// SPDX-License-Identifier: GPL-2.0-only /* * Copyright (c) 2009, Microsoft Corporation. * * Authors: * Haiyang Zhang <haiyangz@microsoft.com> * Hank Janssen <hjanssen@microsoft.com> * K. Y. Srinivasan <kys@microsoft.com> */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include <linux/init.h> #include <linux/module.h> #include <linux/device.h> #include <linux/interrupt.h> #include <linux/sysctl.h> #include <linux/slab.h> #include <linux/acpi.h> #include <linux/completion.h> #include <linux/hyperv.h> #include <linux/kernel_stat.h> #include <linux/clockchips.h> #include <linux/cpu.h> #include <linux/sched/task_stack.h> #include <linux/delay.h> #include <linux/notifier.h> #include <linux/panic_notifier.h> #include <linux/ptrace.h> #include <linux/screen_info.h> #include <linux/kdebug.h> #include <linux/efi.h> #include <linux/random.h> #include <linux/kernel.h> #include <linux/syscore_ops.h> #include <clocksource/hyperv_timer.h> #include "hyperv_vmbus.h" struct vmbus_dynid { struct list_head node; struct hv_vmbus_device_id id; }; static struct acpi_device *hv_acpi_dev; static struct completion probe_event; static int hyperv_cpuhp_online; static void *hv_panic_page; static long __percpu *vmbus_evt; /* Values parsed from ACPI DSDT */ int vmbus_irq; int vmbus_interrupt; /* * Boolean to control whether to report panic messages over Hyper-V. * * It can be set via /proc/sys/kernel/hyperv_record_panic_msg */ static int sysctl_record_panic_msg = 1; static int hyperv_report_reg(void) { return !sysctl_record_panic_msg || !hv_panic_page; } static int hyperv_panic_event(struct notifier_block *nb, unsigned long val, void *args) { struct pt_regs *regs; vmbus_initiate_unload(true); /* * Hyper-V should be notified only once about a panic. If we will be * doing hyperv_report_panic_msg() later with kmsg data, don't do * the notification here. */ if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE && hyperv_report_reg()) { regs = current_pt_regs(); hyperv_report_panic(regs, val, false); } return NOTIFY_DONE; } static int hyperv_die_event(struct notifier_block *nb, unsigned long val, void *args) { struct die_args *die = args; struct pt_regs *regs = die->regs; /* Don't notify Hyper-V if the die event is other than oops */ if (val != DIE_OOPS) return NOTIFY_DONE; /* * Hyper-V should be notified only once about a panic. If we will be * doing hyperv_report_panic_msg() later with kmsg data, don't do * the notification here. */ if (hyperv_report_reg()) hyperv_report_panic(regs, val, true); return NOTIFY_DONE; } static struct notifier_block hyperv_die_block = { .notifier_call = hyperv_die_event, }; static struct notifier_block hyperv_panic_block = { .notifier_call = hyperv_panic_event, }; static const char *fb_mmio_name = "fb_range"; static struct resource *fb_mmio; static struct resource *hyperv_mmio; static DEFINE_MUTEX(hyperv_mmio_lock); static int vmbus_exists(void) { if (hv_acpi_dev == NULL) return -ENODEV; return 0; } static u8 channel_monitor_group(const struct vmbus_channel *channel) { return (u8)channel->offermsg.monitorid / 32; } static u8 channel_monitor_offset(const struct vmbus_channel *channel) { return (u8)channel->offermsg.monitorid % 32; } static u32 channel_pending(const struct vmbus_channel *channel, const struct hv_monitor_page *monitor_page) { u8 monitor_group = channel_monitor_group(channel); return monitor_page->trigger_group[monitor_group].pending; } static u32 channel_latency(const struct vmbus_channel *channel, const struct hv_monitor_page *monitor_page) { u8 monitor_group = channel_monitor_group(channel); u8 monitor_offset = channel_monitor_offset(channel); return monitor_page->latency[monitor_group][monitor_offset]; } static u32 channel_conn_id(struct vmbus_channel *channel, struct hv_monitor_page *monitor_page) { u8 monitor_group = channel_monitor_group(channel); u8 monitor_offset = channel_monitor_offset(channel); return monitor_page->parameter[monitor_group][monitor_offset].connectionid.u.id; } static ssize_t id_show(struct device *dev, struct device_attribute *dev_attr, char *buf) { struct hv_device *hv_dev = device_to_hv_device(dev); if (!hv_dev->channel) return -ENODEV; return sprintf(buf, "%d\n", hv_dev->channel->offermsg.child_relid); } static DEVICE_ATTR_RO(id); static ssize_t state_show(struct device *dev, struct device_attribute *dev_attr, char *buf) { struct hv_device *hv_dev = device_to_hv_device(dev); if (!hv_dev->channel) return -ENODEV; return sprintf(buf, "%d\n", hv_dev->channel->state); } static DEVICE_ATTR_RO(state); static ssize_t monitor_id_show(struct device *dev, struct device_attribute *dev_attr, char *buf) { struct hv_device *hv_dev = device_to_hv_device(dev); if (!hv_dev->channel) return -ENODEV; return sprintf(buf, "%d\n", hv_dev->channel->offermsg.monitorid); } static DEVICE_ATTR_RO(monitor_id); static ssize_t class_id_show(struct device *dev, struct device_attribute *dev_attr, char *buf) { struct hv_device *hv_dev = device_to_hv_device(dev); if (!hv_dev->channel) return -ENODEV; return sprintf(buf, "{%pUl}\n", &hv_dev->channel->offermsg.offer.if_type); } static DEVICE_ATTR_RO(class_id); static ssize_t device_id_show(struct device *dev, struct device_attribute *dev_attr, char *buf) { struct hv_device *hv_dev = device_to_hv_device(dev); if (!hv_dev->channel) return -ENODEV; return sprintf(buf, "{%pUl}\n", &hv_dev->channel->offermsg.offer.if_instance); } static DEVICE_ATTR_RO(device_id); static ssize_t modalias_show(struct device *dev, struct device_attribute *dev_attr, char *buf) { struct hv_device *hv_dev = device_to_hv_device(dev); return sprintf(buf, "vmbus:%*phN\n", UUID_SIZE, &hv_dev->dev_type); } static DEVICE_ATTR_RO(modalias); #ifdef CONFIG_NUMA static ssize_t numa_node_show(struct device *dev, struct device_attribute *attr, char *buf) { struct hv_device *hv_dev = device_to_hv_device(dev); if (!hv_dev->channel) return -ENODEV; return sprintf(buf, "%d\n", cpu_to_node(hv_dev->channel->target_cpu)); } static DEVICE_ATTR_RO(numa_node); #endif static ssize_t server_monitor_pending_show(struct device *dev, struct device_attribute *dev_attr, char *buf) { struct hv_device *hv_dev = device_to_hv_device(dev); if (!hv_dev->channel) return -ENODEV; return sprintf(buf, "%d\n", channel_pending(hv_dev->channel, vmbus_connection.monitor_pages[0])); } static DEVICE_ATTR_RO(server_monitor_pending); static ssize_t client_monitor_pending_show(struct device *dev, struct device_attribute *dev_attr, char *buf) { struct hv_device *hv_dev = device_to_hv_device(dev); if (!hv_dev->channel) return -ENODEV; return sprintf(buf, "%d\n", channel_pending(hv_dev->channel, vmbus_connection.monitor_pages[1])); } static DEVICE_ATTR_RO(client_monitor_pending); static ssize_t server_monitor_latency_show(struct device *dev, struct device_attribute *dev_attr, char *buf) { struct hv_device *hv_dev = device_to_hv_device(dev); if (!hv_dev->channel) return -ENODEV; return sprintf(buf, "%d\n", channel_latency(hv_dev->channel, vmbus_connection.monitor_pages[0])); } static DEVICE_ATTR_RO(server_monitor_latency); static ssize_t client_monitor_latency_show(struct device *dev, struct device_attribute *dev_attr, char *buf) { struct hv_device *hv_dev = device_to_hv_device(dev); if (!hv_dev->channel) return -ENODEV; return sprintf(buf, "%d\n", channel_latency(hv_dev->channel, vmbus_connection.monitor_pages[1])); } static DEVICE_ATTR_RO(client_monitor_latency); static ssize_t server_monitor_conn_id_show(struct device *dev, struct device_attribute *dev_attr, char *buf) { struct hv_device *hv_dev = device_to_hv_device(dev); if (!hv_dev->channel) return -ENODEV; return sprintf(buf, "%d\n", channel_conn_id(hv_dev->channel, vmbus_connection.monitor_pages[0])); } static DEVICE_ATTR_RO(server_monitor_conn_id); static ssize_t client_monitor_conn_id_show(struct device *dev, struct device_attribute *dev_attr, char *buf) { struct hv_device *hv_dev = device_to_hv_device(dev); if (!hv_dev->channel) return -ENODEV; return sprintf(buf, "%d\n", channel_conn_id(hv_dev->channel, vmbus_connection.monitor_pages[1])); } static DEVICE_ATTR_RO(client_monitor_conn_id); static ssize_t out_intr_mask_show(struct device *dev, struct device_attribute *dev_attr, char *buf) { struct hv_device *hv_dev = device_to_hv_device(dev); struct hv_ring_buffer_debug_info outbound; int ret; if (!hv_dev->channel) return -ENODEV; ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound, &outbound); if (ret < 0) return ret; return sprintf(buf, "%d\n", outbound.current_interrupt_mask); } static DEVICE_ATTR_RO(out_intr_mask); static ssize_t out_read_index_show(struct device *dev, struct device_attribute *dev_attr, char *buf) { struct hv_device *hv_dev = device_to_hv_device(dev); struct hv_ring_buffer_debug_info