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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 < sizeof(dev->features)*8; 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 reset
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 reset
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;
276 u64 driver_features;
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 device_features = dev->config->get_features(dev);
284
285 /* Figure out what features the driver supports. */
286 driver_features = 0;
287 for (i = 0; i < drv->feature_table_size; i++) {
288 unsigned int f = drv->feature_table[i];
289 BUG_ON(f >= 64);
290 driver_features |= (1ULL << 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 BUG_ON(f >= 64);
299 driver_features_legacy |= (1ULL << f);
300 }
301 } else {
302 driver_features_legacy = driver_features;
303 }
304
305 if (device_features & (1ULL << VIRTIO_F_VERSION_1))
306 dev->features = driver_features & device_features;
307 else
308 dev->features = driver_features_legacy & device_features;
309
310 /* When debugging, user may filter some features by hand. */
311 virtio_debug_device_filter_features(dev);
312
313 /* Transport features always preserved to pass to finalize_features. */
314 for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++)
315 if (device_features & (1ULL << i))
316 __virtio_set_bit(dev, i);
317
318 err = dev->config->finalize_features(dev);
319 if (err)
320 goto err;
321
322 if (drv->validate) {
323 u64 features = dev->features;
324
325 err = drv->validate(dev);
326 if (err)
327 goto err;
328
329 /* Did validation change any features? Then write them again. */
330 if (features != dev->features) {
331 err = dev->config->finalize_features(dev);
332 if (err)
333 goto err;
334 }
335 }
336
337 err = virtio_features_ok(dev);
338 if (err)
339 goto err;
340
341 err = drv->probe(dev);
342 if (err)
343 goto err;
344
345 /* If probe didn't do it, mark device DRIVER_OK ourselves. */
346 if (!(dev->config->get_status(dev) & VIRTIO_CONFIG_S_DRIVER_OK))
347 virtio_device_ready(dev);
348
349 if (drv->scan)
350 drv->scan(dev);
351
352 virtio_config_core_enable(dev);
353
354 return 0;
355
356err:
357 virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
358 return err;
359
360}
361
362static void virtio_dev_remove(struct device *_d)
363{
364 struct virtio_device *dev = dev_to_virtio(_d);
365 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
366
367 virtio_config_core_disable(dev);
368
369 drv->remove(dev);
370
371 /* Driver should have reset device. */
372 WARN_ON_ONCE(dev->config->get_status(dev));
373
374 /* Acknowledge the device's existence again. */
375 virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
376
377 of_node_put(dev->dev.of_node);
378}
379
380static const struct bus_type virtio_bus = {
381 .name = "virtio",
382 .match = virtio_dev_match,
383 .dev_groups = virtio_dev_groups,
384 .uevent = virtio_uevent,
385 .probe = virtio_dev_probe,
386 .remove = virtio_dev_remove,
387};
388
389int __register_virtio_driver(struct virtio_driver *driver, struct module *owner)
390{
391 /* Catch this early. */
392 BUG_ON(driver->feature_table_size && !driver->feature_table);
393 driver->driver.bus = &virtio_bus;
394 driver->driver.owner = owner;
395
396 return driver_register(&driver->driver);
397}
398EXPORT_SYMBOL_GPL(__register_virtio_driver);
399
400void unregister_virtio_driver(struct virtio_driver *driver)
401{
402 driver_unregister(&driver->driver);
403}
404EXPORT_SYMBOL_GPL(unregister_virtio_driver);
405
406static int virtio_device_of_init(struct virtio_device *dev)
407{
408 struct device_node *np, *pnode = dev_of_node(dev->dev.parent);
409 char compat[] = "virtio,deviceXXXXXXXX";
410 int ret, count;
411
412 if (!pnode)
413 return 0;
414
415 count = of_get_available_child_count(pnode);
416 if (!count)
417 return 0;
418
419 /* There can be only 1 child node */
420 if (WARN_ON(count > 1))
421 return -EINVAL;
422
423 np = of_get_next_available_child(pnode, NULL);
424 if (WARN_ON(!np))
425 return -ENODEV;
426
427 ret = snprintf(compat, sizeof(compat), "virtio,device%x", dev->id.device);
428 BUG_ON(ret >= sizeof(compat));
429
430 /*
431 * On powerpc/pseries virtio devices are PCI devices so PCI
432 * vendor/device ids play the role of the "compatible" property.
