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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/module.h>
6#include <linux/idr.h>
7#include <uapi/linux/virtio_ids.h>
8
9/* Unique numbering for virtio devices. */
10static DEFINE_IDA(virtio_index_ida);
11
12static ssize_t device_show(struct device *_d,
13 struct device_attribute *attr, char *buf)
14{
15 struct virtio_device *dev = dev_to_virtio(_d);
16 return sprintf(buf, "0x%04x\n", dev->id.device);
17}
18static DEVICE_ATTR_RO(device);
19
20static ssize_t vendor_show(struct device *_d,
21 struct device_attribute *attr, char *buf)
22{
23 struct virtio_device *dev = dev_to_virtio(_d);
24 return sprintf(buf, "0x%04x\n", dev->id.vendor);
25}
26static DEVICE_ATTR_RO(vendor);
27
28static ssize_t status_show(struct device *_d,
29 struct device_attribute *attr, char *buf)
30{
31 struct virtio_device *dev = dev_to_virtio(_d);
32 return sprintf(buf, "0x%08x\n", dev->config->get_status(dev));
33}
34static DEVICE_ATTR_RO(status);
35
36static ssize_t modalias_show(struct device *_d,
37 struct device_attribute *attr, char *buf)
38{
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);
42}
43static DEVICE_ATTR_RO(modalias);
44
45static ssize_t features_show(struct device *_d,
46 struct device_attribute *attr, char *buf)
47{
48 struct virtio_device *dev = dev_to_virtio(_d);
49 unsigned int i;
50 ssize_t len = 0;
51
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");
58 return len;
59}
60static DEVICE_ATTR_RO(features);
61
62static 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};
70ATTRIBUTE_GROUPS(virtio_dev);
71
72static inline int virtio_id_match(const struct virtio_device *dev,
73 const struct virtio_device_id *id)
74{
75 if (id->device != dev->id.device && id->device != VIRTIO_DEV_ANY_ID)
76 return 0;
77
78 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(). */
83static int virtio_dev_match(struct device *_dv, struct device_driver *_dr)
84{
85 unsigned int i;
86 struct virtio_device *dev = dev_to_virtio(_dv);
87 const struct virtio_device_id *ids;
88
89 ids = drv_to_virtio(_dr)->id_table;
90 for (i = 0; ids[i].device; i++)
91 if (virtio_id_match(dev, &ids[i]))
92 return 1;
93 return 0;
94}
95
96static int virtio_uevent(struct device *_dv, struct kobj_uevent_env *env)
97{
98 struct virtio_device *dev = dev_to_virtio(_dv);
99
100 return add_uevent_var(env, "MODALIAS=virtio:d%08Xv%08X",
101 dev->id.device, dev->id.vendor);
102}
103
104void virtio_check_driver_offered_feature(const struct virtio_device *vdev,
105 unsigned int fbit)
106{
107 unsigned int i;
108 struct virtio_driver *drv = drv_to_virtio(vdev->dev.driver);
109
110 for (i = 0; i < drv->feature_table_size; i++)
111 if (drv->feature_table[i] == fbit)
112 return;
113
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)
117 return;
118 }
119
120 BUG();
121}
122EXPORT_SYMBOL_GPL(virtio_check_driver_offered_feature);
123
124static void __virtio_config_changed(struct virtio_device *dev)
125{
126 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
127
128 if (!dev->config_enabled)
129 dev->config_change_pending = true;
130 else if (drv && drv->config_changed)
131 drv->config_changed(dev);
132}
133
134void virtio_config_changed(struct virtio_device *dev)
135{
136 unsigned long flags;
137
138 spin_lock_irqsave(&dev->config_lock, flags);
139 __virtio_config_changed(dev);
140 spin_unlock_irqrestore(&dev->config_lock, flags);
141}
142EXPORT_SYMBOL_GPL(virtio_config_changed);
143
144void virtio_config_disable(struct virtio_device *dev)
145{
146 spin_lock_irq(&dev->config_lock);
147 dev->config_enabled = false;
148 spin_unlock_irq(&dev->config_lock);
149}
150EXPORT_SYMBOL_GPL(virtio_config_disable);
151
152void virtio_config_enable(struct virtio_device *dev)
153{
154 spin_lock_irq(&dev->config_lock);
155 dev->config_enabled = true;
156 if (dev->config_change_pending)
157 __virtio_config_changed(dev);
158 dev->config_change_pending = false;
159 spin_unlock_irq(&dev->config_lock);
160}
161EXPORT_SYMBOL_GPL(virtio_config_enable);
162
163void virtio_add_status(struct virtio_device *dev, unsigned int status)
164{
165 might_sleep();
166 dev->config->set_status(dev, dev->config->get_status(dev) | status);
