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-rw-r--r--drivers/hv/hv_util.c744
1 files changed, 744 insertions, 0 deletions
diff --git a/drivers/hv/hv_util.c b/drivers/hv/hv_util.c
new file mode 100644
index 000000000..1b914e418
--- /dev/null
+++ b/drivers/hv/hv_util.c
@@ -0,0 +1,744 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2010, Microsoft Corporation.
+ *
+ * Authors:
+ * Haiyang Zhang <haiyangz@microsoft.com>
+ * Hank Janssen <hjanssen@microsoft.com>
+ */
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/sysctl.h>
+#include <linux/reboot.h>
+#include <linux/hyperv.h>
+#include <linux/clockchips.h>
+#include <linux/ptp_clock_kernel.h>
+#include <clocksource/hyperv_timer.h>
+#include <asm/mshyperv.h>
+
+#include "hyperv_vmbus.h"
+
+#define SD_MAJOR 3
+#define SD_MINOR 0
+#define SD_MINOR_1 1
+#define SD_MINOR_2 2
+#define SD_VERSION_3_1 (SD_MAJOR << 16 | SD_MINOR_1)
+#define SD_VERSION_3_2 (SD_MAJOR << 16 | SD_MINOR_2)
+#define SD_VERSION (SD_MAJOR << 16 | SD_MINOR)
+
+#define SD_MAJOR_1 1
+#define SD_VERSION_1 (SD_MAJOR_1 << 16 | SD_MINOR)
+
+#define TS_MAJOR 4
+#define TS_MINOR 0
+#define TS_VERSION (TS_MAJOR << 16 | TS_MINOR)
+
+#define TS_MAJOR_1 1
+#define TS_VERSION_1 (TS_MAJOR_1 << 16 | TS_MINOR)
+
+#define TS_MAJOR_3 3
+#define TS_VERSION_3 (TS_MAJOR_3 << 16 | TS_MINOR)
+
+#define HB_MAJOR 3
+#define HB_MINOR 0
+#define HB_VERSION (HB_MAJOR << 16 | HB_MINOR)
+
+#define HB_MAJOR_1 1
+#define HB_VERSION_1 (HB_MAJOR_1 << 16 | HB_MINOR)
+
+static int sd_srv_version;
+static int ts_srv_version;
+static int hb_srv_version;
+
+#define SD_VER_COUNT 4
+static const int sd_versions[] = {
+ SD_VERSION_3_2,
+ SD_VERSION_3_1,
+ SD_VERSION,
+ SD_VERSION_1
+};
+
+#define TS_VER_COUNT 3
+static const int ts_versions[] = {
+ TS_VERSION,
+ TS_VERSION_3,
+ TS_VERSION_1
+};
+
+#define HB_VER_COUNT 2
+static const int hb_versions[] = {
+ HB_VERSION,
+ HB_VERSION_1
+};
+
+#define FW_VER_COUNT 2
+static const int fw_versions[] = {
+ UTIL_FW_VERSION,
+ UTIL_WS2K8_FW_VERSION
+};
+
+/*
+ * Send the "hibernate" udev event in a thread context.
