/****************************************************************************** * Talks to Xen Store to figure out what devices we have. * * Copyright (C) 2005 Rusty Russell, IBM Corporation * Copyright (C) 2005 Mike Wray, Hewlett-Packard * Copyright (C) 2005, 2006 XenSource Ltd * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License version 2 * as published by the Free Software Foundation; or, when distributed * separately from the Linux kernel or incorporated into other * software packages, subject to the following license: * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this source file (the "Software"), to deal in the Software without * restriction, including without limitation the rights to use, copy, modify, * merge, publish, distribute, sublicense, and/or sell copies of the Software, * and to permit persons to whom the Software is furnished to do so, subject to * the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS * IN THE SOFTWARE. */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #define dev_fmt pr_fmt #define DPRINTK(fmt, args...) \ pr_debug("xenbus_probe (%s:%d) " fmt ".\n", \ __func__, __LINE__, ##args) #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "xenbus.h" int xen_store_evtchn; EXPORT_SYMBOL_GPL(xen_store_evtchn); struct xenstore_domain_interface *xen_store_interface; EXPORT_SYMBOL_GPL(xen_store_interface); enum xenstore_init xen_store_domain_type; EXPORT_SYMBOL_GPL(xen_store_domain_type); static unsigned long xen_store_gfn; static BLOCKING_NOTIFIER_HEAD(xenstore_chain); /* If something in array of ids matches this device, return it. */ static const struct xenbus_device_id * match_device(const struct xenbus_device_id *arr, struct xenbus_device *dev) { for (; *arr->devicetype != '\0'; arr++) { if (!strcmp(arr->devicetype, dev->devicetype)) return arr; } return NULL; } int xenbus_match(struct device *_dev, struct device_driver *_drv) { struct xenbus_driver *drv = to_xenbus_driver(_drv); if (!drv->ids) return 0; return match_device(drv->ids, to_xenbus_device(_dev)) != NULL; } EXPORT_SYMBOL_GPL(xenbus_match); static void free_otherend_details(struct xenbus_device *dev) { kfree(dev->otherend); dev->otherend = NULL; } static void free_otherend_watch(struct xenbus_device *dev) { if (dev->otherend_watch.node) { unregister_xenbus_watch(&dev->otherend_watch); kfree(dev->otherend_watch.node); dev->otherend_watch.node = NULL; } } static int talk_to_otherend(struct xenbus_device *dev) { struct xenbus_driver *drv = to_xenbus_driver(dev->dev.driver); free_otherend_watch(dev); free_otherend_details(dev); return drv->read_otherend_details(dev); } static int watch_otherend(struct xenbus_device *dev) { struct xen_bus_type *bus = container_of(dev->dev.bus, struct xen_bus_type, bus); return xenbus_watch_pathfmt(dev, &dev->otherend_watch, bus->otherend_will_handle, bus->otherend_changed, "%s/%s", dev->otherend, "state"); } int xenbus_read_otherend_details(struct xenbus_device *xendev, char *id_node, char *path_node) { int err = xenbus_gather(XBT_NIL, xendev->nodename, id_node, "%i", &xendev->otherend_id, path_node, NULL, &xendev->otherend, NULL); if (err) { xenbus_dev_fatal(xendev, err, "reading other end details from %s", xendev->nodename); return err; } if (strlen(xendev->otherend) == 0 || !xenbus_exists(XBT_NIL, xendev->otherend, "")) { xenbus_dev_fatal(xendev, -ENOENT, "unable to read other end from %s. " "missing or