1 // SPDX-License-Identifier: GPL-2.0-only
2 /* Copyright (C) 2024 Intel Corporation
3 */
4 #define pr_fmt(fmt) "iommufd: " fmt
5
6 #include <linux/anon_inodes.h>
7 #include <linux/file.h>
8 #include <linux/fs.h>
9 #include <linux/iommufd.h>
10 #include <linux/module.h>
11 #include <linux/mutex.h>
12 #include <linux/poll.h>
13 #include <uapi/linux/iommufd.h>
14
15 #include "../iommu-priv.h"
16 #include "iommufd_private.h"
17
18 /* IOMMUFD_OBJ_FAULT Functions */
iommufd_auto_response_faults(struct iommufd_hw_pagetable * hwpt,struct iommufd_attach_handle * handle)19 void iommufd_auto_response_faults(struct iommufd_hw_pagetable *hwpt,
20 struct iommufd_attach_handle *handle)
21 {
22 struct iommufd_fault *fault = hwpt->fault;
23 struct iopf_group *group, *next;
24 struct list_head free_list;
25 unsigned long index;
26
27 if (!fault || !handle)
28 return;
29 INIT_LIST_HEAD(&free_list);
30
31 mutex_lock(&fault->mutex);
32 spin_lock(&fault->common.lock);
33 list_for_each_entry_safe(group, next, &fault->common.deliver, node) {
34 if (group->attach_handle != &handle->handle)
35 continue;
36 list_move(&group->node, &free_list);
37 }
38 spin_unlock(&fault->common.lock);
39
40 list_for_each_entry_safe(group, next, &free_list, node) {
41 list_del(&group->node);
42 iopf_group_response(group, IOMMU_PAGE_RESP_INVALID);
43 iopf_free_group(group);
44 }
45
46 xa_for_each(&fault->response, index, group) {
47 if (group->attach_handle != &handle->handle)
48 continue;
49 xa_erase(&fault->response, index);
50 iopf_group_response(group, IOMMU_PAGE_RESP_INVALID);
51 iopf_free_group(group);
52 }
53 mutex_unlock(&fault->mutex);
54 }
55
iommufd_fault_destroy(struct iommufd_object * obj)56 void iommufd_fault_destroy(struct iommufd_object *obj)
57 {
58 struct iommufd_eventq *eventq =
59 container_of(obj, struct iommufd_eventq, obj);
60 struct iommufd_fault *fault = eventq_to_fault(eventq);
61 struct iopf_group *group, *next;
62 unsigned long index;
63
64 /*
65 * The iommufd object's reference count is zero at this point.
66 * We can be confident that no other threads are currently
67 * accessing this pointer. Therefore, acquiring the mutex here
68 * is unnecessary.
69 */
70 list_for_each_entry_safe(group, next, &fault->common.deliver, node) {
71 list_del(&group->node);
72 iopf_group_response(group, IOMMU_PAGE_RESP_INVALID);
73 iopf_free_group(group);
74 }
75 xa_for_each(&fault->response, index, group) {
76 xa_erase(&fault->response, index);
77 iopf_group_response(group, IOMMU_PAGE_RESP_INVALID);
78 iopf_free_group(group);
79 }
80 xa_destroy(&fault->response);
81 mutex_destroy(&fault->mutex);
82 }
83
iommufd_compose_fault_message(struct iommu_fault * fault,struct iommu_hwpt_pgfault * hwpt_fault,struct iommufd_device * idev,u32 cookie)84 static void iommufd_compose_fault_message(struct iommu_fault *fault,
85 struct iommu_hwpt_pgfault *hwpt_fault,
86 struct iommufd_device *idev,
87 u32 cookie)
88 {
89 hwpt_fault->flags = fault->prm.flags;
90 hwpt_fault->dev_id = idev->obj.id;
91 hwpt_fault->pasid = fault->prm.pasid;
92 hwpt_fault->grpid = fault->prm.grpid;
93 hwpt_fault->perm = fault->prm.perm;
94 hwpt_fault->addr = fault->prm.addr;
95 hwpt_fault->length = 0;
96 hwpt_fault->cookie = cookie;
97 }
98
99 /* Fetch the first node out of the fault->deliver list */
100 static struct iopf_group *
iommufd_fault_deliver_fetch(struct iommufd_fault * fault)101 iommufd_fault_deliver_fetch(struct iommufd_fault *fault)
102 {
