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1// SPDX-License-Identifier: GPL-2.0-only
2#include <linux/virtio.h>
3#include <linux/spinlock.h>
4#include <linux/virtio_config.h>
5#include <linux/virtio_anchor.h>
6#include <linux/module.h>
7#include <linux/idr.h>
8#include <linux/of.h>
9#include <uapi/linux/virtio_ids.h>
10
11/* Unique numbering for virtio devices. */
12static DEFINE_IDA(virtio_index_ida);
13
14static ssize_t device_show(struct device *_d,
15 struct device_attribute *attr, char *buf)
16{
17 struct virtio_device *dev = dev_to_virtio(_d);
18 return sysfs_emit(buf, "0x%04x\n", dev->id.device);
19}
20static DEVICE_ATTR_RO(device);
21
22static ssize_t vendor_show(struct device *_d,
23 struct device_attribute *attr, char *buf)
24{
25 struct virtio_device *dev = dev_to_virtio(_d);
26 return sysfs_emit(buf, "0x%04x\n", dev->id.vendor);
27}
28static DEVICE_ATTR_RO(vendor);
29
30static ssize_t status_show(struct device *_d,
31 struct device_attribute *attr, char *buf)
32{
33 struct virtio_device *dev = dev_to_virtio(_d);
34 return sysfs_emit(buf, "0x%08x\n", dev->config->get_status(dev));
35}
36static DEVICE_ATTR_RO(status);
37
38static ssize_t modalias_show(struct device *_d,
39 struct device_attribute *attr, char *buf)
40{
41 struct virtio_device *dev = dev_to_virtio(_d);
42 return sysfs_emit(buf, "virtio:d%08Xv%08X\n",
43 dev->id.device, dev->id.vendor);
44}
45static DEVICE_ATTR_RO(modalias);
46
47static ssize_t features_show(struct device *_d,
48 struct device_attribute *attr, char *buf)
49{
50 struct virtio_device *dev = dev_to_virtio(_d);
51 unsigned int i;
52 ssize_t len = 0;
53
54 /* We actually represent this as a bitstring, as it could be
55 * arbitrary length in future. */
56 for (i = 0; i < VIRTIO_FEATURES_BITS; i++)
57 len += sysfs_emit_at(buf, len, "%c",
58 __virtio_test_bit(dev, i) ? '1' : '0');
59 len += sysfs_emit_at(buf, len, "\n");
60 return len;
61}
62static DEVICE_ATTR_RO(features);
63
64static struct attribute *virtio_dev_attrs[] = {
65 &dev_attr_device.attr,
66 &dev_attr_vendor.attr,
67 &dev_attr_status.attr,
68 &dev_attr_modalias.attr,
69 &dev_attr_features.attr,
70 NULL,
71};
72ATTRIBUTE_GROUPS(virtio_dev);
73
74static inline int virtio_id_match(const struct virtio_device *dev,
75 const struct virtio_device_id *id)
76{
77 if (id->device != dev->id.device && id->device != VIRTIO_DEV_ANY_ID)
78 return 0;
79
80 return id->vendor == VIRTIO_DEV_ANY_ID || id->vendor == dev->id.vendor;
81}
82
83/* This looks through all the IDs a driver claims to support. If any of them
84 * match, we return 1 and the kernel will call virtio_dev_probe(). */
85static int virtio_dev_match(struct device *_dv, const struct device_driver *_dr)
86{
87 unsigned int i;
88 struct virtio_device *dev = dev_to_virtio(_dv);
89 const struct virtio_device_id *ids;
90
91 ids = drv_to_virtio(_dr)->id_table;
92 for (i = 0; ids[i].device; i++)
93 if (virtio_id_match(dev, &ids[i]))
94 return 1;
95 return 0;
96}
97
98static int virtio_uevent(const struct device *_dv, struct kobj_uevent_env *env)
99{
100 const struct virtio_device *dev = dev_to_virtio(_dv);
101
102 return add_uevent_var(env, "MODALIAS=virtio:d%08Xv%08X",
103 dev->id.device, dev->id.vendor);
104}
105
106void virtio_check_driver_offered_feature(const struct virtio_device *vdev,
107 unsigned int fbit)
108{
109 unsigned int i;
110 struct virtio_driver *drv = drv_to_virtio(vdev->dev.driver);
111
112 for (i = 0; i < drv->feature_table_size; i++)
113 if (drv->feature_table[i] == fbit)
114 return;
115
116 if (drv->feature_table_legacy) {
117 for (i = 0; i < drv->feature_table_size_legacy; i++)
