xref: /netbsd-src/sys/arch/xen/xenbus/xenbus_probe.c (revision 82d56013d7b633d116a93943de88e08335357a7c)
1 /* $NetBSD: xenbus_probe.c,v 1.56 2021/04/24 23:36:52 thorpej Exp $ */
2 /******************************************************************************
3  * Talks to Xen Store to figure out what devices we have.
4  *
5  * Copyright (C) 2005 Rusty Russell, IBM Corporation
6  * Copyright (C) 2005 Mike Wray, Hewlett-Packard
7  * Copyright (C) 2005 XenSource Ltd
8  *
9  * This file may be distributed separately from the Linux kernel, or
10  * incorporated into other software packages, subject to the following license:
11  *
12  * Permission is hereby granted, free of charge, to any person obtaining a copy
13  * of this source file (the "Software"), to deal in the Software without
14  * restriction, including without limitation the rights to use, copy, modify,
15  * merge, publish, distribute, sublicense, and/or sell copies of the Software,
16  * and to permit persons to whom the Software is furnished to do so, subject to
17  * the following conditions:
18  *
19  * The above copyright notice and this permission notice shall be included in
20  * all copies or substantial portions of the Software.
21  *
22  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
23  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
24  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
25  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
26  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
27  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
28  * IN THE SOFTWARE.
29  */
30 
31 #include <sys/cdefs.h>
32 __KERNEL_RCSID(0, "$NetBSD: xenbus_probe.c,v 1.56 2021/04/24 23:36:52 thorpej Exp $");
33 
34 #if 0
35 #define DPRINTK(fmt, args...) \
36     printf("xenbus_probe (%s:%d) " fmt ".\n", __func__, __LINE__, ##args)
37 #else
38 #define DPRINTK(fmt, args...) ((void)0)
39 #endif
40 
41 #include <sys/types.h>
42 #include <sys/null.h>
43 #include <sys/errno.h>
44 #include <sys/kmem.h>
45 #include <sys/systm.h>
46 #include <sys/param.h>
47 #include <sys/kthread.h>
48 #include <sys/mutex.h>
49 #include <uvm/uvm.h>
50 
51 #include <xen/xen.h>	/* for xendomain_is_dom0() */
52 #include <xen/hypervisor.h>
53 #include <xen/xenbus.h>
54 #include <xen/evtchn.h>
55 #include <xen/shutdown_xenbus.h>
56 
57 #include "xenbus_comms.h"
58 
59 #include "kernfs.h"
60 
61 static int  xenbus_match(device_t, cfdata_t, void *);
62 static void xenbus_attach(device_t, device_t, void *);
63 static int  xenbus_print(void *, const char *);
64 
65 /* power management, for save/restore */
66 static bool xenbus_suspend(device_t, const pmf_qual_t *);
67 static bool xenbus_resume(device_t, const pmf_qual_t *);
68 
69 /* routines gathering device information from XenStore */
70 static int  read_otherend_details(struct xenbus_device *,
71 		const char *, const char *);
72 static int  read_backend_details (struct xenbus_device *);
73 static int  read_frontend_details(struct xenbus_device *);
74 static void free_otherend_details(struct xenbus_device *);
75 
76 static int  watch_otherend     (struct xenbus_device *);
77 static void free_otherend_watch(struct xenbus_device *);
78 
79 static void xenbus_probe_init(void *);
80 
81 static struct xenbus_device *xenbus_lookup_device_path(const char *);
82 
83 CFATTACH_DECL_NEW(xenbus, 0, xenbus_match, xenbus_attach,
84     NULL, NULL);
85 
86 device_t xenbus_dev;
87 bus_dma_tag_t xenbus_dmat;
88 
89 SLIST_HEAD(, xenbus_device) xenbus_device_list;
90 SLIST_HEAD(, xenbus_backend_driver) xenbus_backend_driver_list =
91 	SLIST_HEAD_INITIALIZER(xenbus_backend_driver);
