Staging: hv: move hyperv code out of staging directory

After many years wandering the desert, it is finally time for the
Microsoft HyperV code to move out of the staging directory.  Or at least
the core hyperv bus code, and the utility driver, the rest still have
some review to get through by the various subsystem maintainers.

Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>

1 files changed, 772 insertions, 0 deletions

diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
new file mode 100644
index 000000000000..b0d08f980de1
--- /dev/null
+++ b/drivers/hv/vmbus_drv.c
@@ -0,0 +1,772 @@
+/*
+ * Copyright (c) 2009, Microsoft Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
+ * Place - Suite 330, Boston, MA 02111-1307 USA.
+ *
+ * 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/irq.h>
+#include <linux/interrupt.h>
+#include <linux/sysctl.h>
+#include <linux/slab.h>
+#include <linux/acpi.h>
+#include <acpi/acpi_bus.h>
+#include <linux/completion.h>
+#include <linux/hyperv.h>
+
+#include "hyperv_vmbus.h"
+
+
+static struct acpi_device  *hv_acpi_dev;
+
+static struct tasklet_struct msg_dpc;
+static struct tasklet_struct event_dpc;
+
+unsigned int vmbus_loglevel = (ALL_MODULES << 16 | INFO_LVL);
+EXPORT_SYMBOL(vmbus_loglevel);
+
+static struct completion probe_event;
+static int irq;
+
+static void get_channel_info(struct hv_device *device,
+			     struct hv_device_info *info)
+{
+	struct vmbus_channel_debug_info debug_info;
+
+	if (!device->channel)
+		return;
+
+	vmbus_get_debug_info(device->channel, &debug_info);
+
+	info->chn_id = debug_info.relid;
+	info->chn_state = debug_info.state;
+	memcpy(&info->chn_type, &debug_info.interfacetype,
+	       sizeof(uuid_le));
+	memcpy(&info->chn_instance, &debug_info.interface_instance,
+	       sizeof(uuid_le));
+
+	info->monitor_id = debug_info.monitorid;
+
+	info->server_monitor_pending = debug_info.servermonitor_pending;
+	info->server_monitor_latency = debug_info.servermonitor_latency;
+	info->server_monitor_conn_id = debug_info.servermonitor_connectionid;
+
+	info->client_monitor_pending = debug_info.clientmonitor_pending;
+	info->client_monitor_latency = debug_info.clientmonitor_latency;
+	info->client_monitor_conn_id = debug_info.clientmonitor_connectionid;
+
+	info->inbound.int_mask = debug_info.inbound.current_interrupt_mask;
+	info->inbound.read_idx = debug_info.inbound.current_read_index;
+	info->inbound.write_idx = debug_info.inbound.current_write_index;
+	info->inbound.bytes_avail_toread =
+		debug_info.inbound.bytes_avail_toread;
+	info->inbound.bytes_avail_towrite =
+		debug_info.inbound.bytes_avail_towrite;
+
+	info->outbound.int_mask =
+		debug_info.outbound.current_interrupt_mask;
+	info->outbound.read_idx = debug_info.outbound.current_read_index;
+	info->outbound.write_idx = debug_info.outbound.current_write_index;
+	info->outbound.bytes_avail_toread =
+		debug_info.outbound.bytes_avail_toread;
+	info->outbound.bytes_avail_towrite =
+		debug_info.outbound.bytes_avail_towrite;
+}
+
+#define VMBUS_ALIAS_LEN ((sizeof((struct hv_vmbus_device_id *)0)->guid) * 2)
+static void print_alias_name(struct hv_device *hv_dev, char *alias_name)
+{
+	int i;
+	for (i = 0; i < VMBUS_ALIAS_LEN; i += 2)
+		sprintf(&alias_name[i], "%02x", hv_dev->dev_type.b[i/2]);
+}
+
+/*
+ * vmbus_show_device_attr - Show the device attribute in sysfs.
