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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
7/* Unique numbering for virtio devices. */
8static DEFINE_IDA(virtio_index_ida);
9
10static ssize_t device_show(struct device *_d,
11 struct device_attribute *attr, char *buf)
12{
13 struct virtio_device *dev = dev_to_virtio(_d);
14 return sprintf(buf, "0x%04x\n", dev->id.device);
15}
16static DEVICE_ATTR_RO(device);
17
18static ssize_t vendor_show(struct device *_d,
19 struct device_attribute *attr, char *buf)
20{
21 struct virtio_device *dev = dev_to_virtio(_d);
22 return sprintf(buf, "0x%04x\n", dev->id.vendor);
23}
24static DEVICE_ATTR_RO(vendor);
25
26static ssize_t status_show(struct device *_d,
27 struct device_attribute *attr, char *buf)
28{
29 struct virtio_device *dev = dev_to_virtio(_d);
30 return sprintf(buf, "0x%08x\n", dev->config->get_status(dev));
31}
32static DEVICE_ATTR_RO(status);
33
34static ssize_t modalias_show(struct device *_d,
35 struct device_attribute *attr, char *buf)
36{
37 struct virtio_device *dev = dev_to_virtio(_d);
38 return sprintf(buf, "virtio:d%08Xv%08X\n",
39 dev->id.device, dev->id.vendor);
40}
41static DEVICE_ATTR_RO(modalias);
42
43static ssize_t features_show(struct device *_d,
44 struct device_attribute *attr, char *buf)
45{
46 struct virtio_device *dev = dev_to_virtio(_d);
47 unsigned int i;
48 ssize_t len = 0;
49
50 /* We actually represent this as a bitstring, as it could be
51 * arbitrary length in future. */
52 for (i = 0; i < ARRAY_SIZE(dev->features)*BITS_PER_LONG; i++)
53 len += sprintf(buf+len, "%c",
54 test_bit(i, dev->features) ? '1' : '0');
55 len += sprintf(buf+len, "\n");
56 return len;
57}
58static DEVICE_ATTR_RO(features);
59
60static struct attribute *virtio_dev_attrs[] = {
61 &dev_attr_device.attr,
62 &dev_attr_vendor.attr,
63 &dev_attr_status.attr,
64 &dev_attr_modalias.attr,
65 &dev_attr_features.attr,
66 NULL,
67};
68ATTRIBUTE_GROUPS(virtio_dev);
69
70static inline int virtio_id_match(const struct virtio_device *dev,
71 const struct virtio_device_id *id)
72{
73 if (id->device != dev->id.device && id->device != VIRTIO_DEV_ANY_ID)
74 return 0;
75
76 return id->vendor == VIRTIO_DEV_ANY_ID || id->vendor == dev->id.vendor;
77}
78
79/* This looks through all the IDs a driver claims to support. If any of them
80 * match, we return 1 and the kernel will call virtio_dev_probe(). */
81static int virtio_dev_match(struct device *_dv, struct device_driver *_dr)
82{
83 unsigned int i;
84 struct virtio_device *dev = dev_to_virtio(_dv);
85 const struct virtio_device_id *ids;
86
87 ids = drv_to_virtio(_dr)->id_table;
88 for (i = 0; ids[i].device; i++)
89 if (virtio_id_match(dev, &ids[i]))
90 return 1;
91 return 0;
92}
93
94static int virtio_uevent(struct device *_dv, struct kobj_uevent_env *env)
95{
96 struct virtio_device *dev = dev_to_virtio(_dv);
97
98 return add_uevent_var(env, "MODALIAS=virtio:d%08Xv%08X",
99 dev->id.device, dev->id.vendor);
100}
101
102static void add_status(struct virtio_device *dev, unsigned status)
103{
104 dev->config->set_status(dev, dev->config->get_status(dev) | status);
105}
106
107void virtio_check_driver_offered_feature(const struct virtio_device *vdev,
108 unsigned int fbit)
109{
110 unsigned int i;
111 struct virtio_driver *drv = drv_to_virtio(vdev->dev.driver);
112
113 for (i = 0; i < drv->feature_table_size; i++)
114 if (drv->feature_table[i] == fbit)
115 return;
116 BUG();
117}
118EXPORT_SYMBOL_GPL(virtio_check_driver_offered_feature);
119
120static int virtio_dev_probe(struct device *_d)
121{
122 int err, i;
123 struct virtio_device *dev = dev_to_virtio(_d);
124 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
125 u32 device_features;