92 
93 int
94 xenbus_match(device_t parent, cfdata_t match, void *aux)
95 {
96 	struct xenbus_attach_args *xa = (struct xenbus_attach_args *)aux;
97 
98 	if (strcmp(xa->xa_device, "xenbus") == 0)
99 		return 1;
100 	return 0;
101 }
102 
103 static void
104 xenbus_attach(device_t parent, device_t self, void *aux)
105 {
106 	struct xenbus_attach_args *xa = (struct xenbus_attach_args *)aux;
107 	int err;
108 
109 	aprint_normal(": Xen Virtual Bus Interface\n");
110 	xenbus_dev = self;
111 	xenbus_dmat = xa->xa_dmat;
112 	config_pending_incr(self);
113 
114 	err = kthread_create(PRI_NONE, KTHREAD_MPSAFE, NULL,
115 	    xenbus_probe_init, NULL, NULL, "xenbus_probe");
116 	if (err)
117 		aprint_error_dev(xenbus_dev,
118 				"kthread_create(xenbus_probe): %d\n", err);
119 
120 	if (!pmf_device_register(self, xenbus_suspend, xenbus_resume))
121 		aprint_error_dev(self, "couldn't establish power handler\n");
122 }
123 
124 static bool
125 xenbus_suspend(device_t dev, const pmf_qual_t *qual)
126 {
127 	xs_suspend();
128 	xb_suspend_comms(dev);
129 
130 	return true;
131 }
132 
133 static bool
134 xenbus_resume(device_t dev, const pmf_qual_t *qual)
135 {
136 	xb_resume_comms(dev);
137 	xs_resume();
138 
139 	return true;
140 }
141 
142 /*
143  * Suspend a xenbus device
144  */
145 bool
146 xenbus_device_suspend(struct xenbus_device *dev) {
147 
148 	free_otherend_details(dev);
149 	return true;
150 }
151 
152 /*
153  * Resume a xenbus device
154  */
155 bool
156 xenbus_device_resume(struct xenbus_device *dev) {
157 
158 	if (dev->xbusd_type == XENBUS_FRONTEND_DEVICE) {
159 		read_backend_details(dev);
160 	}
161 
162 	return true;
163 }
164 
165 void
166 xenbus_backend_register(struct xenbus_backend_driver *xbakd)
167 {
168 	SLIST_INSERT_HEAD(&xenbus_backend_driver_list, xbakd, xbakd_entries);
169 }
170 
171 static int
172 read_otherend_details(struct xenbus_device *xendev,
173 				 const char *id_node, const char *path_node)
174 {
175 	int err;
176 	unsigned long id;
177 
178 	err = xenbus_read_ul(NULL, xendev->xbusd_path, id_node, &id, 10);
179 	if (err) {
180 		printf("reading other end details %s from %s\n",
181 		    id_node, xendev->xbusd_path);
182 		xenbus_dev_fatal(xendev, err,
183 				 "reading other end details %s from %s",
184 				 id_node, xendev->xbusd_path);
185 		return err;
186 	}
187 	xendev->xbusd_otherend_id = (int)id;
188 
189 	err = xenbus_read(NULL, xendev->xbusd_path, path_node,
190 	    xendev->xbusd_otherend, sizeof(xendev->xbusd_otherend));
191 	if (err) {
192 		printf("reading other end details %s from %s (%d)\n",
193 		    path_node, xendev->xbusd_path, err);
194 		xenbus_dev_fatal(xendev, err,
195 				 "reading other end details %s from %s",
196 				 path_node, xendev->xbusd_path);
197 		return err;
198 	}
199 	DPRINTK("read_otherend_details: read %s/%s returned %s\n",
200 	    xendev->xbusd_path, path_node, xendev->xbusd_otherend);
201 
202 	if (strlen(xendev->xbusd_otherend) == 0 ||
203 	    !xenbus_exists(NULL, xendev->xbusd_otherend, "")) {
204 		printf("missing other end from %s\n", xendev->xbusd_path);
205 		xenbus_dev_fatal(xendev, -ENOENT, "missing other end from %s",
206 				 xendev->xbusd_path);
207 		free_otherend_details(xendev);
208 		return ENOENT;
209 	}
210 
211 	return 0;
212 }
213 
214 static int
215 read_backend_details(struct xenbus_device *xendev)
216 {
217 	return read_otherend_details(xendev, "backend-id", "backend");
218 }
219 
220 
221 static int
222 read_frontend_details(struct xenbus_device *xendev)
223 {
224 	return read_otherend_details(xendev, "frontend-id", "frontend");
225 }
226 
227 static void