+ *
+ * This is invoked when user does a
+ * "cat /sys/bus/vmbus/devices/<busdevice>/<attr name>"
+ */
+static ssize_t vmbus_show_device_attr(struct device *dev,
+				      struct device_attribute *dev_attr,
+				      char *buf)
+{
+	struct hv_device *hv_dev = device_to_hv_device(dev);
+	struct hv_device_info *device_info;
+	char alias_name[VMBUS_ALIAS_LEN + 1];
+	int ret = 0;
+
+	device_info = kzalloc(sizeof(struct hv_device_info), GFP_KERNEL);
+	if (!device_info)
+		return ret;
+
+	get_channel_info(hv_dev, device_info);
+
+	if (!strcmp(dev_attr->attr.name, "class_id")) {
+		ret = sprintf(buf, "{%02x%02x%02x%02x-%02x%02x-%02x%02x-"
+			       "%02x%02x%02x%02x%02x%02x%02x%02x}\n",
+			       device_info->chn_type.b[3],
+			       device_info->chn_type.b[2],
+			       device_info->chn_type.b[1],
+			       device_info->chn_type.b[0],
+			       device_info->chn_type.b[5],
+			       device_info->chn_type.b[4],
+			       device_info->chn_type.b[7],
+			       device_info->chn_type.b[6],
+			       device_info->chn_type.b[8],
+			       device_info->chn_type.b[9],
+			       device_info->chn_type.b[10],
+			       device_info->chn_type.b[11],
+			       device_info->chn_type.b[12],
+			       device_info->chn_type.b[13],
+			       device_info->chn_type.b[14],
+			       device_info->chn_type.b[15]);
+	} else if (!strcmp(dev_attr->attr.name, "device_id")) {
+		ret = sprintf(buf, "{%02x%02x%02x%02x-%02x%02x-%02x%02x-"
+			       "%02x%02x%02x%02x%02x%02x%02x%02x}\n",
+			       device_info->chn_instance.b[3],
+			       device_info->chn_instance.b[2],
+			       device_info->chn_instance.b[1],
+			       device_info->chn_instance.b[0],
+			       device_info->chn_instance.b[5],
+			       device_info->chn_instance.b[4],
+			       device_info->chn_instance.b[7],
+			       device_info->chn_instance.b[6],
+			       device_info->chn_instance.b[8],
+			       device_info->chn_instance.b[9],
+			       device_info->chn_instance.b[10],
+			       device_info->chn_instance.b[11],
+			       device_info->chn_instance.b[12],
+			       device_info->chn_instance.b[13],
+			       device_info->chn_instance.b[14],
+			       device_info->chn_instance.b[15]);
+	} else if (!strcmp(dev_attr->attr.name, "modalias")) {
+		print_alias_name(hv_dev, alias_name);
+		ret = sprintf(buf, "vmbus:%s\n", alias_name);
+	} else if (!strcmp(dev_attr->attr.name, "state")) {
+		ret = sprintf(buf, "%d\n", device_info->chn_state);
+	} else if (!strcmp(dev_attr->attr.name, "id")) {
+		ret = sprintf(buf, "%d\n", device_info->chn_id);
+	} else if (!strcmp(dev_attr->attr.name, "out_intr_mask")) {
+		ret = sprintf(buf, "%d\n", device_info->outbound.int_mask);
+	} else if (!strcmp(dev_attr->attr.name, "out_read_index")) {
+		ret = sprintf(buf, "%d\n", device_info->outbound.read_idx);
+	} else if (!strcmp(dev_attr->attr.name, "out_write_index")) {
+		ret = sprintf(buf, "%d\n", device_info->outbound.write_idx);
+	} else if (!strcmp(dev_attr->attr.name, "out_read_bytes_avail")) {
+		ret = sprintf(buf, "%d\n",
+			       device_info->outbound.bytes_avail_toread);
+	} else if (!strcmp(dev_attr->attr.name, "out_write_bytes_avail")) {
+		ret = sprintf(buf, "%d\n",
+			       device_info->outbound.bytes_avail_towrite);
+	} else if (!strcmp(dev_attr->attr.name, "in_intr_mask")) {
+		ret = sprintf(buf, "%d\n", device_info->inbound.int_mask);
+	} else if (!strcmp(dev_attr->attr.name, "in_read_index")) {
+		ret = sprintf(buf, "%d\n", device_info->inbound.read_idx);
+	} else if (!strcmp(dev_attr->attr.name, "in_write_index")) {
+		ret = sprintf(buf, "%d\n", device_info->inbound.write_idx);
+	} else if (!strcmp(dev_attr->attr.name, "in_read_bytes_avail")) {
+		ret = sprintf(buf, "%d\n",
+			       device_info->inbound.bytes_avail_toread);