outbound; int ret; if (!hv_dev->channel) return -ENODEV; ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound, &outbound); if (ret < 0) return ret; return sprintf(buf, "%d\n", outbound.current_read_index); } static DEVICE_ATTR_RO(out_read_index); static ssize_t out_write_index_show(struct device *dev, struct device_attribute *dev_attr, char *buf) { struct hv_device *hv_dev = device_to_hv_device(dev); struct hv_ring_buffer_debug_info outbound; int ret; if (!hv_dev->channel) return -ENODEV; ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound, &outbound); if (ret < 0) return ret; return sprintf(buf, "%d\n", outbound.current_write_index); } static DEVICE_ATTR_RO(out_write_index); static ssize_t out_read_bytes_avail_show(struct device *dev, struct device_attribute *dev_attr, char *buf) { struct hv_device *hv_dev = device_to_hv_device(dev); struct hv_ring_buffer_debug_info outbound; int ret; if (!hv_dev->channel) return -ENODEV; ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound, &outbound); if (ret < 0) return ret; return sprintf(buf, "%d\n", outbound.bytes_avail_toread); } static DEVICE_ATTR_RO(out_read_bytes_avail); static ssize_t out_write_bytes_avail_show(struct device *dev, struct device_attribute *dev_attr, char *buf) { struct hv_device *hv_dev = device_to_hv_device(dev); struct hv_ring_buffer_debug_info outbound; int ret; if (!hv_dev->channel) return -ENODEV; ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound, &outbound); if (ret < 0) return ret; return sprintf(buf, "%d\n", outbound.bytes_avail_towrite); } static DEVICE_ATTR_RO(out_write_bytes_avail); static ssize_t in_intr_mask_show(struct device *dev, struct device_attribute *dev_attr, char *buf) { struct hv_device *hv_dev = device_to_hv_device(dev); struct hv_ring_buffer_debug_info inbound; int ret; if (!hv_dev->channel) return -ENODEV; ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound); if (ret < 0) return ret; return sprintf(buf, "%d\n", inbound.current_interrupt_mask); } static DEVICE_ATTR_RO(in_intr_mask); static ssize_t in_read_index_show(struct device *dev, struct device_attribute *dev_attr, char *buf) { struct hv_device *hv_dev = device_to_hv_device(dev); struct hv_ring_buffer_debug_info inbound; int ret; if (!hv_dev->channel) return -ENODEV; ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound); if (ret < 0) return ret; return sprintf(buf, "%d\n", inbound.current_read_index); } static DEVICE_ATTR_RO(in_read_index); static ssize_t in_write_index_show(struct device *dev, struct device_attribute *dev_attr, char *buf) { struct hv_device *hv_dev = device_to_hv_device(dev); struct hv_ring_buffer_debug_info inbound; int ret; if (!hv_dev->channel) return -ENODEV; ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound); if (ret < 0) return ret; return sprintf(buf, "%d\n", inbound.current_write_index); } static DEVICE_ATTR_RO(in_write_index); static ssize_t in_read_bytes_avail_show(struct device *dev, struct device_attribute *dev_attr, char *buf) { struct hv_device *hv_dev = device_to_hv_device(dev); struct hv_ring_buffer_debug_info inbound; int ret; if (!hv_dev->channel) return -ENODEV; ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound); if (ret < 0) return ret; return sprintf(buf, "%d\n", inbound.bytes_avail_toread); } static DEVICE_ATTR_RO(in_read_bytes_avail); static ssize_t in_write_bytes_avail_show(struct device *dev, struct device_attribute *dev_attr, char *buf) { struct hv_device *hv_dev = device_to_hv_device(dev); struct hv_ring_buffer_debug_info inbound; int ret; if (!hv_dev->channel) return -ENODEV; ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound); if (ret < 0) return ret; return sprintf(buf, "%d\n", inbound.bytes_avail_towrite); } static DEVICE_ATTR_RO(in_write_bytes_avail); static ssize_t channel_vp_mapping_show(struct device *dev, struct device_attribute *dev_attr, char *buf) { struct hv_device *hv_dev = device_to_hv_device(dev); struct vmbus_channel *channel = hv_dev->channel, *cur_sc; int buf_size = PAGE_SIZE, n_written, tot_written; struct list_head *cur; if (!channel) return -ENODEV; mutex_lock(&vmbus_connection.channel_mutex); tot_written = snprintf(buf, buf_size, "%u:%u\n", channel->offermsg.child_relid, channel->target_cpu); list_for_each(cur, &channel->sc_list) { if (tot_written >= buf_size - 1) break; cur_sc = list_entry(cur, struct vmbus_channel, sc_list); n_written = scnprintf(buf + tot_written, buf_size - tot_written, "%u:%u\n", cur_sc->offermsg.child_relid, cur_sc->target_cpu); tot_written += n_written; } mutex_unlock(&vmbus_connection.channel_mutex); return tot_written; } static DEVICE_ATTR_RO(channel_vp_mapping); static ssize_t vendor_show(struct device *dev, struct device_attribute *dev_attr, char *buf) { struct hv_device *hv_dev = device_to_hv_device(dev); return sprintf(buf, "0x%x\n", hv_dev->vendor_id); } static DEVICE_ATTR_RO(vendor); static ssize_t device_show(struct device *dev, struct device_attribute *dev_attr, char *buf) { struct hv_device *hv_dev = device_to_hv_device(dev); return sprintf(buf, "0x%x\n", hv_dev->device_id); } static DEVICE_ATTR_RO(device); static ssize_t driver_override_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { struct hv_device *hv_dev = device_to_hv_device(dev); char *driver_override, *old, *cp; /* We need to keep extra room for a newline */ if (count >= (PAGE_SIZE - 1)) return -EINVAL; driver_override = kstrndup(buf, count, GFP_KERNEL); if (!driver_override) return -ENOMEM; cp = strchr(driver_override, '\n'); if (cp) *cp = '\0'; device_lock(dev); old = hv_dev->driver_override; if (strlen(driver_override)) { hv_dev->driver_override = driver_override; } else { kfree(driver_override); hv_dev->driver_override = NULL; } device_unlock(dev); kfree(old); return count; } static ssize_t driver_override_show(struct device *dev, struct device_attribute *attr, char *buf) { struct hv_device *hv_dev = device_to_hv_device(dev); ssize_t len; device_lock(dev); len = snprintf(buf, PAGE_SIZE, "%s\n", hv_dev->driver_override); device_unlock(dev); return len; } static DEVICE_ATTR_RW(driver_override); /* Set up per device attributes in /sys/bus/vmbus/devices/<bus device> */ static struct attribute *vmbus_dev_attrs[] = { &dev_attr_id.attr, &dev_attr_state.attr, &dev_attr_monitor_id.attr, &dev_attr_class_id.attr, &dev_attr_device_id.attr, &dev_attr_modalias.attr, #ifdef CONFIG_NUMA &dev_attr_numa_node.attr, #endif &dev_attr_server_monitor_pending.attr, &dev_attr_client_monitor_pending.attr, &dev_attr_server_monitor_latency.attr, &dev_attr_client_monitor_latency.attr, &dev_attr_server_monitor_conn_id.attr, &dev_attr_client_monitor_conn_id.attr, &dev_attr_out_intr_mask.attr, &dev_attr_out_read_index.attr, &dev_attr_out_write_index.attr, &dev_attr_out_read_bytes_avail.attr, &dev_attr_out_write_bytes_avail.attr, &dev_attr_in_intr_mask.attr, &dev_attr_in_read_index.attr, &dev_attr_in_write_index.attr, &dev_attr_in_read_bytes_avail.attr, &dev_attr_in_write_bytes_avail.attr, &dev_attr_channel_vp_mapping.attr, &dev_attr_vendor.attr, &dev_attr_device.attr, &dev_attr_driver_override.attr, NULL, }; /* * Device-level attribute_group callback function. Returns the permission for * each attribute, and returns 0 if an attribute is not visible. */ static umode_t vmbus_dev_attr_is_visible(struct kobject *kobj, struct attribute *attr, int idx) { struct device *dev = kobj_to_dev(kobj); const struct hv_device *hv_dev = device_to_hv_device(dev); /* Hide the monitor attributes if the monitor mechanism is not used. */ if (!hv_dev->channel->offermsg.monitor_allocated && (attr == &dev_attr_monitor_id.attr || attr == &dev_attr_server_monitor_pending.attr || attr == &dev_attr_client_monitor_pending.attr || attr == &dev_attr_server_monitor_latency.attr || attr == &dev_attr_client_monitor_latency.attr || attr == &dev_attr_server_monitor_conn_id.attr || attr == &dev_attr_client_monitor_conn_id.attr)) return 0; return attr->mode; } static const struct attribute_group vmbus_dev_group = { .attrs = vmbus_dev_attrs, .is_visible = vmbus_dev_attr_is_visible }; __ATTRIBUTE_GROUPS(vmbus_dev); /* Set up the attribute for /sys/bus/vmbus/hibernation */ static ssize_t hibernation_show(struct bus_type *bus, char *buf) { return sprintf(buf, "%d\n", !!hv_is_hibernation_supported()); } static BUS_ATTR_RO(hibernation); static struct attribute *vmbus_bus_attrs[] = { &bus_attr_hibernation.attr, NULL, }; static const struct attribute_group vmbus_bus_group = { .attrs = vmbus_bus_attrs, }; __ATTRIBUTE_GROUPS(vmbus_bus); /* * vmbus_uevent - add uevent for our device * * This routine is invoked when a device is added or removed on the vmbus to * generate a uevent to udev in the userspace. The udev will then look at its * rule