228 free_otherend_details(struct xenbus_device *dev)
229 {
230 	/* Nothing to free */
231 	dev->xbusd_otherend[0] = '\0';
232 }
233 
234 static void
235 free_otherend_watch(struct xenbus_device *dev)
236 {
237 	if (dev->xbusd_otherend_watch.node)
238 		xenbus_unwatch_path(&dev->xbusd_otherend_watch);
239 }
240 
241 static void
242 otherend_changed(struct xenbus_watch *watch,
243 			     const char **vec, unsigned int len)
244 {
245 	struct xenbus_device *xdev = watch->xbw_dev;
246 	XenbusState state;
247 
248 	/* Protect us against watches firing on old details when the otherend
249 	   details change, say immediately after a resume. */
250 	if (!xdev->xbusd_otherend ||
251 	    strncmp(xdev->xbusd_otherend, vec[XS_WATCH_PATH],
252 		    strlen(xdev->xbusd_otherend))) {
253 		DPRINTK("Ignoring watch at %s", vec[XS_WATCH_PATH]);
254 		return;
255 	}
256 
257 	state = xenbus_read_driver_state(xdev->xbusd_otherend);
258 
259 	DPRINTK("state is %d, %s, %s",
260 		state, xdev->xbusd_otherend_watch.node, vec[XS_WATCH_PATH]);
261 	if (state == XenbusStateClosed) {
262 		int error;
263 		if (xdev->xbusd_type == XENBUS_BACKEND_DEVICE) {
264 			error = xdev->xbusd_u.b.b_detach(
265 			    xdev->xbusd_u.b.b_cookie);
266 			if (error) {
267 				printf("could not detach %s: %d\n",
268 				    xdev->xbusd_path, error);
269 				return;
270 			}
271 		} else {
272 			error = config_detach(xdev->xbusd_u.f.f_dev,
273 			    DETACH_FORCE);
274 			if (error) {
275 				printf("could not detach %s: %d\n",
276 				    device_xname(xdev->xbusd_u.f.f_dev), error);
277 				return;
278 			}
279 		}
280 		xenbus_free_device(xdev);
281 		return;
282 	}
283 	if (xdev->xbusd_otherend_changed)
284 		xdev->xbusd_otherend_changed(
285 		    (xdev->xbusd_type == XENBUS_BACKEND_DEVICE) ?
286 		    xdev->xbusd_u.b.b_cookie : xdev->xbusd_u.f.f_dev, state);
287 }
288 
289 static int
290 watch_otherend(struct xenbus_device *dev)
291 {
292 	free_otherend_watch(dev);
293 
294 	return xenbus_watch_path2(dev, dev->xbusd_otherend, "state",
295 				  &dev->xbusd_otherend_watch,
296 				  otherend_changed);
297 }
298 
299 static struct xenbus_device *
300 xenbus_lookup_device_path(const char *path)
301 {
302 	struct xenbus_device *xbusd;
303 
304 	SLIST_FOREACH(xbusd, &xenbus_device_list, xbusd_entries) {
305 		if (strcmp(xbusd->xbusd_path, path) == 0)
306 			return xbusd;
307 	}
308 	return NULL;
309 }
310 
311 static int
312 xenbus_probe_device_type(const char *path, const char *type,
313     int (*create)(struct xenbus_device *))
314 {
315 	int err, i, pos, msize;
316 	int *lookup = NULL;
317 	size_t lookup_sz = 0;
318 	unsigned long state;
319 	char **dir;
320 	unsigned int orig_dir_n = 0, dir_n;
321 	struct xenbus_device *xbusd;
322 	struct xenbusdev_attach_args xa;
323 	char *ep;
324 
325 	DPRINTK("probe %s type %s", path, type);
326 	err = xenbus_directory(NULL, path, "", &orig_dir_n, &dir);
327 	DPRINTK("directory err %d dir_n %d", err, orig_dir_n);
328 	if (err)
329 		return err;
330 	dir_n = orig_dir_n;
331 
332 	/* Only sort frontend devices i.e. create == NULL*/
333 	if (dir_n > 1 && create == NULL) {
334 		int minp;
335 		unsigned long minv;
336 		unsigned long *id;
337 		size_t id_sz;
338 
339 		lookup_sz = sizeof(int) * dir_n;
340 		lookup = kmem_zalloc(lookup_sz, KM_SLEEP);
341 
342 		id_sz = sizeof(unsigned long) * dir_n;
343 		id = kmem_zalloc(id_sz, KM_SLEEP);
344 
345 		/* Convert string values to numeric; skip invalid */
346 		for (i = 0; i < dir_n; i++) {
347 			/*
348 			 * Add one to differentiate numerical zero from invalid
349 			 * string. Has no effect on sort order.
