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1#define DPRINTK(fmt, args...) \
2 pr_debug("xenbus_probe (%s:%d) " fmt ".\n", \
3 __func__, __LINE__, ##args)
4
5#include <linux/kernel.h>
6#include <linux/err.h>
7#include <linux/string.h>
8#include <linux/ctype.h>
9#include <linux/fcntl.h>
10#include <linux/mm.h>
11#include <linux/proc_fs.h>
12#include <linux/notifier.h>
13#include <linux/kthread.h>
14#include <linux/mutex.h>
15#include <linux/io.h>
16
17#include <asm/page.h>
18#include <asm/pgtable.h>
19#include <asm/xen/hypervisor.h>
20#include <xen/xenbus.h>
21#include <xen/events.h>
22#include <xen/page.h>
23
24#include <xen/platform_pci.h>
25
26#include "xenbus_comms.h"
27#include "xenbus_probe.h"
28
29
30/* device/<type>/<id> => <type>-<id> */
31static int frontend_bus_id(char bus_id[XEN_BUS_ID_SIZE], const char *nodename)
32{
33 nodename = strchr(nodename, '/');
34 if (!nodename || strlen(nodename + 1) >= XEN_BUS_ID_SIZE) {
35 printk(KERN_WARNING "XENBUS: bad frontend %s\n", nodename);
36 return -EINVAL;
37 }
38
39 strlcpy(bus_id, nodename + 1, XEN_BUS_ID_SIZE);
40 if (!strchr(bus_id, '/')) {
41 printk(KERN_WARNING "XENBUS: bus_id %s no slash\n", bus_id);
42 return -EINVAL;
43 }
44 *strchr(bus_id, '/') = '-';
45 return 0;
46}
47
48/* device/<typename>/<name> */
49static int xenbus_probe_frontend(struct xen_bus_type *bus, const char *type,
50 const char *name)
51{
52 char *nodename;
53 int err;
54
55 nodename = kasprintf(GFP_KERNEL, "%s/%s/%s", bus->root, type, name);
56 if (!nodename)
57 return -ENOMEM;
58
59 DPRINTK("%s", nodename);
60
61 err = xenbus_probe_node(bus, type, nodename);
62 kfree(nodename);
63 return err;
64}
65
66static int xenbus_uevent_frontend(struct device *_dev,
67 struct kobj_uevent_env *env)
68{
69 struct xenbus_device *dev = to_xenbus_device(_dev);
70
71 if (add_uevent_var(env, "MODALIAS=xen:%s", dev->devicetype))
72 return -ENOMEM;
73
74 return 0;
75}
76
77
78static void backend_changed(struct xenbus_watch *watch,
79 const char **vec, unsigned int len)
80{
81 xenbus_otherend_changed(watch, vec, len, 1);
82}
83
84static const struct dev_pm_ops xenbus_pm_ops = {
85 .suspend = xenbus_dev_suspend,
86 .resume = xenbus_dev_resume,
87 .freeze = xenbus_dev_suspend,
88 .thaw = xenbus_dev_cancel,
89 .restore = xenbus_dev_resume,
90};
91
92static struct xen_bus_type xenbus_frontend = {
93 .root = "device",
94 .levels = 2, /* device/type/<id> */
95 .get_bus_id = frontend_bus_id,
96 .probe = xenbus_probe_frontend,
97 .otherend_changed = backend_changed,
98 .bus = {
99 .name = "xen",
100 .match = xenbus_match,
101 .uevent = xenbus_uevent_frontend,
102 .probe = xenbus_dev_probe,
103 .remove = xenbus_dev_remove,
104 .shutdown = xenbus_dev_shutdown,
105 .dev_attrs = xenbus_dev_attrs,
106
107 .pm = &xenbus_pm_ops,
108 },
109};
110
111static void frontend_changed(struct xenbus_watch *watch,
112 const char **vec, unsigned int len)
113{
114 DPRINTK("");
115
116 xenbus_dev_changed(vec[XS_WATCH_PATH], &xenbus_frontend);
117}
118
119
120/* We watch for devices appearing and vanishing. */
121static struct xenbus_watch fe_watch = {
122 .node = "device",
123 .callback = frontend_changed,
124};
125
126static int read_backend_details(struct xenbus_device *xendev)
127{
128 return xenbus_read_otherend_details(xendev, "backend-id", "backend");
129}
130
131static int is_device_connecting(struct device *dev, void *data)
132{
133 struct xenbus_device *xendev = to_xenbus_device(dev);
134 struct device_driver *drv = data;
135 struct xenbus_driver *xendrv;
136
137 /*
138 * A device with no driver will never connect. We care only about
139 * devices which should currently be in the process of connecting.