and the uevent generated here to load the appropriate driver * * The alias string will be of the form vmbus:guid where guid is the string * representation of the device guid (each byte of the guid will be * represented with two hex characters. */ static int vmbus_uevent(struct device *device, struct kobj_uevent_env *env) { struct hv_device *dev = device_to_hv_device(device); const char *format = "MODALIAS=vmbus:%*phN"; return add_uevent_var(env, format, UUID_SIZE, &dev->dev_type); } static const struct hv_vmbus_device_id * hv_vmbus_dev_match(const struct hv_vmbus_device_id *id, const guid_t *guid) { if (id == NULL) return NULL; /* empty device table */ for (; !guid_is_null(&id->guid); id++) if (guid_equal(&id->guid, guid)) return id; return NULL; } static const struct hv_vmbus_device_id * hv_vmbus_dynid_match(struct hv_driver *drv, const guid_t *guid) { const struct hv_vmbus_device_id *id = NULL; struct vmbus_dynid *dynid; spin_lock(&drv->dynids.lock); list_for_each_entry(dynid, &drv->dynids.list, node) { if (guid_equal(&dynid->id.guid, guid)) { id = &dynid->id; break; } } spin_unlock(&drv->dynids.lock); return id; } static const struct hv_vmbus_device_id vmbus_device_null; /* * Return a matching hv_vmbus_device_id pointer. * If there is no match, return NULL. */ static const struct hv_vmbus_device_id *hv_vmbus_get_id(struct hv_driver *drv, struct hv_device *dev) { const guid_t *guid = &dev->dev_type; const struct hv_vmbus_device_id *id; /* When driver_override is set, only bind to the matching driver */ if (dev->driver_override && strcmp(dev->driver_override, drv->name)) return NULL; /* Look at the dynamic ids first, before the static ones */ id = hv_vmbus_dynid_match(drv, guid); if (!id) id = hv_vmbus_dev_match(drv->id_table, guid); /* driver_override will always match, send a dummy id */ if (!id && dev->driver_override) id = &vmbus_device_null; return id; } /* vmbus_add_dynid - add a new device ID to this driver and re-probe devices */ static int vmbus_add_dynid(struct hv_driver *drv, guid_t *guid) { struct vmbus_dynid *dynid; dynid = kzalloc(sizeof(*dynid), GFP_KERNEL); if (!dynid) return -ENOMEM; dynid->id.guid = *guid; spin_lock(&drv->dynids.lock); list_add_tail(&dynid->node, &drv->dynids.list); spin_unlock(&drv->dynids.lock); return driver_attach(&drv->driver); } static void vmbus_free_dynids(struct hv_driver *drv) { struct vmbus_dynid *dynid, *n; spin_lock(&drv->dynids.lock); list_for_each_entry_safe(dynid, n, &drv->dynids.list, node) { list_del(&dynid->node); kfree(dynid); } spin_unlock(&drv->dynids.lock); } /* * store_new_id - sysfs frontend to vmbus_add_dynid() * * Allow GUIDs to be added to an existing driver via sysfs. */ static ssize_t new_id_store(struct device_driver *driver, const char *buf, size_t count) { struct hv_driver *drv = drv_to_hv_drv(driver); guid_t guid; ssize_t retval; retval = guid_parse(buf, &guid); if (retval) return retval; if (hv_vmbus_dynid_match(drv, &guid)) return -EEXIST; retval = vmbus_add_dynid(drv, &guid); if (retval) return retval; return count; } static DRIVER_ATTR_WO(new_id); /* * store_remove_id - remove a PCI device ID from this driver * * Removes a dynamic pci device ID to this driver. */ static ssize_t remove_id_store(struct device_driver *driver, const char *buf, size_t count) { struct hv_driver *drv = drv_to_hv_drv(driver); struct vmbus_dynid *dynid, *n; guid_t guid; ssize_t retval; retval = guid_parse(buf, &guid); if (retval) return retval; retval = -ENODEV; spin_lock(&drv->dynids.lock); list_for_each_entry_safe(dynid, n, &drv->dynids.list, node) { struct hv_vmbus_device_id *id = &dynid->id; if (guid_equal(&id->guid, &guid)) { list_del(&dynid->node); kfree(dynid); retval = count; break; } } spin_unlock(&drv->dynids.lock); return retval; } static DRIVER_ATTR_WO(remove_id); static struct attribute *vmbus_drv_attrs[] = { &driver_attr_new_id.attr, &driver_attr_remove_id.attr, NULL, }; ATTRIBUTE_GROUPS(vmbus_drv); /* * vmbus_match - Attempt to match the specified device to the specified driver */ static int vmbus_match(struct device *device, struct device_driver *driver) { struct hv_driver *drv = drv_to_hv_drv(driver); struct hv_device *hv_dev = device_to_hv_device(device); /* The hv_sock driver handles all hv_sock offers. */ if (is_hvsock_channel(hv_dev->channel)) return drv->hvsock; if (hv_vmbus_get_id(drv, hv_dev)) return 1; return 0; } /* * vmbus_probe - Add the new vmbus's child device */ static int vmbus_probe(struct device *child_device) { int ret = 0; struct hv_driver *drv = drv_to_hv_drv(child_device->driver); struct hv_device *dev = device_to_hv_device(child_device); const struct hv_vmbus_device_id *dev_id; dev_id = hv_vmbus_get_id(drv, dev); if (drv->probe) { ret = drv->probe(dev, dev_id); if (ret != 0) pr_err("probe failed for device %s (%d)\n", dev_name(child_device), ret); } else { pr_err("probe not set for driver %s\n", dev_name(child_device)); ret = -ENODEV; } return ret; } /* * vmbus_remove - Remove a vmbus device */ static void vmbus_remove(struct device *child_device) { struct hv_driver *drv; struct hv_device *dev = device_to_hv_device(child_device); if (child_device->driver) { drv = drv_to_hv_drv(child_device->driver); if (drv->remove) drv->remove(dev); } } /* * vmbus_shutdown - Shutdown a vmbus device */ static void vmbus_shutdown(struct device *child_device) { struct hv_driver *drv; struct hv_device *dev = device_to_hv_device(child_device); /* The device may not be attached yet */ if (!child_device->driver) return; drv = drv_to_hv_drv(child_device->driver); if (drv->shutdown) drv->shutdown(dev); } #ifdef CONFIG_PM_SLEEP /* * vmbus_suspend - Suspend a vmbus device */ static int vmbus_suspend(struct device *child_device) { struct hv_driver *drv; struct hv_device *dev = device_to_hv_device(child_device); /* The device may not be attached yet */ if (!child_device->driver) return 0; drv = drv_to_hv_drv(child_device->driver); if (!drv->suspend) return -EOPNOTSUPP; return drv->suspend(dev); } /* * vmbus_resume - Resume a vmbus device */ static int vmbus_resume(struct device *child_device) { struct hv_driver *drv; struct hv_device *dev = device_to_hv_device(child_device); /* The device may not be attached yet */ if (!child_device->driver) return 0; drv = drv_to_hv_drv(child_device->driver); if (!drv->resume) return -EOPNOTSUPP; return drv->resume(dev); } #else #define vmbus_suspend NULL #define vmbus_resume NULL #endif /* CONFIG_PM_SLEEP */ /* * vmbus_device_release - Final callback release of the vmbus child device */ static void vmbus_device_release(struct device *device) { struct hv_device *hv_dev = device_to_hv_device(device); struct vmbus_channel *channel = hv_dev->channel; hv_debug_rm_dev_dir(hv_dev); mutex_lock(&vmbus_connection.channel_mutex); hv_process_channel_removal(channel); mutex_unlock(&vmbus_connection.channel_mutex); kfree(hv_dev); } /* * Note: we must use the "noirq" ops: see the comment before vmbus_bus_pm. * * suspend_noirq/resume_noirq are set to NULL to support Suspend-to-Idle: we * shouldn't suspend the vmbus devices upon Suspend-to-Idle, otherwise there * is no way to wake up a Generation-2 VM. * * The other 4 ops are for hibernation. */ static const struct dev_pm_ops vmbus_pm = { .suspend_noirq = NULL, .resume_noirq = NULL, .freeze_noirq = vmbus_suspend, .thaw_noirq = vmbus_resume, .poweroff_noirq = vmbus_suspend, .restore_noirq = vmbus_resume, }; /* The one and only one */ static struct bus_type hv_bus = { .name = "vmbus", .match = vmbus_match, .shutdown = vmbus_shutdown, .remove = vmbus_remove, .probe = vmbus_probe, .uevent = vmbus_uevent, .dev_groups = vmbus_dev_groups, .drv_groups = vmbus_drv_groups, .bus_groups = vmbus_bus_groups, .pm = &vmbus_pm, }; struct onmessage_work_context { struct work_struct work; struct { struct hv_message_header header; u8 payload[]; } msg; }; static void vmbus_onmessage_work(struct work_struct *work) { struct onmessage_work_context *ctx; /* Do not process messages if we're in DISCONNECTED state */ if (vmbus_connection.conn_state == DISCONNECTED) return; ctx = container_of(work, struct onmessage_work_context, work); vmbus_onmessage((struct vmbus_channel_message_header *) &ctx->msg.payload); kfree(ctx); } void vmbus_on_msg_dpc(unsigned long data) { struct hv_per_cpu_context *hv_cpu = (void *)data; void *page_addr = hv_cpu->synic_message_page; struct hv_message msg_copy, *msg = (struct hv_message *)page_addr + VMBUS_MESSAGE_SINT; struct vmbus_channel_message_header *hdr; enum vmbus_channel_message_type msgtype; const struct vmbus_channel_message_table_entry *entry; struct onmessage_work_context *ctx; __u8 payload_size; u32 message_type; /* * 'enum vmbus_channel_message_type' is supposed to always be 'u32' as * it is being used