103 struct list_head *list = &fault->common.deliver;
104 struct iopf_group *group = NULL;
105
106 spin_lock(&fault->common.lock);
107 if (!list_empty(list)) {
108 group = list_first_entry(list, struct iopf_group, node);
109 list_del(&group->node);
110 }
111 spin_unlock(&fault->common.lock);
112 return group;
113 }
114
115 /* Restore a node back to the head of the fault->deliver list */
iommufd_fault_deliver_restore(struct iommufd_fault * fault,struct iopf_group * group)116 static void iommufd_fault_deliver_restore(struct iommufd_fault *fault,
117 struct iopf_group *group)
118 {
119 spin_lock(&fault->common.lock);
120 list_add(&group->node, &fault->common.deliver);
121 spin_unlock(&fault->common.lock);
122 }
123
iommufd_fault_fops_read(struct file * filep,char __user * buf,size_t count,loff_t * ppos)124 static ssize_t iommufd_fault_fops_read(struct file *filep, char __user *buf,
125 size_t count, loff_t *ppos)
126 {
127 size_t fault_size = sizeof(struct iommu_hwpt_pgfault);
128 struct iommufd_eventq *eventq = filep->private_data;
129 struct iommufd_fault *fault = eventq_to_fault(eventq);
130 struct iommu_hwpt_pgfault data = {};
131 struct iommufd_device *idev;
132 struct iopf_group *group;
133 struct iopf_fault *iopf;
134 size_t done = 0;
135 int rc = 0;
136
137 if (*ppos || count % fault_size)
138 return -ESPIPE;
139
140 mutex_lock(&fault->mutex);
141 while ((group = iommufd_fault_deliver_fetch(fault))) {
142 if (done >= count ||
143 group->fault_count * fault_size > count - done) {
144 iommufd_fault_deliver_restore(fault, group);
145 break;
146 }
147
148 rc = xa_alloc(&fault->response, &group->cookie, group,
149 xa_limit_32b, GFP_KERNEL);
150 if (rc) {
151 iommufd_fault_deliver_restore(fault, group);
152 break;
153 }
154
155 idev = to_iommufd_handle(group->attach_handle)->idev;
156 list_for_each_entry(iopf, &group->faults, list) {
157 iommufd_compose_fault_message(&iopf->fault,
158 &data, idev,
159 group->cookie);
160 if (copy_to_user(buf + done, &data, fault_size)) {
161 xa_erase(&fault->response, group->cookie);
162 iommufd_fault_deliver_restore(fault, group);
163 rc = -EFAULT;
164 break;
165 }
166 done += fault_size;
167 }
168 }
169 mutex_unlock(&fault->mutex);
170
171 return done == 0 ? rc : done;
172 }
173
iommufd_fault_fops_write(struct file * filep,const char __user * buf,size_t count,loff_t * ppos)174 static ssize_t iommufd_fault_fops_write(struct file *filep, const char __user *buf,
175 size_t count, loff_t *ppos)
176 {
177 size_t response_size = sizeof(struct iommu_hwpt_page_response);
178 struct iommufd_eventq *eventq = filep->private_data;
179 struct iommufd_fault *fault = eventq_to_fault(eventq);
180 struct iommu_hwpt_page_response response;
181 struct iopf_group *group;
182 size_t done = 0;
183 int rc = 0;
184
185 if (*ppos || count % response_size)
186 return -ESPIPE;
187
188 mutex_lock(&fault->mutex);
189 while (count > done) {
190 rc = copy_from_user(&response, buf + done, response_size);
191 if (rc)
192 break;
193
194 static_assert((int)IOMMUFD_PAGE_RESP_SUCCESS ==
195 (int)IOMMU_PAGE_RESP_SUCCESS);
196 static_assert((int)IOMMUFD_PAGE_RESP_INVALID ==
197 (int)IOMMU_PAGE_RESP_INVALID);
198 if (response.code != IOMMUFD_PAGE_RESP_SUCCESS &&
199 response.code != IOMMUFD_PAGE_RESP_INVALID) {
200 rc = -EINVAL;
201 break;
202 }
203
204 group = xa_erase(&fault->response, response.cookie);
205 if (!group) {
206 rc = -EINVAL;
207 break;
208 }
209