433 * Simply don't init of_node in this case.
434 */
435 if (!of_device_is_compatible(np, compat)) {
436 ret = 0;
437 goto out;
438 }
439
440 dev->dev.of_node = np;
441 return 0;
442
443out:
444 of_node_put(np);
445 return ret;
446}
447
448/**
449 * register_virtio_device - register virtio device
450 * @dev : virtio device to be registered
451 *
452 * On error, the caller must call put_device on &@dev->dev (and not kfree),
453 * as another code path may have obtained a reference to @dev.
454 *
455 * Returns: 0 on suceess, -error on failure
456 */
457int register_virtio_device(struct virtio_device *dev)
458{
459 int err;
460
461 dev->dev.bus = &virtio_bus;
462 device_initialize(&dev->dev);
463
464 /* Assign a unique device index and hence name. */
465 err = ida_alloc(&virtio_index_ida, GFP_KERNEL);
466 if (err < 0)
467 goto out;
468
469 dev->index = err;
470 err = dev_set_name(&dev->dev, "virtio%u", dev->index);
471 if (err)
472 goto out_ida_remove;
473
474 err = virtio_device_of_init(dev);
475 if (err)
476 goto out_ida_remove;
477
478 spin_lock_init(&dev->config_lock);
479 dev->config_core_enabled = false;
480 dev->config_change_pending = false;
481
482 INIT_LIST_HEAD(&dev->vqs);
483 spin_lock_init(&dev->vqs_list_lock);
484
485 /* We always start by resetting the device, in case a previous
486 * driver messed it up. This also tests that code path a little. */
487 virtio_reset_device(dev);
488
489 /* Acknowledge that we've seen the device. */
490 virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
491
492 virtio_debug_device_init(dev);
493
494 /*
495 * device_add() causes the bus infrastructure to look for a matching
496 * driver.
497 */
498 err = device_add(&dev->dev);
499 if (err)
500 goto out_of_node_put;
501
502 return 0;
503
504out_of_node_put:
505 of_node_put(dev->dev.of_node);
506out_ida_remove:
507 ida_free(&virtio_index_ida, dev->index);
508out:
509 virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
510 return err;
511}
512EXPORT_SYMBOL_GPL(register_virtio_device);
513
514bool is_virtio_device(struct device *dev)
515{
516 return dev->bus == &virtio_bus;
517}
518EXPORT_SYMBOL_GPL(is_virtio_device);
519
520void unregister_virtio_device(struct virtio_device *dev)
521{
522 int index = dev->index; /* save for after device release */
523
524 device_unregister(&dev->dev);
525 virtio_debug_device_exit(dev);
526 ida_free(&virtio_index_ida, index);
527}
528EXPORT_SYMBOL_GPL(unregister_virtio_device);
529
530#ifdef CONFIG_PM_SLEEP
531int virtio_device_freeze(struct virtio_device *dev)
532{
533 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
534 int ret;
535
536 virtio_config_core_disable(dev);
537
538 dev->failed = dev->config->get_status(dev) & VIRTIO_CONFIG_S_FAILED;
539
540 if (drv && drv->freeze) {
541 ret = drv->freeze(dev);
542 if (ret) {
543 virtio_config_core_enable(dev);
544 return ret;
545 }
546 }
547
548 return 0;
549}
550EXPORT_SYMBOL_GPL(virtio_device_freeze);
551
552int virtio_device_restore(struct virtio_device *dev)
553{
554 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
555 int ret;
556
557 /* We always start by resetting the device, in case a previous
558 * driver messed it up. */
559 virtio_reset_device(dev);
560
561 /* Acknowledge that we've seen the device. */
562 virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
563
564 /* Maybe driver failed before freeze.