in 'struct vmbus_channel_message_header' definition * which is supposed to match hypervisor ABI. */ BUILD_BUG_ON(sizeof(enum vmbus_channel_message_type) != sizeof(u32)); /* * Since the message is in memory shared with the host, an erroneous or * malicious Hyper-V could modify the message while vmbus_on_msg_dpc() * or individual message handlers are executing; to prevent this, copy * the message into private memory. */ memcpy(&msg_copy, msg, sizeof(struct hv_message)); message_type = msg_copy.header.message_type; if (message_type == HVMSG_NONE) /* no msg */ return; hdr = (struct vmbus_channel_message_header *)msg_copy.u.payload; msgtype = hdr->msgtype; trace_vmbus_on_msg_dpc(hdr); if (msgtype >= CHANNELMSG_COUNT) { WARN_ONCE(1, "unknown msgtype=%d\n", msgtype); goto msg_handled; } payload_size = msg_copy.header.payload_size; if (payload_size > HV_MESSAGE_PAYLOAD_BYTE_COUNT) { WARN_ONCE(1, "payload size is too large (%d)\n", payload_size); goto msg_handled; } entry = &channel_message_table[msgtype]; if (!entry->message_handler) goto msg_handled; if (payload_size < entry->min_payload_len) { WARN_ONCE(1, "message too short: msgtype=%d len=%d\n", msgtype, payload_size); goto msg_handled; } if (entry->handler_type == VMHT_BLOCKING) { ctx = kmalloc(sizeof(*ctx) + payload_size, GFP_ATOMIC); if (ctx == NULL) return; INIT_WORK(&ctx->work, vmbus_onmessage_work); memcpy(&ctx->msg, &msg_copy, sizeof(msg->header) + payload_size); /* * The host can generate a rescind message while we * may still be handling the original offer. We deal with * this condition by relying on the synchronization provided * by offer_in_progress and by channel_mutex. See also the * inline comments in vmbus_onoffer_rescind(). */ switch (msgtype) { case CHANNELMSG_RESCIND_CHANNELOFFER: /* * If we are handling the rescind message; * schedule the work on the global work queue. * * The OFFER message and the RESCIND message should * not be handled by the same serialized work queue, * because the OFFER handler may call vmbus_open(), * which tries to open the channel by sending an * OPEN_CHANNEL message to the host and waits for * the host's response; however, if the host has * rescinded the channel before it receives the * OPEN_CHANNEL message, the host just silently * ignores the OPEN_CHANNEL message; as a result, * the guest's OFFER handler hangs for ever, if we * handle the RESCIND message in the same serialized * work queue: the RESCIND handler can not start to * run before the OFFER handler finishes. */ schedule_work(&ctx->work); break; case CHANNELMSG_OFFERCHANNEL: /* * The host sends the offer message of a given channel * before sending the rescind message of the same * channel. These messages are sent to the guest's * connect CPU; the guest then starts processing them * in the tasklet handler on this CPU: * * VMBUS_CONNECT_CPU * * [vmbus_on_msg_dpc()] * atomic_inc() // CHANNELMSG_OFFERCHANNEL * queue_work() * ... * [vmbus_on_msg_dpc()] * schedule_work() // CHANNELMSG_RESCIND_CHANNELOFFER * * We rely on the memory-ordering properties of the * queue_work() and schedule_work() primitives, which * guarantee that the atomic increment will be visible * to the CPUs which will execute the offer & rescind * works by the time these works will start execution. */ atomic_inc(&vmbus_connection.offer_in_progress); fallthrough; default: queue_work(vmbus_connection.work_queue, &ctx->work); } } else entry->message_handler(hdr); msg_handled: vmbus_signal_eom(msg, message_type); } #ifdef CONFIG_PM_SLEEP /* * Fake RESCIND_CHANNEL messages to clean up hv_sock channels by force for * hibernation, because hv_sock connections can not persist across hibernation. */ static void vmbus_force_channel_rescinded(struct vmbus_channel *channel) { struct onmessage_work_context *ctx; struct vmbus_channel_rescind_offer *rescind; WARN_ON(!is_hvsock_channel(channel)); /* * Allocation size is small and the allocation should really not fail, * otherwise the state of the hv_sock connections ends up in limbo. */ ctx = kzalloc(sizeof(*ctx) + sizeof(*rescind), GFP_KERNEL | __GFP_NOFAIL); /* * So far, these are not really used by Linux. Just set them to the * reasonable values conforming to the definitions of the fields. */ ctx->msg.header.message_type = 1; ctx->msg.header.payload_size = sizeof(*rescind); /* These values are actually used by Linux. */ rescind = (struct vmbus_channel_rescind_offer *)ctx->msg.payload; rescind->header.msgtype = CHANNELMSG_RESCIND_CHANNELOFFER; rescind->child_relid = channel->offermsg.child_relid; INIT_WORK(&ctx->work, vmbus_onmessage_work); queue_work(vmbus_connection.work_queue, &ctx->work); } #endif /* CONFIG_PM_SLEEP */ /* * Schedule all channels with events pending */ static void vmbus_chan_sched(struct hv_per_cpu_context *hv_cpu) { unsigned long *recv_int_page; u32 maxbits, relid; if (vmbus_proto_version < VERSION_WIN8) { maxbits = MAX_NUM_CHANNELS_SUPPORTED; recv_int_page = vmbus_connection.recv_int_page; } else { /* * When the host is win8 and beyond, the event page * can be directly checked to get the id of the channel * that has the interrupt pending. */ void *page_addr = hv_cpu->synic_event_page; union hv_synic_event_flags *event = (union hv_synic_event_flags *)page_addr + VMBUS_MESSAGE_SINT; maxbits = HV_EVENT_FLAGS_COUNT; recv_int_page = event->flags; } if (unlikely(!recv_int_page)) return; for_each_set_bit(relid, recv_int_page, maxbits) { void (*callback_fn)(void *context); struct vmbus_channel *channel; if (!sync_test_and_clear_bit(relid, recv_int_page)) continue; /* Special case - vmbus channel protocol msg */ if (relid == 0) continue; /* * Pairs with the kfree_rcu() in vmbus_chan_release(). * Guarantees that the channel data structure doesn't * get freed while the channel pointer below is being * dereferenced. */ rcu_read_lock(); /* Find channel based on relid */ channel = relid2channel(relid); if (channel == NULL) goto sched_unlock_rcu; if (channel->rescind) goto sched_unlock_rcu; /* * Make sure that the ring buffer data structure doesn't get * freed while we dereference the ring buffer pointer. Test * for the channel's onchannel_callback being NULL within a * sched_lock critical section. See also the inline comments * in vmbus_reset_channel_cb(). */ spin_lock(&channel->sched_lock); callback_fn = channel->onchannel_callback; if (unlikely(callback_fn == NULL)) goto sched_unlock; trace_vmbus_chan_sched(channel); ++channel->interrupts; switch (channel->callback_mode) { case HV_CALL_ISR: (*callback_fn)(channel->channel_callback_context); break; case HV_CALL_BATCHED: hv_begin_read(&channel->inbound); fallthrough; case HV_CALL_DIRECT: tasklet_schedule(&channel->callback_event); } sched_unlock: spin_unlock(&channel->sched_lock); sched_unlock_rcu: rcu_read_unlock(); } } static void vmbus_isr(void) { struct hv_per_cpu_context *hv_cpu = this_cpu_ptr(hv_context.cpu_context); void *page_addr = hv_cpu->synic_event_page; struct hv_message *msg; union hv_synic_event_flags *event; bool handled = false; if (unlikely(page_addr == NULL)) return; event = (union hv_synic_event_flags *)page_addr + VMBUS_MESSAGE_SINT; /* * Check for events before checking for messages. This is the order * in which events and messages are checked in Windows guests on * Hyper-V, and the Windows team suggested we do the same. */ if ((vmbus_proto_version == VERSION_WS2008) || (vmbus_proto_version == VERSION_WIN7)) { /* Since we are a child, we only need to check bit 0 */ if (sync_test_and_clear_bit(0, event->flags)) handled = true; } else { /* * Our host is win8 or above. The signaling mechanism * has changed and we can directly look at the event page. * If bit n is set then we have an interrup on the channel * whose id is n. */ handled = true; } if (handled) vmbus_chan_sched(hv_cpu); page_addr = hv_cpu->synic_message_page; msg = (struct hv_message *)page_addr + VMBUS_MESSAGE_SINT; /* Check if there are actual msgs to be processed */ if (msg->header.message_type != HVMSG_NONE) { if (msg->header.message_type == HVMSG_TIMER_EXPIRED) { hv_stimer0_isr(); vmbus_signal_eom(msg, HVMSG_TIMER_EXPIRED); } else tasklet_schedule(&hv_cpu->msg_dpc); } add_interrupt_randomness(vmbus_interrupt, 0); } static irqreturn_t vmbus_percpu_isr(int irq, void *dev_id) { vmbus_isr(); return IRQ_HANDLED; } /* * Callback from kmsg_dump. Grab as much as possible from the end of the kmsg * buffer and call into Hyper-V to transfer the data. */ static void hv_kmsg_dump(struct kmsg_dumper *dumper, enum kmsg_dump_reason reason) { struct kmsg_dump_iter iter; size_t bytes_written; /* We are only interested in panics. */ if ((reason != KMSG_DUMP_PANIC) || (!sysctl_record_panic_msg)) return; /* * Write dump contents to the page. No need to synchronize; panic