1 /******************************************************************************
2 * Copyright (C) 2010 Spectra Logic Corporation
3 * Copyright (C) 2008 Doug Rabson
4 * Copyright (C) 2005 Rusty Russell, IBM Corporation
5 * Copyright (C) 2005 Mike Wray, Hewlett-Packard
6 * Copyright (C) 2005 XenSource Ltd
7 *
8 * This file may be distributed separately from the Linux kernel, or
9 * incorporated into other software packages, subject to the following license:
10 *
11 * Permission is hereby granted, free of charge, to any person obtaining a copy
12 * of this source file (the "Software"), to deal in the Software without
13 * restriction, including without limitation the rights to use, copy, modify,
14 * merge, publish, distribute, sublicense, and/or sell copies of the Software,
15 * and to permit persons to whom the Software is furnished to do so, subject to
16 * the following conditions:
17 *
18 * The above copyright notice and this permission notice shall be included in
19 * all copies or substantial portions of the Software.
20 *
21 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
22 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
23 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
24 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
25 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
26 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
27 * IN THE SOFTWARE.
28 */
29
30 /**
31 * \file xenbusb.c
32 *
33 * \brief Shared support functions for managing the NewBus buses that contain
34 * Xen front and back end device instances.
35 *
36 * The NewBus implementation of XenBus attaches a xenbusb_front and xenbusb_back
37 * child bus to the xenstore device. This strategy allows the small differences
38 * in the handling of XenBus operations for front and back devices to be handled
39 * as overrides in xenbusb_front/back.c. Front and back specific device
40 * classes are also provided so device drivers can register for the devices they
41 * can handle without the need to filter within their probe routines. The
42 * net result is a device hierarchy that might look like this:
43 *
44 * xenstore0/
45 * xenbusb_front0/
46 * xn0
47 * xbd0
48 * xbd1
49 * xenbusb_back0/
50 * xbbd0
51 * xnb0
52 * xnb1
53 */
54 #include <sys/cdefs.h>
55 __FBSDID("$FreeBSD$");
56
57 #include <sys/param.h>
58 #include <sys/bus.h>
59 #include <sys/kernel.h>
60 #include <sys/lock.h>
61 #include <sys/malloc.h>
62 #include <sys/module.h>
63 #include <sys/sbuf.h>
64 #include <sys/sysctl.h>
65 #include <sys/syslog.h>
66 #include <sys/systm.h>
67 #include <sys/sx.h>
68 #include <sys/taskqueue.h>
69
70 #include <machine/xen/xen-os.h>
71 #include <machine/stdarg.h>
72
73 #include <xen/gnttab.h>
74 #include <xen/xenstore/xenstorevar.h>
75 #include <xen/xenbus/xenbusb.h>
76 #include <xen/xenbus/xenbusvar.h>
77
78 /*------------------------- Private Functions --------------------------------*/
79 /**
80 * \brief Deallocate XenBus device instance variables.
81 *
82 * \param ivars The instance variable block to free.
83 */
84 static void
85 xenbusb_free_child_ivars(struct xenbus_device_ivars *ivars)
86 {
87 if (ivars->xd_otherend_watch.node != NULL) {
88 xs_unregister_watch(&ivars->xd_otherend_watch);
89 free(ivars->xd_otherend_watch.node, M_XENBUS);
90 ivars->xd_otherend_watch.node = NULL;
91 }
92
93 if (ivars->xd_local_watch.node != NULL) {
94 xs_unregister_watch(&ivars->xd_local_watch);
95 ivars->xd_local_watch.node = NULL;
96 }
97
98 if (ivars->xd_node != NULL) {
99 free(ivars->xd_node, M_XENBUS);
100 ivars->xd_node = NULL;
101 }
102 ivars->xd_node_len = 0;
103
104 if (ivars->xd_type != NULL) {
105 free(ivars->xd_type, M_XENBUS);
106 ivars->xd_type = NULL;
107 }
108
109 if (ivars->xd_otherend_path != NULL) {
110 free(ivars->xd_otherend_path, M_XENBUS);
111 ivars->xd_otherend_path = NULL;
112 }
113 ivars->xd_otherend_path_len = 0;
114
115 free(ivars, M_XENBUS);
116 }
117
118 /**
119 * XenBus watch callback registered against the "state" XenStore
120 * node of the other-end of a split device connection.