210 iopf_group_response(group, response.code);
211 iopf_free_group(group);
212 done += response_size;
213 }
214 mutex_unlock(&fault->mutex);
215
216 return done == 0 ? rc : done;
217 }
218
219 /* IOMMUFD_OBJ_VEVENTQ Functions */
220
iommufd_veventq_abort(struct iommufd_object * obj)221 void iommufd_veventq_abort(struct iommufd_object *obj)
222 {
223 struct iommufd_eventq *eventq =
224 container_of(obj, struct iommufd_eventq, obj);
225 struct iommufd_veventq *veventq = eventq_to_veventq(eventq);
226 struct iommufd_viommu *viommu = veventq->viommu;
227 struct iommufd_vevent *cur, *next;
228
229 lockdep_assert_held_write(&viommu->veventqs_rwsem);
230
231 list_for_each_entry_safe(cur, next, &eventq->deliver, node) {
232 list_del(&cur->node);
233 if (cur != &veventq->lost_events_header)
234 kfree(cur);
235 }
236
237 refcount_dec(&viommu->obj.users);
238 list_del(&veventq->node);
239 }
240
iommufd_veventq_destroy(struct iommufd_object * obj)241 void iommufd_veventq_destroy(struct iommufd_object *obj)
242 {
243 struct iommufd_veventq *veventq = eventq_to_veventq(
244 container_of(obj, struct iommufd_eventq, obj));
245
246 down_write(&veventq->viommu->veventqs_rwsem);
247 iommufd_veventq_abort(obj);
248 up_write(&veventq->viommu->veventqs_rwsem);
249 }
250
251 static struct iommufd_vevent *
iommufd_veventq_deliver_fetch(struct iommufd_veventq * veventq)252 iommufd_veventq_deliver_fetch(struct iommufd_veventq *veventq)
253 {
254 struct iommufd_eventq *eventq = &veventq->common;
255 struct list_head *list = &eventq->deliver;
256 struct iommufd_vevent *vevent = NULL;
257
258 spin_lock(&eventq->lock);
259 if (!list_empty(list)) {
260 struct iommufd_vevent *next;
261
262 next = list_first_entry(list, struct iommufd_vevent, node);
263 /* Make a copy of the lost_events_header for copy_to_user */
264 if (next == &veventq->lost_events_header) {
265 vevent = kzalloc(sizeof(*vevent), GFP_ATOMIC);
266 if (!vevent)
267 goto out_unlock;
268 }
269 list_del(&next->node);
270 if (vevent)
271 memcpy(vevent, next, sizeof(*vevent));
272 else
273 vevent = next;
274 }
275 out_unlock:
276 spin_unlock(&eventq->lock);
277 return vevent;
278 }
279
iommufd_veventq_deliver_restore(struct iommufd_veventq * veventq,struct iommufd_vevent * vevent)280 static void iommufd_veventq_deliver_restore(struct iommufd_veventq *veventq,
281 struct iommufd_vevent *vevent)
282 {
283 struct iommufd_eventq *eventq = &veventq->common;
284 struct list_head *list = &eventq->deliver;
285
286 spin_lock(&eventq->lock);
287 if (vevent_for_lost_events_header(vevent)) {
288 /* Remove the copy of the lost_events_header */
289 kfree(vevent);
290 vevent = NULL;
291 /* An empty list needs the lost_events_header back */
292 if (list_empty(list))
293 vevent = &veventq->lost_events_header;
294 }
295 if (vevent)
296 list_add(&vevent->node, list);
297 spin_unlock(&eventq->lock);
298 }
299
iommufd_veventq_fops_read(struct file * filep,char __user * buf,size_t count,loff_t * ppos)300 static ssize_t iommufd_veventq_fops_read(struct file *filep, char __user *buf,
301 size_t count, loff_t *ppos)
302 {
303 struct iommufd_eventq *eventq = filep->private_data;
304 struct iommufd_veventq *veventq = eventq_to_veventq(eventq);
305 struct iommufd_vevent_header *hdr;
306 struct iommufd_vevent *cur;
307 size_t done = 0;
308 int rc = 0;
309
310 if (*ppos)
311 return -ESPIPE;
312
313 while ((cur = iommufd_veventq_deliver_fetch(veventq))) {
314 /* Validate the remaining bytes against the header size */