118 if (drv->feature_table_legacy[i] == fbit)
119 return;
120 }
121
122 BUG();
123}
124EXPORT_SYMBOL_GPL(virtio_check_driver_offered_feature);
125
126static void __virtio_config_changed(struct virtio_device *dev)
127{
128 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
129
130 if (!dev->config_core_enabled || dev->config_driver_disabled)
131 dev->config_change_pending = true;
132 else if (drv && drv->config_changed) {
133 drv->config_changed(dev);
134 dev->config_change_pending = false;
135 }
136}
137
138void virtio_config_changed(struct virtio_device *dev)
139{
140 unsigned long flags;
141
142 spin_lock_irqsave(&dev->config_lock, flags);
143 __virtio_config_changed(dev);
144 spin_unlock_irqrestore(&dev->config_lock, flags);
145}
146EXPORT_SYMBOL_GPL(virtio_config_changed);
147
148/**
149 * virtio_config_driver_disable - disable config change reporting by drivers
150 * @dev: the device to disable
151 *
152 * This is only allowed to be called by a driver and disabling can't
153 * be nested.
154 */
155void virtio_config_driver_disable(struct virtio_device *dev)
156{
157 spin_lock_irq(&dev->config_lock);
158 dev->config_driver_disabled = true;
159 spin_unlock_irq(&dev->config_lock);
160}
161EXPORT_SYMBOL_GPL(virtio_config_driver_disable);
162
163/**
164 * virtio_config_driver_enable - enable config change reporting by drivers
165 * @dev: the device to enable
166 *
167 * This is only allowed to be called by a driver and enabling can't
168 * be nested.
169 */
170void virtio_config_driver_enable(struct virtio_device *dev)
171{
172 spin_lock_irq(&dev->config_lock);
173 dev->config_driver_disabled = false;
174 if (dev->config_change_pending)
175 __virtio_config_changed(dev);
176 spin_unlock_irq(&dev->config_lock);
177}
178EXPORT_SYMBOL_GPL(virtio_config_driver_enable);
179
180static void virtio_config_core_disable(struct virtio_device *dev)
181{
182 spin_lock_irq(&dev->config_lock);
183 dev->config_core_enabled = false;
184 spin_unlock_irq(&dev->config_lock);
185}
186
187static void virtio_config_core_enable(struct virtio_device *dev)
188{
189 spin_lock_irq(&dev->config_lock);
190 dev->config_core_enabled = true;
191 if (dev->config_change_pending)
192 __virtio_config_changed(dev);
193 spin_unlock_irq(&dev->config_lock);
194}
195
196void virtio_add_status(struct virtio_device *dev, unsigned int status)
197{
198 might_sleep();
199 dev->config->set_status(dev, dev->config->get_status(dev) | status);
200}
201EXPORT_SYMBOL_GPL(virtio_add_status);
202
203/* Do some validation, then set FEATURES_OK */
204static int virtio_features_ok(struct virtio_device *dev)
205{
206 unsigned int status;
207
208 might_sleep();
209
210 if (virtio_check_mem_acc_cb(dev)) {
211 if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1)) {
212 dev_warn(&dev->dev,
213 "device must provide VIRTIO_F_VERSION_1\n");
214 return -ENODEV;
215 }
216
217 if (!virtio_has_feature(dev, VIRTIO_F_ACCESS_PLATFORM)) {
218 dev_warn(&dev->dev,
219 "device must provide VIRTIO_F_ACCESS_PLATFORM\n");
220 return -ENODEV;
221 }
222 }
223
224 if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1))
225 return 0;
226
227 virtio_add_status(dev, VIRTIO_CONFIG_S_FEATURES_OK);
228 status = dev->config->get_status(dev);
229 if (!(status & VIRTIO_CONFIG_S_FEATURES_OK)) {
230 dev_err(&dev->dev, "virtio: device refuses features: %x\n",
231 status);
232 return -ENODEV;
233 }
234 return 0;
235}
236
237/**
238 * virtio_reset_device - quiesce device for removal
239 * @dev: the device to reset
240 *
241 * Prevents device from sending interrupts and accessing memory.