565 * Restore the failed status, for debugging. */
566 if (dev->failed)
567 virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
568
569 if (!drv)
570 return 0;
571
572 /* We have a driver! */
573 virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER);
574
575 ret = dev->config->finalize_features(dev);
576 if (ret)
577 goto err;
578
579 ret = virtio_features_ok(dev);
580 if (ret)
581 goto err;
582
583 if (drv->restore) {
584 ret = drv->restore(dev);
585 if (ret)
586 goto err;
587 }
588
589 /* If restore didn't do it, mark device DRIVER_OK ourselves. */
590 if (!(dev->config->get_status(dev) & VIRTIO_CONFIG_S_DRIVER_OK))
591 virtio_device_ready(dev);
592
593 virtio_config_core_enable(dev);
594
595 return 0;
596
597err:
598 virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
599 return ret;
600}
601EXPORT_SYMBOL_GPL(virtio_device_restore);
602#endif
603
604static int virtio_init(void)
605{
606 if (bus_register(&virtio_bus) != 0)
607 panic("virtio bus registration failed");
608 virtio_debug_init();
609 return 0;
610}
611
612static void __exit virtio_exit(void)
613{
614 virtio_debug_exit();
615 bus_unregister(&virtio_bus);
616 ida_destroy(&virtio_index_ida);
617}
618core_initcall(virtio_init);
619module_exit(virtio_exit);
620
621MODULE_DESCRIPTION("Virtio core interface");
622MODULE_LICENSE("GPL");
1#include <linux/virtio.h>
2#include <linux/spinlock.h>
3#include <linux/virtio_config.h>
4#include <linux/module.h>
5#include <linux/idr.h>
6#include <uapi/linux/virtio_ids.h>
7
8/* Unique numbering for virtio devices. */
9static DEFINE_IDA(virtio_index_ida);
10
11static ssize_t device_show(struct device *_d,
12 struct device_attribute *attr, char *buf)
13{
14 struct virtio_device *dev = dev_to_virtio(_d);
15 return sprintf(buf, "0x%04x\n", dev->id.device);
16}
17static DEVICE_ATTR_RO(device);
18
19static ssize_t vendor_show(struct device *_d,
20 struct device_attribute *attr, char *buf)
21{
22 struct virtio_device *dev = dev_to_virtio(_d);
23 return sprintf(buf, "0x%04x\n", dev->id.vendor);
24}
25static DEVICE_ATTR_RO(vendor);
26
27static ssize_t status_show(struct device *_d,
28 struct device_attribute *attr, char *buf)
29{
30 struct virtio_device *dev = dev_to_virtio(_d);
31 return sprintf(buf, "0x%08x\n", dev->config->get_status(dev));
32}
33static DEVICE_ATTR_RO(status);
34
35static ssize_t modalias_show(struct device *_d,
36 struct device_attribute *attr, char *buf)
37{
38 struct virtio_device *dev = dev_to_virtio(_d);
39 return sprintf(buf, "virtio:d%08Xv%08X\n",
40 dev->id.device, dev->id.vendor);
41}
42static DEVICE_ATTR_RO(modalias);
43
44static ssize_t features_show(struct device *_d,
45 struct device_attribute *attr, char *buf)
46{
47 struct virtio_device *dev = dev_to_virtio(_d);
48 unsigned int i;
49 ssize_t len = 0;
50
51 /* We actually represent this as a bitstring, as it could be
52 * arbitrary length in future. */
53 for (i = 0; i < sizeof(dev->features)*8; i++)
54 len += sprintf(buf+len, "%c",
55 __virtio_test_bit(dev, i) ? '1' : '0');
56 len += sprintf(buf+len, "\n");
57 return len;
58}
59static DEVICE_ATTR_RO(features);
60
61static struct attribute *virtio_dev_attrs[] = {
62 &dev_attr_device.attr,
63 &dev_attr_vendor.attr,
64 &dev_attr_status.attr,
65 &dev_attr_modalias.attr,
66 &dev_attr_features.attr,
67 NULL,
68};
69ATTRIBUTE_GROUPS(virtio_dev);
70
71static inline int virtio_id_match(const struct virtio_device *dev,
72 const struct virtio_device_id *id)
