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. */
9 static DEFINE_IDA(virtio_index_ida);
10
device_show(struct device * _d,struct device_attribute * attr,char * buf)11 static 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 }
17 static DEVICE_ATTR_RO(device);
18
vendor_show(struct device * _d,struct device_attribute * attr,char * buf)19 static 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 }
25 static DEVICE_ATTR_RO(vendor);
26
status_show(struct device * _d,struct device_attribute * attr,char * buf)27 static 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 }
33 static DEVICE_ATTR_RO(status);
34
modalias_show(struct device * _d,struct device_attribute * attr,char * buf)35 static 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 }
42 static DEVICE_ATTR_RO(modalias);
43
features_show(struct device * _d,struct device_attribute * attr,char * buf)44 static 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 }
59 static DEVICE_ATTR_RO(features);
60
61 static 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 };
69 ATTRIBUTE_GROUPS(virtio_dev);
70
virtio_id_match(const struct virtio_device * dev,const struct virtio_device_id * id)71 static 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(). */
virtio_dev_match(struct device * _dv,struct device_driver * _dr)82 static 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
virtio_uevent(struct device * _dv,struct kobj_uevent_env * env)95 static 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
virtio_check_driver_offered_feature(const struct virtio_device * vdev,unsigned int fbit)103 void 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 }
121 EXPORT_SYMBOL_GPL(virtio_check_driver_offered_feature);
122
__virtio_config_changed(struct virtio_device * dev)123 static 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
virtio_config_changed(struct virtio_device * dev)133 void 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 }
141 EXPORT_SYMBOL_GPL(virtio_config_changed);
142
virtio_config_disable(struct virtio_device * dev)143 void 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 }
149 EXPORT_SYMBOL_GPL(virtio_config_disable);
150
virtio_config_enable(struct virtio_device * dev)151 void 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 }
160 EXPORT_SYMBOL_GPL(virtio_config_enable);
161
virtio_add_status(struct virtio_device * dev,unsigned int status)162 void virtio_add_status(struct virtio_device *dev, unsigned int status)
163 {
164 dev->config->set_status(dev, dev->config->get_status(dev) | status);
165 }
166 EXPORT_SYMBOL_GPL(virtio_add_status);
167
virtio_finalize_features(struct virtio_device * dev)168 int 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 }
188 EXPORT_SYMBOL_GPL(virtio_finalize_features);
189
virtio_dev_probe(struct device * _d)190 static 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;
259 err:
260 virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
261 return err;
262
263 }
264
virtio_dev_remove(struct device * _d)265 static 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
282 static 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
register_virtio_driver(struct virtio_driver * driver)291 int 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 }
298 EXPORT_SYMBOL_GPL(register_virtio_driver);
299
unregister_virtio_driver(struct virtio_driver * driver)300 void unregister_virtio_driver(struct virtio_driver *driver)
301 {
302 driver_unregister(&driver->driver);
303 }
304 EXPORT_SYMBOL_GPL(unregister_virtio_driver);
305
register_virtio_device(struct virtio_device * dev)306 int register_virtio_device(struct virtio_device *dev)
307 {
308 int err;
309
310 dev->dev.bus = &virtio_bus;
311
312 /* Assign a unique device index and hence name. */
313 err = ida_simple_get(&virtio_index_ida, 0, 0, GFP_KERNEL);
314 if (err < 0)
315 goto out;
316
317 dev->index = err;
318 dev_set_name(&dev->dev, "virtio%u", dev->index);
319
320 spin_lock_init(&dev->config_lock);
321 dev->config_enabled = false;
322 dev->config_change_pending = false;
323
324 /* We always start by resetting the device, in case a previous
325 * driver messed it up. This also tests that code path a little. */
326 dev->config->reset(dev);
327
328 /* Acknowledge that we've seen the device. */
329 virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
330
331 INIT_LIST_HEAD(&dev->vqs);
332
333 /* device_register() causes the bus infrastructure to look for a
334 * matching driver. */
335 err = device_register(&dev->dev);
336 if (err)
337 ida_simple_remove(&virtio_index_ida, dev->index);
338 out:
339 if (err)
340 virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
341 return err;
342 }
343 EXPORT_SYMBOL_GPL(register_virtio_device);
344
unregister_virtio_device(struct virtio_device * dev)345 void unregister_virtio_device(struct virtio_device *dev)
346 {
347 int index = dev->index; /* save for after device release */
348
349 device_unregister(&dev->dev);
350 ida_simple_remove(&virtio_index_ida, index);
351 }
352 EXPORT_SYMBOL_GPL(unregister_virtio_device);
353
354 #ifdef CONFIG_PM_SLEEP
virtio_device_freeze(struct virtio_device * dev)355 int virtio_device_freeze(struct virtio_device *dev)
356 {
357 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
358
359 virtio_config_disable(dev);
360
361 dev->failed = dev->config->get_status(dev) & VIRTIO_CONFIG_S_FAILED;
362
363 if (drv && drv->freeze)
364 return drv->freeze(dev);
365
366 return 0;
367 }
368 EXPORT_SYMBOL_GPL(virtio_device_freeze);
369
virtio_device_restore(struct virtio_device * dev)370 int virtio_device_restore(struct virtio_device *dev)
371 {
372 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
373 int ret;
374
375 /* We always start by resetting the device, in case a previous
376 * driver messed it up. */
377 dev->config->reset(dev);
378
379 /* Acknowledge that we've seen the device. */
380 virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
381
382 /* Maybe driver failed before freeze.
383 * Restore the failed status, for debugging. */
384 if (dev->failed)
385 virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
386
387 if (!drv)
388 return 0;
389
390 /* We have a driver! */
391 virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER);
392
393 ret = virtio_finalize_features(dev);
394 if (ret)
395 goto err;
396
397 if (drv->restore) {
398 ret = drv->restore(dev);
399 if (ret)
400 goto err;
401 }
402
403 /* Finally, tell the device we're all set */
404 virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK);
405
406 virtio_config_enable(dev);
407
408 return 0;
409
410 err:
411 virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
412 return ret;
413 }
414 EXPORT_SYMBOL_GPL(virtio_device_restore);
415 #endif
416
virtio_init(void)417 static int virtio_init(void)
418 {
419 if (bus_register(&virtio_bus) != 0)
420 panic("virtio bus registration failed");
421 return 0;
422 }
423
virtio_exit(void)424 static void __exit virtio_exit(void)
425 {
426 bus_unregister(&virtio_bus);
427 ida_destroy(&virtio_index_ida);
428 }
429 core_initcall(virtio_init);
430 module_exit(virtio_exit);
431
432 MODULE_LICENSE("GPL");
433