140 */
141 if (!dev->driver)
142 return 0;
143
144 /* Is this search limited to a particular driver? */
145 if (drv && (dev->driver != drv))
146 return 0;
147
148 xendrv = to_xenbus_driver(dev->driver);
149 return (xendev->state < XenbusStateConnected ||
150 (xendev->state == XenbusStateConnected &&
151 xendrv->is_ready && !xendrv->is_ready(xendev)));
152}
153
154static int exists_connecting_device(struct device_driver *drv)
155{
156 return bus_for_each_dev(&xenbus_frontend.bus, NULL, drv,
157 is_device_connecting);
158}
159
160static int print_device_status(struct device *dev, void *data)
161{
162 struct xenbus_device *xendev = to_xenbus_device(dev);
163 struct device_driver *drv = data;
164
165 /* Is this operation limited to a particular driver? */
166 if (drv && (dev->driver != drv))
167 return 0;
168
169 if (!dev->driver) {
170 /* Information only: is this too noisy? */
171 printk(KERN_INFO "XENBUS: Device with no driver: %s\n",
172 xendev->nodename);
173 } else if (xendev->state < XenbusStateConnected) {
174 enum xenbus_state rstate = XenbusStateUnknown;
175 if (xendev->otherend)
176 rstate = xenbus_read_driver_state(xendev->otherend);
177 printk(KERN_WARNING "XENBUS: Timeout connecting "
178 "to device: %s (local state %d, remote state %d)\n",
179 xendev->nodename, xendev->state, rstate);
180 }
181
182 return 0;
183}
184
185/* We only wait for device setup after most initcalls have run. */
186static int ready_to_wait_for_devices;
187
188/*
189 * On a 5-minute timeout, wait for all devices currently configured. We need
190 * to do this to guarantee that the filesystems and / or network devices
191 * needed for boot are available, before we can allow the boot to proceed.
192 *
193 * This needs to be on a late_initcall, to happen after the frontend device
194 * drivers have been initialised, but before the root fs is mounted.
195 *
196 * A possible improvement here would be to have the tools add a per-device
197 * flag to the store entry, indicating whether it is needed at boot time.
198 * This would allow people who knew what they were doing to accelerate their
199 * boot slightly, but of course needs tools or manual intervention to set up
200 * those flags correctly.