167}
168EXPORT_SYMBOL_GPL(virtio_add_status);
169
170int virtio_finalize_features(struct virtio_device *dev)
171{
172 int ret = dev->config->finalize_features(dev);
173 unsigned status;
174
175 might_sleep();
176 if (ret)
177 return ret;
178
179 if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1))
180 return 0;
181
182 virtio_add_status(dev, VIRTIO_CONFIG_S_FEATURES_OK);
183 status = dev->config->get_status(dev);
184 if (!(status & VIRTIO_CONFIG_S_FEATURES_OK)) {
185 dev_err(&dev->dev, "virtio: device refuses features: %x\n",
186 status);
187 return -ENODEV;
188 }
189 return 0;
190}
191EXPORT_SYMBOL_GPL(virtio_finalize_features);
192
193static int virtio_dev_probe(struct device *_d)
194{
195 int err, i;
196 struct virtio_device *dev = dev_to_virtio(_d);
197 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
198 u64 device_features;
199 u64 driver_features;
200 u64 driver_features_legacy;
201
202 /* We have a driver! */
203 virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER);
204
205 /* Figure out what features the device supports. */
206 device_features = dev->config->get_features(dev);
207
208 /* Figure out what features the driver supports. */
209 driver_features = 0;
210 for (i = 0; i < drv->feature_table_size; i++) {
211 unsigned int f = drv->feature_table[i];
212 BUG_ON(f >= 64);
213 driver_features |= (1ULL << f);
214 }
215
216 /* Some drivers have a separate feature table for virtio v1.0 */
217 if (drv->feature_table_legacy) {
218 driver_features_legacy = 0;
219 for (i = 0; i < drv->feature_table_size_legacy; i++) {
220 unsigned int f = drv->feature_table_legacy[i];
221 BUG_ON(f >= 64);
222 driver_features_legacy |= (1ULL << f);
223 }
224 } else {
225 driver_features_legacy = driver_features;
226 }
227
228 if (device_features & (1ULL << VIRTIO_F_VERSION_1))
229 dev->features = driver_features & device_features;
230 else
231 dev->features = driver_features_legacy & device_features;
232
233 /* Transport features always preserved to pass to finalize_features. */
234 for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++)
235 if (device_features & (1ULL << i))
236 __virtio_set_bit(dev, i);
237
238 if (drv->validate) {
239 err = drv->validate(dev);
240 if (err)
241 goto err;
242 }
243
244 err = virtio_finalize_features(dev);
245 if (err)
246 goto err;
247
248 err = drv->probe(dev);
249 if (err)
250 goto err;
251
252 /* If probe didn't do it, mark device DRIVER_OK ourselves. */
253 if (!(dev->config->get_status(dev) & VIRTIO_CONFIG_S_DRIVER_OK))
254 virtio_device_ready(dev);
255
256 if (drv->scan)
257 drv->scan(dev);
258
259 virtio_config_enable(dev);
260
261 return 0;
262err:
263 virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
264 return err;
265
266}
267
268static int virtio_dev_remove(struct device *_d)
269{
270 struct virtio_device *dev = dev_to_virtio(_d);
271 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
272
273 virtio_config_disable(dev);
274
275 drv->remove(dev);
276
277 /* Driver should have reset device. */
278 WARN_ON_ONCE(dev->config->get_status(dev));
279
280 /* Acknowledge the device's existence again. */
281 virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
282 return 0;
283}
284
285static struct bus_type virtio_bus = {
286 .name = "virtio",
287 .match = virtio_dev_match,
288 .dev_groups = virtio_dev_groups,
289 .uevent = virtio_uevent,
290 .probe = virtio_dev_probe,
291 .remove = virtio_dev_remove,
292};
293
294int register_virtio_driver(struct virtio_driver *driver)
295{
296 /* Catch this early. */
297 BUG_ON(driver->feature_table_size && !driver->feature_table);
298 driver->driver.bus = &virtio_bus;
299 return driver_register(&driver->driver);
300}
301EXPORT_SYMBOL_GPL(register_virtio_driver);
302
303void unregister_virtio_driver(struct virtio_driver *driver)
304{
305 driver_unregister(&driver->driver);
306}
307EXPORT_SYMBOL_GPL(unregister_virtio_driver);
308
309/**
310 * register_virtio_device - register virtio device
311 * @dev : virtio device to be registered
312 *
313 * On error, the caller must call put_device on &@dev->dev (and not kfree),
314 * as another code path may have obtained a reference to @dev.