126
127 /* We have a driver! */
128 add_status(dev, VIRTIO_CONFIG_S_DRIVER);
129
130 /* Figure out what features the device supports. */
131 device_features = dev->config->get_features(dev);
132
133 /* Features supported by both device and driver into dev->features. */
134 memset(dev->features, 0, sizeof(dev->features));
135 for (i = 0; i < drv->feature_table_size; i++) {
136 unsigned int f = drv->feature_table[i];
137 BUG_ON(f >= 32);
138 if (device_features & (1 << f))
139 set_bit(f, dev->features);
140 }
141
142 /* Transport features always preserved to pass to finalize_features. */
143 for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++)
144 if (device_features & (1 << i))
145 set_bit(i, dev->features);
146
147 dev->config->finalize_features(dev);
148
149 err = drv->probe(dev);
150 if (err)
151 add_status(dev, VIRTIO_CONFIG_S_FAILED);
152 else {
153 add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK);
154 if (drv->scan)
155 drv->scan(dev);
156 }
157
158 return err;
159}
160
161static int virtio_dev_remove(struct device *_d)
162{
163 struct virtio_device *dev = dev_to_virtio(_d);
164 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
165
166 drv->remove(dev);
167
168 /* Driver should have reset device. */
169 WARN_ON_ONCE(dev->config->get_status(dev));
170
171 /* Acknowledge the device's existence again. */
172 add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
173 return 0;
174}
175
176static struct bus_type virtio_bus = {
177 .name = "virtio",
178 .match = virtio_dev_match,
179 .dev_groups = virtio_dev_groups,
180 .uevent = virtio_uevent,
181 .probe = virtio_dev_probe,
182 .remove = virtio_dev_remove,
183};
184
185int register_virtio_driver(struct virtio_driver *driver)
186{
187 /* Catch this early. */
188 BUG_ON(driver->feature_table_size && !driver->feature_table);
189 driver->driver.bus = &virtio_bus;
190 return driver_register(&driver->driver);
191}
192EXPORT_SYMBOL_GPL(register_virtio_driver);
193
194void unregister_virtio_driver(struct virtio_driver *driver)
195{
196 driver_unregister(&driver->driver);
197}
198EXPORT_SYMBOL_GPL(unregister_virtio_driver);
199
200int register_virtio_device(struct virtio_device *dev)
201{
202 int err;
203
204 dev->dev.bus = &virtio_bus;
205
206 /* Assign a unique device index and hence name. */
207 err = ida_simple_get(&virtio_index_ida, 0, 0, GFP_KERNEL);
208 if (err < 0)
209 goto out;
210
211 dev->index = err;
212 dev_set_name(&dev->dev, "virtio%u", dev->index);
213
214 /* We always start by resetting the device, in case a previous
215 * driver messed it up. This also tests that code path a little. */
216 dev->config->reset(dev);
217
218 /* Acknowledge that we've seen the device. */
219 add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
220
221 INIT_LIST_HEAD(&dev->vqs);
222
223 /* device_register() causes the bus infrastructure to look for a
224 * matching driver. */
225 err = device_register(&dev->dev);
226out:
227 if (err)
228 add_status(dev, VIRTIO_CONFIG_S_FAILED);
229 return err;
230}
231EXPORT_SYMBOL_GPL(register_virtio_device);
232
233void unregister_virtio_device(struct virtio_device *dev)
234{
235 int index = dev->index; /* save for after device release */
236
237 device_unregister(&dev->dev);
238 ida_simple_remove(&virtio_index_ida, index);
239}
240EXPORT_SYMBOL_GPL(unregister_virtio_device);
241
242static int virtio_init(void)
243{
244 if (bus_register(&virtio_bus) != 0)
245 panic("virtio bus registration failed");
246 return 0;
247}
248
249static void __exit virtio_exit(void)
250{
251 bus_unregister(&virtio_bus);
252}
253core_initcall(virtio_init);
254module_exit(virtio_exit);
255
256MODULE_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");