315 if (done >= count || sizeof(*hdr) > count - done) {
316 iommufd_veventq_deliver_restore(veventq, cur);
317 break;
318 }
319 hdr = &cur->header;
320
321 /* If being a normal vEVENT, validate against the full size */
322 if (!vevent_for_lost_events_header(cur) &&
323 sizeof(hdr) + cur->data_len > count - done) {
324 iommufd_veventq_deliver_restore(veventq, cur);
325 break;
326 }
327
328 if (copy_to_user(buf + done, hdr, sizeof(*hdr))) {
329 iommufd_veventq_deliver_restore(veventq, cur);
330 rc = -EFAULT;
331 break;
332 }
333 done += sizeof(*hdr);
334
335 if (cur->data_len &&
336 copy_to_user(buf + done, cur->event_data, cur->data_len)) {
337 iommufd_veventq_deliver_restore(veventq, cur);
338 rc = -EFAULT;
339 break;
340 }
341 spin_lock(&eventq->lock);
342 if (!vevent_for_lost_events_header(cur))
343 veventq->num_events--;
344 spin_unlock(&eventq->lock);
345 done += cur->data_len;
346 kfree(cur);
347 }
348
349 return done == 0 ? rc : done;
350 }
351
352 /* Common Event Queue Functions */
353
iommufd_eventq_fops_poll(struct file * filep,struct poll_table_struct * wait)354 static __poll_t iommufd_eventq_fops_poll(struct file *filep,
355 struct poll_table_struct *wait)
356 {
357 struct iommufd_eventq *eventq = filep->private_data;
358 __poll_t pollflags = 0;
359
360 if (eventq->obj.type == IOMMUFD_OBJ_FAULT)
361 pollflags |= EPOLLOUT;
362
363 poll_wait(filep, &eventq->wait_queue, wait);
364 spin_lock(&eventq->lock);
365 if (!list_empty(&eventq->deliver))
366 pollflags |= EPOLLIN | EPOLLRDNORM;
367 spin_unlock(&eventq->lock);
368
369 return pollflags;
370 }
371
iommufd_eventq_fops_release(struct inode * inode,struct file * filep)372 static int iommufd_eventq_fops_release(struct inode *inode, struct file *filep)
373 {
374 struct iommufd_eventq *eventq = filep->private_data;
375
376 refcount_dec(&eventq->obj.users);
377 iommufd_ctx_put(eventq->ictx);
378 return 0;
379 }
380
381 #define INIT_EVENTQ_FOPS(read_op, write_op) \
382 ((const struct file_operations){ \
383 .owner = THIS_MODULE, \
384 .open = nonseekable_open, \
385 .read = read_op, \
386 .write = write_op, \
387 .poll = iommufd_eventq_fops_poll, \
388 .release = iommufd_eventq_fops_release, \
389 })
390
iommufd_eventq_init(struct iommufd_eventq * eventq,char * name,struct iommufd_ctx * ictx,const struct file_operations * fops)391 static int iommufd_eventq_init(struct iommufd_eventq *eventq, char *name,
392 struct iommufd_ctx *ictx,
393 const struct file_operations *fops)
394 {
395 struct file *filep;
396 int fdno;
397
398 spin_lock_init(&eventq->lock);
399 INIT_LIST_HEAD(&eventq->deliver);
400 init_waitqueue_head(&eventq->wait_queue);
401
402 filep = anon_inode_getfile(name, fops, eventq, O_RDWR);
403 if (IS_ERR(filep))
404 return PTR_ERR(filep);
405
406 eventq->ictx = ictx;
407 iommufd_ctx_get(eventq->ictx);
408 eventq->filep = filep;
409 refcount_inc(&eventq->obj.users);
410
411 fdno = get_unused_fd_flags(O_CLOEXEC);
412 if (fdno < 0)
413 fput(filep);
414 return fdno;
415 }
416
417 static const struct file_operations iommufd_fault_fops =
418 INIT_EVENTQ_FOPS(iommufd_fault_fops_read, iommufd_fault_fops_write);
419
iommufd_fault_alloc(struct iommufd_ucmd * ucmd)420 int iommufd_fault_alloc(struct iommufd_ucmd *ucmd)
421 {
422 struct iommu_fault_alloc *cmd = ucmd->cmd;
423 struct iommufd_fault *fault;
424 int fdno;
425 int rc;
426
427 if (cmd->flags)
428 return -EOPNOTSUPP;
429