+ */
+struct hibernate_work_context {
+ struct work_struct work;
+ struct hv_device *dev;
+};
+
+static struct hibernate_work_context hibernate_context;
+static bool hibernation_supported;
+
+static void send_hibernate_uevent(struct work_struct *work)
+{
+ char *uevent_env[2] = { "EVENT=hibernate", NULL };
+ struct hibernate_work_context *ctx;
+
+ ctx = container_of(work, struct hibernate_work_context, work);
+
+ kobject_uevent_env(&ctx->dev->device.kobj, KOBJ_CHANGE, uevent_env);
+
+ pr_info("Sent hibernation uevent\n");
+}
+
+static int hv_shutdown_init(struct hv_util_service *srv)
+{
+ struct vmbus_channel *channel = srv->channel;
+
+ INIT_WORK(&hibernate_context.work, send_hibernate_uevent);
+ hibernate_context.dev = channel->device_obj;
+
+ hibernation_supported = hv_is_hibernation_supported();
+
+ return 0;
+}
+
+static void shutdown_onchannelcallback(void *context);
+static struct hv_util_service util_shutdown = {
+ .util_cb = shutdown_onchannelcallback,
+ .util_init = hv_shutdown_init,
+};
+
+static int hv_timesync_init(struct hv_util_service *srv);
+static int hv_timesync_pre_suspend(void);
+static void hv_timesync_deinit(void);
+
+static void timesync_onchannelcallback(void *context);
+static struct hv_util_service util_timesynch = {
+ .util_cb = timesync_onchannelcallback,
+ .util_init = hv_timesync_init,
+ .util_pre_suspend = hv_timesync_pre_suspend,
+ .util_deinit = hv_timesync_deinit,
+};
+
+static void heartbeat_onchannelcallback(void *context);
+static struct hv_util_service util_heartbeat = {
+ .util_cb = heartbeat_onchannelcallback,
+};
+
+static struct hv_util_service util_kvp = {
+ .util_cb = hv_kvp_onchannelcallback,
+ .util_init = hv_kvp_init,
+ .util_pre_suspend = hv_kvp_pre_suspend,
+ .util_pre_resume = hv_kvp_pre_resume,
+ .util_deinit = hv_kvp_deinit,
+};
+
+static struct hv_util_service util_vss = {
+ .util_cb = hv_vss_onchannelcallback,
+ .util_init = hv_vss_init,
+ .util_pre_suspend = hv_vss_pre_suspend,
+ .util_pre_resume = hv_vss_pre_resume,
+ .util_deinit = hv_vss_deinit,
+};
+
+static struct hv_util_service util_fcopy = {
+ .util_cb = hv_fcopy_onchannelcallback,
+ .util_init = hv_fcopy_init,
+ .util_pre_suspend = hv_fcopy_pre_suspend,
+ .util_pre_resume = hv_fcopy_pre_resume,
+ .util_deinit = hv_fcopy_deinit,
+};
+
+static void perform_shutdown(struct work_struct *dummy)
+{
+ orderly_poweroff(true);
+}
+
+static void perform_restart(struct work_struct *dummy)
+{
+ orderly_reboot();
+}
+
+/*
+ * Perform the shutdown operation in a thread context.
+ */
+static DECLARE_WORK(shutdown_work, perform_shutdown);
+
+/*
+ * Perform the restart operation in a thread context.
+ */
+static DECLARE_WORK(restart_work, perform_restart);
+
+static void shutdown_onchannelcallback(void *context)
+{
+ struct vmbus_channel *channel = context;
+ struct work_struct *work = NULL;
+ u32 recvlen;
+ u64 requestid;
+ u8 *shut_txf_buf = util_shutdown.recv_buffer;
+
+ struct shutdown_msg_data *shutdown_msg;
+
+ struct icmsg_hdr *icmsghdrp;
+
+ vmbus_recvpacket(channel, shut_txf_buf,
+ HV_HYP_PAGE_SIZE, &recvlen, &requestid);
+
+ if (recvlen > 0) {
+ icmsghdrp = (struct icmsg_hdr *)&shut_txf_buf[
+ sizeof(struct vmbuspipe_hdr)];
+
+ if (icmsghdrp->icmsgtype == ICMSGTYPE_NEGOTIATE) {
+ if (vmbus_prep_negotiate_resp(icmsghdrp, shut_txf_buf,
+ fw_versions, FW_VER_COUNT,
+ sd_versions, SD_VER_COUNT,
+ NULL, &sd_srv_version)) {
+ pr_info("Shutdown IC version %d.%d\n",
+ sd_srv_version >> 16,
+ sd_srv_version & 0xFFFF);
+ }
+ } else {
+ shutdown_msg =
+ (struct shutdown_msg_data *)&shut_txf_buf[
+ sizeof(struct vmbuspipe_hdr) +
+ sizeof(struct icmsg_hdr)];
+
+ /*
+ * shutdown_msg->flags can be 0(shut down), 2(reboot),
+ * or 4(hibernate). It may bitwise-OR 1, which means
+ * performing the request by force. Linux always tries
+ * to perform the request by force.
+ */
+ switch (shutdown_msg->flags) {
+ case 0:
+ case 1:
+ icmsghdrp->status = HV_S_OK;
+ work = &shutdown_work;
+ pr_info("Shutdown request received -"
+ " graceful shutdown initiated\n");
+ break;
+ case 2:
+ case 3:
+ icmsghdrp->status = HV_S_OK;
+ work = &restart_work;
+ pr_info("Restart request received -"
+ " graceful restart initiated\n");
+ break;
+ case 4:
+ case 5:
+ pr_info("Hibernation request received\n");
+ icmsghdrp->status = hibernation_supported ?
