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