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/module.h>
6 : #include <linux/idr.h>
7 : #include <uapi/linux/virtio_ids.h>
8 :
9 : /* Unique numbering for virtio devices. */
10 : static DEFINE_IDA(virtio_index_ida);
11 :
12 0 : static ssize_t device_show(struct device *_d,
13 : struct device_attribute *attr, char *buf)
14 : {
15 0 : struct virtio_device *dev = dev_to_virtio(_d);
16 0 : return sprintf(buf, "0x%04x\n", dev->id.device);
17 : }
18 : static DEVICE_ATTR_RO(device);
19 :
20 0 : static ssize_t vendor_show(struct device *_d,
21 : struct device_attribute *attr, char *buf)
22 : {
23 0 : struct virtio_device *dev = dev_to_virtio(_d);
24 0 : return sprintf(buf, "0x%04x\n", dev->id.vendor);
25 : }
26 : static DEVICE_ATTR_RO(vendor);
27 :
28 0 : static ssize_t status_show(struct device *_d,
29 : struct device_attribute *attr, char *buf)
30 : {
31 0 : struct virtio_device *dev = dev_to_virtio(_d);
32 0 : return sprintf(buf, "0x%08x\n", dev->config->get_status(dev));
33 : }
34 : static DEVICE_ATTR_RO(status);
35 :
36 0 : static ssize_t modalias_show(struct device *_d,
37 : struct device_attribute *attr, char *buf)
38 : {
39 0 : struct virtio_device *dev = dev_to_virtio(_d);
40 0 : return sprintf(buf, "virtio:d%08Xv%08X\n",
41 : dev->id.device, dev->id.vendor);
42 : }
43 : static DEVICE_ATTR_RO(modalias);
44 :
45 0 : static ssize_t features_show(struct device *_d,
46 : struct device_attribute *attr, char *buf)
47 : {
48 0 : struct virtio_device *dev = dev_to_virtio(_d);
49 0 : unsigned int i;
50 0 : ssize_t len = 0;
51 :
52 : /* We actually represent this as a bitstring, as it could be
53 : * arbitrary length in future. */
54 0 : for (i = 0; i < sizeof(dev->features)*8; i++)
55 0 : len += sprintf(buf+len, "%c",
56 0 : __virtio_test_bit(dev, i) ? '1' : '0');
57 0 : len += sprintf(buf+len, "\n");
58 0 : return len;
59 : }
60 : static DEVICE_ATTR_RO(features);
61 :
62 : static struct attribute *virtio_dev_attrs[] = {
63 : &dev_attr_device.attr,
64 : &dev_attr_vendor.attr,
65 : &dev_attr_status.attr,
66 : &dev_attr_modalias.attr,
67 : &dev_attr_features.attr,
68 : NULL,
69 : };
70 : ATTRIBUTE_GROUPS(virtio_dev);
71 :
72 16 : static inline int virtio_id_match(const struct virtio_device *dev,
73 : const struct virtio_device_id *id)
74 : {
75 14 : if (id->device != dev->id.device && id->device != VIRTIO_DEV_ANY_ID)
76 : return 0;
77 :
78 2 : return id->vendor == VIRTIO_DEV_ANY_ID || id->vendor == dev->id.vendor;
79 : }
80 :
81 : /* This looks through all the IDs a driver claims to support. If any of them
82 : * match, we return 1 and the kernel will call virtio_dev_probe(). */
83 18 : static int virtio_dev_match(struct device *_dv, struct device_driver *_dr)
84 : {
85 18 : unsigned int i;
86 18 : struct virtio_device *dev = dev_to_virtio(_dv);
87 18 : const struct virtio_device_id *ids;
88 :
89 18 : ids = drv_to_virtio(_dr)->id_table;
90 32 : for (i = 0; ids[i].device; i++)
91 30 : if (virtio_id_match(dev, &ids[i]))
92 : return 1;
93 : return 0;
94 : }
95 :
96 13 : static int virtio_uevent(struct device *_dv, struct kobj_uevent_env *env)
97 : {
98 13 : struct virtio_device *dev = dev_to_virtio(_dv);
99 :
100 13 : return add_uevent_var(env, "MODALIAS=virtio:d%08Xv%08X",
101 : dev->id.device, dev->id.vendor);
102 : }
103 :
104 49 : void virtio_check_driver_offered_feature(const struct virtio_device *vdev,
105 : unsigned int fbit)
106 : {
107 49 : unsigned int i;
108 49 : struct virtio_driver *drv = drv_to_virtio(vdev->dev.driver);
