts));
1068 ret = virtqueue_add_inbuf(vq, sg, 1, &evts[i], GFP_KERNEL);
1069 if (ret)
1070 return ret;
1071 }
1072
1073 return 0;
1074 }
1075
viommu_probe(struct virtio_device * vdev)1076 static int viommu_probe(struct virtio_device *vdev)
1077 {
1078 struct device *parent_dev = vdev->dev.parent;
1079 struct viommu_dev *viommu = NULL;
1080 struct device *dev = &vdev->dev;
1081 u64 input_start = 0;
1082 u64 input_end = -1UL;
1083 int ret;
1084
1085 if (!virtio_has_feature(vdev, VIRTIO_F_VERSION_1) ||
1086 !virtio_has_feature(vdev, VIRTIO_IOMMU_F_MAP_UNMAP))
1087 return -ENODEV;
1088
1089 viommu = devm_kzalloc(dev, sizeof(*viommu), GFP_KERNEL);
1090 if (!viommu)
1091 return -ENOMEM;
1092
1093 spin_lock_init(&viommu->request_lock);
1094 ida_init(&viommu->domain_ids);
1095 viommu->dev = dev;
1096 viommu->vdev = vdev;
1097 INIT_LIST_HEAD(&viommu->requests);
1098
1099 ret = viommu_init_vqs(viommu);
1100 if (ret)
1101 return ret;
1102
1103 virtio_cread_le(vdev, struct virtio_iommu_config, page_size_mask,
1104 &viommu->pgsize_bitmap);
1105
1106 if (!viommu->pgsize_bitmap) {
1107 ret = -EINVAL;
1108 goto err_free_vqs;
1109 }
1110
1111 viommu->map_flags = VIRTIO_IOMMU_MAP_F_READ | VIRTIO_IOMMU_MAP_F_WRITE;
1112 viommu->last_domain = ~0U;
1113
1114 /* Optional features */
1115 virtio_cread_le_feature(vdev, VIRTIO_IOMMU_F_INPUT_RANGE,
1116 struct virtio_iommu_config, input_range.start,
1117 &input_start);
1118
1119 virtio_cread_le_feature(vdev, VIRTIO_IOMMU_F_INPUT_RANGE,
1120 struct virtio_iommu_config, input_range.end,
1121 &input_end);
1122
1123 virtio_cread_le_feature(vdev, VIRTIO_IOMMU_F_DOMAIN_RANGE,
1124 struct virtio_iommu_config, domain_range.start,
1125 &viommu->first_domain);
1126
1127 virtio_cread_le_feature(vdev, VIRTIO_IOMMU_F_DOMAIN_RANGE,
1128 struct virtio_iommu_config, domain_range.end,
1129 &viommu->last_domain);
1130
1131 virtio_cread_le_feature(vdev, VIRTIO_IOMMU_F_PROBE,
1132 struct virtio_iommu_config, probe_size,
1133 &viommu->probe_size);
1134
1135 viommu->geometry = (struct iommu_domain_geometry) {
1136 .aperture_start = input_start,
1137 .aperture_end = input_end,
1138 .force_aperture = true,
1139 };
1140
1141 if (virtio_has_feature(vdev, VIRTIO_IOMMU_F_MMIO))
1142 viommu->map_flags |= VIRTIO_IOMMU_MAP_F_MMIO;
1143
1144 viommu_ops.pgsize_bitmap = viommu->pgsize_bitmap;
1145
1146 virtio_device_ready(vdev);
1147
1148 /* Populate the event queue with buffers */
1149 ret = viommu_fill_evtq(viommu);
1150 if (ret)
1151 goto err_free_vqs;
1152
1153 ret = iommu_device_sysfs_add(&viommu->iommu, dev, NULL, "%s",
1154 virtio_bus_name(vdev));
1155 if (ret)
1156 goto err_free_vqs;
1157
1158 iommu_device_register(&viommu->iommu, &viommu_ops, parent_dev);
1159
1160 #ifdef CONFIG_PCI
1161 if (pci_bus_type.iommu_ops != &viommu_ops) {
1162 ret = bus_set_iommu(&pci_bus_type, &viommu_ops);
1163 if (ret)
1164 goto err_unregister;
1165 }
1166 #endif
1167 #ifdef CONFIG_ARM_AMBA
1168 if (amba_bustype.iommu_ops != &viommu_ops) {
1169 ret = bus_set_iommu(&amba_bustype, &viommu_ops);
1170 if (ret)
1171 goto err_unregister;
1172 }
1173 #endif
1174 if (platform_bus_type.iommu_ops != &viommu_ops) {
1175 ret = bus_set_iommu(&platform_bus_type, &viommu_ops);
1176 if (ret)
1177 goto err_unregister;
1178 }
1179
1180 vdev->priv = viommu;
1181
1182 dev_info(dev, "input address: %u bits\n",
1183 order_base_2(viommu->geometry.aperture_end));
1184 dev_info(dev, "page mask: %#llx\n", viommu->pgsize_bitmap);
1185
1186 return 0;
1187
1188 err_unregister:
1189 iommu_device_sysfs_remove(&viommu->iommu);
1190 iommu_device_unregister(&viommu->iommu);
1191 err_free_vqs:
1192 vdev->config->del_vqs(vdev);
1193
1194 return ret;
1195 }
1196
viommu_remove(struct virtio_device * vdev)1197 static void viommu_remove(struct virtio_device *vdev)
1198 {
1199 struct viommu_dev *viommu = vdev->priv;
1200
1201 iommu_device_sysfs_remove(&viommu->iommu);
1202 iommu_device_unregister(&viommu->iommu);
1203
1204 /* Stop all virtqueues */
1205 virtio_reset_device(vdev);
1206 vdev->config->del_vqs(vdev);
1207
1208 dev_info(&vdev->dev, "device removed\n");
1209 }
1210
viommu_config_changed(struct virtio_device * vdev)1211 static void viommu_config_changed(struct virtio_device *vdev)
1212 {
1213 dev_warn(&vdev->dev, "config changed\n");
1214 }
1215
1216 static unsigned int features[] = {
1217 VIRTIO_IOMMU_F_MAP_UNMAP,
1218 VIRTIO_IOMMU_F_INPUT_RANGE,
1219 VIRTIO_IOMMU_F_DOMAIN_RANGE,
1220 VIRTIO_IOMMU_F_PROBE,
1221 VIRTIO_IOMMU_F_MMIO,
1222 VIRTIO_IOMMU_F_BYPASS_CONFIG,
1223 };
1224
1225 static struct virtio_device_id id_table[] = {
1226 { VIRTIO_ID_IOMMU, VIRTIO_DEV_ANY_ID },
1227 { 0 },
1228 };
1229 MODULE_DEVICE_TABLE(virtio, id_table);
1230
1231 static struct virtio_driver virtio_iommu_drv = {
1232 .driver.name = KBUILD_MODNAME,
1233 .driver.owner = THIS_MODULE,
1234 .id_table = id_table,
1235 .feature_table = features,
1236 .feature_table_size = ARRAY_SIZE(features),
1237 .probe = viommu_probe,
1238 .remove = viommu_remove,
1239 .config_changed = viommu_config_changed,
1240 };
1241
1242 module_virtio_driver(virtio_iommu_drv);
1243
1244 MODULE_DESCRIPTION("Virtio IOMMU driver");
1245 MODULE_AUTHOR("Jean-Philippe Brucker <jean-philippe.brucker@arm.com>");
1246 MODULE_LICENSE("GPL v2");
1247