242 *
243 * Generally used for cleanup during driver / device removal.
244 *
245 * Once this has been invoked, caller must ensure that
246 * virtqueue_notify / virtqueue_kick are not in progress.
247 *
248 * Note: this guarantees that vq callbacks are not in progress, however caller
249 * is responsible for preventing access from other contexts, such as a system
250 * call/workqueue/bh. Invoking virtio_break_device then flushing any such
251 * contexts is one way to handle that.
252 * */
253void virtio_reset_device(struct virtio_device *dev)
254{
255#ifdef CONFIG_VIRTIO_HARDEN_NOTIFICATION
256 /*
257 * The below virtio_synchronize_cbs() guarantees that any
258 * interrupt for this line arriving after
259 * virtio_synchronize_vqs() has completed is guaranteed to see
260 * vq->broken as true.
261 */
262 virtio_break_device(dev);
263 virtio_synchronize_cbs(dev);
264#endif
265
266 dev->config->reset(dev);
267}
268EXPORT_SYMBOL_GPL(virtio_reset_device);
269
270static int virtio_dev_probe(struct device *_d)
271{
272 int err, i;
273 struct virtio_device *dev = dev_to_virtio(_d);
274 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
275 u64 device_features[VIRTIO_FEATURES_U64S];
276 u64 driver_features[VIRTIO_FEATURES_U64S];
277 u64 driver_features_legacy;
278
279 /* We have a driver! */
280 virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER);
281
282 /* Figure out what features the device supports. */
283 virtio_get_features(dev, device_features);
284
285 /* Figure out what features the driver supports. */
286 virtio_features_zero(driver_features);
287 for (i = 0; i < drv->feature_table_size; i++) {
288 unsigned int f = drv->feature_table[i];
289 if (!WARN_ON_ONCE(f >= VIRTIO_FEATURES_BITS))
290 virtio_features_set_bit(driver_features, f);
291 }
292
293 /* Some drivers have a separate feature table for virtio v1.0 */
294 if (drv->feature_table_legacy) {
295 driver_features_legacy = 0;
296 for (i = 0; i < drv->feature_table_size_legacy; i++) {
297 unsigned int f = drv->feature_table_legacy[i];
298 if (!WARN_ON_ONCE(f >= 64))
299 driver_features_legacy |= (1ULL << f);
300 }
301 } else {
302 driver_features_legacy = driver_features[0];
303 }
304
305 if (virtio_features_test_bit(device_features, VIRTIO_F_VERSION_1)) {
306 for (i = 0; i < VIRTIO_FEATURES_U64S; ++i)
307 dev->features_array[i] = driver_features[i] &
308 device_features[i];
309 } else {
310 virtio_features_from_u64(dev->features_array,
311 driver_features_legacy &
312 device_features[0]);
313 }
314
315 /* When debugging, user may filter some features by hand. */
316 virtio_debug_device_filter_features(dev);
317
318 /* Transport features always preserved to pass to finalize_features. */
319 for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++)
320 if (virtio_features_test_bit(device_features, i))
321 __virtio_set_bit(dev, i);
322
323 err = dev->config->finalize_features(dev);
324 if (err)
325 goto err;
326
327 if (drv->validate) {
328 u64 features[VIRTIO_FEATURES_U64S];