should * be single-threaded. */ kmsg_dump_rewind(&iter); kmsg_dump_get_buffer(&iter, false, hv_panic_page, HV_HYP_PAGE_SIZE, &bytes_written); if (!bytes_written) return; /* * P3 to contain the physical address of the panic page & P4 to * contain the size of the panic data in that page. Rest of the * registers are no-op when the NOTIFY_MSG flag is set. */ hv_set_register(HV_REGISTER_CRASH_P0, 0); hv_set_register(HV_REGISTER_CRASH_P1, 0); hv_set_register(HV_REGISTER_CRASH_P2, 0); hv_set_register(HV_REGISTER_CRASH_P3, virt_to_phys(hv_panic_page)); hv_set_register(HV_REGISTER_CRASH_P4, bytes_written); /* * Let Hyper-V know there is crash data available along with * the panic message. */ hv_set_register(HV_REGISTER_CRASH_CTL, (HV_CRASH_CTL_CRASH_NOTIFY | HV_CRASH_CTL_CRASH_NOTIFY_MSG)); } static struct kmsg_dumper hv_kmsg_dumper = { .dump = hv_kmsg_dump, }; static void hv_kmsg_dump_register(void) { int ret; hv_panic_page = hv_alloc_hyperv_zeroed_page(); if (!hv_panic_page) { pr_err("Hyper-V: panic message page memory allocation failed\n"); return; } ret = kmsg_dump_register(&hv_kmsg_dumper); if (ret) { pr_err("Hyper-V: kmsg dump register error 0x%x\n", ret); hv_free_hyperv_page((unsigned long)hv_panic_page); hv_panic_page = NULL; } } static struct ctl_table_header *hv_ctl_table_hdr; /* * sysctl option to allow the user to control whether kmsg data should be * reported to Hyper-V on panic. */ static struct ctl_table hv_ctl_table[] = { { .procname = "hyperv_record_panic_msg", .data = &sysctl_record_panic_msg, .maxlen = sizeof(int), .mode = 0644, .proc_handler = proc_dointvec_minmax, .extra1 = SYSCTL_ZERO, .extra2 = SYSCTL_ONE }, {} }; static struct ctl_table hv_root_table[] = { { .procname = "kernel", .mode = 0555, .child = hv_ctl_table }, {} }; /* * vmbus_bus_init -Main vmbus driver initialization routine. * * Here, we * - initialize the vmbus driver context * - invoke the vmbus hv main init routine * - retrieve the channel offers */ static int vmbus_bus_init(void) { int ret; ret = hv_init(); if (ret != 0) { pr_err("Unable to initialize the hypervisor - 0x%x\n", ret); return ret; } ret = bus_register(&hv_bus); if (ret) return ret; /* * VMbus interrupts are best modeled as per-cpu interrupts. If * on an architecture with support for per-cpu IRQs (e.g. ARM64), * allocate a per-cpu IRQ using standard Linux kernel functionality. * If not on such an architecture (e.g., x86/x64), then rely on * code in the arch-specific portion of the code tree to connect * the VMbus interrupt handler. */ if (vmbus_irq == -1) { hv_setup_vmbus_handler(vmbus_isr); } else { vmbus_evt = alloc_percpu(long); ret = request_percpu_irq(vmbus_irq, vmbus_percpu_isr, "Hyper-V VMbus", vmbus_evt); if (ret) { pr_err("Can't request Hyper-V VMbus IRQ %d, Err %d", vmbus_irq, ret); free_percpu(vmbus_evt); goto err_setup; } } ret = hv_synic_alloc(); if (ret) goto err_alloc; /* * Initialize the per-cpu interrupt state and stimer state. * Then connect to the host. */ ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "hyperv/vmbus:online", hv_synic_init, hv_synic_cleanup); if (ret < 0) goto err_cpuhp; hyperv_cpuhp_online = ret; ret = vmbus_connect(); if (ret) goto err_connect; /* * Only register if the crash MSRs are available */ if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE) { u64 hyperv_crash_ctl; /* * Sysctl registration is not fatal, since by default * reporting is enabled. */ hv_ctl_table_hdr = register_sysctl_table(hv_root_table); if (!hv_ctl_table_hdr) pr_err("Hyper-V: sysctl table register error"); /* * Register for panic kmsg callback only if the right * capability is supported by the hypervisor. */ hyperv_crash_ctl = hv_get_register(HV_REGISTER_CRASH_CTL); if (hyperv_crash_ctl & HV_CRASH_CTL_CRASH_NOTIFY_MSG) hv_kmsg_dump_register(); register_die_notifier(&hyperv_die_block); } /* * Always register the panic notifier because we need to unload * the VMbus channel connection to prevent any VMbus * activity after the VM panics. */ atomic_notifier_chain_register(&panic_notifier_list, &hyperv_panic_block); vmbus_request_offers(); return 0; err_connect: cpuhp_remove_state(hyperv_cpuhp_online); err_cpuhp: hv_synic_free(); err_alloc: if (vmbus_irq == -1) { hv_remove_vmbus_handler(); } else { free_percpu_irq(vmbus_irq, vmbus_evt); free_percpu(vmbus_evt); } err_setup: bus_unregister(&hv_bus); unregister_sysctl_table(hv_ctl_table_hdr); hv_ctl_table_hdr = NULL; return ret; } /** * __vmbus_child_driver_register() - Register a vmbus's driver * @hv_driver: Pointer to driver structure you want to register * @owner: owner module of the drv * @mod_name: module name string * * Registers the given driver with Linux through the 'driver_register()' call * and sets up the hyper-v vmbus handling for this driver. * It will return the state of the 'driver_register()' call. * */ int __vmbus_driver_register(struct hv_driver *hv_driver, struct module *owner, const char *mod_name) { int ret; pr_info("registering driver %s\n", hv_driver->name); ret = vmbus_exists(); if (ret < 0) return ret; hv_driver->driver.name = hv_driver->name; hv_driver->driver.owner = owner; hv_driver->driver.mod_name = mod_name; hv_driver->driver.bus = &hv_bus; spin_lock_init(&hv_driver->dynids.lock); INIT_LIST_HEAD(&hv_driver->dynids.list); ret = driver_register(&hv_driver->driver); return ret; } EXPORT_SYMBOL_GPL(__vmbus_driver_register); /** * vmbus_driver_unregister() - Unregister a vmbus's driver * @hv_driver: Pointer to driver structure you want to * un-register * * Un-register the given driver that was previous registered with a call to * vmbus_driver_register() */ void vmbus_driver_unregister(struct hv_driver *hv_driver) { pr_info("unregistering driver %s\n", hv_driver->name); if (!vmbus_exists()) { driver_unregister(&hv_driver->driver); vmbus_free_dynids(hv_driver); } } EXPORT_SYMBOL_GPL(vmbus_driver_unregister); /* * Called when last reference to channel is gone. */ static void vmbus_chan_release(struct kobject *kobj) { struct vmbus_channel *channel = container_of(kobj, struct vmbus_channel, kobj); kfree_rcu(channel, rcu); } struct vmbus_chan_attribute { struct attribute attr; ssize_t (*show)(struct vmbus_channel *chan, char *buf); ssize_t (*store)(struct vmbus_channel *chan, const char *buf, size_t count); }; #define VMBUS_CHAN_ATTR(_name, _mode, _show, _store) \ struct vmbus_chan_attribute chan_attr_##_name \ = __ATTR(_name, _mode, _show, _store) #define VMBUS_CHAN_ATTR_RW(_name) \ struct vmbus_chan_attribute chan_attr_##_name = __ATTR_RW(_name) #define VMBUS_CHAN_ATTR_RO(_name) \ struct vmbus_chan_attribute chan_attr_##_name = __ATTR_RO(_name) #define VMBUS_CHAN_ATTR_WO(_name) \ struct vmbus_chan_attribute chan_attr_##_name = __ATTR_WO(_name) static ssize_t vmbus_chan_attr_show(struct kobject *kobj, struct attribute *attr, char *buf) { const struct vmbus_chan_attribute *attribute = container_of(attr, struct vmbus_chan_attribute, attr); struct vmbus_channel *chan = container_of(kobj, struct vmbus_channel, kobj); if (!attribute->show) return -EIO; return attribute->show(chan, buf); } static ssize_t vmbus_chan_attr_store(struct kobject *kobj, struct attribute *attr, const char *buf, size_t count) { const struct vmbus_chan_attribute *attribute = container_of(attr, struct vmbus_chan_attribute, attr); struct vmbus_channel *chan = container_of(kobj, struct vmbus_channel, kobj); if (!attribute->store) return -EIO; return attribute->store(chan, buf, count); } static const struct sysfs_ops vmbus_chan_sysfs_ops = { .show = vmbus_chan_attr_show, .store = vmbus_chan_attr_store, }; static ssize_t out_mask_show(struct vmbus_channel *channel, char *buf) { struct hv_ring_buffer_info *rbi = &channel->outbound; ssize_t ret; mutex_lock(&rbi->ring_buffer_mutex); if (!rbi->ring_buffer) { mutex_unlock(&rbi->ring_buffer_mutex); return -EINVAL; } ret = sprintf(buf, "%u\n", rbi->ring_buffer->interrupt_mask); mutex_unlock(&rbi->ring_buffer_mutex); return ret; } static VMBUS_CHAN_ATTR_RO(out_mask); static ssize_t in_mask_show(struct vmbus_channel *channel, char *buf) { struct hv_ring_buffer_info *rbi = &channel->inbound; ssize_t ret; mutex_lock(&rbi->ring_buffer_mutex); if (!rbi->ring_buffer) { mutex_unlock(&rbi->ring_buffer_mutex); return -EINVAL; } ret = sprintf(buf, "%u\n", rbi->ring_buffer->interrupt_mask); mutex_unlock(&rbi->ring_buffer_mutex); return ret; } static VMBUS_CHAN_ATTR_RO(in_mask); static ssize_t read_avail_show(struct vmbus_channel *channel, char *buf) { struct hv_ring_buffer_info *rbi = &channel->inbound; ssize_t ret; mutex_lock(&rbi->ring_buffer_mutex); if (!rbi->ring_buffer) { mutex_unlock(&rbi->ring_buffer_mutex); return -EINVAL; } ret = sprintf(buf, "%u\n", hv_get_bytes_to_read(rbi)); mutex_unlock(&rbi->ring_buffer_mutex); return