+	} else if (!strcmp(dev_attr->attr.name, "in_write_bytes_avail")) {
+		ret = sprintf(buf, "%d\n",
+			       device_info->inbound.bytes_avail_towrite);
+	} else if (!strcmp(dev_attr->attr.name, "monitor_id")) {
+		ret = sprintf(buf, "%d\n", device_info->monitor_id);
+	} else if (!strcmp(dev_attr->attr.name, "server_monitor_pending")) {
+		ret = sprintf(buf, "%d\n", device_info->server_monitor_pending);
+	} else if (!strcmp(dev_attr->attr.name, "server_monitor_latency")) {
+		ret = sprintf(buf, "%d\n", device_info->server_monitor_latency);
+	} else if (!strcmp(dev_attr->attr.name, "server_monitor_conn_id")) {
+		ret = sprintf(buf, "%d\n",
+			       device_info->server_monitor_conn_id);
+	} else if (!strcmp(dev_attr->attr.name, "client_monitor_pending")) {
+		ret = sprintf(buf, "%d\n", device_info->client_monitor_pending);
+	} else if (!strcmp(dev_attr->attr.name, "client_monitor_latency")) {
+		ret = sprintf(buf, "%d\n", device_info->client_monitor_latency);
+	} else if (!strcmp(dev_attr->attr.name, "client_monitor_conn_id")) {
+		ret = sprintf(buf, "%d\n",
+			       device_info->client_monitor_conn_id);
+	}
+
+	kfree(device_info);
+	return ret;
+}
+
+/* Set up per device attributes in /sys/bus/vmbus/devices/<bus device> */
+static struct device_attribute vmbus_device_attrs[] = {
+	__ATTR(id, S_IRUGO, vmbus_show_device_attr, NULL),
+	__ATTR(state, S_IRUGO, vmbus_show_device_attr, NULL),
+	__ATTR(class_id, S_IRUGO, vmbus_show_device_attr, NULL),
+	__ATTR(device_id, S_IRUGO, vmbus_show_device_attr, NULL),
+	__ATTR(monitor_id, S_IRUGO, vmbus_show_device_attr, NULL),
+	__ATTR(modalias, S_IRUGO, vmbus_show_device_attr, NULL),
+
+	__ATTR(server_monitor_pending, S_IRUGO, vmbus_show_device_attr, NULL),
+	__ATTR(server_monitor_latency, S_IRUGO, vmbus_show_device_attr, NULL),
+	__ATTR(server_monitor_conn_id, S_IRUGO, vmbus_show_device_attr, NULL),
+
+	__ATTR(client_monitor_pending, S_IRUGO, vmbus_show_device_attr, NULL),
+	__ATTR(client_monitor_latency, S_IRUGO, vmbus_show_device_attr, NULL),
+	__ATTR(client_monitor_conn_id, S_IRUGO, vmbus_show_device_attr, NULL),
+
+	__ATTR(out_intr_mask, S_IRUGO, vmbus_show_device_attr, NULL),
+	__ATTR(out_read_index, S_IRUGO, vmbus_show_device_attr, NULL),
+	__ATTR(out_write_index, S_IRUGO, vmbus_show_device_attr, NULL),
+	__ATTR(out_read_bytes_avail, S_IRUGO, vmbus_show_device_attr, NULL),
+	__ATTR(out_write_bytes_avail, S_IRUGO, vmbus_show_device_attr, NULL),
+
+	__ATTR(in_intr_mask, S_IRUGO, vmbus_show_device_attr, NULL),
+	__ATTR(in_read_index, S_IRUGO, vmbus_show_device_attr, NULL),
+	__ATTR(in_write_index, S_IRUGO, vmbus_show_device_attr, NULL),
+	__ATTR(in_read_bytes_avail, S_IRUGO, vmbus_show_device_attr, NULL),
+	__ATTR(in_write_bytes_avail, S_IRUGO, vmbus_show_device_attr, NULL),
+	__ATTR_NULL
+};
+
+
+/*
+ * 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);
+	int ret;
+	char alias_name[VMBUS_ALIAS_LEN + 1];
+
+	print_alias_name(dev, alias_name);
+	ret = add_uevent_var(env, "MODALIAS=vmbus:%s", alias_name);
+	return ret;
+}
+
+static uuid_le null_guid;
+
+static inline bool is_null_guid(const __u8 *guid)
+{
+	if (memcmp(guid, &null_guid, sizeof(uuid_le)))
+		return false;
+	return true;
+}
+
+/*
+ * 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(
+					const struct hv_vmbus_device_id *id,
+					__u8 *guid)
+{
+	for (; !is_null_guid(id->guid); id++)
+		if (!memcmp(&id->guid, guid, sizeof(uuid_le)))
+			return id;
+
+	return NULL;
+}
+
+
+
+/*
+ * 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);
+
+	if (hv_vmbus_get_id(drv->id_table, hv_dev->dev_type.b))
+		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->id_table, dev->dev_type.b);
+	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 int vmbus_remove(struct device *child_device)
+{