121 *
122 * This callback is invoked whenever the state of a device instance's
123 * peer changes.
124 *
125 * \param watch The xs_watch object used to register this callback
126 * function.
127 * \param vec An array of pointers to NUL terminated strings containing
128 * watch event data. The vector should be indexed via the
129 * xs_watch_type enum in xs_wire.h.
130 * \param vec_size The number of elements in vec.
131 */
132 static void
133 xenbusb_otherend_watch_cb(struct xs_watch *watch, const char **vec,
134 unsigned int vec_size __unused)
135 {
136 struct xenbus_device_ivars *ivars;
137 device_t child;
138 device_t bus;
139 const char *path;
140 enum xenbus_state newstate;
141
142 ivars = (struct xenbus_device_ivars *)watch->callback_data;
143 child = ivars->xd_dev;
144 bus = device_get_parent(child);
145
146 path = vec[XS_WATCH_PATH];
147 if (ivars->xd_otherend_path == NULL
148 || strncmp(ivars->xd_otherend_path, path, ivars->xd_otherend_path_len))
149 return;
150
151 newstate = xenbus_read_driver_state(ivars->xd_otherend_path);
152 XENBUSB_OTHEREND_CHANGED(bus, child, newstate);
153 }
154
155 /**
156 * XenBus watch callback registered against the XenStore sub-tree
157 * represnting the local half of a split device connection.
158 *
159 * This callback is invoked whenever any XenStore data in the subtree
160 * is modified, either by us or another privledged domain.
161 *
162 * \param watch The xs_watch object used to register this callback
163 * function.
164 * \param vec An array of pointers to NUL terminated strings containing
165 * watch event data. The vector should be indexed via the
166 * xs_watch_type enum in xs_wire.h.
167 * \param vec_size The number of elements in vec.
168 *
169 */
170 static void
171 xenbusb_local_watch_cb(struct xs_watch *watch, const char **vec,
172 unsigned int vec_size __unused)
173 {
174 struct xenbus_device_ivars *ivars;
175 device_t child;
176 device_t bus;
177 const char *path;
178
179 ivars = (struct xenbus_device_ivars *)watch->callback_data;
180 child = ivars->xd_dev;
181 bus = device_get_parent(child);
182
183 path = vec[XS_WATCH_PATH];
184 if (ivars->xd_node == NULL
185 || strncmp(ivars->xd_node, path, ivars->xd_node_len))
186 return;
187
188 XENBUSB_LOCALEND_CHANGED(bus, child, &path[ivars->xd_node_len]);
189 }
190
191 /**
192 * Search our internal record of configured devices (not the XenStore)
193 * to determine if the XenBus device indicated by \a node is known to
194 * the system.
195 *
196 * \param dev The XenBus bus instance to search for device children.
197 * \param node The XenStore node path for the device to find.
198 *
199 * \return The device_t of the found device if any, or NULL.
200 *
201 * \note device_t is a pointer type, so it can be compared against
202 * NULL for validity.
203 */
204 static device_t
205 xenbusb_device_exists(device_t dev, const char *node)
206 {
207 device_t *kids;
208 device_t result;
209 struct xenbus_device_ivars *ivars;
210 int i, count;
211
212 if (device_get_children(dev, &kids, &count))
213 return (FALSE);
214
215 result = NULL;
216 for (i = 0; i < count; i++) {
217 ivars = device_get_ivars(kids[i]);
218 if (!strcmp(ivars->xd_node, node)) {
219 result = kids[i];
220 break;
221 }
222 }
223 free(kids, M_TEMP);
224
225 return (result);
226 }
227
228 static void
229 xenbusb_delete_child(device_t dev, device_t child)
230 {
231 struct xenbus_device_ivars *ivars;
232
233 ivars = device_get_ivars(child);
234
235 /*
236 * We no longer care about the otherend of the
237 * connection. Cancel the watches now so that we
238 * don't try to handle an event for a partially
239 * detached child.