+ HV_S_OK : HV_E_FAIL;
+ if (hibernation_supported)
+ work = &hibernate_context.work;
+ break;
+ default:
+ icmsghdrp->status = HV_E_FAIL;
+ pr_info("Shutdown request received -"
+ " Invalid request\n");
+ break;
+ }
+ }
+
+ icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION
+ | ICMSGHDRFLAG_RESPONSE;
+
+ vmbus_sendpacket(channel, shut_txf_buf,
+ recvlen, requestid,
+ VM_PKT_DATA_INBAND, 0);
+ }
+
+ if (work)
+ schedule_work(work);
+}
+
+/*
+ * Set the host time in a process context.
+ */
+static struct work_struct adj_time_work;
+
+/*
+ * The last time sample, received from the host. PTP device responds to
+ * requests by using this data and the current partition-wide time reference
+ * count.
+ */
+static struct {
+ u64 host_time;
+ u64 ref_time;
+ spinlock_t lock;
+} host_ts;
+
+static inline u64 reftime_to_ns(u64 reftime)
+{
+ return (reftime - WLTIMEDELTA) * 100;
+}
+
+/*
+ * Hard coded threshold for host timesync delay: 600 seconds
+ */
+static const u64 HOST_TIMESYNC_DELAY_THRESH = 600 * (u64)NSEC_PER_SEC;
+
+static int hv_get_adj_host_time(struct timespec64 *ts)
+{
+ u64 newtime, reftime, timediff_adj;
+ unsigned long flags;
+ int ret = 0;
+
+ spin_lock_irqsave(&host_ts.lock, flags);
+ reftime = hv_read_reference_counter();
+
+ /*
+ * We need to let the caller know that last update from host
+ * is older than the max allowable threshold. clock_gettime()
+ * and PTP ioctl do not have a documented error that we could
+ * return for this specific case. Use ESTALE to report this.
+ */
+ timediff_adj = reftime - host_ts.ref_time;
+ if (timediff_adj * 100 > HOST_TIMESYNC_DELAY_THRESH) {
+ pr_warn_once("TIMESYNC IC: Stale time stamp, %llu nsecs old\n",
+ (timediff_adj * 100));
+ ret = -ESTALE;
+ }
+
+ newtime = host_ts.host_time + timediff_adj;
+ *ts = ns_to_timespec64(reftime_to_ns(newtime));
+ spin_unlock_irqrestore(&host_ts.lock, flags);
+
+ return ret;
+}
+
+static void hv_set_host_time(struct work_struct *work)
+{
+
+ struct timespec64 ts;
+
+ if (!hv_get_adj_host_time(&ts))
+ do_settimeofday64(&ts);
+}
+
+/*
+ * Synchronize time with host after reboot, restore, etc.
+ *
+ * ICTIMESYNCFLAG_SYNC flag bit indicates reboot, restore events of the VM.
+ * After reboot the flag ICTIMESYNCFLAG_SYNC is included in the first time
+ * message after the timesync channel is opened. Since the hv_utils module is
+ * loaded after hv_vmbus, the first message is usually missed. This bit is
+ * considered a hard request to discipline the clock.
+ *
+ * ICTIMESYNCFLAG_SAMPLE bit indicates a time sample from host. This is
+ * typically used as a hint to the guest. The guest is under no obligation
+ * to discipline the clock.
+ */
+static inline void adj_guesttime(u64 hosttime, u64 reftime, u8 adj_flags)
+{
+ unsigned long flags;
+ u64 cur_reftime;
+
+ /*
+ * Save the adjusted time sample from the host and the snapshot
+ * of the current system time.
+ */
+ spin_lock_irqsave(&host_ts.lock, flags);
+
+ cur_reftime = hv_read_reference_counter();
+ host_ts.host_time = hosttime;
+ host_ts.ref_time = cur_reftime;
+
+ /*
+ * TimeSync v4 messages contain reference time (guest's Hyper-V
+ * clocksource read when the time sample was generated), we can
+ * improve the precision by adding the delta between now and the
+ * time of generation. For older protocols we set
+ * reftime == cur_reftime on call.
