diff options
Diffstat (limited to 'drivers/xen/xenbus/xenbus_probe.c')
| -rw-r--r-- | drivers/xen/xenbus/xenbus_probe.c | 1072 |
1 files changed, 1072 insertions, 0 deletions
diff --git a/drivers/xen/xenbus/xenbus_probe.c b/drivers/xen/xenbus/xenbus_probe.c new file mode 100644 index 000000000..3205e5d72 --- /dev/null +++ b/drivers/xen/xenbus/xenbus_probe.c @@ -0,0 +1,1072 @@ +/****************************************************************************** + * 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 <linux/kernel.h> +#include <linux/err.h> +#include <linux/string.h> +#include <linux/ctype.h> +#include <linux/fcntl.h> +#include <linux/mm.h> +#include <linux/proc_fs.h> +#include <linux/notifier.h> +#include <linux/kthread.h> +#include <linux/mutex.h> +#include <linux/io.h> +#include <linux/slab.h> +#include <linux/module.h> + +#include <asm/page.h> +#include <asm/xen/hypervisor.h> + +#include <xen/xen.h> +#include <xen/xenbus.h> +#include <xen/events.h> +#include <xen/xen-ops.h> +#include <xen/page.h> + +#include <xen/hvm.h> + +#include "xenbus.h" + + +static int xs_init_irq; +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); + +#define XENBUS_SHOW_STAT(name) \ +static ssize_t name##_show(struct device *_dev, \ + struct device_attribute *attr, \ + char *buf) \ +{ \ + struct xenbus_device *dev = to_xenbus_device(_dev); \ + \ + return sprintf(buf, "%d\n", atomic_read(&dev->name)); \ +} \ +static DEVICE_ATTR_RO(name) + +XENBUS_SHOW_STAT(event_channels); +XENBUS_SHOW_STAT(events); +XENBUS_SHOW_STAT(spurious_events); +XENBUS_SHOW_STAT(jiffies_eoi_delayed); + +static ssize_t spurious_threshold_show(struct device *_dev, + struct device_attribute *attr, + char *buf) +{ + struct xenbus_device *dev = to_xenbus_device(_dev); + + return sprintf(buf, "%d\n", dev->spurious_threshold); +} + +static ssize_t spurious_threshold_store(struct device *_dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + struct xenbus_device *dev = to_xenbus_device(_dev); + unsigned int val; + ssize_t ret; + + ret = kstrtouint(buf, 0, &val); + if (ret) + return ret; + + dev->spurious_threshold = val; + + return count; +} + +static DEVICE_ATTR_RW(spurious_threshold); + +static struct attribute *xenbus_attrs[] = { + &dev_attr_event_channels.attr, + &dev_attr_events.attr, + &dev_attr_spurious_events.attr, + &dev_attr_jiffies_eoi_delayed.attr, + &dev_attr_spurious_threshold.attr, + NULL +}; + +static const struct attribute_group xenbus_group = { + .name = "xenbus", + .attrs = xenbus_attrs, +}; + +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; + } + + dev->spurious_threshold = 1; + if (sysfs_create_group(&dev->dev.kobj, &xenbus_group)) + dev_warn(&dev->dev, "sysfs_create_group on %s failed.\n", + dev->nodename); + + 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); + +void 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); + + sysfs_remove_group(&dev->dev.kobj, &xenbus_group); + + 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); +} +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/<type>/... or device/<type>/... */ + 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; + + if (!xen_store_interface) { + xen_store_interface = memremap(xen_store_gfn << XEN_PAGE_SHIFT, + XEN_PAGE_SIZE, MEMREMAP_WB); + /* + * Now it is safe to free the IRQ used for xenstore late + * initialization. No need to unbind: it is about to be + * bound again from xb_init_comms. Note that calling + * unbind_from_irqhandler now would result in xen_evtchn_close() + * being called and the event channel not being enabled again + * afterwards, resulting in missed event notifications. + */ + free_irq(xs_init_irq, &xb_waitq); + } + + /* + * 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) +{ + if (!xen_domain()) + return -ENODEV; + + /* + * 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 or + * xen_store_interface is not ready. + */ + if (xen_store_domain_type == XS_PV || + (xen_store_domain_type == XS_HVM && + !xs_hvm_defer_init_for_callback() && + xen_store_interface != NULL)) + xenbus_probe(); + + /* + * For XS_LOCAL or when xen_store_interface is not ready, 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 || xen_store_interface == NULL) { + 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 irqreturn_t xenbus_late_init(int irq, void *unused) +{ + int err; + uint64_t v = 0; + + err = hvm_get_parameter(HVM_PARAM_STORE_PFN, &v); + if (err || !v || !~v) + return IRQ_HANDLED; + xen_store_gfn = (unsigned long)v; + + wake_up(&xb_waitq); + return IRQ_HANDLED; +} + +static int __init xenbus_init(void) +{ + int err; + uint64_t v = 0; + bool wait = false; + 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/uninitialized value. + */ + if (!v) { + err = -ENOENT; + goto out_error; + } + if (v == ~0ULL) { + wait = true; + } else { + /* 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 = + memremap(xen_store_gfn << XEN_PAGE_SHIFT, + XEN_PAGE_SIZE, MEMREMAP_WB); + if (xen_store_interface->connection != XENSTORE_CONNECTED) + wait = true; + } + if (wait) { + err = bind_evtchn_to_irqhandler(xen_store_evtchn, + xenbus_late_init, + 0, "xenstore_late_init", + &xb_waitq); + if (err < 0) { + pr_err("xenstore_late_init couldn't bind irq err=%d\n", + err); + goto out_error; + } + + xs_init_irq = err; + } + 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"); |