109 :
110 530 : for (i = 0; i < drv->feature_table_size; i++)
111 529 : if (drv->feature_table[i] == fbit)
112 : return;
113 :
114 1 : if (drv->feature_table_legacy) {
115 25 : for (i = 0; i < drv->feature_table_size_legacy; i++)
116 25 : if (drv->feature_table_legacy[i] == fbit)
117 : return;
118 : }
119 :
120 0 : BUG();
121 : }
122 : EXPORT_SYMBOL_GPL(virtio_check_driver_offered_feature);
123 :
124 0 : static void __virtio_config_changed(struct virtio_device *dev)
125 : {
126 0 : struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
127 :
128 0 : if (!dev->config_enabled)
129 0 : dev->config_change_pending = true;
130 0 : else if (drv && drv->config_changed)
131 0 : drv->config_changed(dev);
132 0 : }
133 :
134 0 : void virtio_config_changed(struct virtio_device *dev)
135 : {
136 0 : unsigned long flags;
137 :
138 0 : spin_lock_irqsave(&dev->config_lock, flags);
139 0 : __virtio_config_changed(dev);
140 0 : spin_unlock_irqrestore(&dev->config_lock, flags);
141 0 : }
142 : EXPORT_SYMBOL_GPL(virtio_config_changed);
143 :
144 0 : void virtio_config_disable(struct virtio_device *dev)
145 : {
146 0 : spin_lock_irq(&dev->config_lock);
147 0 : dev->config_enabled = false;
148 0 : spin_unlock_irq(&dev->config_lock);
149 0 : }
150 : EXPORT_SYMBOL_GPL(virtio_config_disable);
151 :
152 2 : void virtio_config_enable(struct virtio_device *dev)
153 : {
154 2 : spin_lock_irq(&dev->config_lock);
155 2 : dev->config_enabled = true;
156 2 : if (dev->config_change_pending)
157 0 : __virtio_config_changed(dev);
158 2 : dev->config_change_pending = false;
159 2 : spin_unlock_irq(&dev->config_lock);
160 2 : }
161 : EXPORT_SYMBOL_GPL(virtio_config_enable);
162 :
163 4 : void virtio_add_status(struct virtio_device *dev, unsigned int status)
164 : {
165 4 : might_sleep();
166 4 : dev->config->set_status(dev, dev->config->get_status(dev) | status);
167 4 : }
168 : EXPORT_SYMBOL_GPL(virtio_add_status);
169 :
170 2 : int virtio_finalize_features(struct virtio_device *dev)
171 : {
172 2 : int ret = dev->config->finalize_features(dev);
173 2 : unsigned status;
174 :
175 2 : might_sleep();
176 2 : if (ret)
177 : return ret;
178 :
179 2 : ret = arch_has_restricted_virtio_memory_access();
180 2 : if (ret) {
181 : if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1)) {
182 : dev_warn(&dev->dev,
183 : "device must provide VIRTIO_F_VERSION_1\n");
184 : return -ENODEV;
185 : }
186 :
187 : if (!virtio_has_feature(dev, VIRTIO_F_ACCESS_PLATFORM)) {
188 : dev_warn(&dev->dev,
189 : "device must provide VIRTIO_F_ACCESS_PLATFORM\n");
190 : return -ENODEV;
191 : }
192 : }
193 :
194 2 : if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1))
195 : return 0;
196 :
197 0 : virtio_add_status(dev, VIRTIO_CONFIG_S_FEATURES_OK);
198 0 : status = dev->config->get_status(dev);
199 0 : if (!(status & VIRTIO_CONFIG_S_FEATURES_OK)) {
200 0 : dev_err(&dev->dev, "virtio: device refuses features: %x\n",
201 : status);
202 0 : return -ENODEV;
203 : }
204 : return 0;
205 : }
206 : EXPORT_SYMBOL_GPL(virtio_finalize_features);
207 :
208 2 : static int virtio_dev_probe(struct device *_d)
209 : {
210 2 : int err, i;
211 2 : struct virtio_device *dev = dev_to_virtio(_d);
212 2 : struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
213 2 : u64 device_features;
214 2 : u64 driver_features;
215 2 : u64 driver_features_legacy;
216 :
217 : /* We have a driver! */
218 2 : virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER);
219 :