350 			 */
351 			id[i] = strtoul(dir[i], &ep, 10) + 1;
352 			if (dir[i][0] == '\0' || *ep != '\0')
353 				id[i] = 0;
354 		}
355 
356 		/* Build lookup table in ascending order */
357 		for (pos = 0; pos < dir_n; ) {
358 			minv = UINT32_MAX;
359 			minp = -1;
360 			for (i = 0; i < dir_n; i++) {
361 				if (id[i] < minv && id[i] > 0) {
362 					minv = id[i];
363 					minp = i;
364 				}
365 			}
366 			if (minp >= 0) {
367 				lookup[pos++] = minp;
368 				id[minp] = 0;
369 			}
370 			else
371 				break;
372 		}
373 
374 		kmem_free(id, id_sz);
375 
376 		/* Adjust in case we had to skip non-numeric entries */
377 		dir_n = pos;
378 	}
379 
380 	for (pos = 0; pos < dir_n; pos++) {
381 		err = 0;
382 		if (lookup)
383 			i = lookup[pos];
384 		else
385 			i = pos;
386 		/*
387 		 * add size of path to size of xenbus_device. xenbus_device
388 		 * already has room for one char in xbusd_path.
389 		 */
390 		msize = sizeof(*xbusd) + strlen(path) + strlen(dir[i]) + 2;
391 		xbusd = kmem_zalloc(msize, KM_SLEEP);
392 		xbusd->xbusd_sz = msize;
393 		xbusd->xbusd_dmat = xenbus_dmat;
394 
395 		snprintf(__UNCONST(xbusd->xbusd_path),
396 		    msize - sizeof(*xbusd) + 1, "%s/%s", path, dir[i]);
397 		if (xenbus_lookup_device_path(xbusd->xbusd_path) != NULL) {
398 			/* device already registered */
399 			kmem_free(xbusd, xbusd->xbusd_sz);
400 			continue;
401 		}
402 		err = xenbus_read_ul(NULL, xbusd->xbusd_path, "state",
403 		    &state, 10);
404 		if (err) {
405 			aprint_error_dev(xenbus_dev, "can't get state "
406 			    "for %s (%d)\n", xbusd->xbusd_path, err);
407 			kmem_free(xbusd, xbusd->xbusd_sz);
408 			err = 0;
409 			continue;
410 		}
411 		if (state != XenbusStateInitialising) {
412 			/* device is not new */
413 			kmem_free(xbusd, xbusd->xbusd_sz);
414 			continue;
415 		}
416 
417 		xbusd->xbusd_otherend_watch.xbw_dev = xbusd;
418 		DPRINTK("xenbus_probe_device_type probe %s\n",
419 		    xbusd->xbusd_path);
420 		if (create != NULL) {
421 			xbusd->xbusd_type = XENBUS_BACKEND_DEVICE;
422 			err = read_frontend_details(xbusd);
423 			if (err != 0) {
424 				aprint_error_dev(xenbus_dev,
425 				    "can't get frontend details for %s (%d)\n",
426 				    xbusd->xbusd_path, err);
427 				break;
428 			}
429 			if (create(xbusd)) {
430 				kmem_free(xbusd, xbusd->xbusd_sz);
431 				continue;
432 			}
433 		} else {
434 			xbusd->xbusd_type = XENBUS_FRONTEND_DEVICE;
435 			xa.xa_xbusd = xbusd;
436 			xa.xa_type = type;
437 			xa.xa_id = strtoul(dir[i], &ep, 0);
438 			if (dir[i][0] == '\0' || *ep != '\0') {
439 				aprint_error_dev(xenbus_dev,
440 				    "device type %s: id %s is not a number\n",
441 				    type, dir[i]);
442 				err = EFTYPE;
443 				kmem_free(xbusd, xbusd->xbusd_sz);
444 				break;
445 			}
446 			if (strcmp(xa.xa_type, "vbd") == 0) {
447 				char dtype[10];
448 				if (xenbus_read(NULL, xbusd->xbusd_path,
449 				    "device-type", dtype, sizeof(dtype)) !=0) {
450 					aprint_error_dev(xenbus_dev,
451 					    "%s: can't read device-type\n",
452 					    xbusd->xbusd_path);
453 					kmem_free(xbusd, xbusd->xbusd_sz);
454 					break;
455 				}
456 				if (strcmp(dtype, "cdrom") == 0) {