430 fault = __iommufd_object_alloc(ucmd->ictx, fault, IOMMUFD_OBJ_FAULT,
431 common.obj);
432 if (IS_ERR(fault))
433 return PTR_ERR(fault);
434
435 xa_init_flags(&fault->response, XA_FLAGS_ALLOC1);
436 mutex_init(&fault->mutex);
437
438 fdno = iommufd_eventq_init(&fault->common, "[iommufd-pgfault]",
439 ucmd->ictx, &iommufd_fault_fops);
440 if (fdno < 0) {
441 rc = fdno;
442 goto out_abort;
443 }
444
445 cmd->out_fault_id = fault->common.obj.id;
446 cmd->out_fault_fd = fdno;
447
448 rc = iommufd_ucmd_respond(ucmd, sizeof(*cmd));
449 if (rc)
450 goto out_put_fdno;
451 iommufd_object_finalize(ucmd->ictx, &fault->common.obj);
452
453 fd_install(fdno, fault->common.filep);
454
455 return 0;
456 out_put_fdno:
457 put_unused_fd(fdno);
458 fput(fault->common.filep);
459 out_abort:
460 iommufd_object_abort_and_destroy(ucmd->ictx, &fault->common.obj);
461
462 return rc;
463 }
464
iommufd_fault_iopf_handler(struct iopf_group * group)465 int iommufd_fault_iopf_handler(struct iopf_group *group)
466 {
467 struct iommufd_hw_pagetable *hwpt;
468 struct iommufd_fault *fault;
469
470 hwpt = group->attach_handle->domain->iommufd_hwpt;
471 fault = hwpt->fault;
472
473 spin_lock(&fault->common.lock);
474 list_add_tail(&group->node, &fault->common.deliver);
475 spin_unlock(&fault->common.lock);
476
477 wake_up_interruptible(&fault->common.wait_queue);
478
479 return 0;
480 }
481
482 static const struct file_operations iommufd_veventq_fops =
483 INIT_EVENTQ_FOPS(iommufd_veventq_fops_read, NULL);
484
iommufd_veventq_alloc(struct iommufd_ucmd * ucmd)485 int iommufd_veventq_alloc(struct iommufd_ucmd *ucmd)
486 {
487 struct iommu_veventq_alloc *cmd = ucmd->cmd;
488 struct iommufd_veventq *veventq;
489 struct iommufd_viommu *viommu;
490 int fdno;
491 int rc;
492
493 if (cmd->flags || cmd->__reserved ||
494 cmd->type == IOMMU_VEVENTQ_TYPE_DEFAULT)
495 return -EOPNOTSUPP;
496 if (!cmd->veventq_depth)
497 return -EINVAL;
498
499 viommu = iommufd_get_viommu(ucmd, cmd->viommu_id);
500 if (IS_ERR(viommu))
501 return PTR_ERR(viommu);
502
503 down_write(&viommu->veventqs_rwsem);
504
505 if (iommufd_viommu_find_veventq(viommu, cmd->type)) {
506 rc = -EEXIST;
507 goto out_unlock_veventqs;
508 }
509
510 veventq = __iommufd_object_alloc(ucmd->ictx, veventq,
511 IOMMUFD_OBJ_VEVENTQ, common.obj);
512 if (IS_ERR(veventq)) {
513 rc = PTR_ERR(veventq);
514 goto out_unlock_veventqs;
515 }
516
517 veventq->type = cmd->type;
518 veventq->viommu = viommu;
519 refcount_inc(&viommu->obj.users);
520 veventq->depth = cmd->veventq_depth;
521 list_add_tail(&veventq->node, &viommu->veventqs);
522 veventq->lost_events_header.header.flags =
523 IOMMU_VEVENTQ_FLAG_LOST_EVENTS;
524
525 fdno = iommufd_eventq_init(&veventq->common, "[iommufd-viommu-event]",
526 ucmd->ictx, &iommufd_veventq_fops);
527 if (fdno < 0) {
528 rc = fdno;
529 goto out_abort;
530 }
531
532 cmd->out_veventq_id = veventq->common.obj.id;
533 cmd->out_veventq_fd = fdno;
534
535 rc = iommufd_ucmd_respond(ucmd, sizeof(*cmd));
536 if (rc)
537 goto out_put_fdno;
538
539 iommufd_object_finalize(ucmd->ictx, &veventq->common.obj);
540 fd_install(fdno, veventq->common.filep);
541 goto out_unlock_veventqs;
542
543 out_put_fdno:
544 put_unused_fd(fdno);
545 fput(veventq->common.filep);
546 out_abort:
547 iommufd_object_abort_and_destroy(ucmd->ictx, &veventq->common.obj);
548 out_unlock_veventqs:
549 up_write(&viommu->veventqs_rwsem);
550 iommufd_put_object(ucmd->ictx, &viommu->obj);
551 return rc;
552 }
553