201 */
202static void wait_for_devices(struct xenbus_driver *xendrv)
203{
204 unsigned long start = jiffies;
205 struct device_driver *drv = xendrv ? &xendrv->driver : NULL;
206 unsigned int seconds_waited = 0;
207
208 if (!ready_to_wait_for_devices || !xen_domain())
209 return;
210
211 while (exists_connecting_device(drv)) {
212 if (time_after(jiffies, start + (seconds_waited+5)*HZ)) {
213 if (!seconds_waited)
214 printk(KERN_WARNING "XENBUS: Waiting for "
215 "devices to initialise: ");
216 seconds_waited += 5;
217 printk("%us...", 300 - seconds_waited);
218 if (seconds_waited == 300)
219 break;
220 }
221
222 schedule_timeout_interruptible(HZ/10);
223 }
224
225 if (seconds_waited)
226 printk("\n");
227
228 bus_for_each_dev(&xenbus_frontend.bus, NULL, drv,
229 print_device_status);
230}
231
232int __xenbus_register_frontend(struct xenbus_driver *drv,
233 struct module *owner, const char *mod_name)
234{
235 int ret;
236
237 drv->read_otherend_details = read_backend_details;
238
239 ret = xenbus_register_driver_common(drv, &xenbus_frontend,
240 owner, mod_name);
241 if (ret)
242 return ret;
243
244 /* If this driver is loaded as a module wait for devices to attach. */
245 wait_for_devices(drv);
246
247 return 0;
248}
249EXPORT_SYMBOL_GPL(__xenbus_register_frontend);
250
251static int frontend_probe_and_watch(struct notifier_block *notifier,
252 unsigned long event,
253 void *data)
254{
255 /* Enumerate devices in xenstore and watch for changes. */
256 xenbus_probe_devices(&xenbus_frontend);
257 register_xenbus_watch(&fe_watch);
258
259 return NOTIFY_DONE;
260}
261
262
263static int __init xenbus_probe_frontend_init(void)
264{
265 static struct notifier_block xenstore_notifier = {
266 .notifier_call = frontend_probe_and_watch
267 };
268 int err;
269
270 DPRINTK("");
271
272 /* Register ourselves with the kernel bus subsystem */
273 err = bus_register(&xenbus_frontend.bus);
274 if (err)
275 return err;
276
277 register_xenstore_notifier(&xenstore_notifier);
278
279 return 0;
280}
281subsys_initcall(xenbus_probe_frontend_init);
282
283#ifndef MODULE
284static int __init boot_wait_for_devices(void)
285{
286 if (xen_hvm_domain() && !xen_platform_pci_unplug)
287 return -ENODEV;
288
289 ready_to_wait_for_devices = 1;
290 wait_for_devices(NULL);
291 return 0;
292}
293
294late_initcall(boot_wait_for_devices);
295#endif
296
297MODULE_LICENSE("GPL");
1// SPDX-License-Identifier: GPL-2.0-only
2#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
3
4#define DPRINTK(fmt, ...) \
5 pr_debug("(%s:%d) " fmt "\n", \
6 __func__, __LINE__, ##__VA_ARGS__)
7
8#include <linux/kernel.h>
9#include <linux/err.h>
10#include <linux/string.h>
11#include <linux/ctype.h>
12#include <linux/fcntl.h>
13#include <linux/mm.h>
14#include <linux/proc_fs.h>
15#include <linux/notifier.h>
16#include <linux/kthread.h>
17#include <linux/mutex.h>
18#include <linux/io.h>
19#include <linux/module.h>
20
21#include <asm/page.h>
22#include <asm/xen/hypervisor.h>
23#include <xen/xenbus.h>
24#include <xen/events.h>
25#include <xen/page.h>
26#include <xen/xen.h>
27
28#include <xen/platform_pci.h>
29
30#include "xenbus.h"
31
32
33
34/* device/<type>/<id> => <type>-<id> */
35static int frontend_bus_id(char bus_id[XEN_BUS_ID_SIZE], const char *nodename)
36{
37 nodename = strchr(nodename, '/');
38 if (!nodename || strlen(nodename + 1) >= XEN_BUS_ID_SIZE) {
39 pr_warn("bad frontend %s\n", nodename);
40 return -EINVAL;
41 }
42
43 strscpy(bus_id, nodename + 1, XEN_BUS_ID_SIZE);
44 if (!strchr(bus_id, '/')) {
45 pr_warn("bus_id %s no slash\n", bus_id);
46 return -EINVAL;
47 }
48 *strchr(bus_id, '/') = '-';
49 return 0;
50}
51
52/* device/<typename>/<name> */
53static int xenbus_probe_frontend(struct xen_bus_type *bus, const char *type,
54 const char *name)
55{
56 char *nodename;
57 int err;
58
59 /* ignore console/0 */
60 if (!strncmp(type, "console", 7) && !strncmp(name, "0", 1)) {