240 */
241 if (ivars->xd_otherend_watch.node != NULL)
242 xs_unregister_watch(&ivars->xd_otherend_watch);
243 if (ivars->xd_local_watch.node != NULL)
244 xs_unregister_watch(&ivars->xd_local_watch);
245
246 device_delete_child(dev, child);
247 xenbusb_free_child_ivars(ivars);
248 }
249
250 /**
251 * \param dev The NewBus device representing this XenBus bus.
252 * \param child The NewBus device representing a child of dev%'s XenBus bus.
253 */
254 static void
255 xenbusb_verify_device(device_t dev, device_t child)
256 {
257 if (xs_exists(XST_NIL, xenbus_get_node(child), "") == 0) {
258 /*
259 * Device tree has been removed from Xenbus.
260 * Tear down the device.
261 */
262 xenbusb_delete_child(dev, child);
263 }
264 }
265
266 /**
267 * \brief Enumerate the devices on a XenBus bus and register them with
268 * the NewBus device tree.
269 *
270 * xenbusb_enumerate_bus() will create entries (in state DS_NOTPRESENT)
271 * for nodes that appear in the XenStore, but will not invoke probe/attach
272 * operations on drivers. Probe/Attach processing must be separately
273 * performed via an invocation of xenbusb_probe_children(). This is usually
274 * done via the xbs_probe_children task.
275 *
276 * \param xbs XenBus Bus device softc of the owner of the bus to enumerate.
277 *
278 * \return On success, 0. Otherwise an errno value indicating the
279 * type of failure.
280 */
281 static int
282 xenbusb_enumerate_bus(struct xenbusb_softc *xbs)
283 {
284 const char **types;
285 u_int type_idx;
286 u_int type_count;
287 int error;
288
289 error = xs_directory(XST_NIL, xbs->xbs_node, "", &type_count, &types);
290 if (error)
291 return (error);
292
293 for (type_idx = 0; type_idx < type_count; type_idx++)
294 XENBUSB_ENUMERATE_TYPE(xbs->xbs_dev, types[type_idx]);
295
296 free(types, M_XENSTORE);
297
298 return (0);
299 }
300
301 /**
302 * Handler for all generic XenBus device systcl nodes.
303 */
304 static int
305 xenbusb_device_sysctl_handler(SYSCTL_HANDLER_ARGS)
306 {
307 device_t dev;
308 const char *value;
309
310 dev = (device_t)arg1;
311 switch (arg2) {
312 case XENBUS_IVAR_NODE:
313 value = xenbus_get_node(dev);
314 break;
315 case XENBUS_IVAR_TYPE:
316 value = xenbus_get_type(dev);
317 break;
318 case XENBUS_IVAR_STATE:
319 value = xenbus_strstate(xenbus_get_state(dev));
320 break;
321 case XENBUS_IVAR_OTHEREND_ID:
322 return (sysctl_handle_int(oidp, NULL,
323 xenbus_get_otherend_id(dev),
324 req));
325 /* NOTREACHED */
326 case XENBUS_IVAR_OTHEREND_PATH:
327 value = xenbus_get_otherend_path(dev);
328 break;
329 default:
330 return (EINVAL);
331 }
332 return (SYSCTL_OUT_STR(req, value));
333 }
334
335 /**
336 * Create read-only systcl nodes for xenbusb device ivar data.
337 *
338 * \param dev The XenBus device instance to register with sysctl.
