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/stdarg.h>
71
72 #include <xen/xen-os.h>
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), "state") == 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 existence 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 bus_topo_lock();
537 xenbusb_probe_children(dev);
538 bus_topo_unlock();
539 }
540
541 /**
542 * \brief XenStore watch callback for the root node of the XenStore
543 * subtree representing a XenBus.
544 *
545 * This callback performs, or delegates to the xbs_probe_children task,
546 * all processing necessary to handle dynmaic device arrival and departure
547 * events from a XenBus.
548 *
549 * \param watch The XenStore watch object associated with this callback.
550 * \param vec The XenStore watch event data.
551 * \param len The number of fields in the event data stream.
552 */
553 static void
554 xenbusb_devices_changed(struct xs_watch *watch, const char **vec,
555 unsigned int len)
556 {
557 struct xenbusb_softc *xbs;
558 device_t dev;
559 char *node;
560 char *type;
561 char *id;
562 char *p;
563 u_int component;
564
565 xbs = (struct xenbusb_softc *)watch->callback_data;
566 dev = xbs->xbs_dev;
567
568 if (len <= XS_WATCH_PATH) {
569 device_printf(dev, "xenbusb_devices_changed: "
570 "Short Event Data.\n");
571 return;
572 }
573
574 node = strdup(vec[XS_WATCH_PATH], M_XENBUS);
575 p = strchr(node, '/');
576 if (p == NULL)
577 goto out;
578 *p = 0;
579 type = p + 1;
580
581 p = strchr(type, '/');
582 if (p == NULL)
583 goto out;
584 *p++ = 0;
585
586 /*
587 * Extract the device ID. A device ID has one or more path
588 * components separated by the '/' character.
589 *
590 * e.g. "<frontend vm id>/<frontend dev id>" for backend devices.
591 */
592 id = p;
593 for (component = 0; component < xbs->xbs_id_components; component++) {
594 p = strchr(p, '/');
595 if (p == NULL)
596 break;
597 p++;
598 }
599 if (p != NULL)
600 *p = 0;
601
602 if (*id != 0 && component >= xbs->xbs_id_components - 1) {
603 xenbusb_add_device(xbs->xbs_dev, type, id);
604 taskqueue_enqueue(taskqueue_thread, &xbs->xbs_probe_children);
605 }
606 out:
607 free(node, M_XENBUS);
608 }
609
610 /**
611 * \brief Interrupt configuration hook callback associated with xbs_attch_ch.
612 *
613 * Since interrupts are always functional at the time of XenBus configuration,
614 * there is nothing to be done when the callback occurs. This hook is only
615 * registered to hold up boot processing while XenBus devices come online.
616 *
617 * \param arg Unused configuration hook callback argument.
618 */
619 static void
620 xenbusb_nop_confighook_cb(void *arg __unused)
621 {
622 }
623
624 /*--------------------------- Public Functions -------------------------------*/
625 /*--------- API comments for these methods can be found in xenbusb.h ---------*/
626 void
627 xenbusb_identify(driver_t *driver __unused, device_t parent)
628 {
629 /*
630 * A single instance of each bus type for which we have a driver
631 * is always present in a system operating under Xen.
632 */
633 BUS_ADD_CHILD(parent, 0, driver->name, 0);
634 }
635
636 int
637 xenbusb_add_device(device_t dev, const char *type, const char *id)
638 {
639 struct xenbusb_softc *xbs;
640 struct sbuf *devpath_sbuf;
641 char *devpath;
642 struct xenbus_device_ivars *ivars;
643 int error;
644
645 xbs = device_get_softc(dev);
646 devpath_sbuf = sbuf_new_auto();
647 sbuf_printf(devpath_sbuf, "%s/%s/%s", xbs->xbs_node, type, id);
648 sbuf_finish(devpath_sbuf);
649 devpath = sbuf_data(devpath_sbuf);
650
651 ivars = malloc(sizeof(*ivars), M_XENBUS, M_ZERO|M_WAITOK);
652 error = ENXIO;
653
654 if (xs_exists(XST_NIL, devpath, "") != 0) {
655 device_t child;
656 enum xenbus_state state;
657 char *statepath;
658
659 child = xenbusb_device_exists(dev, devpath);
660 if (child != NULL) {
661 /*
662 * We are already tracking this node
663 */
664 error = 0;
665 goto out;
666 }
667
668 state = xenbus_read_driver_state(devpath);
669 if (state != XenbusStateInitialising) {
670 /*
671 * Device is not new, so ignore it. This can
672 * happen if a device is going away after
673 * switching to Closed.