61 DPRINTK("Ignoring buggy device entry console/0");
62 return 0;
63 }
64
65 nodename = kasprintf(GFP_KERNEL, "%s/%s/%s", bus->root, type, name);
66 if (!nodename)
67 return -ENOMEM;
68
69 DPRINTK("%s", nodename);
70
71 err = xenbus_probe_node(bus, type, nodename);
72 kfree(nodename);
73 return err;
74}
75
76static int xenbus_uevent_frontend(struct device *_dev,
77 struct kobj_uevent_env *env)
78{
79 struct xenbus_device *dev = to_xenbus_device(_dev);
80
81 if (add_uevent_var(env, "MODALIAS=xen:%s", dev->devicetype))
82 return -ENOMEM;
83
84 return 0;
85}
86
87
88static void backend_changed(struct xenbus_watch *watch,
89 const char *path, const char *token)
90{
91 xenbus_otherend_changed(watch, path, token, 1);
92}
93
94static void xenbus_frontend_delayed_resume(struct work_struct *w)
95{
96 struct xenbus_device *xdev = container_of(w, struct xenbus_device, work);
97
98 xenbus_dev_resume(&xdev->dev);
99}
100
101static int xenbus_frontend_dev_resume(struct device *dev)
102{
103 /*
104 * If xenstored is running in this domain, we cannot access the backend
105 * state at the moment, so we need to defer xenbus_dev_resume
106 */
107 if (xen_store_domain_type == XS_LOCAL) {
108 struct xenbus_device *xdev = to_xenbus_device(dev);
109
110 schedule_work(&xdev->work);
111
112 return 0;
113 }
114
115 return xenbus_dev_resume(dev);
116}
117
118static int xenbus_frontend_dev_probe(struct device *dev)
119{
120 if (xen_store_domain_type == XS_LOCAL) {
121 struct xenbus_device *xdev = to_xenbus_device(dev);
122 INIT_WORK(&xdev->work, xenbus_frontend_delayed_resume);
123 }
124
125 return xenbus_dev_probe(dev);
126}
127
128static void xenbus_frontend_dev_shutdown(struct device *_dev)
129{
130 struct xenbus_device *dev = to_xenbus_device(_dev);
131 unsigned long timeout = 5*HZ;
132
133 DPRINTK("%s", dev->nodename);
134
135 get_device(&dev->dev);
136 if (dev->state != XenbusStateConnected) {
137 pr_info("%s: %s: %s != Connected, skipping\n",
138 __func__, dev->nodename, xenbus_strstate(dev->state));
139 goto out;
140 }
141 xenbus_switch_state(dev, XenbusStateClosing);
142 timeout = wait_for_completion_timeout(&dev->down, timeout);
143 if (!timeout)
144 pr_info("%s: %s timeout closing device\n",
145 __func__, dev->nodename);
146 out:
147 put_device(&dev->dev);
148}
149
150static const struct dev_pm_ops xenbus_pm_ops = {
151 .suspend = xenbus_dev_suspend,
152 .resume = xenbus_frontend_dev_resume,
153 .freeze = xenbus_dev_suspend,
154 .thaw = xenbus_dev_cancel,
155 .restore = xenbus_dev_resume,
156};
157
158static struct xen_bus_type xenbus_frontend = {
159 .root = "device",
160 .levels = 2, /* device/type/<id> */
161 .get_bus_id = frontend_bus_id,
162 .probe = xenbus_probe_frontend,
163 .otherend_changed = backend_changed,
164 .bus = {
165 .name = "xen",
166 .match = xenbus_match,
167 .uevent = xenbus_uevent_frontend,
168 .probe = xenbus_frontend_dev_probe,
169 .remove = xenbus_dev_remove,
170 .shutdown = xenbus_frontend_dev_shutdown,
171 .dev_groups = xenbus_dev_groups,
172
173 .pm = &xenbus_pm_ops,
174 },
175};
176
177static void frontend_changed(struct xenbus_watch *watch,
178 const char *path, const char *token)
179{
180 DPRINTK("");
181
182 xenbus_dev_changed(path, &xenbus_frontend);
183}
184
185
186/* We watch for devices appearing and vanishing. */
187static struct xenbus_watch fe_watch = {
188 .node = "device",
189 .callback = frontend_changed,
190};
191
192static int read_backend_details(struct xenbus_device *xendev)
193{
194 return xenbus_read_otherend_details(xendev, "backend-id", "backend");
195}
196
197static int is_device_connecting(struct device *dev, void *data, bool ignore_nonessential)
198{
199 struct xenbus_device *xendev = to_xenbus_device(dev);
200 struct device_driver *drv = data;
201 struct xenbus_driver *xendrv;
202
203 /*
204 * A device with no driver will never connect. We care only about
205 * devices which should currently be in the process of connecting.
