1 /******************************************************************************
2 * Talks to Xen Store to figure out what devices we have.
4 * Copyright (C) 2005 Rusty Russell, IBM Corporation
5 * Copyright (C) 2005 Mike Wray, Hewlett-Packard
6 * Copyright (C) 2005, 2006 XenSource Ltd
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License version 2
10 * as published by the Free Software Foundation; or, when distributed
11 * separately from the Linux kernel or incorporated into other
12 * software packages, subject to the following license:
14 * Permission is hereby granted, free of charge, to any person obtaining a copy
15 * of this source file (the "Software"), to deal in the Software without
16 * restriction, including without limitation the rights to use, copy, modify,
17 * merge, publish, distribute, sublicense, and/or sell copies of the Software,
18 * and to permit persons to whom the Software is furnished to do so, subject to
19 * the following conditions:
21 * The above copyright notice and this permission notice shall be included in
22 * all copies or substantial portions of the Software.
24 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
25 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
26 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
27 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
28 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
29 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
33 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
34 #define dev_fmt pr_fmt
36 #define DPRINTK(fmt, args...) \
37 pr_debug("xenbus_probe (%s:%d) " fmt ".\n", \
38 __func__, __LINE__, ##args)
40 #include <linux/kernel.h>
41 #include <linux/err.h>
42 #include <linux/string.h>
43 #include <linux/ctype.h>
44 #include <linux/fcntl.h>
46 #include <linux/proc_fs.h>
47 #include <linux/notifier.h>
48 #include <linux/kthread.h>
49 #include <linux/mutex.h>
51 #include <linux/slab.h>
52 #include <linux/module.h>
55 #include <asm/xen/hypervisor.h>
58 #include <xen/xenbus.h>
59 #include <xen/events.h>
60 #include <xen/xen-ops.h>
69 EXPORT_SYMBOL_GPL(xen_store_evtchn);
71 struct xenstore_domain_interface *xen_store_interface;
72 EXPORT_SYMBOL_GPL(xen_store_interface);
74 enum xenstore_init xen_store_domain_type;
75 EXPORT_SYMBOL_GPL(xen_store_domain_type);
77 static unsigned long xen_store_gfn;
79 static BLOCKING_NOTIFIER_HEAD(xenstore_chain);
81 /* If something in array of ids matches this device, return it. */
82 static const struct xenbus_device_id *
83 match_device(const struct xenbus_device_id *arr, struct xenbus_device *dev)
85 for (; *arr->devicetype != '\0'; arr++) {
86 if (!strcmp(arr->devicetype, dev->devicetype))
92 int xenbus_match(struct device *_dev, struct device_driver *_drv)
94 struct xenbus_driver *drv = to_xenbus_driver(_drv);
99 return match_device(drv->ids, to_xenbus_device(_dev)) != NULL;
101 EXPORT_SYMBOL_GPL(xenbus_match);
104 static void free_otherend_details(struct xenbus_device *dev)
106 kfree(dev->otherend);
107 dev->otherend = NULL;
111 static void free_otherend_watch(struct xenbus_device *dev)
113 if (dev->otherend_watch.node) {
114 unregister_xenbus_watch(&dev->otherend_watch);
115 kfree(dev->otherend_watch.node);
116 dev->otherend_watch.node = NULL;
121 static int talk_to_otherend(struct xenbus_device *dev)
123 struct xenbus_driver *drv = to_xenbus_driver(dev->dev.driver);
125 free_otherend_watch(dev);