inaccessible.", xendev->nodename); free_otherend_details(xendev); return -ENOENT; } return 0; } EXPORT_SYMBOL_GPL(xenbus_read_otherend_details); void xenbus_otherend_changed(struct xenbus_watch *watch, const char *path, const char *token, int ignore_on_shutdown) { struct xenbus_device *dev = container_of(watch, struct xenbus_device, otherend_watch); struct xenbus_driver *drv = to_xenbus_driver(dev->dev.driver); enum xenbus_state state; /* Protect us against watches firing on old details when the otherend details change, say immediately after a resume. */ if (!dev->otherend || strncmp(dev->otherend, path, strlen(dev->otherend))) { dev_dbg(&dev->dev, "Ignoring watch at %s\n", path); return; } state = xenbus_read_driver_state(dev->otherend); dev_dbg(&dev->dev, "state is %d, (%s), %s, %s\n", state, xenbus_strstate(state), dev->otherend_watch.node, path); /* * Ignore xenbus transitions during shutdown. This prevents us doing * work that can fail e.g., when the rootfs is gone. */ if (system_state > SYSTEM_RUNNING) { if (ignore_on_shutdown && (state == XenbusStateClosing)) xenbus_frontend_closed(dev); return; } if (drv->otherend_changed) drv->otherend_changed(dev, state); } EXPORT_SYMBOL_GPL(xenbus_otherend_changed); int xenbus_dev_probe(struct device *_dev) { struct xenbus_device *dev = to_xenbus_device(_dev); struct xenbus_driver *drv = to_xenbus_driver(_dev->driver); const struct xenbus_device_id *id; int err; DPRINTK("%s", dev->nodename); if (!drv->probe) { err = -ENODEV; goto fail; } id = match_device(drv->ids, dev); if (!id) { err = -ENODEV; goto fail; } err = talk_to_otherend(dev); if (err) { dev_warn(&dev->dev, "talk_to_otherend on %s failed.\n", dev->nodename); return err; } if (!try_module_get(drv->driver.owner)) { dev_warn(&dev->dev, "failed to acquire module reference on '%s'\n", drv->driver.name); err = -ESRCH; goto fail; } down(&dev->reclaim_sem); err = drv->probe(dev, id); up(&dev->reclaim_sem); if (err) goto fail_put; err = watch_otherend(dev); if (err) { dev_warn(&dev->dev, "watch_otherend on %s failed.\n", dev->nodename); return err; } return 0; fail_put: module_put(drv->driver.owner); fail: xenbus_dev_error(dev, err, "xenbus_dev_probe on %s", dev->nodename); return err; } EXPORT_SYMBOL_GPL(xenbus_dev_probe); int xenbus_dev_remove(struct device *_dev) { struct xenbus_device *dev = to_xenbus_device(_dev); struct xenbus_driver *drv = to_xenbus_driver(_dev->driver); DPRINTK("%s", dev->nodename); free_otherend_watch(dev); if (drv->remove) { down(&dev->reclaim_sem); drv->remove(dev); up(&dev->reclaim_sem); } module_put(drv->driver.owner); free_otherend_details(dev); /* * If the toolstack has forced the device state to closing then set * the state to closed now to allow it to be cleaned up. * Similarly, if the driver does not support re-bind, set the * closed. */ if (!drv->allow_rebind || xenbus_read_driver_state(dev->nodename) == XenbusStateClosing) xenbus_switch_state(dev, XenbusStateClosed); return 0; } EXPORT_SYMBOL_GPL(xenbus_dev_remove); int xenbus_register_driver_common(struct xenbus_driver *drv, struct xen_bus_type *bus, struct module *owner, const char *mod_name) { drv->driver.name = drv->name ? drv->name : drv->ids[0].devicetype; drv->driver.bus = &bus->bus; drv->driver.owner = owner; drv->driver.mod_name = mod_name; return driver_register(&drv->driver); } EXPORT_SYMBOL_GPL(xenbus_register_driver_common); void xenbus_unregister_driver(struct