457 					aprint_verbose_dev(xenbus_dev,
458 					    "ignoring %s type cdrom\n",
459 					    xbusd->xbusd_path);
460 					kmem_free(xbusd, xbusd->xbusd_sz);
461 					continue;
462 				}
463 			}
464 			err = read_backend_details(xbusd);
465 			if (err != 0) {
466 				aprint_error_dev(xenbus_dev,
467 				    "can't get backend details for %s (%d)\n",
468 				    xbusd->xbusd_path, err);
469 				kmem_free(xbusd, xbusd->xbusd_sz);
470 				break;
471 			}
472 			xbusd->xbusd_u.f.f_dev = config_found(xenbus_dev,
473 			    &xa, xenbus_print, CFARG_EOL);
474 			if (xbusd->xbusd_u.f.f_dev == NULL) {
475 				kmem_free(xbusd, xbusd->xbusd_sz);
476 				continue;
477 			}
478 		}
479 		SLIST_INSERT_HEAD(&xenbus_device_list,
480 		    xbusd, xbusd_entries);
481 		watch_otherend(xbusd);
482 	}
483 	xenbus_directory_free(orig_dir_n, dir);
484 	if (lookup)
485 		kmem_free(lookup, lookup_sz);
486 
487 	return err;
488 }
489 
490 static int
491 xenbus_print(void *aux, const char *pnp)
492 {
493 	struct xenbusdev_attach_args *xa = aux;
494 
495 	if (pnp) {
496 		if (strcmp(xa->xa_type, "vbd") == 0)
497 			aprint_normal("xbd");
498 		else if (strcmp(xa->xa_type, "vif") == 0)
499 			aprint_normal("xennet");
500 		else if (strcmp(xa->xa_type, "balloon") == 0)
501 			aprint_normal("balloon");
502 		else
503 			aprint_normal("unknown type %s", xa->xa_type);
504 		aprint_normal(" at %s", pnp);
505 	}
506 	aprint_normal(" id %d", xa->xa_id);
507 	return(UNCONF);
508 }
509 
510 static int
511 xenbus_probe_frontends(void)
512 {
513 	int err;
514 	char **dir;
515 	unsigned int i, dir_n;
516 	char path[30];
517 
518 	DPRINTK("probe device");
519 	err = xenbus_directory(NULL, "device", "", &dir_n, &dir);
520 	DPRINTK("directory err %d dir_n %d", err, dir_n);
521 	if (err)
522 		return err;
523 
524 	for (i = 0; i < dir_n; i++) {
525 		/*
526 		 * console is configured through xen_start_info when
527 		 * xencons is attaching to hypervisor, so avoid console
528 		 * probing when configuring xenbus devices
529 		 */
530 		if (strcmp(dir[i], "console") == 0)
531 			continue;
532 
533 		snprintf(path, sizeof(path), "device/%s", dir[i]);
534 		err = xenbus_probe_device_type(path, dir[i], NULL);
535 		if (err)
536 			break;
537 	}
538 	xenbus_directory_free(dir_n, dir);
539 	return err;
540 }
541 
542 static int
543 xenbus_probe_backends(void)
544 {
545 	int err;
546 	char **dirt, **dirid;
547 	unsigned int type, id, dirt_n, dirid_n;
548 	char path[30];
549 	struct xenbus_backend_driver *xbakd;
550 
551 	DPRINTK("probe backend");
552 	err = xenbus_directory(NULL, "backend", "", &dirt_n, &dirt);
553 	DPRINTK("directory err %d dirt_n %d", err, dirt_n);
554 	if (err)
555 		return err;
556 
557 	for (type = 0; type < dirt_n; type++) {
558 		SLIST_FOREACH(xbakd, &xenbus_backend_driver_list,
559 		    xbakd_entries) {
560 			if (strcmp(dirt[type], xbakd->xbakd_type) == 0)
561 				break;
562 		}
563 		if (xbakd == NULL)
564 			continue;
565 		err = xenbus_directory(NULL, "backend", dirt[type],
566 		    &dirid_n, &dirid);
567 		DPRINTK("directory backend/%s err %d dirid_n %d",
568 		    dirt[type], err, dirid_n);
569 		if (err)
570 			goto out;
571 