ret; } static VMBUS_CHAN_ATTR_RO(read_avail); static ssize_t write_avail_show(struct vmbus_channel *channel, char *buf) { struct hv_ring_buffer_info *rbi = &channel->outbound; ssize_t ret; mutex_lock(&rbi->ring_buffer_mutex); if (!rbi->ring_buffer) { mutex_unlock(&rbi->ring_buffer_mutex); return -EINVAL; } ret = sprintf(buf, "%u\n", hv_get_bytes_to_write(rbi)); mutex_unlock(&rbi->ring_buffer_mutex); return ret; } static VMBUS_CHAN_ATTR_RO(write_avail); static ssize_t target_cpu_show(struct vmbus_channel *channel, char *buf) { return sprintf(buf, "%u\n", channel->target_cpu); } static ssize_t target_cpu_store(struct vmbus_channel *channel, const char *buf, size_t count) { u32 target_cpu, origin_cpu; ssize_t ret = count; if (vmbus_proto_version < VERSION_WIN10_V4_1) return -EIO; if (sscanf(buf, "%uu", &target_cpu) != 1) return -EIO; /* Validate target_cpu for the cpumask_test_cpu() operation below. */ if (target_cpu >= nr_cpumask_bits) return -EINVAL; /* No CPUs should come up or down during this. */ cpus_read_lock(); if (!cpu_online(target_cpu)) { cpus_read_unlock(); return -EINVAL; } /* * Synchronizes target_cpu_store() and channel closure: * * { Initially: state = CHANNEL_OPENED } * * CPU1 CPU2 * * [target_cpu_store()] [vmbus_disconnect_ring()] * * LOCK channel_mutex LOCK channel_mutex * LOAD r1 = state LOAD r2 = state * IF (r1 == CHANNEL_OPENED) IF (r2 == CHANNEL_OPENED) * SEND MODIFYCHANNEL STORE state = CHANNEL_OPEN * [...] SEND CLOSECHANNEL * UNLOCK channel_mutex UNLOCK channel_mutex * * Forbids: r1 == r2 == CHANNEL_OPENED (i.e., CPU1's LOCK precedes * CPU2's LOCK) && CPU2's SEND precedes CPU1's SEND * * Note. The host processes the channel messages "sequentially", in * the order in which they are received on a per-partition basis. */ mutex_lock(&vmbus_connection.channel_mutex); /* * Hyper-V will ignore MODIFYCHANNEL messages for "non-open" channels; * avoid sending the message and fail here for such channels. */ if (channel->state != CHANNEL_OPENED_STATE) { ret = -EIO; goto cpu_store_unlock; } origin_cpu = channel->target_cpu; if (target_cpu == origin_cpu) goto cpu_store_unlock; if (vmbus_send_modifychannel(channel, hv_cpu_number_to_vp_number(target_cpu))) { ret = -EIO; goto cpu_store_unlock; } /* * For version before VERSION_WIN10_V5_3, the following warning holds: * * Warning. At this point, there is *no* guarantee that the host will * have successfully processed the vmbus_send_modifychannel() request. * See the header comment of vmbus_send_modifychannel() for more info. * * Lags in the processing of the above vmbus_send_modifychannel() can * result in missed interrupts if the "old" target CPU is taken offline * before Hyper-V starts sending interrupts to the "new" target CPU. * But apart from this offlining scenario, the code tolerates such * lags. It will function correctly even if a channel interrupt comes * in on a CPU that is different from the channel target_cpu value. */ channel->target_cpu = target_cpu; /* See init_vp_index(). */ if (hv_is_perf_channel(channel)) hv_update_alloced_cpus(origin_cpu, target_cpu); /* Currently set only for storvsc channels. */ if (channel->change_target_cpu_callback) { (*channel->change_target_cpu_callback)(channel, origin_cpu, target_cpu); } cpu_store_unlock: mutex_unlock(&vmbus_connection.channel_mutex); cpus_read_unlock(); return ret; } static VMBUS_CHAN_ATTR(cpu, 0644, target_cpu_show, target_cpu_store); static ssize_t channel_pending_show(struct vmbus_channel *channel, char *buf) { return sprintf(buf, "%d\n", channel_pending(channel, vmbus_connection.monitor_pages[1])); } static VMBUS_CHAN_ATTR(pending, 0444, channel_pending_show, NULL); static ssize_t channel_latency_show(struct vmbus_channel *channel, char *buf) { return sprintf(buf, "%d\n", channel_latency(channel, vmbus_connection.monitor_pages[1])); } static VMBUS_CHAN_ATTR(latency, 0444, channel_latency_show, NULL); static ssize_t channel_interrupts_show(struct vmbus_channel *channel, char *buf) { return sprintf(buf, "%llu\n", channel->interrupts); } static VMBUS_CHAN_ATTR(interrupts, 0444, channel_interrupts_show, NULL); static ssize_t channel_events_show(struct vmbus_channel *channel, char *buf) { return sprintf(buf, "%llu\n", channel->sig_events); } static VMBUS_CHAN_ATTR(events, 0444, channel_events_show, NULL); static ssize_t channel_intr_in_full_show(struct vmbus_channel *channel, char *buf) { return sprintf(buf, "%llu\n", (unsigned long long)channel->intr_in_full); } static VMBUS_CHAN_ATTR(intr_in_full, 0444, channel_intr_in_full_show, NULL); static ssize_t channel_intr_out_empty_show(struct vmbus_channel *channel, char *buf) { return sprintf(buf, "%llu\n", (unsigned long long)channel->intr_out_empty); } static VMBUS_CHAN_ATTR(intr_out_empty, 0444, channel_intr_out_empty_show, NULL); static ssize_t channel_out_full_first_show(struct vmbus_channel *channel, char *buf) { return sprintf(buf, "%llu\n", (unsigned long long)channel->out_full_first); } static VMBUS_CHAN_ATTR(out_full_first, 0444, channel_out_full_first_show, NULL); static ssize_t channel_out_full_total_show(struct vmbus_channel *channel, char *buf) { return sprintf(buf, "%llu\n", (unsigned long long)channel->out_full_total); } static VMBUS_CHAN_ATTR(out_full_total, 0444, channel_out_full_total_show, NULL); static ssize_t subchannel_monitor_id_show(struct vmbus_channel *channel, char *buf) { return sprintf(buf, "%u\n", channel->offermsg.monitorid); } static VMBUS_CHAN_ATTR(monitor_id, 0444, subchannel_monitor_id_show, NULL); static ssize_t subchannel_id_show(struct vmbus_channel *channel, char *buf) { return sprintf(buf, "%u\n", channel->offermsg.offer.sub_channel_index); } static VMBUS_CHAN_ATTR_RO(subchannel_id); static struct attribute *vmbus_chan_attrs[] = { &chan_attr_out_mask.attr, &chan_attr_in_mask.attr, &chan_attr_read_avail.attr, &chan_attr_write_avail.attr, &chan_attr_cpu.attr, &chan_attr_pending.attr, &chan_attr_latency.attr, &chan_attr_interrupts.attr, &chan_attr_events.attr, &chan_attr_intr_in_full.attr, &chan_attr_intr_out_empty.attr, &chan_attr_out_full_first.attr, &chan_attr_out_full_total.attr, &chan_attr_monitor_id.attr, &chan_attr_subchannel_id.attr, NULL }; /* * Channel-level attribute_group callback function. Returns the permission for * each attribute, and returns 0 if an attribute is not visible. */ static umode_t vmbus_chan_attr_is_visible(struct kobject *kobj, struct attribute *attr, int idx) { const struct vmbus_channel *channel = container_of(kobj, struct vmbus_channel, kobj); /* Hide the monitor attributes if the monitor mechanism is not used. */ if (!channel->offermsg.monitor_allocated && (attr == &chan_attr_pending.attr || attr == &chan_attr_latency.attr || attr == &chan_attr_monitor_id.attr)) return 0; return attr->mode; } static struct attribute_group vmbus_chan_group = { .attrs = vmbus_chan_attrs, .is_visible = vmbus_chan_attr_is_visible }; static struct kobj_type vmbus_chan_ktype = { .sysfs_ops = &vmbus_chan_sysfs_ops, .release = vmbus_chan_release, }; /* * vmbus_add_channel_kobj - setup a sub-directory under device/channels */ int vmbus_add_channel_kobj(struct hv_device *dev, struct vmbus_channel *channel) { const struct device *device = &dev->device; struct kobject *kobj = &channel->kobj; u32 relid = channel->offermsg.child_relid; int ret; kobj->kset = dev->channels_kset; ret = kobject_init_and_add(kobj, &vmbus_chan_ktype, NULL, "%u", relid); if (ret) return ret; ret = sysfs_create_group(kobj, &vmbus_chan_group); if (ret) { /* * The calling functions' error handling paths will cleanup the * empty channel directory. */ dev_err(device, "Unable to set up channel sysfs files\n"); return ret; } kobject_uevent(kobj, KOBJ_ADD); return 0; } /* * vmbus_remove_channel_attr_group - remove the channel's attribute group */ void vmbus_remove_channel_attr_group(struct vmbus_channel *channel) { sysfs_remove_group(&channel->kobj, &vmbus_chan_group); } /* * vmbus_device_create - Creates and registers a new child device * on the vmbus. */ struct hv_device *vmbus_device_create(const guid_t *type, const guid_t *instance, struct vmbus_channel *channel) { struct hv_device *child_device_obj; child_device_obj = kzalloc(sizeof(struct hv_device), GFP_KERNEL); if (!child_device_obj) { pr_err("Unable to allocate device object for child device\n"); return NULL; } child_device_obj->channel = channel; guid_copy(&child_device_obj->dev_type, type); guid_copy(&child_device_obj->dev_instance, instance); child_device_obj->vendor_id = 0x1414; /* MSFT vendor ID */ return child_device_obj; } /* * vmbus_device_register - Register the child device */ int vmbus_device_register(struct hv_device *child_device_obj) { struct kobject *kobj = &child_device_obj->device.kobj; int