329
330 virtio_features_copy(features, dev->features_array);
331 err = drv->validate(dev);
332 if (err)
333 goto err;
334
335 /* Did validation change any features? Then write them again. */
336 if (!virtio_features_equal(features, dev->features_array)) {
337 err = dev->config->finalize_features(dev);
338 if (err)
339 goto err;
340 }
341 }
342
343 err = virtio_features_ok(dev);
344 if (err)
345 goto err;
346
347 err = drv->probe(dev);
348 if (err)
349 goto err;
350
351 /* If probe didn't do it, mark device DRIVER_OK ourselves. */
352 if (!(dev->config->get_status(dev) & VIRTIO_CONFIG_S_DRIVER_OK))
353 virtio_device_ready(dev);
354
355 if (drv->scan)
356 drv->scan(dev);
357
358 virtio_config_core_enable(dev);
359
360 return 0;
361
362err:
363 virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
364 return err;
365
366}
367
368static void virtio_dev_remove(struct device *_d)
369{
370 struct virtio_device *dev = dev_to_virtio(_d);
371 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
372
373 virtio_config_core_disable(dev);
374
375 drv->remove(dev);
376
377 /* Driver should have reset device. */
378 WARN_ON_ONCE(dev->config->get_status(dev));
379
380 /* Acknowledge the device's existence again. */
381 virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
382
383 of_node_put(dev->dev.of_node);
384}
385
386/*
387 * virtio_irq_get_affinity - get IRQ affinity mask for device
388 * @_d: ptr to dev structure
389 * @irq_vec: interrupt vector number
390 *
391 * Return the CPU affinity mask for @_d and @irq_vec.
392 */
393static const struct cpumask *virtio_irq_get_affinity(struct device *_d,
394 unsigned int irq_vec)
395{
396 struct virtio_device *dev = dev_to_virtio(_d);
397
398 if (!dev->config->get_vq_affinity)
399 return NULL;
400
401 return dev->config->get_vq_affinity(dev, irq_vec);
402}
403
404/**
405 * virtio_device_shutdown - break and reset a device on shutdown
406 * @dev: the device
407 *
408 * Drivers with their own .shutdown method should quiesce their activity and
409 * then call this to stop the device the way the generic shutdown path does.
410 */
411void virtio_device_shutdown(struct virtio_device *dev)
412{
413 /*
414 * Some devices get wedged if you kick them after they are
415 * reset. Mark all vqs as broken to make sure we don't.
416 */
417 virtio_break_device(dev);
418 /*
419 * Guarantee that any callback will see vq->broken as true.
420 */
421 virtio_synchronize_cbs(dev);
422 /*
423 * As IOMMUs are reset on shutdown, this will block device access to memory.
424 * Some devices get wedged if this happens, so reset to make sure it does not.
425 */
426 dev->config->reset(dev);
427}
428EXPORT_SYMBOL_GPL(virtio_device_shutdown);
429
430static void virtio_dev_shutdown(struct device *_d)
431{
432 struct virtio_device *dev = dev_to_virtio(_d);
433 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
434
435 /*
436 * Stop accesses to or from the device.
437 * We only need to do it if there's a driver - no accesses otherwise.