674 */
675 printf("xenbusb_add_device: Device %s ignored. "
676 "State %d\n", devpath, state);
677 error = 0;
678 goto out;
679 }
680
681 sx_init(&ivars->xd_lock, "xdlock");
682 ivars->xd_flags = XDF_CONNECTING;
683 ivars->xd_node = strdup(devpath, M_XENBUS);
684 ivars->xd_node_len = strlen(devpath);
685 ivars->xd_type = strdup(type, M_XENBUS);
686 ivars->xd_state = XenbusStateInitialising;
687
688 error = XENBUSB_GET_OTHEREND_NODE(dev, ivars);
689 if (error) {
690 printf("xenbus_update_device: %s no otherend id\n",
691 devpath);
692 goto out;
693 }
694
695 statepath = malloc(ivars->xd_otherend_path_len
696 + strlen("/state") + 1, M_XENBUS, M_WAITOK);
697 sprintf(statepath, "%s/state", ivars->xd_otherend_path);
698 ivars->xd_otherend_watch.node = statepath;
699 ivars->xd_otherend_watch.callback = xenbusb_otherend_watch_cb;
700 ivars->xd_otherend_watch.callback_data = (uintptr_t)ivars;
701 /*
702 * Other end state node watch, limit to one pending event
703 * to prevent frontends from queuing too many events that
704 * could cause resource starvation.
705 */
706 ivars->xd_otherend_watch.max_pending = 1;
707
708 ivars->xd_local_watch.node = ivars->xd_node;
709 ivars->xd_local_watch.callback = xenbusb_local_watch_cb;
710 ivars->xd_local_watch.callback_data = (uintptr_t)ivars;
711 /*
712 * Watch our local path, only writable by us or a privileged
713 * domain, no need to limit.
714 */
715 ivars->xd_local_watch.max_pending = 0;
716
717 mtx_lock(&xbs->xbs_lock);
718 xbs->xbs_connecting_children++;
719 mtx_unlock(&xbs->xbs_lock);
720
721 child = device_add_child(dev, NULL, -1);
722 ivars->xd_dev = child;
723 device_set_ivars(child, ivars);
724 }
725
726 out:
727 sbuf_delete(devpath_sbuf);
728 if (error != 0)
729 xenbusb_free_child_ivars(ivars);
730
731 return (error);
732 }
733
734 int
735 xenbusb_attach(device_t dev, char *bus_node, u_int id_components)
736 {
737 struct xenbusb_softc *xbs;
738
739 xbs = device_get_softc(dev);
740 mtx_init(&xbs->xbs_lock, "xenbusb softc lock", NULL, MTX_DEF);
741 xbs->xbs_node = bus_node;
742 xbs->xbs_id_components = id_components;
743 xbs->xbs_dev = dev;
744
745 /*
746 * Since XenBus buses are attached to the XenStore, and
747 * the XenStore does not probe children until after interrupt
748 * services are available, this config hook is used solely
749 * to ensure that the remainder of the boot process (e.g.
750 * mount root) is deferred until child devices are adequately
751 * probed. We unblock the boot process as soon as the
752 * connecting child count in our softc goes to 0.
753 */
754 xbs->xbs_attach_ch.ich_func = xenbusb_nop_confighook_cb;
755 xbs->xbs_attach_ch.ich_arg = dev;
756 config_intrhook_establish(&xbs->xbs_attach_ch);
757 xbs->xbs_flags |= XBS_ATTACH_CH_ACTIVE;
758 xbs->xbs_connecting_children = 1;
759
760 /*
761 * The subtree for this bus type may not yet exist
762 * causing initial enumeration to fail. We still
763 * want to return success from our attach though
764 * so that we are ready to handle devices for this
765 * bus when they are dynamically attached to us
766 * by a Xen management action.