315 *
316 * Returns: 0 on suceess, -error on failure
317 */
318int register_virtio_device(struct virtio_device *dev)
319{
320 int err;
321
322 dev->dev.bus = &virtio_bus;
323 device_initialize(&dev->dev);
324
325 /* Assign a unique device index and hence name. */
326 err = ida_simple_get(&virtio_index_ida, 0, 0, GFP_KERNEL);
327 if (err < 0)
328 goto out;
329
330 dev->index = err;
331 dev_set_name(&dev->dev, "virtio%u", dev->index);
332
333 spin_lock_init(&dev->config_lock);
334 dev->config_enabled = false;
335 dev->config_change_pending = false;
336
337 /* We always start by resetting the device, in case a previous
338 * driver messed it up. This also tests that code path a little. */
339 dev->config->reset(dev);
340
341 /* Acknowledge that we've seen the device. */
342 virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
343
344 INIT_LIST_HEAD(&dev->vqs);
345
346 /*
347 * device_add() causes the bus infrastructure to look for a matching
348 * driver.
349 */
350 err = device_add(&dev->dev);
351 if (err)
352 ida_simple_remove(&virtio_index_ida, dev->index);
353out:
354 if (err)
355 virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
356 return err;
357}
358EXPORT_SYMBOL_GPL(register_virtio_device);
359
360void unregister_virtio_device(struct virtio_device *dev)
361{
362 int index = dev->index; /* save for after device release */
363
364 device_unregister(&dev->dev);
365 ida_simple_remove(&virtio_index_ida, index);
366}
367EXPORT_SYMBOL_GPL(unregister_virtio_device);
368
369#ifdef CONFIG_PM_SLEEP
370int virtio_device_freeze(struct virtio_device *dev)
371{
372 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
373
374 virtio_config_disable(dev);
375
376 dev->failed = dev->config->get_status(dev) & VIRTIO_CONFIG_S_FAILED;
377
378 if (drv && drv->freeze)
379 return drv->freeze(dev);
380
381 return 0;
382}
383EXPORT_SYMBOL_GPL(virtio_device_freeze);
384
385int virtio_device_restore(struct virtio_device *dev)
386{
387 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
388 int ret;
389
390 /* We always start by resetting the device, in case a previous
391 * driver messed it up. */
392 dev->config->reset(dev);
393
394 /* Acknowledge that we've seen the device. */
395 virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
396
397 /* Maybe driver failed before freeze.
