Index: sys/dev/hyperv/vmbus/hv_et.c
===================================================================
--- sys/dev/hyperv/vmbus/hv_et.c
+++ sys/dev/hyperv/vmbus/hv_et.c
@@ -28,6 +28,9 @@
 __FBSDID("$FreeBSD$");
 
 #include <sys/param.h>
+#include <sys/bus.h>
+#include <sys/kernel.h>
+#include <sys/module.h>
 #include <sys/proc.h>
 #include <sys/systm.h>
 #include <sys/smp.h>
@@ -40,8 +43,7 @@
 #define HV_MAX_DELTA_TICKS		0xffffffffLL
 #define HV_MIN_DELTA_TICKS		1LL
 
-static struct eventtimer et;
-static uint64_t periodticks[MAXCPU];
+static struct eventtimer *et;
 
 static inline uint64_t
 sbintime2tick(sbintime_t time)
@@ -62,10 +64,6 @@
 	timer_cfg.auto_enable = 1;
 	timer_cfg.sintx = HV_VMBUS_TIMER_SINT;
 
-	periodticks[curcpu] = sbintime2tick(periodtime);
-	if (firsttime == 0)
-		firsttime = periodtime;
-
 	current = rdmsr(HV_X64_MSR_TIME_REF_COUNT);
 	current += sbintime2tick(firsttime);
 
@@ -87,45 +85,77 @@
 void
 hv_et_intr(struct trapframe *frame)
 {
-	union hv_timer_config timer_cfg;
 	struct trapframe *oldframe;
 	struct thread *td;
 
-	if (periodticks[curcpu] != 0) {
-		uint64_t tick = sbintime2tick(periodticks[curcpu]);
-		timer_cfg.as_uint64 = rdmsr(HV_X64_MSR_STIMER0_CONFIG);
-		timer_cfg.enable = 0;
-		timer_cfg.auto_enable = 1;
-		timer_cfg.periodic = 1;
-		periodticks[curcpu] = 0;
-
-		wrmsr(HV_X64_MSR_STIMER0_CONFIG, timer_cfg.as_uint64);
-		wrmsr(HV_X64_MSR_STIMER0_COUNT, tick);
-	}
-
-	if (et.et_active) {
+	if (et->et_active) {
 		td = curthread;
 		td->td_intr_nesting_level++;
 		oldframe = td->td_intr_frame;
 		td->td_intr_frame = frame;
-		et.et_event_cb(&et, et.et_arg);
+		et->et_event_cb(et, et->et_arg);
 		td->td_intr_frame = oldframe;
 		td->td_intr_nesting_level--;
 	}
 }
 
-void
-hv_et_init(void)
+static void
+hv_et_identify (driver_t *driver, device_t parent)
 {
-	et.et_name = "HyperV";
-	et.et_flags = ET_FLAGS_ONESHOT | ET_FLAGS_PERCPU | ET_FLAGS_PERIODIC;
-	et.et_quality = 1000;
-	et.et_frequency = HV_TIMER_FREQUENCY;
-	et.et_min_period = (1LL << 32) / HV_TIMER_FREQUENCY;
-	et.et_max_period = HV_MAX_DELTA_TICKS * ((1LL << 32) / HV_TIMER_FREQUENCY);
-	et.et_start = hv_et_start;
-	et.et_stop = hv_et_stop;
-	et.et_priv = &et;
-	et_register(&et);
+	if (device_find_child(parent, "hv_et", -1) != NULL)
+		return;
+
+	BUS_ADD_CHILD(parent, 0, "hv_et", -1);
+}
+
+static int
+hv_et_probe(device_t dev)
+{
+	device_set_desc(dev, "Hyper-V event timer");
+
+	return (BUS_PROBE_NOWILDCARD);
 }
 
+static int
+hv_et_attach(device_t dev)
+{
+	/* XXX: need allocate SINT and remove global et */
+	et = device_get_softc(dev);
+
+	et->et_name = "HyperV";
+	et->et_flags = ET_FLAGS_ONESHOT | ET_FLAGS_PERCPU;
+	et->et_quality = 1000;
+	et->et_frequency = HV_TIMER_FREQUENCY;
+	et->et_min_period = HV_MIN_DELTA_TICKS * ((1LL << 32) / HV_TIMER_FREQUENCY);
+	et->et_max_period = HV_MAX_DELTA_TICKS * ((1LL << 32) / HV_TIMER_FREQUENCY);
+	et->et_start = hv_et_start;
+	et->et_stop = hv_et_stop;
+	et->et_priv = dev;
+
+	return (et_register(et));
+}
+
+static int
+hv_et_detach(device_t dev)
+{
+	return (et_deregister(et));
+}
+
+static device_method_t hv_et_methods[] = {
+	DEVMETHOD(device_identify,      hv_et_identify),
+	DEVMETHOD(device_probe,         hv_et_probe),
+	DEVMETHOD(device_attach,        hv_et_attach),
+	DEVMETHOD(device_detach,        hv_et_detach),
+
+	DEVMETHOD_END
+};
+
+static driver_t hv_et_driver = {
+	"hv_et",
+	hv_et_methods,
+	sizeof(struct eventtimer)
+};
+
+static devclass_t hv_et_devclass;
+DRIVER_MODULE(hv_et, vmbus, hv_et_driver, hv_et_devclass, NULL, 0);
+MODULE_VERSION(hv_et, 1);
Index: sys/dev/hyperv/vmbus/hv_hv.c
===================================================================
--- sys/dev/hyperv/vmbus/hv_hv.c
+++ sys/dev/hyperv/vmbus/hv_hv.c
@@ -208,8 +208,6 @@
 
 	hv_vmbus_g_context.hypercall_page = virt_addr;
 
-	hv_et_init();
-	
 	return (0);
 
 	cleanup:
Index: sys/dev/hyperv/vmbus/hv_vmbus_drv_freebsd.c
===================================================================
--- sys/dev/hyperv/vmbus/hv_vmbus_drv_freebsd.c
+++ sys/dev/hyperv/vmbus/hv_vmbus_drv_freebsd.c
@@ -289,6 +289,9 @@
 	char guidbuf[40];
 	struct hv_device *dev_ctx = device_get_ivars(child);
 
+	if (dev_ctx == NULL)
+		return (0);
+
 	strlcat(buf, "classid=", buflen);
 	snprintf_hv_guid(guidbuf, sizeof(guidbuf), &dev_ctx->class_id);
 	strlcat(buf, guidbuf, buflen);
@@ -566,6 +569,9 @@
 	if (ret != 0)
 		goto cleanup1;
 
+	/* delay attach until inerrupt is on */
+	bus_generic_attach(vmbus_devp);
+
 	hv_vmbus_request_channel_offers();
 	return (ret);
 
@@ -611,6 +617,7 @@
 	if (!cold)
 		vmbus_bus_init();
 
+	bus_generic_probe(dev);
 	return (0);
 }