126 free_otherend_details(dev);
128 return drv->read_otherend_details(dev);
133 static int watch_otherend(struct xenbus_device *dev)
135 struct xen_bus_type *bus =
136 container_of(dev->dev.bus, struct xen_bus_type, bus);
138 return xenbus_watch_pathfmt(dev, &dev->otherend_watch,
139 bus->otherend_will_handle,
140 bus->otherend_changed,
141 "%s/%s", dev->otherend, "state");
145 int xenbus_read_otherend_details(struct xenbus_device *xendev,
146 char *id_node, char *path_node)
148 int err = xenbus_gather(XBT_NIL, xendev->nodename,
149 id_node, "%i", &xendev->otherend_id,
150 path_node, NULL, &xendev->otherend,
153 xenbus_dev_fatal(xendev, err,
154 "reading other end details from %s",
158 if (strlen(xendev->otherend) == 0 ||
159 !xenbus_exists(XBT_NIL, xendev->otherend, "")) {
160 xenbus_dev_fatal(xendev, -ENOENT,
161 "unable to read other end from %s. "
162 "missing or inaccessible.",
164 free_otherend_details(xendev);
170 EXPORT_SYMBOL_GPL(xenbus_read_otherend_details);
172 void xenbus_otherend_changed(struct xenbus_watch *watch,
173 const char *path, const char *token,
174 int ignore_on_shutdown)
176 struct xenbus_device *dev =
177 container_of(watch, struct xenbus_device, otherend_watch);
178 struct xenbus_driver *drv = to_xenbus_driver(dev->dev.driver);
179 enum xenbus_state state;
181 /* Protect us against watches firing on old details when the otherend
182 details change, say immediately after a resume. */
183 if (!dev->otherend ||
184 strncmp(dev->otherend, path, strlen(dev->otherend))) {
185 dev_dbg(&dev->dev, "Ignoring watch at %s\n", path);
189 state = xenbus_read_driver_state(dev->otherend);
191 dev_dbg(&dev->dev, "state is %d, (%s), %s, %s\n",
192 state, xenbus_strstate(state), dev->otherend_watch.node, path);
195 * Ignore xenbus transitions during shutdown. This prevents us doing
196 * work that can fail e.g., when the rootfs is gone.
198 if (system_state > SYSTEM_RUNNING) {
199 if (ignore_on_shutdown && (state == XenbusStateClosing))
200 xenbus_frontend_closed(dev);
204 if (drv->otherend_changed)
205 drv->otherend_changed(dev, state);
207 EXPORT_SYMBOL_GPL(xenbus_otherend_changed);
209 int xenbus_dev_probe(struct device *_dev)
211 struct xenbus_device *dev = to_xenbus_device(_dev);
212 struct xenbus_driver *drv = to_xenbus_driver(_dev->driver);
213 const struct xenbus_device_id *id;
216 DPRINTK("%s", dev->nodename);
223 id = match_device(drv->ids, dev);
229 err = talk_to_otherend(dev);
231 dev_warn(&dev->dev, "talk_to_otherend on %s failed.\n",
236 if (!try_module_get(drv->driver.owner)) {
237 dev_warn(&dev->dev, "failed to acquire module reference on '%s'\n",
243 down(&dev->reclaim_sem);
244 err = drv->probe(dev, id);
245 up(&dev->reclaim_sem);
249 err = watch_otherend(dev);
251 dev_warn(&dev->dev, "watch_otherend on %s failed.\n",
258 module_put(drv->driver.owner);
260 xenbus_dev_error(dev, err, "xenbus_dev_probe on %s", dev->nodename);
263 EXPORT_SYMBOL_GPL(xenbus_dev_probe);
265 int xenbus_dev_remove(struct device *_dev)
267 struct xenbus_device *dev = to_xenbus_device(_dev);
268 struct xenbus_driver *drv = to_xenbus_driver(_dev->driver);
270 DPRINTK("%s", dev->nodename);
272 free_otherend_watch(dev);
275 down(&dev->reclaim_sem);
277 up(&dev->reclaim_sem);
280 module_put(drv->driver.owner);
282 free_otherend_details(dev);
285 * If the toolstack has forced the device state to closing then set
286 * the state to closed now to allow it to be cleaned up.