+ */
+ host_ts.host_time += (cur_reftime - reftime);
+
+ spin_unlock_irqrestore(&host_ts.lock, flags);
+
+ /* Schedule work to do do_settimeofday64() */
+ if (adj_flags & ICTIMESYNCFLAG_SYNC)
+ schedule_work(&adj_time_work);
+}
+
+/*
+ * Time Sync Channel message handler.
+ */
+static void timesync_onchannelcallback(void *context)
+{
+ struct vmbus_channel *channel = context;
+ u32 recvlen;
+ u64 requestid;
+ struct icmsg_hdr *icmsghdrp;
+ struct ictimesync_data *timedatap;
+ struct ictimesync_ref_data *refdata;
+ u8 *time_txf_buf = util_timesynch.recv_buffer;
+
+ /*
+ * Drain the ring buffer and use the last packet to update
+ * host_ts
+ */
+ while (1) {
+ int ret = vmbus_recvpacket(channel, time_txf_buf,
+ HV_HYP_PAGE_SIZE, &recvlen,
+ &requestid);
+ if (ret) {
+ pr_warn_once("TimeSync IC pkt recv failed (Err: %d)\n",
+ ret);
+ break;
+ }
+
+ if (!recvlen)
+ break;
+
+ icmsghdrp = (struct icmsg_hdr *)&time_txf_buf[
+ sizeof(struct vmbuspipe_hdr)];
+
+ if (icmsghdrp->icmsgtype == ICMSGTYPE_NEGOTIATE) {
+ if (vmbus_prep_negotiate_resp(icmsghdrp, time_txf_buf,
+ fw_versions, FW_VER_COUNT,
+ ts_versions, TS_VER_COUNT,
+ NULL, &ts_srv_version)) {
+ pr_info("TimeSync IC version %d.%d\n",
+ ts_srv_version >> 16,
+ ts_srv_version & 0xFFFF);
+ }
+ } else {
+ if (ts_srv_version > TS_VERSION_3) {
+ refdata = (struct ictimesync_ref_data *)
+ &time_txf_buf[
+ sizeof(struct vmbuspipe_hdr) +
+ sizeof(struct icmsg_hdr)];
+
+ adj_guesttime(refdata->parenttime,
+ refdata->vmreferencetime,
+ refdata->flags);
+ } else {
+ timedatap = (struct ictimesync_data *)
+ &time_txf_buf[
+ sizeof(struct vmbuspipe_hdr) +
+ sizeof(struct icmsg_hdr)];
+ adj_guesttime(timedatap->parenttime,
+ hv_read_reference_counter(),
+ timedatap->flags);
+ }
+ }
+
+ icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION
+ | ICMSGHDRFLAG_RESPONSE;
+
+ vmbus_sendpacket(channel, time_txf_buf,
+ recvlen, requestid,
+ VM_PKT_DATA_INBAND, 0);
+ }
+}
+
+/*
+ * Heartbeat functionality.
+ * Every two seconds, Hyper-V send us a heartbeat request message.
+ * we respond to this message, and Hyper-V knows we are alive.