220 : /* Figure out what features the device supports. */
221 2 : device_features = dev->config->get_features(dev);
222 :
223 : /* Figure out what features the driver supports. */
224 2 : driver_features = 0;
225 38 : for (i = 0; i < drv->feature_table_size; i++) {
226 34 : unsigned int f = drv->feature_table[i];
227 34 : BUG_ON(f >= 64);
228 34 : driver_features |= (1ULL << f);
229 : }
230 :
231 : /* Some drivers have a separate feature table for virtio v1.0 */
232 2 : if (drv->feature_table_legacy) {
233 : driver_features_legacy = 0;
234 38 : for (i = 0; i < drv->feature_table_size_legacy; i++) {
235 36 : unsigned int f = drv->feature_table_legacy[i];
236 36 : BUG_ON(f >= 64);
237 36 : driver_features_legacy |= (1ULL << f);
238 : }
239 : } else {
240 : driver_features_legacy = driver_features;
241 : }
242 :
243 2 : if (device_features & (1ULL << VIRTIO_F_VERSION_1))
244 0 : dev->features = driver_features & device_features;
245 : else
246 2 : dev->features = driver_features_legacy & device_features;
247 :
248 : /* Transport features always preserved to pass to finalize_features. */
249 22 : for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++)
250 20 : if (device_features & (1ULL << i))
251 4 : __virtio_set_bit(dev, i);
252 :
253 2 : if (drv->validate) {
254 1 : err = drv->validate(dev);
255 1 : if (err)
256 0 : goto err;
257 : }
258 :
259 2 : err = virtio_finalize_features(dev);
260 2 : if (err)
261 0 : goto err;
262 :
263 2 : err = drv->probe(dev);
264 2 : if (err)
265 0 : goto err;
266 :
267 : /* If probe didn't do it, mark device DRIVER_OK ourselves. */
268 2 : if (!(dev->config->get_status(dev) & VIRTIO_CONFIG_S_DRIVER_OK))
269 0 : virtio_device_ready(dev);
270 :
271 2 : if (drv->scan)
272 0 : drv->scan(dev);
273 :
274 2 : virtio_config_enable(dev);
275 :
276 2 : return 0;
277 0 : err:
278 0 : virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
279 0 : return err;
280 :
281 : }
282 :
283 0 : static int virtio_dev_remove(struct device *_d)
284 : {
285 0 : struct virtio_device *dev = dev_to_virtio(_d);
286 0 : struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
287 :
288 0 : virtio_config_disable(dev);
289 :
290 0 : drv->remove(dev);
291 :
292 : /* Driver should have reset device. */
293 0 : WARN_ON_ONCE(dev->config->get_status(dev));
294 :
295 : /* Acknowledge the device's existence again. */
296 0 : virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
297 0 : return 0;
298 : }
299 :
300 : static struct bus_type virtio_bus = {
301 : .name = "virtio",
302 : .match = virtio_dev_match,
303 : .dev_groups = virtio_dev_groups,
304 : .uevent = virtio_uevent,
305 : .probe = virtio_dev_probe,
306 : .remove = virtio_dev_remove,
307 : };
308 :
309 9 : int register_virtio_driver(struct virtio_driver *driver)
310 : {
311 : /* Catch this early. */
312 9 : BUG_ON(driver->feature_table_size && !driver->feature_table);
313 9 : driver->driver.bus = &virtio_bus;
314 9 : return driver_register(&driver->driver);
315 : }
316 : EXPORT_SYMBOL_GPL(register_virtio_driver);
317 :
318 0 : void unregister_virtio_driver(struct virtio_driver *driver)
319 : {
320 0 : driver_unregister(&driver->driver);
321 0 : }
322 : EXPORT_SYMBOL_GPL(unregister_virtio_driver);
323 :
324 : /**
325 : * register_virtio_device - register virtio device
326 : * @dev : virtio device to be registered
327 : *
328 : * On error, the caller must call put_device on &@dev->dev (and not kfree),
329 : * as another code path may have obtained a reference to @dev.