287 * Similarly, if the driver does not support re-bind, set the
290 if (!drv->allow_rebind ||
291 xenbus_read_driver_state(dev->nodename) == XenbusStateClosing)
292 xenbus_switch_state(dev, XenbusStateClosed);
296 EXPORT_SYMBOL_GPL(xenbus_dev_remove);
298 int xenbus_register_driver_common(struct xenbus_driver *drv,
299 struct xen_bus_type *bus,
300 struct module *owner, const char *mod_name)
302 drv->driver.name = drv->name ? drv->name : drv->ids[0].devicetype;
303 drv->driver.bus = &bus->bus;
304 drv->driver.owner = owner;
305 drv->driver.mod_name = mod_name;
307 return driver_register(&drv->driver);
309 EXPORT_SYMBOL_GPL(xenbus_register_driver_common);
311 void xenbus_unregister_driver(struct xenbus_driver *drv)
313 driver_unregister(&drv->driver);
315 EXPORT_SYMBOL_GPL(xenbus_unregister_driver);
317 struct xb_find_info {
318 struct xenbus_device *dev;
319 const char *nodename;
322 static int cmp_dev(struct device *dev, void *data)
324 struct xenbus_device *xendev = to_xenbus_device(dev);
325 struct xb_find_info *info = data;
327 if (!strcmp(xendev->nodename, info->nodename)) {
335 static struct xenbus_device *xenbus_device_find(const char *nodename,
336 struct bus_type *bus)
338 struct xb_find_info info = { .dev = NULL, .nodename = nodename };
340 bus_for_each_dev(bus, NULL, &info, cmp_dev);
344 static int cleanup_dev(struct device *dev, void *data)
346 struct xenbus_device *xendev = to_xenbus_device(dev);
347 struct xb_find_info *info = data;
348 int len = strlen(info->nodename);
350 DPRINTK("%s", info->nodename);
352 /* Match the info->nodename path, or any subdirectory of that path. */
353 if (strncmp(xendev->nodename, info->nodename, len))
356 /* If the node name is longer, ensure it really is a subdirectory. */
357 if ((strlen(xendev->nodename) > len) && (xendev->nodename[len] != '/'))
365 static void xenbus_cleanup_devices(const char *path, struct bus_type *bus)
367 struct xb_find_info info = { .nodename = path };
371 bus_for_each_dev(bus, NULL, &info, cleanup_dev);
373 device_unregister(&info.dev->dev);
374 put_device(&info.dev->dev);
379 static void xenbus_dev_release(struct device *dev)
382 kfree(to_xenbus_device(dev));
385 static ssize_t nodename_show(struct device *dev,
386 struct device_attribute *attr, char *buf)
388 return sprintf(buf, "%s\n", to_xenbus_device(dev)->nodename);
390 static DEVICE_ATTR_RO(nodename);
392 static ssize_t devtype_show(struct device *dev,
393 struct device_attribute *attr, char *buf)
395 return sprintf(buf, "%s\n", to_xenbus_device(dev)->devicetype);
397 static DEVICE_ATTR_RO(devtype);
399 static ssize_t modalias_show(struct device *dev,
400 struct device_attribute *attr, char *buf)
402 return sprintf(buf, "%s:%s\n", dev->bus->name,
403 to_xenbus_device(dev)->devicetype);
405 static DEVICE_ATTR_RO(modalias);
407 static ssize_t state_show(struct device *dev,
408 struct device_attribute *attr, char *buf)
410 return sprintf(buf, "%s\n",
411 xenbus_strstate(to_xenbus_device(dev)->state));
413 static DEVICE_ATTR_RO(state);
415 static struct attribute *xenbus_dev_attrs[] = {
416 &dev_attr_nodename.attr,
417 &dev_attr_devtype.attr,
418 &dev_attr_modalias.attr,
419 &dev_attr_state.attr,
423 static const struct attribute_group xenbus_dev_group = {