+ */
+static void heartbeat_onchannelcallback(void *context)
+{
+ struct vmbus_channel *channel = context;
+ u32 recvlen;
+ u64 requestid;
+ struct icmsg_hdr *icmsghdrp;
+ struct heartbeat_msg_data *heartbeat_msg;
+ u8 *hbeat_txf_buf = util_heartbeat.recv_buffer;
+
+ while (1) {
+
+ vmbus_recvpacket(channel, hbeat_txf_buf,
+ HV_HYP_PAGE_SIZE, &recvlen, &requestid);
+
+ if (!recvlen)
+ break;
+
+ icmsghdrp = (struct icmsg_hdr *)&hbeat_txf_buf[
+ sizeof(struct vmbuspipe_hdr)];
+
+ if (icmsghdrp->icmsgtype == ICMSGTYPE_NEGOTIATE) {
+ if (vmbus_prep_negotiate_resp(icmsghdrp,
+ hbeat_txf_buf,
+ fw_versions, FW_VER_COUNT,
+ hb_versions, HB_VER_COUNT,
+ NULL, &hb_srv_version)) {
+
+ pr_info("Heartbeat IC version %d.%d\n",
+ hb_srv_version >> 16,
+ hb_srv_version & 0xFFFF);
+ }
+ } else {
+ heartbeat_msg =
+ (struct heartbeat_msg_data *)&hbeat_txf_buf[
+ sizeof(struct vmbuspipe_hdr) +
+ sizeof(struct icmsg_hdr)];
+
+ heartbeat_msg->seq_num += 1;
+ }
+
+ icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION
+ | ICMSGHDRFLAG_RESPONSE;
+
+ vmbus_sendpacket(channel, hbeat_txf_buf,
+ recvlen, requestid,
+ VM_PKT_DATA_INBAND, 0);
+ }
+}
+
+#define HV_UTIL_RING_SEND_SIZE VMBUS_RING_SIZE(3 * HV_HYP_PAGE_SIZE)
+#define HV_UTIL_RING_RECV_SIZE VMBUS_RING_SIZE(3 * HV_HYP_PAGE_SIZE)
+
+static int util_probe(struct hv_device *dev,
+ const struct hv_vmbus_device_id *dev_id)
+{
+ struct hv_util_service *srv =
+ (struct hv_util_service *)dev_id->driver_data;
+ int ret;
+
+ srv->recv_buffer = kmalloc(HV_HYP_PAGE_SIZE * 4, GFP_KERNEL);
+ if (!srv->recv_buffer)
+ return -ENOMEM;
+ srv->channel = dev->channel;
+ if (srv->util_init) {
+ ret = srv->util_init(srv);
+ if (ret) {
+ ret = -ENODEV;
+ goto error1;
+ }
+ }
+
+ /*
+ * The set of services managed by the util driver are not performance
+ * critical and do not need batched reading. Furthermore, some services
+ * such as KVP can only handle one message from the host at a time.
+ * Turn off batched reading for all util drivers before we open the
+ * channel.
+ */
+ set_channel_read_mode(dev->channel, HV_CALL_DIRECT);
+
+ hv_set_drvdata(dev, srv);
+
+ ret = vmbus_open(dev->channel, HV_UTIL_RING_SEND_SIZE,
+ HV_UTIL_RING_RECV_SIZE, NULL, 0, srv->util_cb,
+ dev->channel);
+ if (ret)
+ goto error;
+
+ return 0;
+
+error:
+ if (srv->util_deinit)
+ srv->util_deinit();
+error1:
+ kfree(srv->recv_buffer);
+ return ret;
+}
+
+static int util_remove(struct hv_device *dev)
+{
+ struct hv_util_service *srv = hv_get_drvdata(dev);
+
+ if (srv->util_deinit)
+ srv->util_deinit();
+ vmbus_close(dev->channel);
+ kfree(srv->recv_buffer);
+
+ return 0;
+}
+
+/*
+ * When we're in util_suspend(), all the userspace processes have been frozen
+ * (refer to hibernate() -> freeze_processes()). The userspace is thawed only
+ * after the whole resume procedure, including util_resume(), finishes.