73{
74 if (id->device != dev->id.device && id->device != VIRTIO_DEV_ANY_ID)
75 return 0;
76
77 return id->vendor == VIRTIO_DEV_ANY_ID || id->vendor == dev->id.vendor;
78}
79
80/* This looks through all the IDs a driver claims to support. If any of them
81 * match, we return 1 and the kernel will call virtio_dev_probe(). */
82static int virtio_dev_match(struct device *_dv, struct device_driver *_dr)
83{
84 unsigned int i;
85 struct virtio_device *dev = dev_to_virtio(_dv);
86 const struct virtio_device_id *ids;
87
88 ids = drv_to_virtio(_dr)->id_table;
89 for (i = 0; ids[i].device; i++)
90 if (virtio_id_match(dev, &ids[i]))
91 return 1;
92 return 0;
93}
94
95static int virtio_uevent(struct device *_dv, struct kobj_uevent_env *env)
96{
97 struct virtio_device *dev = dev_to_virtio(_dv);
98
99 return add_uevent_var(env, "MODALIAS=virtio:d%08Xv%08X",
100 dev->id.device, dev->id.vendor);
101}
102
103void virtio_check_driver_offered_feature(const struct virtio_device *vdev,
104 unsigned int fbit)
105{
106 unsigned int i;
107 struct virtio_driver *drv = drv_to_virtio(vdev->dev.driver);
108
109 for (i = 0; i < drv->feature_table_size; i++)
110 if (drv->feature_table[i] == fbit)
111 return;
112
113 if (drv->feature_table_legacy) {
114 for (i = 0; i < drv->feature_table_size_legacy; i++)
115 if (drv->feature_table_legacy[i] == fbit)
116 return;
117 }
118
119 BUG();
120}
121EXPORT_SYMBOL_GPL(virtio_check_driver_offered_feature);
122
123static void __virtio_config_changed(struct virtio_device *dev)
124{
125 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
126
127 if (!dev->config_enabled)
128 dev->config_change_pending = true;
129 else if (drv && drv->config_changed)
130 drv->config_changed(dev);
131}
132
133void virtio_config_changed(struct virtio_device *dev)
134{
135 unsigned long flags;
136
137 spin_lock_irqsave(&dev->config_lock, flags);
138 __virtio_config_changed(dev);
139 spin_unlock_irqrestore(&dev->config_lock, flags);
140}
141EXPORT_SYMBOL_GPL(virtio_config_changed);
142
143void virtio_config_disable(struct virtio_device *dev)
144{
145 spin_lock_irq(&dev->config_lock);
146 dev->config_enabled = false;
147 spin_unlock_irq(&dev->config_lock);
148}
149EXPORT_SYMBOL_GPL(virtio_config_disable);
150
151void virtio_config_enable(struct virtio_device *dev)
152{
153 spin_lock_irq(&dev->config_lock);
154 dev->config_enabled = true;
155 if (dev->config_change_pending)
156 __virtio_config_changed(dev);
157 dev->config_change_pending = false;
158 spin_unlock_irq(&dev->config_lock);
159}
160EXPORT_SYMBOL_GPL(virtio_config_enable);
161
162void virtio_add_status(struct virtio_device *dev, unsigned int status)
163{
164 dev->config->set_status(dev, dev->config->get_status(dev) | status);
165}
166EXPORT_SYMBOL_GPL(virtio_add_status);
167
168int virtio_finalize_features(struct virtio_device *dev)
169{
170 int ret = dev->config->finalize_features(dev);
171 unsigned status;
172
173 if (ret)
174 return ret;
175
176 if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1))
177 return 0;
178
179 virtio_add_status(dev, VIRTIO_CONFIG_S_FEATURES_OK);
180 status = dev->config->get_status(dev);
181 if (!(status & VIRTIO_CONFIG_S_FEATURES_OK)) {
182 dev_err(&dev->dev, "virtio: device refuses features: %x\n",
183 status);
184 return -ENODEV;
185 }
186 return 0;
187}
188EXPORT_SYMBOL_GPL(virtio_finalize_features);
189
190static int virtio_dev_probe(struct device *_d)
191{
192 int err, i;