424 .attrs = xenbus_dev_attrs,
427 const struct attribute_group *xenbus_dev_groups[] = {
431 EXPORT_SYMBOL_GPL(xenbus_dev_groups);
433 int xenbus_probe_node(struct xen_bus_type *bus,
435 const char *nodename)
437 char devname[XEN_BUS_ID_SIZE];
439 struct xenbus_device *xendev;
443 enum xenbus_state state = xenbus_read_driver_state(nodename);
445 if (state != XenbusStateInitialising) {
446 /* Device is not new, so ignore it. This can happen if a
447 device is going away after switching to Closed. */
451 stringlen = strlen(nodename) + 1 + strlen(type) + 1;
452 xendev = kzalloc(sizeof(*xendev) + stringlen, GFP_KERNEL);
456 xendev->state = XenbusStateInitialising;
458 /* Copy the strings into the extra space. */
460 tmpstring = (char *)(xendev + 1);
461 strcpy(tmpstring, nodename);
462 xendev->nodename = tmpstring;
464 tmpstring += strlen(tmpstring) + 1;
465 strcpy(tmpstring, type);
466 xendev->devicetype = tmpstring;
467 init_completion(&xendev->down);
469 xendev->dev.bus = &bus->bus;
470 xendev->dev.release = xenbus_dev_release;
472 err = bus->get_bus_id(devname, xendev->nodename);
476 dev_set_name(&xendev->dev, "%s", devname);
477 sema_init(&xendev->reclaim_sem, 1);
479 /* Register with generic device framework. */
480 err = device_register(&xendev->dev);
482 put_device(&xendev->dev);
492 EXPORT_SYMBOL_GPL(xenbus_probe_node);
494 static int xenbus_probe_device_type(struct xen_bus_type *bus, const char *type)
498 unsigned int dir_n = 0;
501 dir = xenbus_directory(XBT_NIL, bus->root, type, &dir_n);
505 for (i = 0; i < dir_n; i++) {
506 err = bus->probe(bus, type, dir[i]);
515 int xenbus_probe_devices(struct xen_bus_type *bus)
519 unsigned int i, dir_n;
521 dir = xenbus_directory(XBT_NIL, bus->root, "", &dir_n);
525 for (i = 0; i < dir_n; i++) {
526 err = xenbus_probe_device_type(bus, dir[i]);
534 EXPORT_SYMBOL_GPL(xenbus_probe_devices);
536 static unsigned int char_count(const char *str, char c)
538 unsigned int i, ret = 0;
540 for (i = 0; str[i]; i++)
546 static int strsep_len(const char *str, char c, unsigned int len)
550 for (i = 0; str[i]; i++)
556 return (len == 0) ? i : -ERANGE;
559 void xenbus_dev_changed(const char *node, struct xen_bus_type *bus)
562 struct xenbus_device *dev;
563 char type[XEN_BUS_ID_SIZE];
564 const char *p, *root;
566 if (char_count(node, '/') < 2)
569 exists = xenbus_exists(XBT_NIL, node, "");
571 xenbus_cleanup_devices(node, &bus->bus);
575 /* backend/<type>/... or device/<type>/... */
576 p = strchr(node, '/') + 1;
577 snprintf(type, XEN_BUS_ID_SIZE, "%.*s", (int)strcspn(p, "/"), p);
578 type[XEN_BUS_ID_SIZE-1] = '\0';
580 rootlen = strsep_len(node, '/', bus->levels);
583 root = kasprintf(GFP_KERNEL, "%.*s", rootlen, node);
587 dev = xenbus_device_find(root, &bus->bus);
589 xenbus_probe_node(bus, type, root);
591 put_device(&dev->dev);
595 EXPORT_SYMBOL_GPL(xenbus_dev_changed);
597 int xenbus_dev_suspend(struct device *dev)
600 struct xenbus_driver *drv;
601 struct xenbus_device *xdev
602 = container_of(dev, struct xenbus_device, dev);
604 DPRINTK("%s", xdev->nodename);
606 if (dev->driver == NULL)
608 drv = to_xenbus_driver(dev->driver);
610 err = drv->suspend(xdev);
612 dev_warn(dev, "suspend failed: %i\n", err);