+ */
+static int util_suspend(struct hv_device *dev)
+{
+ struct hv_util_service *srv = hv_get_drvdata(dev);
+ int ret = 0;
+
+ if (srv->util_pre_suspend) {
+ ret = srv->util_pre_suspend();
+ if (ret)
+ return ret;
+ }
+
+ vmbus_close(dev->channel);
+
+ return 0;
+}
+
+static int util_resume(struct hv_device *dev)
+{
+ struct hv_util_service *srv = hv_get_drvdata(dev);
+ int ret = 0;
+
+ if (srv->util_pre_resume) {
+ ret = srv->util_pre_resume();
+ if (ret)
+ return ret;
+ }
+
+ ret = vmbus_open(dev->channel, HV_UTIL_RING_SEND_SIZE,
+ HV_UTIL_RING_RECV_SIZE, NULL, 0, srv->util_cb,
+ dev->channel);
+ return ret;
+}
+
+static const struct hv_vmbus_device_id id_table[] = {
+ /* Shutdown guid */
+ { HV_SHUTDOWN_GUID,
+ .driver_data = (unsigned long)&util_shutdown
+ },
+ /* Time synch guid */
+ { HV_TS_GUID,
+ .driver_data = (unsigned long)&util_timesynch
+ },
+ /* Heartbeat guid */
+ { HV_HEART_BEAT_GUID,
+ .driver_data = (unsigned long)&util_heartbeat
+ },
+ /* KVP guid */
+ { HV_KVP_GUID,
+ .driver_data = (unsigned long)&util_kvp
+ },
+ /* VSS GUID */
+ { HV_VSS_GUID,
+ .driver_data = (unsigned long)&util_vss
+ },
+ /* File copy GUID */
+ { HV_FCOPY_GUID,
+ .driver_data = (unsigned long)&util_fcopy
+ },
+ { },
+};
+
+MODULE_DEVICE_TABLE(vmbus, id_table);
+
+/* The one and only one */
+static struct hv_driver util_drv = {
+ .name = "hv_utils",
+ .id_table = id_table,
+ .probe = util_probe,
+ .remove = util_remove,
+ .suspend = util_suspend,
+ .resume = util_resume,
+ .driver = {
+ .probe_type = PROBE_PREFER_ASYNCHRONOUS,
+ },
+};
+
+static int hv_ptp_enable(struct ptp_clock_info *info,
+ struct ptp_clock_request *request, int on)
+{
+ return -EOPNOTSUPP;
+}
+
+static int hv_ptp_settime(struct ptp_clock_info *p, const struct timespec64 *ts)
+{
+ return -EOPNOTSUPP;
+}
+
+static int hv_ptp_adjfreq(struct ptp_clock_info *ptp, s32 delta)
+{
+ return -EOPNOTSUPP;
+}
+static int hv_ptp_adjtime(struct ptp_clock_info *ptp, s64 delta)
+{
+ return -EOPNOTSUPP;
+}
+
+static int hv_ptp_gettime(struct ptp_clock_info *info, struct timespec64 *ts)
+{
+ return hv_get_adj_host_time(ts);
+}
+
+static struct ptp_clock_info ptp_hyperv_info = {
+ .name = "hyperv",
+ .enable = hv_ptp_enable,
+ .adjtime = hv_ptp_adjtime,
+ .adjfreq = hv_ptp_adjfreq,
+ .gettime64 = hv_ptp_gettime,
+ .settime64 = hv_ptp_settime,
+ .owner = THIS_MODULE,
+};
+
+static struct ptp_clock *hv_ptp_clock;
+
+static int hv_timesync_init(struct hv_util_service *srv)
+{
+ /* TimeSync requires Hyper-V clocksource. */
+ if (!hv_read_reference_counter)
+ return -ENODEV;
+
+ spin_lock_init(&host_ts.lock);
+
+ INIT_WORK(&adj_time_work, hv_set_host_time);
+
+ /*
+ * ptp_clock_register() returns NULL when CONFIG_PTP_1588_CLOCK is
+ * disabled but the driver is still useful without the PTP device
+ * as it still handles the ICTIMESYNCFLAG_SYNC case.
+ */
+ hv_ptp_clock = ptp_clock_register(&ptp_hyperv_info, NULL);
+ if (IS_ERR_OR_NULL(hv_ptp_clock)) {
+ pr_err("cannot register PTP clock: %d\n",
+ PTR_ERR_OR_ZERO(hv_ptp_clock));
+ hv_ptp_clock = NULL;
+ }
+
+ return 0;
+}
+
+static void hv_timesync_cancel_work(void)
+{
+ cancel_work_sync(&adj_time_work);
+}
+
+static int hv_timesync_pre_suspend(void)
+{
+ hv_timesync_cancel_work();
+ return 0;
+}
+
+static void hv_timesync_deinit(void)
+{
+ if (hv_ptp_clock)
+ ptp_clock_unregister(hv_ptp_clock);
+
+ hv_timesync_cancel_work();
+}
+
+static int __init init_hyperv_utils(void)
+{
+ pr_info("Registering HyperV Utility Driver\n");
+
+ return vmbus_driver_register(&util_drv);
+}
+
+static void exit_hyperv_utils(void)
+{
+ pr_info("De-Registered HyperV Utility Driver\n");
+
+ vmbus_driver_unregister(&util_drv);
+}
+
+module_init(init_hyperv_utils);
+module_exit(exit_hyperv_utils);
+
+MODULE_DESCRIPTION("Hyper-V Utilities");
+MODULE_LICENSE("GPL");