330 : *
331 : * Returns: 0 on suceess, -error on failure
332 : */
333 2 : int register_virtio_device(struct virtio_device *dev)
334 : {
335 2 : int err;
336 :
337 2 : dev->dev.bus = &virtio_bus;
338 2 : device_initialize(&dev->dev);
339 :
340 : /* Assign a unique device index and hence name. */
341 2 : err = ida_simple_get(&virtio_index_ida, 0, 0, GFP_KERNEL);
342 2 : if (err < 0)
343 0 : goto out;
344 :
345 2 : dev->index = err;
346 2 : dev_set_name(&dev->dev, "virtio%u", dev->index);
347 :
348 2 : spin_lock_init(&dev->config_lock);
349 2 : dev->config_enabled = false;
350 2 : dev->config_change_pending = false;
351 :
352 : /* We always start by resetting the device, in case a previous
353 : * driver messed it up. This also tests that code path a little. */
354 2 : dev->config->reset(dev);
355 :
356 : /* Acknowledge that we've seen the device. */
357 2 : virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
358 :
359 2 : INIT_LIST_HEAD(&dev->vqs);
360 :
361 : /*
362 : * device_add() causes the bus infrastructure to look for a matching
363 : * driver.
364 : */
365 2 : err = device_add(&dev->dev);
366 2 : if (err)
367 0 : ida_simple_remove(&virtio_index_ida, dev->index);
368 2 : out:
369 2 : if (err)
370 0 : virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
371 2 : return err;
372 : }
373 : EXPORT_SYMBOL_GPL(register_virtio_device);
374 :
375 0 : bool is_virtio_device(struct device *dev)
376 : {
377 0 : return dev->bus == &virtio_bus;
378 : }
379 : EXPORT_SYMBOL_GPL(is_virtio_device);
380 :
381 0 : void unregister_virtio_device(struct virtio_device *dev)
382 : {
383 0 : int index = dev->index; /* save for after device release */
384 :
385 0 : device_unregister(&dev->dev);
386 0 : ida_simple_remove(&virtio_index_ida, index);
387 0 : }
388 : EXPORT_SYMBOL_GPL(unregister_virtio_device);
389 :
390 : #ifdef CONFIG_PM_SLEEP
391 : int virtio_device_freeze(struct virtio_device *dev)
392 : {
393 : struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
394 :
395 : virtio_config_disable(dev);
396 :
397 : dev->failed = dev->config->get_status(dev) & VIRTIO_CONFIG_S_FAILED;
398 :
399 : if (drv && drv->freeze)
400 : return drv->freeze(dev);
401 :
402 : return 0;
403 : }
404 : EXPORT_SYMBOL_GPL(virtio_device_freeze);
405 :
406 : int virtio_device_restore(struct virtio_device *dev)
407 : {
408 : struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
409 : int ret;
410 :
411 : /* We always start by resetting the device, in case a previous
412 : * driver messed it up. */
413 : dev->config->reset(dev);
414 :
415 : /* Acknowledge that we've seen the device. */
416 : virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
417 :
418 : /* Maybe driver failed before freeze.
419 : * Restore the failed status, for debugging. */
420 : if (dev->failed)
421 : virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
422 :
423 : if (!drv)
424 : return 0;
425 :
426 : /* We have a driver! */
427 : virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER);
428 :
429 : ret = virtio_finalize_features(dev);
430 : if (ret)
431 : goto err;
432 :
433 : if (drv->restore) {
434 : ret = drv->restore(dev);
435 : if (ret)
436 : goto err;
437 : }
438 :
439 : /* Finally, tell the device we're all set */
440 : virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK);
441 :
442 : virtio_config_enable(dev);
443 :
444 : return 0;
445 :
446 : err:
447 : virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
448 : return ret;
449 : }
450 : EXPORT_SYMBOL_GPL(virtio_device_restore);
451 : #endif
452 :
453 1 : static int virtio_init(void)
454 : {
455 1 : if (bus_register(&virtio_bus) != 0)
456 0 : panic("virtio bus registration failed");
457 1 : return 0;
458 : }
459 :
460 0 : static void __exit virtio_exit(void)
461 : {
462 0 : bus_unregister(&virtio_bus);
463 0 : ida_destroy(&virtio_index_ida);
464 0 : }
465 : core_initcall(virtio_init);
466 : module_exit(virtio_exit);
467 :
468 : MODULE_LICENSE("GPL");
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