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