398 * Restore the failed status, for debugging. */
399 if (dev->failed)
400 virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
401
402 if (!drv)
403 return 0;
404
405 /* We have a driver! */
406 virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER);
407
408 ret = virtio_finalize_features(dev);
409 if (ret)
410 goto err;
411
412 if (drv->restore) {
413 ret = drv->restore(dev);
414 if (ret)
415 goto err;
416 }
417
418 /* Finally, tell the device we're all set */
419 virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK);
420
421 virtio_config_enable(dev);
422
423 return 0;
424
425err:
426 virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
427 return ret;
428}
429EXPORT_SYMBOL_GPL(virtio_device_restore);
430#endif
431
432static int virtio_init(void)
433{
434 if (bus_register(&virtio_bus) != 0)
435 panic("virtio bus registration failed");
436 return 0;
437}
438
439static void __exit virtio_exit(void)
440{
441 bus_unregister(&virtio_bus);
442 ida_destroy(&virtio_index_ida);
443}
444core_initcall(virtio_init);
445module_exit(virtio_exit);
446
447MODULE_LICENSE("GPL");
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. */
10static DEFINE_IDA(virtio_index_ida);
11
12static ssize_t device_show(struct device *_d,
13 struct device_attribute *attr, char *buf)
14{
15 struct virtio_device *dev = dev_to_virtio(_d);
16 return sprintf(buf, "0x%04x\n", dev->id.device);
17}
18static DEVICE_ATTR_RO(device);
19
20static ssize_t vendor_show(struct device *_d,
21 struct device_attribute *attr, char *buf)
22{
23 struct virtio_device *dev = dev_to_virtio(_d);
24 return sprintf(buf, "0x%04x\n", dev->id.vendor);
25}
26static DEVICE_ATTR_RO(vendor);
27
28static ssize_t status_show(struct device *_d,
29 struct device_attribute *attr, char *buf)
30{
31 struct virtio_device *dev = dev_to_virtio(_d);
32 return sprintf(buf, "0x%08x\n", dev->config->get_status(dev));
33}
34static DEVICE_ATTR_RO(status);
35
36static ssize_t modalias_show(struct device *_d,
37 struct device_attribute *attr, char *buf)
38{
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);
42}
43static DEVICE_ATTR_RO(modalias);
44
45static ssize_t features_show(struct device *_d,
46 struct device_attribute *attr, char *buf)
47{
48 struct virtio_device *dev = dev_to_virtio(_d);
49 unsigned int i;
50 ssize_t len = 0;
51
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");
58 return len;
59}
60static DEVICE_ATTR_RO(features);
61
62static 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};
70ATTRIBUTE_GROUPS(virtio_dev);
71
72static inline int virtio_id_match(const struct virtio_device *dev,
73 const struct virtio_device_id *id)
74{
75 if (id->device != dev->id.device && id->device != VIRTIO_DEV_ANY_ID)
76 return 0;
77
78 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(). */
83static int virtio_dev_match(struct device *_dv, struct device_driver *_dr)
84{
85 unsigned int i;
86 struct virtio_device *dev = dev_to_virtio(_dv);
87 const struct virtio_device_id *ids;
88
89 ids = drv_to_virtio(_dr)->id_table;
90 for (i = 0; ids[i].device; i++)
91 if (virtio_id_match(dev, &ids[i]))
92 return 1;
93 return 0;
94}
95
96static int virtio_uevent(struct device *_dv, struct kobj_uevent_env *env)
97{
98 struct virtio_device *dev = dev_to_virtio(_dv);
99
100 return add_uevent_var(env, "MODALIAS=virtio:d%08Xv%08X",
101 dev->id.device, dev->id.vendor);
102}
103
104void virtio_check_driver_offered_feature(const struct virtio_device *vdev,
105 unsigned int fbit)
106{
107 unsigned int i;
108 struct virtio_driver *drv = drv_to_virtio(vdev->dev.driver);
109
110 for (i = 0; i < drv->feature_table_size; i++)
111 if (drv->feature_table[i] == fbit)
112 return;
113
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)
117 return;
118 }
119
120 BUG();
121}
122EXPORT_SYMBOL_GPL(virtio_check_driver_offered_feature);
123
124static void __virtio_config_changed(struct virtio_device *dev)
125{
126 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
127
128 if (!dev->config_enabled)
129 dev->config_change_pending = true;
130 else if (drv && drv->config_changed)
131 drv->config_changed(dev);
132}
133
134void virtio_config_changed(struct virtio_device *dev)
135{
136 unsigned long flags;
137
138 spin_lock_irqsave(&dev->config_lock, flags);
139 __virtio_config_changed(dev);
140 spin_unlock_irqrestore(&dev->config_lock, flags);
141}
142EXPORT_SYMBOL_GPL(virtio_config_changed);
143
144static void virtio_config_disable(struct virtio_device *dev)
145{
146 spin_lock_irq(&dev->config_lock);
147 dev->config_enabled = false;
148 spin_unlock_irq(&dev->config_lock);
149}
150