339 */
340 static void
341 xenbusb_device_sysctl_init(device_t dev)
342 {
343 struct sysctl_ctx_list *ctx;
344 struct sysctl_oid *tree;
345
346 ctx = device_get_sysctl_ctx(dev);
347 tree = device_get_sysctl_tree(dev);
348
349 SYSCTL_ADD_PROC(ctx,
350 SYSCTL_CHILDREN(tree),
351 OID_AUTO,
352 "xenstore_path",
353 CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE,
354 dev,
355 XENBUS_IVAR_NODE,
356 xenbusb_device_sysctl_handler,
357 "A",
358 "XenStore path to device");
359
360 SYSCTL_ADD_PROC(ctx,
361 SYSCTL_CHILDREN(tree),
362 OID_AUTO,
363 "xenbus_dev_type",
364 CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE,
365 dev,
366 XENBUS_IVAR_TYPE,
367 xenbusb_device_sysctl_handler,
368 "A",
369 "XenBus device type");
370
371 SYSCTL_ADD_PROC(ctx,
372 SYSCTL_CHILDREN(tree),
373 OID_AUTO,
374 "xenbus_connection_state",
375 CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE,
376 dev,
377 XENBUS_IVAR_STATE,
378 xenbusb_device_sysctl_handler,
379 "A",
380 "XenBus state of peer connection");
381
382 SYSCTL_ADD_PROC(ctx,
383 SYSCTL_CHILDREN(tree),
384 OID_AUTO,
385 "xenbus_peer_domid",
386 CTLTYPE_INT | CTLFLAG_RD | CTLFLAG_MPSAFE,
387 dev,
388 XENBUS_IVAR_OTHEREND_ID,
389 xenbusb_device_sysctl_handler,
390 "I",
391 "Xen domain ID of peer");
392
393 SYSCTL_ADD_PROC(ctx,
394 SYSCTL_CHILDREN(tree),
395 OID_AUTO,
396 "xenstore_peer_path",
397 CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE,
398 dev,
399 XENBUS_IVAR_OTHEREND_PATH,
400 xenbusb_device_sysctl_handler,
401 "A",
402 "XenStore path to peer device");
403 }
404
405 /**
406 * \brief Decrement the number of XenBus child devices in the
407 * connecting state by one and release the xbs_attch_ch
408 * interrupt configuration hook if the connecting count
409 * drops to zero.
410 *
411 * \param xbs XenBus Bus device softc of the owner of the bus to enumerate.
412 */
413 static void
414 xenbusb_release_confighook(struct xenbusb_softc *xbs)
415 {
416 mtx_lock(&xbs->xbs_lock);
417 KASSERT(xbs->xbs_connecting_children > 0,
418 ("Connecting device count error\n"));
419 xbs->xbs_connecting_children--;
420 if (xbs->xbs_connecting_children == 0
421 && (xbs->xbs_flags & XBS_ATTACH_CH_ACTIVE) != 0) {
422 xbs->xbs_flags &= ~XBS_ATTACH_CH_ACTIVE;
423 mtx_unlock(&xbs->xbs_lock);
424 config_intrhook_disestablish(&xbs->xbs_attach_ch);
425 } else {
426 mtx_unlock(&xbs->xbs_lock);
427 }
428 }
429
430 /**
431 * \brief Verify the existance of attached device instances and perform
432 * probe/attach processing for newly arrived devices.
433 *
434 * \param dev The NewBus device representing this XenBus bus.
435 *
436 * \return On success, 0. Otherwise an errno value indicating the
437 * type of failure.
438 */
439 static int
440 xenbusb_probe_children(device_t dev)
441 {
442 device_t *kids;
443 struct xenbus_device_ivars *ivars;
444 int i, count, error;
445
446 if (device_get_children(dev, &kids, &count) == 0) {
447 for (i = 0; i < count; i++) {
448 if (device_get_state(kids[i]) != DS_NOTPRESENT) {
449 /*
450 * We already know about this one.
451 * Make sure it's still here.
452 */
453 xenbusb_verify_device(dev, kids[i]);
454 continue;
455 }
456
457 error = device_probe_and_attach(kids[i]);
458 if (error == ENXIO) {
459 struct xenbusb_softc *xbs;
460
461 /*
462 * We don't have a PV driver for this device.
463 * However, an emulated device we do support
464 * may share this backend. Hide the node from
465 * XenBus until the next rescan, but leave it's
466 * state unchanged so we don't inadvertently
467 * prevent attachment of any emulated device.
468 */
469 xenbusb_delete_child(dev, kids[i]);
470
471 /*
472 * Since the XenStore state of this device
473 * still indicates a pending attach, manually
474 * release it's hold on the boot process.
475 */
476 xbs = device_get_softc(dev);
477 xenbusb_release_confighook(xbs);
478
479 continue;
480 } else if (error) {
481 /*
482 * Transition device to the closed state
483 * so the world knows that attachment will
484 * not occur.
485 */
486 xenbus_set_state(kids[i], XenbusStateClosed);
487
488 /*
489 * Remove our record of this device.
490 * So long as it remains in the closed
491 * state in the XenStore, we will not find
492 * it again. The state will only change
493 * if the control domain actively reconfigures
494 * this device.