193 struct virtio_device *dev = dev_to_virtio(_d);
194 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
195 u64 device_features;
196 u64 driver_features;
197 u64 driver_features_legacy;
198
199 /* We have a driver! */
200 virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER);
201
202 /* Figure out what features the device supports. */
203 device_features = dev->config->get_features(dev);
204
205 /* Figure out what features the driver supports. */
206 driver_features = 0;
207 for (i = 0; i < drv->feature_table_size; i++) {
208 unsigned int f = drv->feature_table[i];
209 BUG_ON(f >= 64);
210 driver_features |= (1ULL << f);
211 }
212
213 /* Some drivers have a separate feature table for virtio v1.0 */
214 if (drv->feature_table_legacy) {
215 driver_features_legacy = 0;
216 for (i = 0; i < drv->feature_table_size_legacy; i++) {
217 unsigned int f = drv->feature_table_legacy[i];
218 BUG_ON(f >= 64);
219 driver_features_legacy |= (1ULL << f);
220 }
221 } else {
222 driver_features_legacy = driver_features;
223 }
224
225 if (device_features & (1ULL << VIRTIO_F_VERSION_1))
226 dev->features = driver_features & device_features;
227 else
228 dev->features = driver_features_legacy & device_features;
229
230 /* Transport features always preserved to pass to finalize_features. */
231 for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++)
232 if (device_features & (1ULL << i))
233 __virtio_set_bit(dev, i);
234
235 if (drv->validate) {
236 err = drv->validate(dev);
237 if (err)
238 goto err;
239 }
240
241 err = virtio_finalize_features(dev);
242 if (err)
243 goto err;
244
245 err = drv->probe(dev);
246 if (err)
247 goto err;
248
249 /* If probe didn't do it, mark device DRIVER_OK ourselves. */
250 if (!(dev->config->get_status(dev) & VIRTIO_CONFIG_S_DRIVER_OK))
251 virtio_device_ready(dev);
252
253 if (drv->scan)
254 drv->scan(dev);
255
256 virtio_config_enable(dev);
257
258 return 0;
259err:
260 virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
261 return err;
262
263}
264
265static int virtio_dev_remove(struct device *_d)
266{
267 struct virtio_device *dev = dev_to_virtio(_d);
268 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
269
270 virtio_config_disable(dev);
271
272 drv->remove(dev);
273
274 /* Driver should have reset device. */
275 WARN_ON_ONCE(dev->config->get_status(dev));
276
277 /* Acknowledge the device's existence again. */
278 virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
279 return 0;
280}
281
282static struct bus_type virtio_bus = {
283 .name = "virtio",
284 .match = virtio_dev_match,
285 .dev_groups = virtio_dev_groups,
286 .uevent = virtio_uevent,
287 .probe = virtio_dev_probe,
288 .remove = virtio_dev_remove,
289};
290
291int register_virtio_driver(struct virtio_driver *driver)
292{
293 /* Catch this early. */
294 BUG_ON(driver->feature_table_size && !driver->feature_table);
295 driver->driver.bus = &virtio_bus;
296 return driver_register(&driver->driver);
297}
298EXPORT_SYMBOL_GPL(register_virtio_driver);
299
300void unregister_virtio_driver(struct virtio_driver *driver)
301{
302 driver_unregister(&driver->driver);
303}
304EXPORT_SYMBOL_GPL(unregister_virtio_driver);
305
306/**
307 * register_virtio_device - register virtio device
308 * @dev : virtio device to be registered
309 *
310 * On error, the caller must call put_device on &@dev->dev (and not kfree),
311 * as another code path may have obtained a reference to @dev.