206 */
207 if (!dev->driver)
208 return 0;
209
210 /* Is this search limited to a particular driver? */
211 if (drv && (dev->driver != drv))
212 return 0;
213
214 xendrv = to_xenbus_driver(dev->driver);
215
216 if (ignore_nonessential && xendrv->not_essential)
217 return 0;
218
219 return (xendev->state < XenbusStateConnected ||
220 (xendev->state == XenbusStateConnected &&
221 xendrv->is_ready && !xendrv->is_ready(xendev)));
222}
223static int essential_device_connecting(struct device *dev, void *data)
224{
225 return is_device_connecting(dev, data, true /* ignore PV[KBB+FB] */);
226}
227static int non_essential_device_connecting(struct device *dev, void *data)
228{
229 return is_device_connecting(dev, data, false);
230}
231
232static int exists_essential_connecting_device(struct device_driver *drv)
233{
234 return bus_for_each_dev(&xenbus_frontend.bus, NULL, drv,
235 essential_device_connecting);
236}
237static int exists_non_essential_connecting_device(struct device_driver *drv)
238{
239 return bus_for_each_dev(&xenbus_frontend.bus, NULL, drv,
240 non_essential_device_connecting);
241}
242
243static int print_device_status(struct device *dev, void *data)
244{
245 struct xenbus_device *xendev = to_xenbus_device(dev);
246 struct device_driver *drv = data;
247
248 /* Is this operation limited to a particular driver? */
249 if (drv && (dev->driver != drv))
250 return 0;
251
252 if (!dev->driver) {
253 /* Information only: is this too noisy? */
254 pr_info("Device with no driver: %s\n", xendev->nodename);
255 } else if (xendev->state < XenbusStateConnected) {
256 enum xenbus_state rstate = XenbusStateUnknown;
257 if (xendev->otherend)
258 rstate = xenbus_read_driver_state(xendev->otherend);
259 pr_warn("Timeout connecting to device: %s (local state %d, remote state %d)\n",
260 xendev->nodename, xendev->state, rstate);
261 }
262
263 return 0;
264}
265
266/* We only wait for device setup after most initcalls have run. */
267static int ready_to_wait_for_devices;
268
269static bool wait_loop(unsigned long start, unsigned int max_delay,
270 unsigned int *seconds_waited)
271{
272 if (time_after(jiffies, start + (*seconds_waited+5)*HZ)) {
273 if (!*seconds_waited)
274 pr_warn("Waiting for devices to initialise: ");
275 *seconds_waited += 5;
276 pr_cont("%us...", max_delay - *seconds_waited);
277 if (*seconds_waited == max_delay) {
278 pr_cont("\n");
279 return true;
280 }
281 }
282
283 schedule_timeout_interruptible(HZ/10);
284
285 return false;
286}
287/*
288 * On a 5-minute timeout, wait for all devices currently configured. We need
289 * to do this to guarantee that the filesystems and / or network devices
290 * needed for boot are available, before we can allow the boot to proceed.