151static 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
161void virtio_add_status(struct virtio_device *dev, unsigned int status)
162{
163 might_sleep();
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 might_sleep();
174 if (ret)
175 return ret;
176
177 ret = arch_has_restricted_virtio_memory_access();
178 if (ret) {
179 if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1)) {
180 dev_warn(&dev->dev,
181 "device must provide VIRTIO_F_VERSION_1\n");
182 return -ENODEV;
183 }
184
185 if (!virtio_has_feature(dev, VIRTIO_F_ACCESS_PLATFORM)) {
186 dev_warn(&dev->dev,
187 "device must provide VIRTIO_F_ACCESS_PLATFORM\n");
188 return -ENODEV;
189 }
190 }
191
192 if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1))
193 return 0;
194
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",
199 status);
200 return -ENODEV;
201 }
202 return 0;
203}
204EXPORT_SYMBOL_GPL(virtio_finalize_features);
205
206static int virtio_dev_probe(struct device *_d)
207{
208 int err, i;
209 struct virtio_device *dev = dev_to_virtio(_d);
210 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
211 u64 device_features;
212 u64 driver_features;
213 u64 driver_features_legacy;
214
215 /* We have a driver! */
216 virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER);
217
218 /* Figure out what features the device supports. */
219 device_features = dev->config->get_features(dev);
220
221 /* Figure out what features the driver supports. */
222 driver_features = 0;
223 for (i = 0; i < drv->feature_table_size; i++) {
224 unsigned int f = drv->feature_table[i];
225 BUG_ON(f >= 64);
226 driver_features |= (1ULL << f);
227 }
228
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];
234 BUG_ON(f >= 64);
235 driver_features_legacy |= (1ULL << f);
236 }
237 } else {
238 driver_features_legacy = driver_features;
239 }
240
241 /*
242 * Some devices detect legacy solely via F_VERSION_1. Write
243 * F_VERSION_1 to force LE config space accesses before FEATURES_OK for
244 * these when needed.
245 */
246 if (drv->validate && !virtio_legacy_is_little_endian()
247 && device_features & BIT_ULL(VIRTIO_F_VERSION_1)) {
248 dev->features = BIT_ULL(VIRTIO_F_VERSION_1);
249 dev->config->finalize_features(dev);
250 }
251
252 if (device_features & (1ULL << VIRTIO_F_VERSION_1))
253 dev->features = driver_features & device_features;
254 else
255 dev->features = driver_features_legacy & device_features;
256
257 /* Transport features always preserved to pass to finalize_features. */
258 for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++)
259 if (device_features & (1ULL << i))
260 __virtio_set_bit(dev, i);
261
262 if (drv->validate) {
263 err = drv->validate(dev);
264 if (err)
265 goto err;
266 }
267
268 err = virtio_finalize_features(dev);
269 if (err)
270 goto err;
271
272 err = drv->probe(dev);
273 if (err)
274 goto err;
275
276 /* If probe didn't do it, mark device DRIVER_OK ourselves. */
277 if (!(dev->config->get_status(dev) & VIRTIO_CONFIG_S_DRIVER_OK))
278 virtio_device_ready(dev);
279
280 if (drv->scan)
281 drv->scan(dev);
282
283 virtio_config_enable(dev);
284
285 return 0;
286err:
287 virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
288 return err;
289
290}
291
292static int virtio_dev_remove(struct device *_d)
293{
294 struct virtio_device *dev = dev_to_virtio(_d);
295 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
296
297 virtio_config_disable(dev);
298
299 drv->remove(dev);
300
301 /* Driver should have reset device. */
302 WARN_ON_ONCE(dev->config->get_status(dev));
303
304 /* Acknowledge the device's existence again. */
305 virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
306 return 0;
307}
308
309static struct bus_type virtio_bus = {
310 .name = "virtio",
311 .match = virtio_dev_match,
312 .dev_groups = virtio_dev_groups,
313 .uevent = virtio_uevent,
314 .probe = virtio_dev_probe,
315 .remove = virtio_dev_remove,
316};
317
318int register_virtio_driver(struct virtio_driver *driver)
319{
320 /* Catch this early. */
321 BUG_ON(driver->feature_table_size && !driver->feature_table);
322 driver->driver.bus = &virtio_bus;
323 return driver_register(&driver->driver);
324}
325EXPORT_SYMBOL_GPL(register_virtio_driver);
326
327void unregister_virtio_driver(struct virtio_driver *driver)
328{
329 driver_unregister(&driver->driver);
330}
331EXPORT_SYMBOL_GPL(unregister_virtio_driver);
332
333/**
334 * register_virtio_device - register virtio device
335 * @dev : virtio device to be registered
336 *
337 * On error, the caller must call put_device on &@dev->dev (and not kfree),
338 * as another code path may have obtained a reference to @dev.