312 *
313 * Returns: 0 on suceess, -error on failure
314 */
315int register_virtio_device(struct virtio_device *dev)
316{
317 int err;
318
319 dev->dev.bus = &virtio_bus;
320 device_initialize(&dev->dev);
321
322 /* Assign a unique device index and hence name. */
323 err = ida_simple_get(&virtio_index_ida, 0, 0, GFP_KERNEL);
324 if (err < 0)
325 goto out;
326
327 dev->index = err;
328 dev_set_name(&dev->dev, "virtio%u", dev->index);
329
330 spin_lock_init(&dev->config_lock);
331 dev->config_enabled = false;
332 dev->config_change_pending = false;
333
334 /* We always start by resetting the device, in case a previous
335 * driver messed it up. This also tests that code path a little. */
336 dev->config->reset(dev);
337
338 /* Acknowledge that we've seen the device. */
339 virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
340
341 INIT_LIST_HEAD(&dev->vqs);
342
343 /*
344 * device_add() causes the bus infrastructure to look for a matching
345 * driver.
346 */
347 err = device_add(&dev->dev);
348 if (err)
349 ida_simple_remove(&virtio_index_ida, dev->index);
350out:
351 if (err)
352 virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
353 return err;
354}
355EXPORT_SYMBOL_GPL(register_virtio_device);
356
357void unregister_virtio_device(struct virtio_device *dev)
358{
359 int index = dev->index; /* save for after device release */
360
361 device_unregister(&dev->dev);
362 ida_simple_remove(&virtio_index_ida, index);
363}
364EXPORT_SYMBOL_GPL(unregister_virtio_device);
365
366#ifdef CONFIG_PM_SLEEP
367int virtio_device_freeze(struct virtio_device *dev)
368{
369 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
370
371 virtio_config_disable(dev);
372
373 dev->failed = dev->config->get_status(dev) & VIRTIO_CONFIG_S_FAILED;
374
375 if (drv && drv->freeze)
376 return drv->freeze(dev);
377
378 return 0;
379}
380EXPORT_SYMBOL_GPL(virtio_device_freeze);
381
382int virtio_device_restore(struct virtio_device *dev)
383{
384 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
385 int ret;
386
387 /* We always start by resetting the device, in case a previous
388 * driver messed it up. */
389 dev->config->reset(dev);
390
391 /* Acknowledge that we've seen the device. */
392 virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
393
394 /* Maybe driver failed before freeze.
395 * Restore the failed status, for debugging. */
396 if (dev->failed)
397 virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
398
399 if (!drv)
400 return 0;
401
402 /* We have a driver! */
403 virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER);
404
405 ret = virtio_finalize_features(dev);
406 if (ret)
407 goto err;
408
409 if (drv->restore) {
410 ret = drv->restore(dev);
411 if (ret)
412 goto err;
413 }
414
415 /* Finally, tell the device we're all set */
416 virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK);
417
418 virtio_config_enable(dev);
419
420 return 0;
421
422err:
423 virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
424 return ret;
425}
426EXPORT_SYMBOL_GPL(virtio_device_restore);
427#endif
428
429static int virtio_init(void)
430{
431 if (bus_register(&virtio_bus) != 0)
432 panic("virtio bus registration failed");
433 return 0;
434}
435
436static void __exit virtio_exit(void)
437{
438 bus_unregister(&virtio_bus);
439 ida_destroy(&virtio_index_ida);
440}
441core_initcall(virtio_init);
442module_exit(virtio_exit);
443
444MODULE_LICENSE("GPL");