291 *
292 * This needs to be on a late_initcall, to happen after the frontend device
293 * drivers have been initialised, but before the root fs is mounted.
294 *
295 * A possible improvement here would be to have the tools add a per-device
296 * flag to the store entry, indicating whether it is needed at boot time.
297 * This would allow people who knew what they were doing to accelerate their
298 * boot slightly, but of course needs tools or manual intervention to set up
299 * those flags correctly.
300 */
301static void wait_for_devices(struct xenbus_driver *xendrv)
302{
303 unsigned long start = jiffies;
304 struct device_driver *drv = xendrv ? &xendrv->driver : NULL;
305 unsigned int seconds_waited = 0;
306
307 if (!ready_to_wait_for_devices || !xen_domain())
308 return;
309
310 while (exists_non_essential_connecting_device(drv))
311 if (wait_loop(start, 30, &seconds_waited))
312 break;
313
314 /* Skips PVKB and PVFB check.*/
315 while (exists_essential_connecting_device(drv))
316 if (wait_loop(start, 270, &seconds_waited))
317 break;
318
319 if (seconds_waited)
320 printk("\n");
321
322 bus_for_each_dev(&xenbus_frontend.bus, NULL, drv,
323 print_device_status);
324}
325
326int __xenbus_register_frontend(struct xenbus_driver *drv, struct module *owner,
327 const char *mod_name)
328{
329 int ret;
330
331 drv->read_otherend_details = read_backend_details;
332
333 ret = xenbus_register_driver_common(drv, &xenbus_frontend,
334 owner, mod_name);
335 if (ret)
336 return ret;
337
338 /* If this driver is loaded as a module wait for devices to attach. */
339 wait_for_devices(drv);
340
341 return 0;
342}
343EXPORT_SYMBOL_GPL(__xenbus_register_frontend);
344
345static DECLARE_WAIT_QUEUE_HEAD(backend_state_wq);
346static int backend_state;
347
348static void xenbus_reset_backend_state_changed(struct xenbus_watch *w,
349 const char *path, const char *token)
350{
351 if (xenbus_scanf(XBT_NIL, path, "", "%i",
352 &backend_state) != 1)
353 backend_state = XenbusStateUnknown;
354 printk(KERN_DEBUG "XENBUS: backend %s %s\n",
355 path, xenbus_strstate(backend_state));
356 wake_up(&backend_state_wq);
357}
358
359static void xenbus_reset_wait_for_backend(char *be, int expected)
360{
361 long timeout;
362 timeout = wait_event_interruptible_timeout(backend_state_wq,
363 backend_state == expected, 5 * HZ);
364 if (timeout <= 0)
365 pr_info("backend %s timed out\n", be);
366}
367
368/*
369 * Reset frontend if it is in Connected or Closed state.
370 * Wait for backend to catch up.
371 * State Connected happens during kdump, Closed after kexec.