438 */
439 if (!drv)
440 return;
441
442 /* If the driver has its own shutdown method, use that. */
443 if (drv->shutdown) {
444 drv->shutdown(dev);
445 return;
446 }
447
448 virtio_device_shutdown(dev);
449}
450
451static int virtio_dev_num_vf(struct device *dev)
452{
453 struct virtio_device *vdev = dev_to_virtio(dev);
454
455 return dev_num_vf(vdev->dev.parent);
456}
457
458
459static const struct bus_type virtio_bus = {
460 .name = "virtio",
461 .match = virtio_dev_match,
462 .dev_groups = virtio_dev_groups,
463 .uevent = virtio_uevent,
464 .probe = virtio_dev_probe,
465 .remove = virtio_dev_remove,
466 .irq_get_affinity = virtio_irq_get_affinity,
467 .shutdown = virtio_dev_shutdown,
468 .num_vf = virtio_dev_num_vf,
469};
470
471int __register_virtio_driver(struct virtio_driver *driver, struct module *owner)
472{
473 /* Catch this early. */
474 BUG_ON(driver->feature_table_size && !driver->feature_table);
475 driver->driver.bus = &virtio_bus;
476 driver->driver.owner = owner;
477
478 return driver_register(&driver->driver);
479}
480EXPORT_SYMBOL_GPL(__register_virtio_driver);
481
482void unregister_virtio_driver(struct virtio_driver *driver)
483{
484 driver_unregister(&driver->driver);
485}
486EXPORT_SYMBOL_GPL(unregister_virtio_driver);
487
488static int virtio_device_of_init(struct virtio_device *dev)
489{
490 struct device_node *np, *pnode = dev_of_node(dev->dev.parent);
491 char compat[] = "virtio,deviceXXXXXXXX";
492 int ret, count;
493
494 if (!pnode)
495 return 0;
496
497 count = of_get_available_child_count(pnode);
498 if (!count)
499 return 0;
500
501 /* There can be only 1 child node */
502 if (WARN_ON(count > 1))
503 return -EINVAL;
504
505 np = of_get_next_available_child(pnode, NULL);
506 if (WARN_ON(!np))
507 return -ENODEV;
508
509 ret = snprintf(compat, sizeof(compat), "virtio,device%x", dev->id.device);
510 BUG_ON(ret >= sizeof(compat));
511
512 /*
513 * On powerpc/pseries virtio devices are PCI devices so PCI
514 * vendor/device ids play the role of the "compatible" property.
515 * Simply don't init of_node in this case.
516 */
517 if (!of_device_is_compatible(np, compat)) {
518 ret = 0;
519 goto out;
520 }
521
522 dev->dev.of_node = np;
523 return 0;
524
525out:
526 of_node_put(np);
527 return ret;
528}
529
530/**
531 * register_virtio_device - register virtio device
532 * @dev : virtio device to be registered
533 *
534 * On error, the caller must call put_device on &@dev->dev (and not kfree),
535 * as another code path may have obtained a reference to @dev.
536 *
537 * Returns: 0 on success, -error on failure
538 */
539int register_virtio_device(struct virtio_device *dev)
540{
541 int err;
542
543 dev->dev.bus = &virtio_bus;
544 device_initialize(&dev->dev);
545
546 /* Assign a unique device index and hence name. */
547 err = ida_alloc(&virtio_index_ida, GFP_KERNEL);
548 if (err < 0)
549 goto out;
550
551 dev->index = err;
552 err = dev_set_name(&dev->dev, "virtio%u", dev->index);
553 if (err)
554 goto out_ida_remove;
555
556 err = virtio_device_of_init(dev);
557 if (err)
558 goto out_ida_remove;
559
560 spin_lock_init(&dev->config_lock);
561 dev->config_driver_disabled = false;
562 dev->config_core_enabled = false;
563 dev->config_change_pending = false;
564
565 INIT_LIST_HEAD(&dev->vqs);
566 spin_lock_init(&dev->vqs_list_lock);
567
568 /* We always start by resetting the device, in case a previous
569 * driver messed it up. This also tests that code path a little. */
570 virtio_reset_device(dev);
571
572 /* Acknowledge that we've seen the device. */
573 virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
574
575 virtio_debug_device_init(dev);
576
577 /*
578 * device_add() causes the bus infrastructure to look for a matching
579 * driver.
580 */
581 err = device_add(&dev->dev);
582 if (err)
583 goto out_of_node_put;
584
585 return 0;
586
587out_of_node_put:
588 of_node_put(dev->dev.of_node);
589out_ida_remove:
590 ida_free(&virtio_index_ida, dev->index);
591out:
592 virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
593 return err;
594}
595EXPORT_SYMBOL_GPL(register_virtio_device);
596
597bool is_virtio_device(struct device *dev)
598{
599 return dev->bus == &virtio_bus;
600}
601EXPORT_SYMBOL_GPL(is_virtio_device);
602
603void unregister_virtio_device(struct virtio_device *dev)
604{
605 int index = dev->index; /* save for after device release */
606
607 virtio_debug_device_exit(dev);
608 device_unregister(&dev->dev);
609 ida_free(&virtio_index_ida, index);
610}
611EXPORT_SYMBOL_GPL(unregister_virtio_device);
612
613static int virtio_device_restore_priv(struct virtio_device *dev, bool restore)
614{
615 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
616 int ret;
617
618 /* We always start by resetting the device, in case a previous
619 * driver messed it up. */
620 virtio_reset_device(dev);
621
622 /* Acknowledge that we've seen the device. */
623 virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
624
625 /* Maybe driver failed before freeze.