xenbus_driver *drv) { driver_unregister(&drv->driver); } EXPORT_SYMBOL_GPL(xenbus_unregister_driver); struct xb_find_info { struct xenbus_device *dev; const char *nodename; }; static int cmp_dev(struct device *dev, void *data) { struct xenbus_device *xendev = to_xenbus_device(dev); struct xb_find_info *info = data; if (!strcmp(xendev->nodename, info->nodename)) { info->dev = xendev; get_device(dev); return 1; } return 0; } static struct xenbus_device *xenbus_device_find(const char *nodename, struct bus_type *bus) { struct xb_find_info info = { .dev = NULL, .nodename = nodename }; bus_for_each_dev(bus, NULL, &info, cmp_dev); return info.dev; } static int cleanup_dev(struct device *dev, void *data) { struct xenbus_device *xendev = to_xenbus_device(dev); struct xb_find_info *info = data; int len = strlen(info->nodename); DPRINTK("%s", info->nodename); /* Match the info->nodename path, or any subdirectory of that path. */ if (strncmp(xendev->nodename, info->nodename, len)) return 0; /* If the node name is longer, ensure it really is a subdirectory. */ if ((strlen(xendev->nodename) > len) && (xendev->nodename[len] != '/')) return 0; info->dev = xendev; get_device(dev); return 1; } static void xenbus_cleanup_devices(const char *path, struct bus_type *bus) { struct xb_find_info info = { .nodename = path }; do { info.dev = NULL; bus_for_each_dev(bus, NULL, &info, cleanup_dev); if (info.dev) { device_unregister(&info.dev->dev); put_device(&info.dev->dev); } } while (info.dev); } static void xenbus_dev_release(struct device *dev) { if (dev) kfree(to_xenbus_device(dev)); } static ssize_t nodename_show(struct device *dev, struct device_attribute *attr, char *buf) { return sprintf(buf, "%s\n", to_xenbus_device(dev)->nodename); } static DEVICE_ATTR_RO(nodename); static ssize_t devtype_show(struct device *dev, struct device_attribute *attr, char *buf) { return sprintf(buf, "%s\n", to_xenbus_device(dev)->devicetype); } static DEVICE_ATTR_RO(devtype); static ssize_t modalias_show(struct device *dev, struct device_attribute *attr, char *buf) { return sprintf(buf, "%s:%s\n", dev->bus->name, to_xenbus_device(dev)->devicetype); } static DEVICE_ATTR_RO(modalias); static ssize_t state_show(struct device *dev, struct device_attribute *attr, char *buf) { return sprintf(buf, "%s\n", xenbus_strstate(to_xenbus_device(dev)->state)); } static DEVICE_ATTR_RO(state); static struct attribute *xenbus_dev_attrs[] = { &dev_attr_nodename.attr, &dev_attr_devtype.attr, &dev_attr_modalias.attr, &dev_attr_state.attr, NULL, }; static const struct attribute_group xenbus_dev_group = { .attrs = xenbus_dev_attrs, }; const struct attribute_group *xenbus_dev_groups[] = { &xenbus_dev_group, NULL, }; EXPORT_SYMBOL_GPL(xenbus_dev_groups); int xenbus_probe_node(struct xen_bus_type *bus, const char *type, const char *nodename) { char devname[XEN_BUS_ID_SIZE]; int err; struct xenbus_device *xendev; size_t stringlen; char *tmpstring; enum xenbus_state state = xenbus_read_driver_state(nodename); if (state != XenbusStateInitialising) { /* Device is not new, so ignore it. This can happen if a device is going away after switching to Closed. */ return 0; } stringlen = strlen(nodename) + 1 + strlen(type) + 1; xendev = kzalloc(sizeof(*xendev) + stringlen, GFP_KERNEL); if (!xendev) return -ENOMEM; xendev->state = XenbusStateInitialising; /* Copy the strings into the extra space. */ tmpstring = (char *)(xendev + 