372 */
373static void xenbus_reset_frontend(char *fe, char *be, int be_state)
374{
375 struct xenbus_watch be_watch;
376
377 printk(KERN_DEBUG "XENBUS: backend %s %s\n",
378 be, xenbus_strstate(be_state));
379
380 memset(&be_watch, 0, sizeof(be_watch));
381 be_watch.node = kasprintf(GFP_NOIO | __GFP_HIGH, "%s/state", be);
382 if (!be_watch.node)
383 return;
384
385 be_watch.callback = xenbus_reset_backend_state_changed;
386 backend_state = XenbusStateUnknown;
387
388 pr_info("triggering reconnect on %s\n", be);
389 register_xenbus_watch(&be_watch);
390
391 /* fall through to forward backend to state XenbusStateInitialising */
392 switch (be_state) {
393 case XenbusStateConnected:
394 xenbus_printf(XBT_NIL, fe, "state", "%d", XenbusStateClosing);
395 xenbus_reset_wait_for_backend(be, XenbusStateClosing);
396 fallthrough;
397
398 case XenbusStateClosing:
399 xenbus_printf(XBT_NIL, fe, "state", "%d", XenbusStateClosed);
400 xenbus_reset_wait_for_backend(be, XenbusStateClosed);
401 fallthrough;
402
403 case XenbusStateClosed:
404 xenbus_printf(XBT_NIL, fe, "state", "%d", XenbusStateInitialising);
405 xenbus_reset_wait_for_backend(be, XenbusStateInitWait);
406 }
407
408 unregister_xenbus_watch(&be_watch);
409 pr_info("reconnect done on %s\n", be);
410 kfree(be_watch.node);
411}
412
413static void xenbus_check_frontend(char *class, char *dev)
414{
415 int be_state, fe_state, err;
416 char *backend, *frontend;
417
418 frontend = kasprintf(GFP_NOIO | __GFP_HIGH, "device/%s/%s", class, dev);
419 if (!frontend)
420 return;
421
422 err = xenbus_scanf(XBT_NIL, frontend, "state", "%i", &fe_state);
423 if (err != 1)
424 goto out;
425
426 switch (fe_state) {
427 case XenbusStateConnected:
428 case XenbusStateClosed:
429 printk(KERN_DEBUG "XENBUS: frontend %s %s\n",
430 frontend, xenbus_strstate(fe_state));
431 backend = xenbus_read(XBT_NIL, frontend, "backend", NULL);
432 if (!backend || IS_ERR(backend))
433 goto out;
434 err = xenbus_scanf(XBT_NIL, backend, "state", "%i", &be_state);
435 if (err == 1)
436 xenbus_reset_frontend(frontend, backend, be_state);
437 kfree(backend);
438 break;
439 default:
440 break;
441 }
442out:
443 kfree(frontend);
444}
445
446static void xenbus_reset_state(void)
447{
448 char **devclass, **dev;
449 int devclass_n, dev_n;
450 int i, j;
451
452 devclass = xenbus_directory(XBT_NIL, "device", "", &devclass_n);
453 if (IS_ERR(devclass))
454 return;
455
456 for (i = 0; i < devclass_n; i++) {
457 dev = xenbus_directory(XBT_NIL, "device", devclass[i], &dev_n);
458 if (IS_ERR(dev))
459 continue;
460 for (j = 0; j < dev_n; j++)
461 xenbus_check_frontend(devclass[i], dev[j]);
462 kfree(dev);
463 }
464 kfree(devclass);
465}
466
467static int frontend_probe_and_watch(struct notifier_block *notifier,
468 unsigned long event,
469 void *data)
470{
471 /* reset devices in Connected or Closed state */
472 if (xen_hvm_domain())
473 xenbus_reset_state();
474 /* Enumerate devices in xenstore and watch for changes. */
475 xenbus_probe_devices(&xenbus_frontend);
476 register_xenbus_watch(&fe_watch);
477
478 return NOTIFY_DONE;
479}
480
481
482static int __init xenbus_probe_frontend_init(void)
483{
484 static struct notifier_block xenstore_notifier = {
485 .notifier_call = frontend_probe_and_watch
486 };
487 int err;
488
489 DPRINTK("");
490
491 /* Register ourselves with the kernel bus subsystem */
492 err = bus_register(&xenbus_frontend.bus);
493 if (err)
494 return err;
495
496 register_xenstore_notifier(&xenstore_notifier);
497
498 return 0;
499}
500subsys_initcall(xenbus_probe_frontend_init);
501
502#ifndef MODULE
503static int __init boot_wait_for_devices(void)
504{
505 if (!xen_has_pv_devices())
506 return -ENODEV;
507
508 ready_to_wait_for_devices = 1;
509 wait_for_devices(NULL);
510 return 0;
511}
512
513late_initcall(boot_wait_for_devices);
514#endif
515
516MODULE_LICENSE("GPL");