+	struct hv_driver *drv = drv_to_hv_drv(child_device->driver);
+	struct hv_device *dev = device_to_hv_device(child_device);
+
+	if (drv->remove)
+		drv->remove(dev);
+	else
+		pr_err("remove not set for driver %s\n",
+			dev_name(child_device));
+
+	return 0;
+}
+
+
+/*
+ * 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);
+
+	return;
+}
+
+
+/*
+ * 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);
+
+	kfree(hv_dev);
+
+}
+
+/* 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_attrs =	vmbus_device_attrs,
+};
+
+static const char *driver_name = "hyperv";
+
+
+struct onmessage_work_context {
+	struct work_struct work;
+	struct hv_message msg;
+};
+
+static void vmbus_onmessage_work(struct work_struct *work)
+{
+	struct onmessage_work_context *ctx;
+
+	ctx = container_of(work, struct onmessage_work_context,
+			   work);
+	vmbus_onmessage(&ctx->msg);
+	kfree(ctx);
+}
+
+static void vmbus_on_msg_dpc(unsigned long data)
+{
+	int cpu = smp_processor_id();
+	void *page_addr = hv_context.synic_message_page[cpu];
+	struct hv_message *msg = (struct hv_message *)page_addr +
+				  VMBUS_MESSAGE_SINT;
+	struct onmessage_work_context *ctx;
+
+	while (1) {
+		if (msg->header.message_type == HVMSG_NONE) {
+			/* no msg */
+			break;
+		} else {
+			ctx = kmalloc(sizeof(*ctx), GFP_ATOMIC);
+			if (ctx == NULL)
+				continue;
+			INIT_WORK(&ctx->work, vmbus_onmessage_work);
+			memcpy(&ctx->msg, msg, sizeof(*msg));
+			queue_work(vmbus_connection.work_queue, &ctx->work);
+		}
+
+		msg->header.message_type = HVMSG_NONE;
+
+		/*
+		 * Make sure the write to MessageType (ie set to
+		 * HVMSG_NONE) happens before we read the
+		 * MessagePending and EOMing. Otherwise, the EOMing
+		 * will not deliver any more messages since there is
+		 * no empty slot
+		 */
+		smp_mb();
+
+		if (msg->header.message_flags.msg_pending) {
+			/*
+			 * This will cause message queue rescan to
+			 * possibly deliver another msg from the
+			 * hypervisor
+			 */
+			wrmsrl(HV_X64_MSR_EOM, 0);
+		}
+	}
+}
+
+static irqreturn_t vmbus_isr(int irq, void *dev_id)
+{
+	int cpu = smp_processor_id();
+	void *page_addr;
+	struct hv_message *msg;
+	union hv_synic_event_flags *event;
+	bool handled = false;
+
+	/*
+	 * 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.
+	 */
+
+	page_addr = hv_context.synic_event_page[cpu];
+	event = (union hv_synic_event_flags *)page_addr + VMBUS_MESSAGE_SINT;
+
+	/* Since we are a child, we only need to check bit 0 */
+	if (sync_test_and_clear_bit(0, (unsigned long *) &event->flags32[0])) {
+		handled = true;
+		tasklet_schedule(&event_dpc);
+	}
+
+	page_addr = hv_context.synic_message_page[cpu];
+	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) {
+		handled = true;
+		tasklet_schedule(&msg_dpc);
+	}
+
+	if (handled)
+		return IRQ_HANDLED;
+	else
+		return IRQ_NONE;
+}
+
+/*
+ * vmbus_bus_init -Main vmbus driver initialization routine.
+ *
+ * Here, we
+ *	- initialize the vmbus driver context
+ *	- invoke the vmbus hv main init routine
+ *	- get the irq resource
+ *	- retrieve the channel offers
+ */
+static int vmbus_bus_init(int irq)
+{
+	int ret;
+	unsigned int vector;
+
+	/* Hypervisor initialization...setup hypercall page..etc */
+	ret = hv_init();
+	if (ret != 0) {
+		pr_err("Unable to initialize the hypervisor - 0x%x\n", ret);
+		return ret;
+	}
+
+	tasklet_init(&msg_dpc, vmbus_on_msg_dpc, 0);
+	tasklet_init(&event_dpc, vmbus_on_event, 0);
+
+	ret = bus_register(&hv_bus);
+	if (ret)
+		goto err_cleanup;
+
+	ret = request_irq(irq, vmbus_isr, IRQF_SAMPLE_RANDOM,
+			driver_name, hv_acpi_dev);
+
+	if (ret != 0) {
+		pr_err("Unable to request IRQ %d\n",
+			   irq);
+		goto err_unregister;
+	}
+
+	vector = IRQ0_VECTOR + irq;
+
+	/*
+	 * Notify the hypervisor of our irq and
+	 * connect to the host.