1); strcpy(tmpstring, nodename); xendev->nodename = tmpstring; tmpstring += strlen(tmpstring) + 1; strcpy(tmpstring, type); xendev->devicetype = tmpstring; init_completion(&xendev->down); xendev->dev.bus = &bus->bus; xendev->dev.release = xenbus_dev_release; err = bus->get_bus_id(devname, xendev->nodename); if (err) goto fail; dev_set_name(&xendev->dev, "%s", devname); sema_init(&xendev->reclaim_sem, 1); /* Register with generic device framework. */ err = device_register(&xendev->dev); if (err) { put_device(&xendev->dev); xendev = NULL; goto fail; } return 0; fail: kfree(xendev); return err; } EXPORT_SYMBOL_GPL(xenbus_probe_node); static int xenbus_probe_device_type(struct xen_bus_type *bus, const char *type) { int err = 0; char **dir; unsigned int dir_n = 0; int i; dir = xenbus_directory(XBT_NIL, bus->root, type, &dir_n); if (IS_ERR(dir)) return PTR_ERR(dir); for (i = 0; i < dir_n; i++) { err = bus->probe(bus, type, dir[i]); if (err) break; } kfree(dir); return err; } int xenbus_probe_devices(struct xen_bus_type *bus) { int err = 0; char **dir; unsigned int i, dir_n; dir = xenbus_directory(XBT_NIL, bus->root, "", &dir_n); if (IS_ERR(dir)) return PTR_ERR(dir); for (i = 0; i < dir_n; i++) { err = xenbus_probe_device_type(bus, dir[i]); if (err) break; } kfree(dir); return err; } EXPORT_SYMBOL_GPL(xenbus_probe_devices); static unsigned int char_count(const char *str, char c) { unsigned int i, ret = 0; for (i = 0; str[i]; i++) if (str[i] == c) ret++; return ret; } static int strsep_len(const char *str, char c, unsigned int len) { unsigned int i; for (i = 0; str[i]; i++) if (str[i] == c) { if (len == 0) return i; len--; } return (len == 0) ? i : -ERANGE; } void xenbus_dev_changed(const char *node, struct xen_bus_type *bus) { int exists, rootlen; struct xenbus_device *dev; char type[XEN_BUS_ID_SIZE]; const char *p, *root; if (char_count(node, '/') < 2) return; exists = xenbus_exists(XBT_NIL, node, ""); if (!exists) { xenbus_cleanup_devices(node, &bus->bus); return; } /* backend//... or device//... */ p = strchr(node, '/') + 1; snprintf(type, XEN_BUS_ID_SIZE, "%.*s", (int)strcspn(p, "/"), p); type[XEN_BUS_ID_SIZE-1] = '\0'; rootlen = strsep_len(node, '/', bus->levels); if (rootlen < 0) return; root = kasprintf(GFP_KERNEL, "%.*s", rootlen, node); if (!root) return; dev = xenbus_device_find(root, &bus->bus); if (!dev) xenbus_probe_node(bus, type, root); else put_device(&dev->dev); kfree(root); } EXPORT_SYMBOL_GPL(xenbus_dev_changed); int xenbus_dev_suspend(struct device *dev) { int err = 0; struct xenbus_driver *drv; struct xenbus_device *xdev = container_of(dev, struct xenbus_device, dev); DPRINTK("%s", xdev->nodename); if (dev->driver == NULL) return 0; drv = to_xenbus_driver(dev->driver); if (drv->suspend) err = drv->suspend(xdev); if (err) dev_warn(dev, "suspend failed: %i\n", err); return 0; } EXPORT_SYMBOL_GPL(xenbus_dev_suspend); int xenbus_dev_resume(struct device *dev) { int err; struct xenbus_driver *drv; struct xenbus_device *xdev = container_of(dev, struct xenbus_device, dev); DPRINTK("%s", xdev->nodename); if (dev->driver == NULL) return 0; drv = to_xenbus_driver(dev->driver); err = talk_to_otherend(xdev); if (err) { dev_warn(dev, "resume (talk_to_otherend) failed: %i\n", err); return err; } xdev->state = XenbusStateInitialising; if (drv->resume) { err = drv->resume(xdev); if (err) { dev_warn(dev, "resume failed: %i\n", err); return err; } } err = watch_otherend(xdev); if (err) { dev_warn(dev, "resume (watch_otherend) failed: %d\n", err); return err; } return 0; } EXPORT_SYMBOL_GPL(xenbus_dev_resume); int xenbus_dev_cancel(struct device *dev) { /* Do nothing */ DPRINTK("cancel"); return 0; } EXPORT_SYMBOL_GPL(xenbus_dev_cancel); /* A flag to determine if xenstored is 'ready' (i.e. has started) */ int xenstored_ready; int register_xenstore_notifier(struct notifier_block *nb) { int ret = 0; if (xenstored_ready > 0) ret = nb->notifier_call(nb, 0, NULL); else blocking_notifier_chain_register(&xenstore_chain, nb); return ret; } EXPORT_SYMBOL_GPL(register_xenstore_notifier); void unregister_xenstore_notifier(struct notifier_block *nb) { blocking_notifier_chain_unregister(&xenstore_chain, nb); } EXPORT_SYMBOL_GPL(unregister_xenstore_notifier); static void xenbus_probe(void) { xenstored_ready = 1; /* * In the HVM case, xenbus_init() deferred its call to * xs_init() in case callbacks were not operational yet. * So do it now. */ if (xen_store_domain_type == XS_HVM) xs_init(); /* Notify others that xenstore is up */ blocking_notifier_call_chain(&xenstore_chain, 0, NULL); } /* * Returns true when XenStore init must be deferred in order to * allow the PCI platform device to be initialised, before we * can actually have event channel interrupts working. */ static bool xs_hvm_defer_init_for_callback(void) { #ifdef CONFIG_XEN_PVHVM return xen_store_domain_type == XS_HVM && !xen_have_vector_callback; #else return false; #endif } static int xenbus_probe_thread(void *unused) { DEFINE_WAIT(w); /* * We actually just want to wait for *any* trigger of xb_waitq, * and run xenbus_probe() the moment it occurs. */ prepare_to_wait(&xb_waitq, &w, TASK_INTERRUPTIBLE); schedule(); finish_wait(&xb_waitq, &w); DPRINTK("probing"); xenbus_probe(); return 0; } static int __init xenbus_probe_initcall(void) { /* * Probe XenBus here in the XS_PV case, and also XS_HVM unless we * need to wait for the platform PCI device to come up. */ if (xen_store_domain_type == XS_PV || (xen_store_domain_type == XS_HVM && !xs_hvm_defer_init_for_callback())) xenbus_probe(); /* * For XS_LOCAL, spawn a thread which will wait for xenstored * or a xenstore-stubdom to be started, then probe. It will be * triggered when communication starts happening, by waiting * on xb_waitq. */ if (xen_store_domain_type == XS_LOCAL) { struct task_struct *probe_task; probe_task = kthread_run(xenbus_probe_thread, NULL, "xenbus_probe"); if (IS_ERR(probe_task)) return PTR_ERR(probe_task); } return 0; } device_initcall(xenbus_probe_initcall); int xen_set_callback_via(uint64_t via) { struct xen_hvm_param a; int ret; a.domid = DOMID_SELF; a.index = HVM_PARAM_CALLBACK_IRQ; a.value = via; ret = HYPERVISOR_hvm_op(HVMOP_set_param, &a); if (ret) return ret; /* * If xenbus_probe_initcall() deferred the xenbus_probe() * due to the callback not functioning yet, we can do it now. */ if (!xenstored_ready && xs_hvm_defer_init_for_callback()) xenbus_probe(); return ret; } EXPORT_SYMBOL_GPL(xen_set_callback_via); /* Set up event channel for xenstored which is run as a local process * (this is normally used only in dom0) */ static int __init xenstored_local_init(void) { int err = -ENOMEM; unsigned long page = 0; struct evtchn_alloc_unbound alloc_unbound; /* Allocate Xenstore page */ page = get_zeroed_page(GFP_KERNEL); if (!page) goto out_err; xen_store_gfn = virt_to_gfn((void *)page); /* Next