615 EXPORT_SYMBOL_GPL(xenbus_dev_suspend);
617 int xenbus_dev_resume(struct device *dev)
620 struct xenbus_driver *drv;
621 struct xenbus_device *xdev
622 = container_of(dev, struct xenbus_device, dev);
624 DPRINTK("%s", xdev->nodename);
626 if (dev->driver == NULL)
628 drv = to_xenbus_driver(dev->driver);
629 err = talk_to_otherend(xdev);
631 dev_warn(dev, "resume (talk_to_otherend) failed: %i\n", err);
635 xdev->state = XenbusStateInitialising;
638 err = drv->resume(xdev);
640 dev_warn(dev, "resume failed: %i\n", err);
645 err = watch_otherend(xdev);
647 dev_warn(dev, "resume (watch_otherend) failed: %d\n", err);
653 EXPORT_SYMBOL_GPL(xenbus_dev_resume);
655 int xenbus_dev_cancel(struct device *dev)
661 EXPORT_SYMBOL_GPL(xenbus_dev_cancel);
663 /* A flag to determine if xenstored is 'ready' (i.e. has started) */
667 int register_xenstore_notifier(struct notifier_block *nb)
671 if (xenstored_ready > 0)
672 ret = nb->notifier_call(nb, 0, NULL);
674 blocking_notifier_chain_register(&xenstore_chain, nb);
678 EXPORT_SYMBOL_GPL(register_xenstore_notifier);
680 void unregister_xenstore_notifier(struct notifier_block *nb)
682 blocking_notifier_chain_unregister(&xenstore_chain, nb);
684 EXPORT_SYMBOL_GPL(unregister_xenstore_notifier);
686 static void xenbus_probe(void)
691 * In the HVM case, xenbus_init() deferred its call to
692 * xs_init() in case callbacks were not operational yet.
695 if (xen_store_domain_type == XS_HVM)
698 /* Notify others that xenstore is up */
699 blocking_notifier_call_chain(&xenstore_chain, 0, NULL);
703 * Returns true when XenStore init must be deferred in order to
704 * allow the PCI platform device to be initialised, before we
705 * can actually have event channel interrupts working.
707 static bool xs_hvm_defer_init_for_callback(void)
709 #ifdef CONFIG_XEN_PVHVM
710 return xen_store_domain_type == XS_HVM &&
711 !xen_have_vector_callback;
717 static int xenbus_probe_thread(void *unused)
722 * We actually just want to wait for *any* trigger of xb_waitq,
723 * and run xenbus_probe() the moment it occurs.
725 prepare_to_wait(&xb_waitq, &w, TASK_INTERRUPTIBLE);
727 finish_wait(&xb_waitq, &w);
734 static int __init xenbus_probe_initcall(void)
737 * Probe XenBus here in the XS_PV case, and also XS_HVM unless we
738 * need to wait for the platform PCI device to come up.
740 if (xen_store_domain_type == XS_PV ||
741 (xen_store_domain_type == XS_HVM &&
742 !xs_hvm_defer_init_for_callback()))
746 * For XS_LOCAL, spawn a thread which will wait for xenstored
747 * or a xenstore-stubdom to be started, then probe. It will be
748 * triggered when communication starts happening, by waiting
751 if (xen_store_domain_type == XS_LOCAL) {
752 struct task_struct *probe_task;
754 probe_task = kthread_run(xenbus_probe_thread, NULL,
756 if (IS_ERR(probe_task))
757 return PTR_ERR(probe_task);
761 device_initcall(xenbus_probe_initcall);
763 int xen_set_callback_via(uint64_t via)
765 struct xen_hvm_param a;
768 a.domid = DOMID_SELF;
769 a.index = HVM_PARAM_CALLBACK_IRQ;
772 ret = HYPERVISOR_hvm_op(HVMOP_set_param, &a);
777 * If xenbus_probe_initcall() deferred the xenbus_probe()
778 * due to the callback not functioning yet, we can do it now.