495 */
496 xenbusb_delete_child(dev, kids[i]);
497
498 continue;
499 }
500 /*
501 * Augment default newbus provided dynamic sysctl
502 * variables with the standard ivar contents of
503 * XenBus devices.
504 */
505 xenbusb_device_sysctl_init(kids[i]);
506
507 /*
508 * Now that we have a driver managing this device
509 * that can receive otherend state change events,
510 * hook up a watch for them.
511 */
512 ivars = device_get_ivars(kids[i]);
513 xs_register_watch(&ivars->xd_otherend_watch);
514 xs_register_watch(&ivars->xd_local_watch);
515 }
516 free(kids, M_TEMP);
517 }
518
519 return (0);
520 }
521
522 /**
523 * \brief Task callback function to perform XenBus probe operations
524 * from a known safe context.
525 *
526 * \param arg The NewBus device_t representing the bus instance to
527 * on which to perform probe processing.
528 * \param pending The number of times this task was queued before it could
529 * be run.
530 */
531 static void
532 xenbusb_probe_children_cb(void *arg, int pending __unused)
533 {
534 device_t dev = (device_t)arg;
535
536 /*
537 * Hold Giant until the Giant free newbus changes are committed.
538 */
539 mtx_lock(&Giant);
540 xenbusb_probe_children(dev);
541 mtx_unlock(&Giant);
542 }
543
544 /**
545 * \brief XenStore watch callback for the root node of the XenStore
546 * subtree representing a XenBus.
547 *
548 * This callback performs, or delegates to the xbs_probe_children task,
549 * all processing necessary to handle dynmaic device arrival and departure
550 * events from a XenBus.
551 *
552 * \param watch The XenStore watch object associated with this callback.
553 * \param vec The XenStore watch event data.
554 * \param len The number of fields in the event data stream.
555 */
556 static void
557 xenbusb_devices_changed(struct xs_watch *watch, const char **vec,
558 unsigned int len)
559 {
560 struct xenbusb_softc *xbs;
561 device_t dev;
562 char *node;
563 char *type;
564 char *id;
565 char *p;
566 u_int component;
567
568 xbs = (struct xenbusb_softc *)watch->callback_data;
569 dev = xbs->xbs_dev;
570
571 if (len <= XS_WATCH_PATH) {
572 device_printf(dev, "xenbusb_devices_changed: "
573 "Short Event Data.\n");
574 return;
575 }
576
577 node = strdup(vec[XS_WATCH_PATH], M_XENBUS);
578 p = strchr(node, '/');
579 if (p == NULL)
580 goto out;
581 *p = 0;
582 type = p + 1;
583
584 p = strchr(type, '/');
585 if (p == NULL)
586 goto out;
587 *p++ = 0;
588
589 /*
590 * Extract the device ID. A device ID has one or more path
591 * components separated by the '/' character.
592 *
593 * e.g. "<frontend vm id>/<frontend dev id>" for backend devices.
594 */
595 id = p;
596 for (component = 0; component < xbs->xbs_id_components; component++) {
597 p = strchr(p, '/');
598 if (p == NULL)
599 break;
600 p++;
601 }
602 if (p != NULL)
603 *p = 0;
604
605 if (*id != 0 && component >= xbs->xbs_id_components - 1) {
606 xenbusb_add_device(xbs->xbs_dev, type, id);
607 taskqueue_enqueue(taskqueue_thread, &xbs->xbs_probe_children);
608 }
609 out:
610 free(node, M_XENBUS);
611 }
612
613 /**
614 * \brief Interrupt configuration hook callback associated with xbs_attch_ch.
615 *
616 * Since interrupts are always functional at the time of XenBus configuration,
617 * there is nothing to be done when the callback occurs. This hook is only
618 * registered to hold up boot processing while XenBus devices come online.
619 *
620 * \param arg Unused configuration hook callback argument.
621 */
622 static void
623 xenbusb_nop_confighook_cb(void *arg __unused)
624 {
625 }
626
627 /*--------------------------- Public Functions -------------------------------*/
628 /*--------- API comments for these methods can be found in xenbusb.h ---------*/
629 void
630 xenbusb_identify(driver_t *driver __unused, device_t parent)
631 {
632 /*
633 * A single instance of each bus type for which we have a driver
634 * is always present in a system operating under Xen.
