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>
7 #include <uapi/linux/virtio_ids.h>
9 /* Unique numbering for virtio devices. */
10 static DEFINE_IDA(virtio_index_ida);
12 static ssize_t device_show(struct device *_d,
13 struct device_attribute *attr, char *buf)
15 struct virtio_device *dev = dev_to_virtio(_d);
16 return sprintf(buf, "0x%04x\n", dev->id.device);
18 static DEVICE_ATTR_RO(device);
20 static ssize_t vendor_show(struct device *_d,
21 struct device_attribute *attr, char *buf)
23 struct virtio_device *dev = dev_to_virtio(_d);
24 return sprintf(buf, "0x%04x\n", dev->id.vendor);
26 static DEVICE_ATTR_RO(vendor);
28 static ssize_t status_show(struct device *_d,
29 struct device_attribute *attr, char *buf)
31 struct virtio_device *dev = dev_to_virtio(_d);
32 return sprintf(buf, "0x%08x\n", dev->config->get_status(dev));
34 static DEVICE_ATTR_RO(status);
36 static ssize_t modalias_show(struct device *_d,
37 struct device_attribute *attr, char *buf)
39 struct virtio_device *dev = dev_to_virtio(_d);
40 return sprintf(buf, "virtio:d%08Xv%08X\n",
41 dev->id.device, dev->id.vendor);
43 static DEVICE_ATTR_RO(modalias);
45 static ssize_t features_show(struct device *_d,
46 struct device_attribute *attr, char *buf)
48 struct virtio_device *dev = dev_to_virtio(_d);
52 /* We actually represent this as a bitstring, as it could be
53 * arbitrary length in future. */
54 for (i = 0; i < sizeof(dev->features)*8; i++)
55 len += sprintf(buf+len, "%c",
56 __virtio_test_bit(dev, i) ? '1' : '0');
57 len += sprintf(buf+len, "\n");
60 static DEVICE_ATTR_RO(features);
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,
70 ATTRIBUTE_GROUPS(virtio_dev);
72 static inline int virtio_id_match(const struct virtio_device *dev,
73 const struct virtio_device_id *id)
75 if (id->device != dev->id.device && id->device != VIRTIO_DEV_ANY_ID)
78 return id->vendor == VIRTIO_DEV_ANY_ID || id->vendor == dev->id.vendor;
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 static int virtio_dev_match(struct device *_dv, struct device_driver *_dr)
86 struct virtio_device *dev = dev_to_virtio(_dv);
87 const struct virtio_device_id *ids;
89 ids = drv_to_virtio(_dr)->id_table;
90 for (i = 0; ids[i].device; i++)
91 if (virtio_id_match(dev, &ids[i]))
96 static int virtio_uevent(struct device *_dv, struct kobj_uevent_env *env)
98 struct virtio_device *dev = dev_to_virtio(_dv);
100 return add_uevent_var(env, "MODALIAS=virtio:d%08Xv%08X",
101 dev->id.device, dev->id.vendor);
104 void virtio_check_driver_offered_feature(const struct virtio_device *vdev,
108 struct virtio_driver *drv = drv_to_virtio(vdev->dev.driver);
110 for (i = 0; i < drv->feature_table_size; i++)
111 if (drv->feature_table[i] == fbit)
114 if (drv->feature_table_legacy) {
115 for (i = 0; i < drv->feature_table_size_legacy; i++)
116 if (drv->feature_table_legacy[i] == fbit)
122 EXPORT_SYMBOL_GPL(virtio_check_driver_offered_feature);
124 static void __virtio_config_changed(struct virtio_device *dev)
126 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
128 if (!dev->config_enabled)
129 dev->config_change_pending = true;
130 else if (drv && drv->config_changed)
131 drv->config_changed(dev);
134 void virtio_config_changed(struct virtio_device *dev)
138 spin_lock_irqsave(&dev->config_lock, flags);
139 __virtio_config_changed(dev);
140 spin_unlock_irqrestore(&dev->config_lock, flags);
142 EXPORT_SYMBOL_GPL(virtio_config_changed);
144 static void virtio_config_disable(struct virtio_device *dev)
146 spin_lock_irq(&dev->config_lock);
147 dev->config_enabled = false;
148 spin_unlock_irq(&dev->config_lock);
151 static void virtio_config_enable(struct virtio_device *dev)
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);
161 void virtio_add_status(struct virtio_device *dev, unsigned int status)
164 dev->config->set_status(dev, dev->config->get_status(dev) | status);
166 EXPORT_SYMBOL_GPL(virtio_add_status);
168 int virtio_finalize_features(struct virtio_device *dev)
170 int ret = dev->config->finalize_features(dev);
177 ret = arch_has_restricted_virtio_memory_access();
179 if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1)) {
181 "device must provide VIRTIO_F_VERSION_1\n");
185 if (!virtio_has_feature(dev, VIRTIO_F_ACCESS_PLATFORM)) {
187 "device must provide VIRTIO_F_ACCESS_PLATFORM\n");
192 if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1))
195 virtio_add_status(dev, VIRTIO_CONFIG_S_FEATURES_OK);
196 status = dev->config->get_status(dev);
197 if (!(status & VIRTIO_CONFIG_S_FEATURES_OK)) {
198 dev_err(&dev->dev, "virtio: device refuses features: %x\n",
204 EXPORT_SYMBOL_GPL(virtio_finalize_features);
206 static int virtio_dev_probe(struct device *_d)
209 struct virtio_device *dev = dev_to_virtio(_d);
210 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
213 u64 driver_features_legacy;
215 /* We have a driver! */
216 virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER);
218 /* Figure out what features the device supports. */
219 device_features = dev->config->get_features(dev);
221 /* Figure out what features the driver supports. */
223 for (i = 0; i < drv->feature_table_size; i++) {
224 unsigned int f = drv->feature_table[i];
226 driver_features |= (1ULL << f);
229 /* Some drivers have a separate feature table for virtio v1.0 */