780 if (!xenstored_ready && xs_hvm_defer_init_for_callback())
785 EXPORT_SYMBOL_GPL(xen_set_callback_via);
787 /* Set up event channel for xenstored which is run as a local process
788 * (this is normally used only in dom0)
790 static int __init xenstored_local_init(void)
793 unsigned long page = 0;
794 struct evtchn_alloc_unbound alloc_unbound;
796 /* Allocate Xenstore page */
797 page = get_zeroed_page(GFP_KERNEL);
801 xen_store_gfn = virt_to_gfn((void *)page);
803 /* Next allocate a local port which xenstored can bind to */
804 alloc_unbound.dom = DOMID_SELF;
805 alloc_unbound.remote_dom = DOMID_SELF;
807 err = HYPERVISOR_event_channel_op(EVTCHNOP_alloc_unbound,
813 xen_store_evtchn = alloc_unbound.port;
823 static int xenbus_resume_cb(struct notifier_block *nb,
824 unsigned long action, void *data)
828 if (xen_hvm_domain()) {
831 err = hvm_get_parameter(HVM_PARAM_STORE_EVTCHN, &v);
833 xen_store_evtchn = v;
835 pr_warn("Cannot update xenstore event channel: %d\n",
838 xen_store_evtchn = xen_start_info->store_evtchn;
843 static struct notifier_block xenbus_resume_nb = {
844 .notifier_call = xenbus_resume_cb,
847 static int __init xenbus_init(void)
851 xen_store_domain_type = XS_UNKNOWN;
856 xenbus_ring_ops_init();
859 xen_store_domain_type = XS_PV;
860 if (xen_hvm_domain())
861 xen_store_domain_type = XS_HVM;
862 if (xen_hvm_domain() && xen_initial_domain())
863 xen_store_domain_type = XS_LOCAL;
864 if (xen_pv_domain() && !xen_start_info->store_evtchn)
865 xen_store_domain_type = XS_LOCAL;
866 if (xen_pv_domain() && xen_start_info->store_evtchn)
869 switch (xen_store_domain_type) {
871 err = xenstored_local_init();
874 xen_store_interface = gfn_to_virt(xen_store_gfn);
877 xen_store_evtchn = xen_start_info->store_evtchn;
878 xen_store_gfn = xen_start_info->store_mfn;
879 xen_store_interface = gfn_to_virt(xen_store_gfn);
882 err = hvm_get_parameter(HVM_PARAM_STORE_EVTCHN, &v);
885 xen_store_evtchn = (int)v;
886 err = hvm_get_parameter(HVM_PARAM_STORE_PFN, &v);
890 * Uninitialized hvm_params are zero and return no error.
891 * Although it is theoretically possible to have
892 * HVM_PARAM_STORE_PFN set to zero on purpose, in reality it is
893 * not zero when valid. If zero, it means that Xenstore hasn't
894 * been properly initialized. Instead of attempting to map a
895 * wrong guest physical address return error.
897 * Also recognize all bits set as an invalid value.
903 /* Avoid truncation on 32-bit. */
904 #if BITS_PER_LONG == 32
906 pr_err("%s: cannot handle HVM_PARAM_STORE_PFN=%llx > ULONG_MAX\n",
912 xen_store_gfn = (unsigned long)v;
913 xen_store_interface =
914 xen_remap(xen_store_gfn << XEN_PAGE_SHIFT,
918 pr_warn("Xenstore state unknown\n");
923 * HVM domains may not have a functional callback yet. In that
924 * case let xs_init() be called from xenbus_probe(), which will
925 * get invoked at an appropriate time.
927 if (xen_store_domain_type != XS_HVM) {
930 pr_warn("Error initializing xenstore comms: %i\n", err);
935 if ((xen_store_domain_type != XS_LOCAL) &&
936 (xen_store_domain_type != XS_UNKNOWN))
937 xen_resume_notifier_register(&xenbus_resume_nb);
939 #ifdef CONFIG_XEN_COMPAT_XENFS
941 * Create xenfs mountpoint in /proc for compatibility with
942 * utilities that expect to find "xenbus" under "/proc/xen".
944 proc_create_mount_point("xen");
949 xen_store_domain_type = XS_UNKNOWN;
953 postcore_initcall(xenbus_init);
955 MODULE_LICENSE("GPL");