635 */
636 BUS_ADD_CHILD(parent, 0, driver->name, 0);
637 }
638
639 int
640 xenbusb_add_device(device_t dev, const char *type, const char *id)
641 {
642 struct xenbusb_softc *xbs;
643 struct sbuf *devpath_sbuf;
644 char *devpath;
645 struct xenbus_device_ivars *ivars;
646 int error;
647
648 xbs = device_get_softc(dev);
649 devpath_sbuf = sbuf_new_auto();
650 sbuf_printf(devpath_sbuf, "%s/%s/%s", xbs->xbs_node, type, id);
651 sbuf_finish(devpath_sbuf);
652 devpath = sbuf_data(devpath_sbuf);
653
654 ivars = malloc(sizeof(*ivars), M_XENBUS, M_ZERO|M_WAITOK);
655 error = ENXIO;
656
657 if (xs_exists(XST_NIL, devpath, "") != 0) {
658 device_t child;
659 enum xenbus_state state;
660 char *statepath;
661
662 child = xenbusb_device_exists(dev, devpath);
663 if (child != NULL) {
664 /*
665 * We are already tracking this node
666 */
667 error = 0;
668 goto out;
669 }
670
671 state = xenbus_read_driver_state(devpath);
672 if (state != XenbusStateInitialising) {
673 /*
674 * Device is not new, so ignore it. This can
675 * happen if a device is going away after
676 * switching to Closed.
677 */
678 printf("xenbusb_add_device: Device %s ignored. "
679 "State %d\n", devpath, state);
680 error = 0;
681 goto out;
682 }
683
684 sx_init(&ivars->xd_lock, "xdlock");
685 ivars->xd_flags = XDF_CONNECTING;
686 ivars->xd_node = strdup(devpath, M_XENBUS);
687 ivars->xd_node_len = strlen(devpath);
688 ivars->xd_type = strdup(type, M_XENBUS);
689 ivars->xd_state = XenbusStateInitialising;
690
691 error = XENBUSB_GET_OTHEREND_NODE(dev, ivars);
692 if (error) {
693 printf("xenbus_update_device: %s no otherend id\n",
694 devpath);
695 goto out;
696 }
697
698 statepath = malloc(ivars->xd_otherend_path_len
699 + strlen("/state") + 1, M_XENBUS, M_WAITOK);
700 sprintf(statepath, "%s/state", ivars->xd_otherend_path);
701 ivars->xd_otherend_watch.node = statepath;
702 ivars->xd_otherend_watch.callback = xenbusb_otherend_watch_cb;
703 ivars->xd_otherend_watch.callback_data = (uintptr_t)ivars;
704 /*
705 * Other end state node watch, limit to one pending event
706 * to prevent frontends from queuing too many events that
707 * could cause resource starvation.
708 */
709 ivars->xd_otherend_watch.max_pending = 1;
710
711 ivars->xd_local_watch.node = ivars->xd_node;
712 ivars->xd_local_watch.callback = xenbusb_local_watch_cb;
713 ivars->xd_local_watch.callback_data = (uintptr_t)ivars;
714 /*
715 * Watch our local path, only writable by us or a privileged
716 * domain, no need to limit.
717 */
718 ivars->xd_local_watch.max_pending = 0;
719
720 mtx_lock(&xbs->xbs_lock);
721 xbs->xbs_connecting_children++;
722 mtx_unlock(&xbs->xbs_lock);
723
724 child = device_add_child(dev, NULL, -1);
725 ivars->xd_dev = child;
726 device_set_ivars(child, ivars);
727 }
728
729 out:
730 sbuf_delete(devpath_sbuf);
731 if (error != 0)
732 xenbusb_free_child_ivars(ivars);
733
734 return (error);
735 }
736
737 int
738 xenbusb_attach(device_t dev, char *bus_node, u_int id_components)
739 {
740 struct xenbusb_softc *xbs;
741
742 xbs = device_get_softc(dev);
743 mtx_init(&xbs->xbs_lock, "xenbusb softc lock", NULL, MTX_DEF);
744 xbs->xbs_node = bus_node;
745 xbs->xbs_id_components = id_components;
746 xbs->xbs_dev = dev;
747
748 /*
749 * Since XenBus buses are attached to the XenStore, and
750 * the XenStore does not probe children until after interrupt
751 * services are available, this config hook is used solely
752 * to ensure that the remainder of the boot process (e.g.