230 if (drv->feature_table_legacy) {
231 driver_features_legacy = 0;
232 for (i = 0; i < drv->feature_table_size_legacy; i++) {
233 unsigned int f = drv->feature_table_legacy[i];
235 driver_features_legacy |= (1ULL << f);
238 driver_features_legacy = driver_features;
241 if (device_features & (1ULL << VIRTIO_F_VERSION_1))
242 dev->features = driver_features & device_features;
244 dev->features = driver_features_legacy & device_features;
246 /* Transport features always preserved to pass to finalize_features. */
247 for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++)
248 if (device_features & (1ULL << i))
249 __virtio_set_bit(dev, i);
252 err = drv->validate(dev);
257 err = virtio_finalize_features(dev);
261 err = drv->probe(dev);
265 /* If probe didn't do it, mark device DRIVER_OK ourselves. */
266 if (!(dev->config->get_status(dev) & VIRTIO_CONFIG_S_DRIVER_OK))
267 virtio_device_ready(dev);
272 virtio_config_enable(dev);
276 virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
281 static int virtio_dev_remove(struct device *_d)
283 struct virtio_device *dev = dev_to_virtio(_d);
284 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
286 virtio_config_disable(dev);
290 /* Driver should have reset device. */
291 WARN_ON_ONCE(dev->config->get_status(dev));
293 /* Acknowledge the device's existence again. */
294 virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
298 static struct bus_type virtio_bus = {
300 .match = virtio_dev_match,
301 .dev_groups = virtio_dev_groups,
302 .uevent = virtio_uevent,
303 .probe = virtio_dev_probe,
304 .remove = virtio_dev_remove,
307 int register_virtio_driver(struct virtio_driver *driver)
309 /* Catch this early. */
310 BUG_ON(driver->feature_table_size && !driver->feature_table);
311 driver->driver.bus = &virtio_bus;
312 return driver_register(&driver->driver);
314 EXPORT_SYMBOL_GPL(register_virtio_driver);
316 void unregister_virtio_driver(struct virtio_driver *driver)
318 driver_unregister(&driver->driver);
320 EXPORT_SYMBOL_GPL(unregister_virtio_driver);
323 * register_virtio_device - register virtio device
324 * @dev : virtio device to be registered
326 * On error, the caller must call put_device on &@dev->dev (and not kfree),
327 * as another code path may have obtained a reference to @dev.
329 * Returns: 0 on suceess, -error on failure
331 int register_virtio_device(struct virtio_device *dev)
335 dev->dev.bus = &virtio_bus;
336 device_initialize(&dev->dev);
338 /* Assign a unique device index and hence name. */
339 err = ida_simple_get(&virtio_index_ida, 0, 0, GFP_KERNEL);
344 dev_set_name(&dev->dev, "virtio%u", dev->index);
346 spin_lock_init(&dev->config_lock);
347 dev->config_enabled = false;
348 dev->config_change_pending = false;
350 /* We always start by resetting the device, in case a previous
351 * driver messed it up. This also tests that code path a little. */
352 dev->config->reset(dev);
354 /* Acknowledge that we've seen the device. */
355 virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
357 INIT_LIST_HEAD(&dev->vqs);
360 * device_add() causes the bus infrastructure to look for a matching
363 err = device_add(&dev->dev);
365 ida_simple_remove(&virtio_index_ida, dev->index);
368 virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
371 EXPORT_SYMBOL_GPL(register_virtio_device);
373 bool is_virtio_device(struct device *dev)
375 return dev->bus == &virtio_bus;
377 EXPORT_SYMBOL_GPL(is_virtio_device);
379 void unregister_virtio_device(struct virtio_device *dev)
381 int index = dev->index; /* save for after device release */
383 device_unregister(&dev->dev);
384 ida_simple_remove(&virtio_index_ida, index);
386 EXPORT_SYMBOL_GPL(unregister_virtio_device);
388 #ifdef CONFIG_PM_SLEEP
389 int virtio_device_freeze(struct virtio_device *dev)
391 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
393 virtio_config_disable(dev);
395 dev->failed = dev->config->get_status(dev) & VIRTIO_CONFIG_S_FAILED;
397 if (drv && drv->freeze)
398 return drv->freeze(dev);
402 EXPORT_SYMBOL_GPL(virtio_device_freeze);
404 int virtio_device_restore(struct virtio_device *dev)
406 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
409 /* We always start by resetting the device, in case a previous
410 * driver messed it up. */
411 dev->config->reset(dev);
413 /* Acknowledge that we've seen the device. */
414 virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
416 /* Maybe driver failed before freeze.
417 * Restore the failed status, for debugging. */
419 virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
424 /* We have a driver! */
425 virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER);
427 ret = virtio_finalize_features(dev);
432 ret = drv->restore(dev);
437 /* Finally, tell the device we're all set */
438 virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK);
440 virtio_config_enable(dev);
445 virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
448 EXPORT_SYMBOL_GPL(virtio_device_restore);
451 static int virtio_init(void)
453 if (bus_register(&virtio_bus) != 0)
454 panic("virtio bus registration failed");
458 static void __exit virtio_exit(void)
460 bus_unregister(&virtio_bus);
461 ida_destroy(&virtio_index_ida);
463 core_initcall(virtio_init);
464 module_exit(virtio_exit);
466 MODULE_LICENSE("GPL");