allocate a local port which xenstored can bind to */ alloc_unbound.dom = DOMID_SELF; alloc_unbound.remote_dom = DOMID_SELF; err = HYPERVISOR_event_channel_op(EVTCHNOP_alloc_unbound, &alloc_unbound); if (err == -ENOSYS) goto out_err; BUG_ON(err); xen_store_evtchn = alloc_unbound.port; return 0; out_err: if (page != 0) free_page(page); return err; } static int xenbus_resume_cb(struct notifier_block *nb, unsigned long action, void *data) { int err = 0; if (xen_hvm_domain()) { uint64_t v = 0; err = hvm_get_parameter(HVM_PARAM_STORE_EVTCHN, &v); if (!err && v) xen_store_evtchn = v; else pr_warn("Cannot update xenstore event channel: %d\n", err); } else xen_store_evtchn = xen_start_info->store_evtchn; return err; } static struct notifier_block xenbus_resume_nb = { .notifier_call = xenbus_resume_cb, }; static int __init xenbus_init(void) { int err; uint64_t v = 0; xen_store_domain_type = XS_UNKNOWN; if (!xen_domain()) return -ENODEV; xenbus_ring_ops_init(); if (xen_pv_domain()) xen_store_domain_type = XS_PV; if (xen_hvm_domain()) xen_store_domain_type = XS_HVM; if (xen_hvm_domain() && xen_initial_domain()) xen_store_domain_type = XS_LOCAL; if (xen_pv_domain() && !xen_start_info->store_evtchn) xen_store_domain_type = XS_LOCAL; if (xen_pv_domain() && xen_start_info->store_evtchn) xenstored_ready = 1; switch (xen_store_domain_type) { case XS_LOCAL: err = xenstored_local_init(); if (err) goto out_error; xen_store_interface = gfn_to_virt(xen_store_gfn); break; case XS_PV: xen_store_evtchn = xen_start_info->store_evtchn; xen_store_gfn = xen_start_info->store_mfn; xen_store_interface = gfn_to_virt(xen_store_gfn); break; case XS_HVM: err = hvm_get_parameter(HVM_PARAM_STORE_EVTCHN, &v); if (err) goto out_error; xen_store_evtchn = (int)v; err = hvm_get_parameter(HVM_PARAM_STORE_PFN, &v); if (err) goto out_error; /* * Uninitialized hvm_params are zero and return no error. * Although it is theoretically possible to have * HVM_PARAM_STORE_PFN set to zero on purpose, in reality it is * not zero when valid. If zero, it means that Xenstore hasn't * been properly initialized. Instead of attempting to map a * wrong guest physical address return error. * * Also recognize all bits set as an invalid value. */ if (!v || !~v) { err = -ENOENT; goto out_error; } /* Avoid truncation on 32-bit. */ #if BITS_PER_LONG == 32 if (v > ULONG_MAX) { pr_err("%s: cannot handle HVM_PARAM_STORE_PFN=%llx > ULONG_MAX\n", __func__, v); err = -EINVAL; goto out_error; } #endif xen_store_gfn = (unsigned long)v; xen_store_interface = xen_remap(xen_store_gfn << XEN_PAGE_SHIFT, XEN_PAGE_SIZE); break; default: pr_warn("Xenstore state unknown\n"); break; } /* * HVM domains may not have a functional callback yet. In that * case let xs_init() be called from xenbus_probe(), which will * get invoked at an appropriate time. */ if (xen_store_domain_type != XS_HVM) { err = xs_init(); if (err) { pr_warn("Error initializing xenstore comms: %i\n", err); goto out_error; } } if ((xen_store_domain_type != XS_LOCAL) && (xen_store_domain_type != XS_UNKNOWN)) xen_resume_notifier_register(&xenbus_resume_nb); #ifdef CONFIG_XEN_COMPAT_XENFS /* * Create xenfs mountpoint in /proc for compatibility with * utilities that expect to find "xenbus" under "/proc/xen". */ proc_create_mount_point("xen"); #endif return 0; out_error: xen_store_domain_type = XS_UNKNOWN; return err; } postcore_initcall(xenbus_init); MODULE_LICENSE("GPL");