767 */
768 (void)xenbusb_enumerate_bus(xbs);
769 xenbusb_probe_children(dev);
770
771 xbs->xbs_device_watch.node = bus_node;
772 xbs->xbs_device_watch.callback = xenbusb_devices_changed;
773 xbs->xbs_device_watch.callback_data = (uintptr_t)xbs;
774 /*
775 * Allow for unlimited pending watches, as those are local paths
776 * either controlled by the guest or only writable by privileged
777 * domains.
778 */
779 xbs->xbs_device_watch.max_pending = 0;
780
781 TASK_INIT(&xbs->xbs_probe_children, 0, xenbusb_probe_children_cb, dev);
782
783 xs_register_watch(&xbs->xbs_device_watch);
784
785 xenbusb_release_confighook(xbs);
786
787 return (0);
788 }
789
790 int
791 xenbusb_resume(device_t dev)
792 {
793 device_t *kids;
794 struct xenbus_device_ivars *ivars;
795 int i, count, error;
796 char *statepath;
797
798 /*
799 * We must re-examine each device and find the new path for
800 * its backend.
801 */
802 if (device_get_children(dev, &kids, &count) == 0) {
803 for (i = 0; i < count; i++) {
804 if (device_get_state(kids[i]) == DS_NOTPRESENT)
805 continue;
806
807 if (xen_suspend_cancelled) {
808 DEVICE_RESUME(kids[i]);
809 continue;
810 }
811
812 ivars = device_get_ivars(kids[i]);
813
814 xs_unregister_watch(&ivars->xd_otherend_watch);
815 xenbus_set_state(kids[i], XenbusStateInitialising);
816
817 /*
818 * Find the new backend details and
819 * re-register our watch.
820 */
821 error = XENBUSB_GET_OTHEREND_NODE(dev, ivars);
822 if (error)
823 return (error);
824
825 statepath = malloc(ivars->xd_otherend_path_len
826 + strlen("/state") + 1, M_XENBUS, M_WAITOK);
827 sprintf(statepath, "%s/state", ivars->xd_otherend_path);
828
829 free(ivars->xd_otherend_watch.node, M_XENBUS);
830 ivars->xd_otherend_watch.node = statepath;
831
832 DEVICE_RESUME(kids[i]);
833
834 xs_register_watch(&ivars->xd_otherend_watch);
835 #if 0
836 /*
837 * Can't do this yet since we are running in
838 * the xenwatch thread and if we sleep here,
839 * we will stop delivering watch notifications
840 * and the device will never come back online.
841 */
842 sx_xlock(&ivars->xd_lock);
843 while (ivars->xd_state != XenbusStateClosed
844 && ivars->xd_state != XenbusStateConnected)
845 sx_sleep(&ivars->xd_state, &ivars->xd_lock,
846 0, "xdresume", 0);
847 sx_xunlock(&ivars->xd_lock);
848 #endif
849 }
850 free(kids, M_TEMP);
851 }
852
853 return (0);
854 }
855
856 int
857 xenbusb_print_child(device_t dev, device_t child)
858 {
859 struct xenbus_device_ivars *ivars = device_get_ivars(child);
860 int retval = 0;
861
862 retval += bus_print_child_header(dev, child);
863 retval += printf(" at %s", ivars->xd_node);
864 retval += bus_print_child_footer(dev, child);
865
866 return (retval);
867 }
868
869 int
870 xenbusb_read_ivar(device_t dev, device_t child, int index, uintptr_t *result)
871 {
872 struct xenbus_device_ivars *ivars = device_get_ivars(child);
873
874 switch (index) {
875 case XENBUS_IVAR_NODE:
876 *result = (uintptr_t) ivars->xd_node;
877 return (0);
878
879 case XENBUS_IVAR_TYPE:
880 *result = (uintptr_t) ivars->xd_type;
881 return (0);
882
883 case XENBUS_IVAR_STATE:
884 *result = (uintptr_t) ivars->xd_state;