753 * mount root) is deferred until child devices are adequately
754 * probed. We unblock the boot process as soon as the
755 * connecting child count in our softc goes to 0.
756 */
757 xbs->xbs_attach_ch.ich_func = xenbusb_nop_confighook_cb;
758 xbs->xbs_attach_ch.ich_arg = dev;
759 config_intrhook_establish(&xbs->xbs_attach_ch);
760 xbs->xbs_flags |= XBS_ATTACH_CH_ACTIVE;
761 xbs->xbs_connecting_children = 1;
762
763 /*
764 * The subtree for this bus type may not yet exist
765 * causing initial enumeration to fail. We still
766 * want to return success from our attach though
767 * so that we are ready to handle devices for this
768 * bus when they are dynamically attached to us
769 * by a Xen management action.
770 */
771 (void)xenbusb_enumerate_bus(xbs);
772 xenbusb_probe_children(dev);
773
774 xbs->xbs_device_watch.node = bus_node;
775 xbs->xbs_device_watch.callback = xenbusb_devices_changed;
776 xbs->xbs_device_watch.callback_data = (uintptr_t)xbs;
777 /*
778 * Allow for unlimited pending watches, as those are local paths
779 * either controlled by the guest or only writable by privileged
780 * domains.
781 */
782 xbs->xbs_device_watch.max_pending = 0;
783
784 TASK_INIT(&xbs->xbs_probe_children, 0, xenbusb_probe_children_cb, dev);
785
786 xs_register_watch(&xbs->xbs_device_watch);
787
788 xenbusb_release_confighook(xbs);
789
790 return (0);
791 }
792
793 int
794 xenbusb_resume(device_t dev)
795 {
796 device_t *kids;
797 struct xenbus_device_ivars *ivars;
798 int i, count, error;
799 char *statepath;
800
801 /*
802 * We must re-examine each device and find the new path for
803 * its backend.
804 */
805 if (device_get_children(dev, &kids, &count) == 0) {
806 for (i = 0; i < count; i++) {
807 if (device_get_state(kids[i]) == DS_NOTPRESENT)
808 continue;
809
810 if (xen_suspend_cancelled) {
811 DEVICE_RESUME(kids[i]);
812 continue;
813 }
814
815 ivars = device_get_ivars(kids[i]);
816
817 xs_unregister_watch(&ivars->xd_otherend_watch);
818 xenbus_set_state(kids[i], XenbusStateInitialising);
819
820 /*
821 * Find the new backend details and
822 * re-register our watch.
823 */
824 error = XENBUSB_GET_OTHEREND_NODE(dev, ivars);
825 if (error)
826 return (error);
827
828 statepath = malloc(ivars->xd_otherend_path_len
829 + strlen("/state") + 1, M_XENBUS, M_WAITOK);
830 sprintf(statepath, "%s/state", ivars->xd_otherend_path);
831
832 free(ivars->xd_otherend_watch.node, M_XENBUS);
833 ivars->xd_otherend_watch.node = statepath;
834
835 DEVICE_RESUME(kids[i]);
836
837 xs_register_watch(&ivars->xd_otherend_watch);
838 #if 0
839 /*
840 * Can't do this yet since we are running in
841 * the xenwatch thread and if we sleep here,
842 * we will stop delivering watch notifications
843 * and the device will never come back online.