ret; dev_set_name(&child_device_obj->device, "%pUl", &child_device_obj->channel->offermsg.offer.if_instance); child_device_obj->device.bus = &hv_bus; child_device_obj->device.parent = &hv_acpi_dev->dev; child_device_obj->device.release = vmbus_device_release; /* * Register with the LDM. This will kick off the driver/device * binding...which will eventually call vmbus_match() and vmbus_probe() */ ret = device_register(&child_device_obj->device); if (ret) { pr_err("Unable to register child device\n"); return ret; } child_device_obj->channels_kset = kset_create_and_add("channels", NULL, kobj); if (!child_device_obj->channels_kset) { ret = -ENOMEM; goto err_dev_unregister; } ret = vmbus_add_channel_kobj(child_device_obj, child_device_obj->channel); if (ret) { pr_err("Unable to register primary channeln"); goto err_kset_unregister; } hv_debug_add_dev_dir(child_device_obj); return 0; err_kset_unregister: kset_unregister(child_device_obj->channels_kset); err_dev_unregister: device_unregister(&child_device_obj->device); return ret; } /* * vmbus_device_unregister - Remove the specified child device * from the vmbus. */ void vmbus_device_unregister(struct hv_device *device_obj) { pr_debug("child device %s unregistered\n", dev_name(&device_obj->device)); kset_unregister(device_obj->channels_kset); /* * Kick off the process of unregistering the device. * This will call vmbus_remove() and eventually vmbus_device_release() */ device_unregister(&device_obj->device); } /* * VMBUS is an acpi enumerated device. Get the information we * need from DSDT. */ #define VTPM_BASE_ADDRESS 0xfed40000 static acpi_status vmbus_walk_resources(struct acpi_resource *res, void *ctx) { resource_size_t start = 0; resource_size_t end = 0; struct resource *new_res; struct resource **old_res = &hyperv_mmio; struct resource **prev_res = NULL; struct resource r; switch (res->type) { /* * "Address" descriptors are for bus windows. Ignore * "memory" descriptors, which are for registers on * devices. */ case ACPI_RESOURCE_TYPE_ADDRESS32: start = res->data.address32.address.minimum; end = res->data.address32.address.maximum; break; case ACPI_RESOURCE_TYPE_ADDRESS64: start = res->data.address64.address.minimum; end = res->data.address64.address.maximum; break; /* * The IRQ information is needed only on ARM64, which Hyper-V * sets up in the extended format. IRQ information is present * on x86/x64 in the non-extended format but it is not used by * Linux. So don't bother checking for the non-extended format. */ case ACPI_RESOURCE_TYPE_EXTENDED_IRQ: if (!acpi_dev_resource_interrupt(res, 0, &r)) { pr_err("Unable to parse Hyper-V ACPI interrupt\n"); return AE_ERROR; } /* ARM64 INTID for VMbus */ vmbus_interrupt = res->data.extended_irq.interrupts[0]; /* Linux IRQ number */ vmbus_irq = r.start; return AE_OK; default: /* Unused resource type */ return AE_OK; } /* * Ignore ranges that are below 1MB, as they're not * necessary or useful here. */ if (end < 0x100000) return AE_OK; new_res = kzalloc(sizeof(*new_res), GFP_ATOMIC); if (!new_res) return AE_NO_MEMORY; /* If this range overlaps the virtual TPM, truncate it. */ if (end > VTPM_BASE_ADDRESS && start < VTPM_BASE_ADDRESS) end = VTPM_BASE_ADDRESS; new_res->name = "hyperv mmio"; new_res->flags = IORESOURCE_MEM; new_res->start = start; new_res->end = end; /* * If two ranges are adjacent, merge them. */ do { if (!*old_res) { *old_res = new_res; break; } if (((*old_res)->end + 1) == new_res->start) { (*old_res)->end = new_res->end; kfree(new_res); break; } if ((*old_res)->start == new_res->end + 1) { (*old_res)->start = new_res->start; kfree(new_res); break; } if ((*old_res)->start > new_res->end) { new_res->sibling = *old_res; if (prev_res) (*prev_res)->sibling = new_res; *old_res = new_res; break; } prev_res = old_res; old_res = &(*old_res)->sibling; } while (1); return AE_OK; } static int vmbus_acpi_remove(struct acpi_device *device) { struct resource *cur_res; struct resource *next_res; if (hyperv_mmio) { if (fb_mmio) { __release_region(hyperv_mmio, fb_mmio->start, resource_size(fb_mmio)); fb_mmio = NULL; } for (cur_res = hyperv_mmio; cur_res; cur_res = next_res) { next_res = cur_res->sibling; kfree(cur_res); } } return 0; } static void vmbus_reserve_fb(void) { int size; /* * Make a claim for the frame buffer in the resource tree under the * first node, which will be the one below 4GB. The length seems to * be underreported, particularly in a Generation 1 VM. So start out * reserving a larger area and make it smaller until it succeeds. */ if (screen_info.lfb_base) { if (efi_enabled(EFI_BOOT)) size = max_t(__u32, screen_info.lfb_size, 0x800000); else size = max_t(__u32, screen_info.lfb_size, 0x4000000); for (; !fb_mmio && (size >= 0x100000); size >>= 1) { fb_mmio = __request_region(hyperv_mmio, screen_info.lfb_base, size, fb_mmio_name, 0); } } } /** * vmbus_allocate_mmio() - Pick a memory-mapped I/O range. * @new: If successful, supplied a pointer to the * allocated MMIO space. * @device_obj: Identifies the caller * @min: Minimum guest physical address of the * allocation * @max: Maximum guest physical address * @size: Size of the range to be allocated * @align: Alignment of the range to be allocated * @fb_overlap_ok: Whether this allocation can be allowed * to overlap the video frame buffer. * * This function walks the resources granted to VMBus by the * _CRS object in the ACPI namespace underneath the parent * "bridge" whether that's a root PCI bus in the Generation 1 * case or a Module Device in the Generation 2 case. It then * attempts to allocate from the global MMIO pool in a way that * matches the constraints supplied in these parameters and by * that _CRS. * * Return: 0 on success, -errno on failure */ int vmbus_allocate_mmio(struct resource **new, struct hv_device *device_obj, resource_size_t min, resource_size_t max, resource_size_t size, resource_size_t align, bool fb_overlap_ok) { struct resource *iter, *shadow; resource_size_t range_min, range_max, start; const char *dev_n = dev_name(&device_obj->device); int retval; retval = -ENXIO; mutex_lock(&hyperv_mmio_lock); /* * If overlaps with frame buffers are allowed, then first attempt to * make the allocation from within the reserved region. Because it * is already reserved, no shadow allocation is necessary. */ if (fb_overlap_ok && fb_mmio && !(min > fb_mmio->end) && !(max < fb_mmio->start)) { range_min = fb_mmio->start; range_max = fb_mmio->end; start = (range_min + align - 1) & ~(align - 1); for (; start + size - 1 <= range_max; start += align) { *new = request_mem_region_exclusive(start, size, dev_n); if (*new) { retval = 0; goto exit; } } } for (iter = hyperv_mmio; iter; iter = iter->sibling) { if ((iter->start >= max) || (iter->end <= min)) continue; range_min = iter->start; range_max = iter->end; start = (range_min + align - 1) & ~(align - 1); for (; start + size - 1 <= range_max; start += align) { shadow = __request_region(iter, start, size, NULL, IORESOURCE_BUSY); if (!shadow) continue; *new = request_mem_region_exclusive(start, size, dev_n); if (*new) { shadow->name = (char *)*new; retval = 0; goto exit; } __release_region(iter, start, size); } } exit: mutex_unlock(&hyperv_mmio_lock); return retval; } EXPORT_SYMBOL_GPL(vmbus_allocate_mmio); /** * vmbus_free_mmio() - Free a memory-mapped I/O range. * @start: Base address of region to release. * @size: Size of the range to be allocated * * This function releases anything requested by * vmbus_mmio_allocate(). */ void vmbus_free_mmio(resource_size_t start, resource_size_t size) { struct resource *iter; mutex_lock(&hyperv_mmio_lock); for (iter = hyperv_mmio; iter; iter = iter->sibling) { if ((iter->start >= start + size) || (iter->end <= start)) continue; __release_region(iter, start, size); } release_mem_region(start, size); mutex_unlock(&hyperv_mmio_lock); } EXPORT_SYMBOL_GPL(vmbus_free_mmio); static int vmbus_acpi_add(struct acpi_device *device) { acpi_status result; int ret_val = -ENODEV; struct acpi_device *ancestor; hv_acpi_dev = device; result = acpi_walk_resources(device->handle, METHOD_NAME__CRS, vmbus_walk_resources, NULL); if (ACPI_FAILURE(result)) goto acpi_walk_err; /* * Some ancestor of the vmbus acpi device (Gen1 or Gen2 * firmware) is the VMOD that has the mmio ranges. Get that. */ for (ancestor = device->parent; ancestor; ancestor = ancestor->parent) { result = acpi_walk_resources(ancestor->handle, METHOD_NAME__CRS, vmbus_walk_resources, NULL); if (ACPI_FAILURE(result)) continue; if (hyperv_mmio) { vmbus_reserve_fb(); break; } } ret_val = 0; acpi_walk_err: complete(&probe_event); if (ret_val) vmbus_acpi_remove(device); return ret_val; } #ifdef CONFIG_PM_SLEEP static int vmbus_bus_suspend(struct device *dev) { struct vmbus_channel *channel, *sc; while (atomic_read(&vmbus_connection.offer_in_progress) != 0) { /* * We wait here until the completion of any channel * offers that are currently in progress. */ usleep_range(1000, 2000); } mutex_lock(&vmbus_connection.channel_mutex); list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) { if (!is_hvsock_channel(channel)) continue; vmbus_force_channel_rescinded(channel); } mutex_unlock(&vmbus_connection.channel_mutex); /* * Wait until all the sub-channels and hv_sock channels have been * cleaned up. Sub-channels should be destroyed upon suspend, otherwise * they would conflict with the new sub-channels that will be created * in the resume path. hv_sock channels should also be destroyed, but * a hv_sock channel of an established hv_sock connection can not be * really destroyed since it may still be referenced by the userspace * application, so we just force the hv_sock channel to be rescinded * by vmbus_force_channel_rescinded(), and the userspace application * will thoroughly destroy the channel after hibernation. * * Note: the counter nr_chan_close_on_suspend may never go above 0 if * the VM has no sub-channel and hv_sock channel, e.g. a 1-vCPU VM. */ if (atomic_read(&vmbus_connection.nr_chan_close_on_suspend) > 0) wait_for_completion(&vmbus_connection.ready_for_suspend_event); if (atomic_read(&vmbus_connection.nr_chan_fixup_on_resume) != 0) { pr_err("Can not suspend due to a previous failed resuming\n"); return -EBUSY; } mutex_lock(&vmbus_connection.channel_mutex); list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) { /* * Remove the channel from the array of channels and invalidate * the channel's relid. Upon resume, vmbus_onoffer() will fix * up the relid (and other fields, if necessary) and add the * channel back to the array. */ vmbus_channel_unmap_relid(channel); channel->offermsg.child_relid = INVALID_RELID; if (is_hvsock_channel(channel)) { if (!channel->rescind) { pr_err("hv_sock channel not rescinded!\n"); WARN_ON_ONCE(1); } continue; } list_for_each_entry(sc, &channel->sc_list, sc_list) { pr_err("Sub-channel not deleted!\n"); WARN_ON_ONCE(1); } atomic_inc(&vmbus_connection.nr_chan_fixup_on_resume); } mutex_unlock(&vmbus_connection.channel_mutex); vmbus_initiate_unload(false); /* Reset the event for the next resume. */ reinit_completion(&vmbus_connection.ready_for_resume_event); return 0; } static int vmbus_bus_resume(struct device *dev) { struct vmbus_channel_msginfo *msginfo; size_t msgsize; int ret; /* * We only use the 'vmbus_proto_version', which was in use before * hibernation, to re-negotiate with the host. */ if (!vmbus_proto_version) { pr_err("Invalid proto version = 0x%x\n", vmbus_proto_version); return -EINVAL; } msgsize = sizeof(*msginfo) + sizeof(struct vmbus_channel_initiate_contact); msginfo = kzalloc(msgsize, GFP_KERNEL); if (msginfo == NULL) return -ENOMEM; ret = vmbus_negotiate_version(msginfo, vmbus_proto_version); kfree(msginfo); if (ret != 0) return ret; WARN_ON(atomic_read(&vmbus_connection.nr_chan_fixup_on_resume) == 0); vmbus_request_offers(); if (wait_for_completion_timeout( &vmbus_connection.ready_for_resume_event, 10 * HZ) == 0) pr_err("Some vmbus device is missing after suspending?\n"); /* Reset the event for the next suspend. */ reinit_completion(&vmbus_connection.ready_for_suspend_event); return 0; } #else #define vmbus_bus_suspend NULL #define vmbus_bus_resume NULL #endif /* CONFIG_PM_SLEEP */ static const struct acpi_device_id vmbus_acpi_device_ids[] = { {"VMBUS", 0}, {"VMBus", 0}, {"", 0}, }; MODULE_DEVICE_TABLE(acpi, vmbus_acpi_device_ids); /* * Note: we must use the "no_irq" ops, otherwise hibernation can not work with * PCI device assignment, because "pci_dev_pm_ops" uses the "noirq" ops: in * the resume path, the pci "noirq" restore op runs before "non-noirq" op (see * resume_target_kernel() -> dpm_resume_start(), and hibernation_restore() -> * dpm_resume_end()). This means vmbus_bus_resume() and the pci-hyperv's * resume callback must also run via the "noirq" ops. * * Set suspend_noirq/resume_noirq to NULL for Suspend-to-Idle: see the comment * earlier in this file before vmbus_pm. */ static const struct dev_pm_ops vmbus_bus_pm = { .suspend_noirq = NULL, .resume_noirq = NULL, .freeze_noirq = vmbus_bus_suspend, .thaw_noirq = vmbus_bus_resume, .poweroff_noirq = vmbus_bus_suspend, .restore_noirq = vmbus_bus_resume }; static struct acpi_driver vmbus_acpi_driver = { .name = "vmbus", .ids = vmbus_acpi_device_ids, .ops = { .add = vmbus_acpi_add, .remove = vmbus_acpi_remove, }, .drv.pm = &vmbus_bus_pm, }; static void hv_kexec_handler(void) { hv_stimer_global_cleanup(); vmbus_initiate_unload(false); /* Make sure conn_state is set as hv_synic_cleanup checks for it */ mb(); cpuhp_remove_state(hyperv_cpuhp_online); }; static void hv_crash_handler(struct pt_regs *regs) { int cpu; vmbus_initiate_unload(true); /* * In crash handler we can't schedule synic cleanup for all CPUs, * doing the cleanup for current CPU only. This should be sufficient * for kdump. */ cpu = smp_processor_id(); hv_stimer_cleanup(cpu); hv_synic_disable_regs(cpu); }; static int hv_synic_suspend(void) { /* * When we reach here, all the non-boot CPUs have been offlined. * If we're in a legacy configuration where stimer Direct Mode is * not enabled, the stimers on the non-boot CPUs have been unbound * in hv_synic_cleanup() -> hv_stimer_legacy_cleanup() -> * hv_stimer_cleanup() -> clockevents_unbind_device(). * * hv_synic_suspend() only runs on CPU0 with interrupts disabled. * Here we do not call hv_stimer_legacy_cleanup() on CPU0 because: * 1) it's unnecessary as interrupts remain disabled between * syscore_suspend() and syscore_resume(): see create_image() and * resume_target_kernel() * 2) the stimer on CPU0 is automatically disabled later by * syscore_suspend() -> timekeeping_suspend() -> tick_suspend() -> ... * -> clockevents_shutdown() -> ... -> hv_ce_shutdown() * 3) a warning would be triggered if we call * clockevents_unbind_device(), which may sleep, in an * interrupts-disabled context. */ hv_synic_disable_regs(0); return 0; } static void hv_synic_resume(void) { hv_synic_enable_regs(0); /* * Note: we don't need to call hv_stimer_init(0), because the timer * on CPU0 is not unbound in hv_synic_suspend(), and the timer is * automatically re-enabled in timekeeping_resume(). */ } /* The callbacks run only on CPU0, with irqs_disabled. */ static struct syscore_ops hv_synic_syscore_ops = { .suspend = hv_synic_suspend, .resume = hv_synic_resume, }; static int __init hv_acpi_init(void) { int ret, t; if (!hv_is_hyperv_initialized()) return -ENODEV; if (hv_root_partition) return 0; init_completion(&probe_event); /* * Get ACPI resources first. */ ret = acpi_bus_register_driver(&vmbus_acpi_driver); if (ret) return ret; t = wait_for_completion_timeout(&probe_event, 5*HZ); if (t == 0) { ret = -ETIMEDOUT; goto cleanup; } /* * If we're on an architecture with a hardcoded hypervisor * vector (i.e. x86/x64), override the VMbus interrupt found * in the ACPI tables. Ensure vmbus_irq is not set since the * normal Linux IRQ mechanism is not used in this case. */ #ifdef HYPERVISOR_CALLBACK_VECTOR vmbus_interrupt = HYPERVISOR_CALLBACK_VECTOR; vmbus_irq = -1; #endif hv_debug_init(); ret = vmbus_bus_init(); if (ret) goto cleanup; hv_setup_kexec_handler(hv_kexec_handler); hv_setup_crash_handler(hv_crash_handler); register_syscore_ops(&hv_synic_syscore_ops); return 0; cleanup: acpi_bus_unregister_driver(&vmbus_acpi_driver); hv_acpi_dev = NULL; return ret; } static void __exit vmbus_exit(void) { int cpu; unregister_syscore_ops(&hv_synic_syscore_ops); hv_remove_kexec_handler(); hv_remove_crash_handler(); vmbus_connection.conn_state = DISCONNECTED; hv_stimer_global_cleanup(); vmbus_disconnect(); if (vmbus_irq == -1) { hv_remove_vmbus_handler(); } else { free_percpu_irq(vmbus_irq, vmbus_evt); free_percpu(vmbus_evt); } for_each_online_cpu(cpu) { struct hv_per_cpu_context *hv_cpu = per_cpu_ptr(hv_context.cpu_context, cpu); tasklet_kill(&hv_cpu->msg_dpc); } hv_debug_rm_all_dir(); vmbus_free_channels(); kfree(vmbus_connection.channels); if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE) { kmsg_dump_unregister(&hv_kmsg_dumper); unregister_die_notifier(&hyperv_die_block); atomic_notifier_chain_unregister(&panic_notifier_list, &hyperv_panic_block); } free_page((unsigned long)hv_panic_page); unregister_sysctl_table(hv_ctl_table_hdr); hv_ctl_table_hdr = NULL; bus_unregister(&hv_bus); cpuhp_remove_state(hyperv_cpuhp_online); hv_synic_free(); acpi_bus_unregister_driver(&vmbus_acpi_driver); } MODULE_LICENSE("GPL"); MODULE_DESCRIPTION("Microsoft Hyper-V VMBus Driver"); subsys_initcall(hv_acpi_init); module_exit(vmbus_exit);