339 *
340 * Returns: 0 on suceess, -error on failure
341 */
342int register_virtio_device(struct virtio_device *dev)
343{
344 int err;
345
346 dev->dev.bus = &virtio_bus;
347 device_initialize(&dev->dev);
348
349 /* Assign a unique device index and hence name. */
350 err = ida_simple_get(&virtio_index_ida, 0, 0, GFP_KERNEL);
351 if (err < 0)
352 goto out;
353
354 dev->index = err;
355 dev_set_name(&dev->dev, "virtio%u", dev->index);
356
357 spin_lock_init(&dev->config_lock);
358 dev->config_enabled = false;
359 dev->config_change_pending = false;
360
361 /* We always start by resetting the device, in case a previous
362 * driver messed it up. This also tests that code path a little. */
363 dev->config->reset(dev);
364
365 /* Acknowledge that we've seen the device. */
366 virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
367
368 INIT_LIST_HEAD(&dev->vqs);
369 spin_lock_init(&dev->vqs_list_lock);
370
371 /*
372 * device_add() causes the bus infrastructure to look for a matching
373 * driver.
374 */
375 err = device_add(&dev->dev);
376 if (err)
377 ida_simple_remove(&virtio_index_ida, dev->index);
378out:
379 if (err)
380 virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
381 return err;
382}
383EXPORT_SYMBOL_GPL(register_virtio_device);
384
385bool is_virtio_device(struct device *dev)
386{
387 return dev->bus == &virtio_bus;
388}
389EXPORT_SYMBOL_GPL(is_virtio_device);
390
391void unregister_virtio_device(struct virtio_device *dev)
392{
393 int index = dev->index; /* save for after device release */
394
395 device_unregister(&dev->dev);
396 ida_simple_remove(&virtio_index_ida, index);
397}
398EXPORT_SYMBOL_GPL(unregister_virtio_device);
399
400#ifdef CONFIG_PM_SLEEP
401int virtio_device_freeze(struct virtio_device *dev)
402{
403 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
404
405 virtio_config_disable(dev);
406
407 dev->failed = dev->config->get_status(dev) & VIRTIO_CONFIG_S_FAILED;
408
409 if (drv && drv->freeze)
410 return drv->freeze(dev);
411
412 return 0;
413}
414EXPORT_SYMBOL_GPL(virtio_device_freeze);
415
416int virtio_device_restore(struct virtio_device *dev)
417{
418 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
419 int ret;
420
421 /* We always start by resetting the device, in case a previous
422 * driver messed it up. */
423 dev->config->reset(dev);
424
425 /* Acknowledge that we've seen the device. */
426 virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
427
428 /* Maybe driver failed before freeze.
429 * Restore the failed status, for debugging. */
430 if (dev->failed)
431 virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
432
433 if (!drv)
434 return 0;
435
436 /* We have a driver! */
437 virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER);
438
439 ret = virtio_finalize_features(dev);
440 if (ret)
441 goto err;
442
443 if (drv->restore) {
444 ret = drv->restore(dev);
445 if (ret)
446 goto err;
447 }
448
449 /* Finally, tell the device we're all set */
450 virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK);
451
452 virtio_config_enable(dev);
453
454 return 0;
455
456err:
457 virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
458 return ret;
459}
460EXPORT_SYMBOL_GPL(virtio_device_restore);
461#endif
462
463static int virtio_init(void)
464{
465 if (bus_register(&virtio_bus) != 0)
466 panic("virtio bus registration failed");
467 return 0;
468}
469
470static void __exit virtio_exit(void)
471{
472 bus_unregister(&virtio_bus);
473 ida_destroy(&virtio_index_ida);
474}
475core_initcall(virtio_init);
476module_exit(virtio_exit);
477
478MODULE_LICENSE("GPL");