572 		for (id = 0; id < dirid_n; id++) {
573 			snprintf(path, sizeof(path), "backend/%s/%s",
574 			    dirt[type], dirid[id]);
575 			err = xenbus_probe_device_type(path, dirt[type],
576 			    xbakd->xbakd_create);
577 			if (err)
578 				break;
579 		}
580 		xenbus_directory_free(dirid_n, dirid);
581 	}
582 
583 out:
584 	xenbus_directory_free(dirt_n, dirt);
585 	return err;
586 }
587 
588 int
589 xenbus_free_device(struct xenbus_device *xbusd)
590 {
591 	KASSERT(xenbus_lookup_device_path(xbusd->xbusd_path) == xbusd);
592 	SLIST_REMOVE(&xenbus_device_list, xbusd, xenbus_device, xbusd_entries);
593 	free_otherend_watch(xbusd);
594 	free_otherend_details(xbusd);
595 	xenbus_switch_state(xbusd, NULL, XenbusStateClosed);
596 	kmem_free(xbusd, xbusd->xbusd_sz);
597 	return 0;
598 }
599 
600 static void
601 frontend_changed(struct xenbus_watch *watch,
602 			     const char **vec, unsigned int len)
603 {
604 	DPRINTK("frontend_changed %s\n", vec[XS_WATCH_PATH]);
605 	xenbus_probe_frontends();
606 }
607 
608 static void
609 backend_changed(struct xenbus_watch *watch,
610 			    const char **vec, unsigned int len)
611 {
612 	DPRINTK("backend_changed %s\n", vec[XS_WATCH_PATH]);
613 	xenbus_probe_backends();
614 }
615 
616 
617 /* We watch for devices appearing and vanishing. */
618 static struct xenbus_watch fe_watch;
619 
620 static struct xenbus_watch be_watch;
621 
622 /* A flag to determine if xenstored is 'ready' (i.e. has started) */
623 int xenstored_ready = 0;
624 static kmutex_t xenstored_lock;
625 static kcondvar_t xenstored_cv;
626 
627 void
628 xenbus_probe(void *unused)
629 {
630 	struct xenbusdev_attach_args balloon_xa = {
631 		.xa_id = 0,
632 		.xa_type = "balloon"
633 	};
634 
635 	KASSERT((xenstored_ready > 0));
636 
637 	/* Enumerate devices in xenstore. */
638 	xenbus_probe_frontends();
639 	xenbus_probe_backends();
640 
641 	/* Watch for changes. */
642 	fe_watch.node_sz = strlen("device") + 1;
643 	fe_watch.node = kmem_alloc(fe_watch.node_sz, KM_SLEEP);
644 	strcpy(fe_watch.node, "device");
645 	fe_watch.xbw_callback = frontend_changed;
646 	register_xenbus_watch(&fe_watch);
647 
648 	be_watch.node_sz = strlen("backend") + 1;
649 	be_watch.node = kmem_alloc(be_watch.node_sz, KM_SLEEP);
650 	strcpy(be_watch.node, "backend");
651 	be_watch.xbw_callback = backend_changed;
652 	register_xenbus_watch(&be_watch);
653 
654 	/* attach balloon. */
655 	config_found(xenbus_dev, &balloon_xa, xenbus_print,
656 	    CFARG_EOL);
657 
658 	shutdown_xenbus_setup();
659 
660 	/* Notify others that xenstore is up */
661 	//notifier_call_chain(&xenstore_chain, 0, NULL);
662 }
663 
664 void
665 xb_xenstored_make_ready(void)
666 {
667 	mutex_enter(&xenstored_lock);
668 	xenstored_ready = 1;
669 	cv_broadcast(&xenstored_cv);
670 	mutex_exit(&xenstored_lock);
671 }
672 
673 static void
674 xenbus_probe_init(void *unused)
675 {
676 	int err = 0;
677 	bool dom0;
678 	vaddr_t page = 0;
679 
680 	DPRINTK("");
681 
682 	SLIST_INIT(&xenbus_device_list);
683 	mutex_init(&xenstored_lock, MUTEX_DEFAULT, IPL_TTY);
684 	cv_init(&xenstored_cv, "xsready");
685 
686 	/*
687 	** Domain0 doesn't have a store_evtchn or store_mfn yet.