+	 */
+	on_each_cpu(hv_synic_init, (void *)&vector, 1);
+	ret = vmbus_connect();
+	if (ret)
+		goto err_irq;
+
+	vmbus_request_offers();
+
+	return 0;
+
+err_irq:
+	free_irq(irq, hv_acpi_dev);
+
+err_unregister:
+	bus_unregister(&hv_bus);
+
+err_cleanup:
+	hv_cleanup();
+
+	return ret;
+}
+
+/**
+ * __vmbus_child_driver_register - Register a vmbus's driver
+ * @drv: 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);
+
+	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;
+
+	ret = driver_register(&hv_driver->driver);
+
+	vmbus_request_offers();
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(__vmbus_driver_register);
+
+/**
+ * vmbus_driver_unregister() - Unregister a vmbus's driver
+ * @drv: 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);
+
+	driver_unregister(&hv_driver->driver);
+
+}
+EXPORT_SYMBOL_GPL(vmbus_driver_unregister);
+
+/*
+ * vmbus_device_create - Creates and registers a new child device
+ * on the vmbus.
+ */
+struct hv_device *vmbus_device_create(uuid_le *type,
+					    uuid_le *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;
+	memcpy(&child_device_obj->dev_type, type, sizeof(uuid_le));
+	memcpy(&child_device_obj->dev_instance, instance,
+	       sizeof(uuid_le));
+
+
+	return child_device_obj;
+}
+
+/*
+ * vmbus_device_register - Register the child device
+ */
+int vmbus_device_register(struct hv_device *child_device_obj)
+{
+	int ret = 0;
+
+	static atomic_t device_num = ATOMIC_INIT(0);
+
+	dev_set_name(&child_device_obj->device, "vmbus_0_%d",
+		     atomic_inc_return(&device_num));
+
+	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");
+	else
+		pr_info("child device %s registered\n",
+			dev_name(&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)
+{
+	/*
+	 * Kick off the process of unregistering the device.
+	 * This will call vmbus_remove() and eventually vmbus_device_release()
+	 */
+	device_unregister(&device_obj->device);
+
+	pr_info("child device %s unregistered\n",
+		dev_name(&device_obj->device));
+}
+
+
+/*
+ * VMBUS is an acpi enumerated device. Get the the IRQ information
+ * from DSDT.
+ */
+
+static acpi_status vmbus_walk_resources(struct acpi_resource *res, void *irq)
+{
+
+	if (res->type == ACPI_RESOURCE_TYPE_IRQ) {
+		struct acpi_resource_irq *irqp;
+		irqp = &res->data.irq;
+
+		*((unsigned int *)irq) = irqp->interrupts[0];
+	}
+
+	return AE_OK;
+}
+
+static int vmbus_acpi_add(struct acpi_device *device)
+{
+	acpi_status result;
+
+	hv_acpi_dev = device;
+
+	result = acpi_walk_resources(device->handle, METHOD_NAME__CRS,
+					vmbus_walk_resources, &irq);
+
+	if (ACPI_FAILURE(result)) {
+		complete(&probe_event);
+		return -ENODEV;
+	}
+	complete(&probe_event);
+	return 0;
+}
+
+static const struct acpi_device_id vmbus_acpi_device_ids[] = {
+	{"VMBUS", 0},
+	{"VMBus", 0},
+	{"", 0},
+};
+MODULE_DEVICE_TABLE(acpi, vmbus_acpi_device_ids);
+
+static struct acpi_driver vmbus_acpi_driver = {
+	.name = "vmbus",
+	.ids = vmbus_acpi_device_ids,
+	.ops = {
+		.add = vmbus_acpi_add,
+	},
+};
+
+static int __init hv_acpi_init(void)
+{
+	int ret, t;
+
+	init_completion(&probe_event);
+
+	/*
+	 * Get irq 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 (irq <= 0) {
+		ret = -ENODEV;
+		goto cleanup;
+	}
+
+	ret = vmbus_bus_init(irq);
+	if (ret)
+		goto cleanup;
+
+	return 0;
+
+cleanup:
+	acpi_bus_unregister_driver(&vmbus_acpi_driver);
+	return ret;
+}
+
+
+MODULE_LICENSE("GPL");
+MODULE_VERSION(HV_DRV_VERSION);
+module_param(vmbus_loglevel, int, S_IRUGO|S_IWUSR);
+
+module_init(hv_acpi_init);