885 return (0);
886
887 case XENBUS_IVAR_OTHEREND_ID:
888 *result = (uintptr_t) ivars->xd_otherend_id;
889 return (0);
890
891 case XENBUS_IVAR_OTHEREND_PATH:
892 *result = (uintptr_t) ivars->xd_otherend_path;
893 return (0);
894 }
895
896 return (ENOENT);
897 }
898
899 int
900 xenbusb_write_ivar(device_t dev, device_t child, int index, uintptr_t value)
901 {
902 struct xenbus_device_ivars *ivars = device_get_ivars(child);
903 enum xenbus_state newstate;
904 int currstate;
905
906 switch (index) {
907 case XENBUS_IVAR_STATE:
908 {
909 int error;
910 struct xs_transaction xst;
911
912 newstate = (enum xenbus_state)value;
913 sx_xlock(&ivars->xd_lock);
914 if (ivars->xd_state == newstate) {
915 error = 0;
916 goto out;
917 }
918
919 do {
920 error = xs_transaction_start(&xst);
921 if (error != 0)
922 goto out;
923
924 do {
925 error = xs_scanf(xst, ivars->xd_node, "state",
926 NULL, "%d", &currstate);
927 } while (error == EAGAIN);
928 if (error)
929 goto out;
930
931 do {
932 error = xs_printf(xst, ivars->xd_node, "state",
933 "%d", newstate);
934 } while (error == EAGAIN);
935 if (error) {
936 /*
937 * Avoid looping through xenbus_dev_fatal()
938 * which calls xenbus_write_ivar to set the
939 * state to closing.
940 */
941 if (newstate != XenbusStateClosing)
942 xenbus_dev_fatal(dev, error,
943 "writing new state");
944 goto out;
945 }
946 } while (xs_transaction_end(xst, 0));
947 ivars->xd_state = newstate;
948
949 if ((ivars->xd_flags & XDF_CONNECTING) != 0 &&
950 (newstate == XenbusStateClosed ||
951 newstate == XenbusStateConnected)) {
952 struct xenbusb_softc *xbs;
953
954 ivars->xd_flags &= ~XDF_CONNECTING;
955 xbs = device_get_softc(dev);
956 xenbusb_release_confighook(xbs);
957 }
958
959 wakeup(&ivars->xd_state);
960 out:
961 if (error != 0)
962 xs_transaction_end(xst, 1);
963 sx_xunlock(&ivars->xd_lock);
964 /*
965 * Shallow ENOENT errors, as returning an error here will
966 * trigger a panic. ENOENT is fine to ignore, because it means
967 * the toolstack has removed the state node as part of
968 * destroying the device, and so we have to shut down the
969 * device without recreating it or else the node would be
970 * leaked.
971 */
972 return (error == ENOENT ? 0 : error);
973 }
974
975 case XENBUS_IVAR_NODE:
976 case XENBUS_IVAR_TYPE:
977 case XENBUS_IVAR_OTHEREND_ID:
978 case XENBUS_IVAR_OTHEREND_PATH:
979 /*
980 * These variables are read-only.
981 */
982 return (EINVAL);
983 }
984
985 return (ENOENT);
986 }
987
988 void
989 xenbusb_otherend_changed(device_t bus, device_t child, enum xenbus_state state)
990 {
991 XENBUS_OTHEREND_CHANGED(child, state);
992 }
993
994 void
995 xenbusb_localend_changed(device_t bus, device_t child, const char *path)
996 {
997
998 if (strcmp(path, "/state") != 0) {
999 struct xenbus_device_ivars *ivars;
1000
1001 ivars = device_get_ivars(child);
1002 sx_xlock(&ivars->xd_lock);
1003 ivars->xd_state = xenbus_read_driver_state(ivars->xd_node);
1004 sx_xunlock(&ivars->xd_lock);
1005 }
1006 XENBUS_LOCALEND_CHANGED(child, path);
1007 }
Cache object: 4903dab4b51399dbecb04c433024a399
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