844 */
845 sx_xlock(&ivars->xd_lock);
846 while (ivars->xd_state != XenbusStateClosed
847 && ivars->xd_state != XenbusStateConnected)
848 sx_sleep(&ivars->xd_state, &ivars->xd_lock,
849 0, "xdresume", 0);
850 sx_xunlock(&ivars->xd_lock);
851 #endif
852 }
853 free(kids, M_TEMP);
854 }
855
856 return (0);
857 }
858
859 int
860 xenbusb_print_child(device_t dev, device_t child)
861 {
862 struct xenbus_device_ivars *ivars = device_get_ivars(child);
863 int retval = 0;
864
865 retval += bus_print_child_header(dev, child);
866 retval += printf(" at %s", ivars->xd_node);
867 retval += bus_print_child_footer(dev, child);
868
869 return (retval);
870 }
871
872 int
873 xenbusb_read_ivar(device_t dev, device_t child, int index, uintptr_t *result)
874 {
875 struct xenbus_device_ivars *ivars = device_get_ivars(child);
876
877 switch (index) {
878 case XENBUS_IVAR_NODE:
879 *result = (uintptr_t) ivars->xd_node;
880 return (0);
881
882 case XENBUS_IVAR_TYPE:
883 *result = (uintptr_t) ivars->xd_type;
884 return (0);
885
886 case XENBUS_IVAR_STATE:
887 *result = (uintptr_t) ivars->xd_state;
888 return (0);
889
890 case XENBUS_IVAR_OTHEREND_ID:
891 *result = (uintptr_t) ivars->xd_otherend_id;
892 return (0);
893
894 case XENBUS_IVAR_OTHEREND_PATH:
895 *result = (uintptr_t) ivars->xd_otherend_path;
896 return (0);
897 }
898
899 return (ENOENT);
900 }
901
902 int
903 xenbusb_write_ivar(device_t dev, device_t child, int index, uintptr_t value)
904 {
905 struct xenbus_device_ivars *ivars = device_get_ivars(child);
906 enum xenbus_state newstate;
907 int currstate;
908
909 switch (index) {
910 case XENBUS_IVAR_STATE:
911 {
912 int error;
913
914 newstate = (enum xenbus_state)value;
915 sx_xlock(&ivars->xd_lock);
916 if (ivars->xd_state == newstate) {
917 error = 0;
918 goto out;
919 }
920
921 error = xs_scanf(XST_NIL, ivars->xd_node, "state",
922 NULL, "%d", &currstate);
923 if (error)
924 goto out;
925
926 do {
927 error = xs_printf(XST_NIL, ivars->xd_node, "state",
928 "%d", newstate);
929 } while (error == EAGAIN);
930 if (error) {
931 /*
932 * Avoid looping through xenbus_dev_fatal()
933 * which calls xenbus_write_ivar to set the
934 * state to closing.
935 */
936 if (newstate != XenbusStateClosing)
937 xenbus_dev_fatal(dev, error,
938 "writing new state");
939 goto out;
940 }
941 ivars->xd_state = newstate;
942
943 if ((ivars->xd_flags & XDF_CONNECTING) != 0
944 && (newstate == XenbusStateClosed
945 || newstate == XenbusStateConnected)) {
946 struct xenbusb_softc *xbs;
947
948 ivars->xd_flags &= ~XDF_CONNECTING;
949 xbs = device_get_softc(dev);
950 xenbusb_release_confighook(xbs);
951 }
952
953 wakeup(&ivars->xd_state);
954 out:
955 sx_xunlock(&ivars->xd_lock);
956 return (error);
957 }
958
959 case XENBUS_IVAR_NODE:
960 case XENBUS_IVAR_TYPE:
961 case XENBUS_IVAR_OTHEREND_ID:
962 case XENBUS_IVAR_OTHEREND_PATH:
963 /*
964 * These variables are read-only.
965 */
966 return (EINVAL);
967 }
968
969 return (ENOENT);
970 }
971
972 void
973 xenbusb_otherend_changed(device_t bus, device_t child, enum xenbus_state state)
974 {
975 XENBUS_OTHEREND_CHANGED(child, state);
976 }
977
978 void
979 xenbusb_localend_changed(device_t bus, device_t child, const char *path)
980 {
981
982 if (strcmp(path, "/state") != 0) {
983 struct xenbus_device_ivars *ivars;
984
985 ivars = device_get_ivars(child);
986 sx_xlock(&ivars->xd_lock);
987 ivars->xd_state = xenbus_read_driver_state(ivars->xd_node);
988 sx_xunlock(&ivars->xd_lock);
989 }
990 XENBUS_LOCALEND_CHANGED(child, path);
991 }
Cache object: 3fe71b42803317c90615b76f931a22bd
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