688 	*/
689 	dom0 = xendomain_is_dom0();
690 	if (dom0) {
691 #if defined(DOM0OPS)
692 		paddr_t ma;
693 		evtchn_op_t op = { .cmd = 0 };
694 
695 		/* Allocate page. */
696 		page = uvm_km_alloc(kernel_map, PAGE_SIZE, 0,
697 		    UVM_KMF_ZERO | UVM_KMF_WIRED);
698 		if (!page)
699 			panic("can't get xenstore page");
700 
701 		(void)pmap_extract_ma(pmap_kernel(), page, &ma);
702 		xen_start_info.store_mfn = ma >> PAGE_SHIFT;
703 		xenstore_interface = (void *)page;
704 
705 		/* Next allocate a local port which xenstored can bind to */
706 		op.cmd = EVTCHNOP_alloc_unbound;
707 		op.u.alloc_unbound.dom        = DOMID_SELF;
708 		op.u.alloc_unbound.remote_dom = 0;
709 
710 		err = HYPERVISOR_event_channel_op(&op);
711 		if (err) {
712 			aprint_error_dev(xenbus_dev,
713 				"can't register xenstore event\n");
714 			goto err0;
715 		}
716 
717 		xen_start_info.store_evtchn = op.u.alloc_unbound.port;
718 
719 		DELAY(1000);
720 #else /* DOM0OPS */
721 		kthread_exit(0); /* can't get a working xenstore in this case */
722 #endif /* DOM0OPS */
723 	}
724 
725 #if NKERNFS > 0
726 	/* Publish xenbus and Xenstore info in /kern/xen */
727 	xenbus_kernfs_init();
728 #endif
729 
730 	/* register event handler */
731 	xb_init_comms(xenbus_dev);
732 
733 	/* Initialize the interface to xenstore. */
734 	err = xs_init(xenbus_dev);
735 	if (err) {
736 		aprint_error_dev(xenbus_dev,
737 		    "Error initializing xenstore comms: %i\n", err);
738 		goto err0;
739 	}
740 
741 	if (!dom0) {
742 		xenstored_ready = 1;
743 		xenbus_probe(NULL);
744 	}
745 
746 	DPRINTK("done");
747 	config_pending_decr(xenbus_dev);
748 #ifdef DOM0OPS
749 	if (dom0) {
750 		mutex_enter(&xenstored_lock);
751 		while (xenstored_ready == 0) {
752 			cv_wait(&xenstored_cv, &xenstored_lock);
753 			mutex_exit(&xenstored_lock);
754 			xenbus_probe(NULL);
755 			mutex_enter(&xenstored_lock);
756 		}
757 		mutex_exit(&xenstored_lock);
758 	}
759 #endif
760 	kthread_exit(0);
761 
762 err0:
763 	if (page)
764 		uvm_km_free(kernel_map, page, PAGE_SIZE,
765 				UVM_KMF_ZERO | UVM_KMF_WIRED);
766 	kthread_exit(err);
767 }
768 
769 /*
770  * Local variables:
771  *  c-file-style: "linux"
772  *  indent-tabs-mode: t
773  *  c-indent-level: 8
774  *  c-basic-offset: 8
775  *  tab-width: 8
776  * End:
777  */
778