626 * Restore the failed status, for debugging. */
627 if (dev->failed)
628 virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
629
630 if (!drv)
631 return 0;
632
633 /* We have a driver! */
634 virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER);
635
636 ret = dev->config->finalize_features(dev);
637 if (ret)
638 goto err;
639
640 ret = virtio_features_ok(dev);
641 if (ret)
642 goto err;
643
644 if (restore) {
645 if (drv->restore) {
646 ret = drv->restore(dev);
647 if (ret)
648 goto err;
649 }
650 } else {
651 ret = drv->reset_done(dev);
652 if (ret)
653 goto err;
654 }
655
656 /* If restore didn't do it, mark device DRIVER_OK ourselves. */
657 if (!(dev->config->get_status(dev) & VIRTIO_CONFIG_S_DRIVER_OK))
658 virtio_device_ready(dev);
659
660 virtio_config_core_enable(dev);
661
662 return 0;
663
664err:
665 virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
666 return ret;
667}
668
669#ifdef CONFIG_PM_SLEEP
670int virtio_device_freeze(struct virtio_device *dev)
671{
672 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
673 int ret;
674
675 virtio_config_core_disable(dev);
676
677 dev->failed = dev->config->get_status(dev) & VIRTIO_CONFIG_S_FAILED;
678
679 if (drv && drv->freeze) {
680 ret = drv->freeze(dev);
681 if (ret) {
682 virtio_config_core_enable(dev);
683 return ret;
684 }
685 }
686
687 return 0;
688}
689EXPORT_SYMBOL_GPL(virtio_device_freeze);
690
691int virtio_device_restore(struct virtio_device *dev)
692{
693 return virtio_device_restore_priv(dev, true);
694}
695EXPORT_SYMBOL_GPL(virtio_device_restore);
696#endif
697
698int virtio_device_reset_prepare(struct virtio_device *dev)
699{
700 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
701 int ret;
702
703 if (!drv || !drv->reset_prepare)
704 return -EOPNOTSUPP;
705
706 virtio_config_core_disable(dev);
707
708 dev->failed = dev->config->get_status(dev) & VIRTIO_CONFIG_S_FAILED;
709
710 ret = drv->reset_prepare(dev);
711 if (ret) {
712 virtio_config_core_enable(dev);
713 return ret;
714 }
715
716 return 0;
717}
718EXPORT_SYMBOL_GPL(virtio_device_reset_prepare);
719
720int virtio_device_reset_done(struct virtio_device *dev)
721{
722 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
723
724 if (!drv || !drv->reset_done)
725 return -EOPNOTSUPP;
726
727 return virtio_device_restore_priv(dev, false);
728}
729EXPORT_SYMBOL_GPL(virtio_device_reset_done);
730
731static int virtio_init(void)
732{
733 BUILD_BUG_ON(offsetof(struct virtio_device, features) !=
734 offsetof(struct virtio_device, features_array[0]));
735
736 if (bus_register(&virtio_bus) != 0)
737 panic("virtio bus registration failed");
738 virtio_debug_init();
739 return 0;
740}
741
742static void __exit virtio_exit(void)
743{
744 virtio_debug_exit();
745 bus_unregister(&virtio_bus);
746 ida_destroy(&virtio_index_ida);
747}
748core_initcall(virtio_init);
749module_exit(virtio_exit);
750
751MODULE_DESCRIPTION("Virtio core interface");
752MODULE_LICENSE("GPL");