diff --git a/hw/misc/hyperv_testdev.c b/hw/misc/hyperv_testdev.c
index 02ef606469..ee77bbac8b 100644
--- a/hw/misc/hyperv_testdev.c
+++ b/hw/misc/hyperv_testdev.c
@@ -12,6 +12,7 @@
  */
 
 #include "qemu/osdep.h"
+#include "qemu/main-loop.h"
 #include "qemu/queue.h"
 #include "hw/qdev.h"
 #include "hw/isa/isa.h"
@@ -24,10 +25,26 @@ typedef struct TestSintRoute {
     HvSintRoute *sint_route;
 } TestSintRoute;
 
+typedef struct TestMsgConn {
+    QLIST_ENTRY(TestMsgConn) le;
+    uint8_t conn_id;
+    HvSintRoute *sint_route;
+    struct hyperv_message msg;
+} TestMsgConn;
+
+typedef struct TestEvtConn {
+    QLIST_ENTRY(TestEvtConn) le;
+    uint8_t conn_id;
+    HvSintRoute *sint_route;
+    EventNotifier notifier;
+} TestEvtConn;
+
 struct HypervTestDev {
     ISADevice parent_obj;
     MemoryRegion sint_control;
     QLIST_HEAD(, TestSintRoute) sint_routes;
+    QLIST_HEAD(, TestMsgConn) msg_conns;
+    QLIST_HEAD(, TestEvtConn) evt_conns;
 };
 typedef struct HypervTestDev HypervTestDev;
 
@@ -38,7 +55,11 @@ typedef struct HypervTestDev HypervTestDev;
 enum {
     HV_TEST_DEV_SINT_ROUTE_CREATE = 1,
     HV_TEST_DEV_SINT_ROUTE_DESTROY,
-    HV_TEST_DEV_SINT_ROUTE_SET_SINT
+    HV_TEST_DEV_SINT_ROUTE_SET_SINT,
+    HV_TEST_DEV_MSG_CONN_CREATE,
+    HV_TEST_DEV_MSG_CONN_DESTROY,
+    HV_TEST_DEV_EVT_CONN_CREATE,
+    HV_TEST_DEV_EVT_CONN_DESTROY,
 };
 
 static void sint_route_create(HypervTestDev *dev,
@@ -93,6 +114,133 @@ static void sint_route_set_sint(HypervTestDev *dev,
     hyperv_sint_route_set_sint(sint_route->sint_route);
 }
 
+static void msg_retry(void *opaque)
+{
+    TestMsgConn *conn = opaque;
+    assert(!hyperv_post_msg(conn->sint_route, &conn->msg));
+}
+
+static void msg_cb(void *data, int status)
+{
+    TestMsgConn *conn = data;
+
+    if (!status) {
+        return;
+    }
+
+    assert(status == -EAGAIN);
+
+    aio_bh_schedule_oneshot(qemu_get_aio_context(), msg_retry, conn);
+}
+
+static uint16_t msg_handler(const struct hyperv_post_message_input *msg,
+                            void *data)
+{
+    int ret;
+    TestMsgConn *conn = data;
+
+    /* post the same message we've got */
+    conn->msg.header.message_type = msg->message_type;
+    assert(msg->payload_size < sizeof(conn->msg.payload));
+    conn->msg.header.payload_size = msg->payload_size;
+    memcpy(&conn->msg.payload, msg->payload, msg->payload_size);
+
+    ret = hyperv_post_msg(conn->sint_route, &conn->msg);
+
+    switch (ret) {
+    case 0:
+        return HV_STATUS_SUCCESS;
+    case -EAGAIN:
+        return HV_STATUS_INSUFFICIENT_BUFFERS;
+    default:
+        return HV_STATUS_INVALID_HYPERCALL_INPUT;
+    }
+}
+
+static void msg_conn_create(HypervTestDev *dev, uint8_t vp_index,
+                            uint8_t sint, uint8_t conn_id)
+{
+    TestMsgConn *conn;
+
+    conn = g_new0(TestMsgConn, 1);
+    assert(conn);
+
+    conn->conn_id = conn_id;
+
+    conn->sint_route = hyperv_sint_route_new(vp_index, sint, msg_cb, conn);
+    assert(conn->sint_route);
+
+    assert(!hyperv_set_msg_handler(conn->conn_id, msg_handler, conn));
+
+    QLIST_INSERT_HEAD(&dev->msg_conns, conn, le);
+}
+
+static void msg_conn_destroy(HypervTestDev *dev, uint8_t conn_id)
+{
+    TestMsgConn *conn;
+
+    QLIST_FOREACH(conn, &dev->msg_conns, le) {
+        if (conn->conn_id == conn_id) {
+            QLIST_REMOVE(conn, le);
+            hyperv_set_msg_handler(conn->conn_id, NULL, NULL);
+            hyperv_sint_route_unref(conn->sint_route);
+            g_free(conn);
+            return;
+        }
+    }
+    assert(false);
+}
+
+static void evt_conn_handler(EventNotifier *notifier)
+{
+    TestEvtConn *conn = container_of(notifier, TestEvtConn, notifier);
+
+    event_notifier_test_and_clear(notifier);
+
+    /* signal the same event flag we've got */
+    assert(!hyperv_set_event_flag(conn->sint_route, conn->conn_id));
+}
+
+static void evt_conn_create(HypervTestDev *dev, uint8_t vp_index,
+                            uint8_t sint, uint8_t conn_id)
+{
+    TestEvtConn *conn;
+
+    conn = g_new0(TestEvtConn, 1);
+    assert(conn);
+
+    conn->conn_id = conn_id;
+
+    conn->sint_route = hyperv_sint_route_new(vp_index, sint, NULL, NULL);
+    assert(conn->sint_route);
+
+    assert(!event_notifier_init(&conn->notifier, false));
+
+    event_notifier_set_handler(&conn->notifier, evt_conn_handler);
+
+    assert(!hyperv_set_event_flag_handler(conn_id, &conn->notifier));
+
+    QLIST_INSERT_HEAD(&dev->evt_conns, conn, le);
+}
+
+static void evt_conn_destroy(HypervTestDev *dev, uint8_t conn_id)
+{
+    TestEvtConn *conn;
+
+    QLIST_FOREACH(conn, &dev->evt_conns, le) {
+        if (conn->conn_id == conn_id) {
+            QLIST_REMOVE(conn, le);
+            hyperv_set_event_flag_handler(conn->conn_id, NULL);
+            event_notifier_set_handler(&conn->notifier, NULL);
+            event_notifier_cleanup(&conn->notifier);
+            hyperv_sint_route_unref(conn->sint_route);
+            g_free(conn);
+            return;
+        }
+    }
+    assert(false);
+}
+
 static void hv_test_dev_control(void *opaque, hwaddr addr, uint64_t data,
                                 uint32_t len)
 {
@@ -100,6 +248,7 @@ static void hv_test_dev_control(void *opaque, hwaddr addr, uint64_t data,
     uint8_t sint = data & 0xFF;
     uint8_t vp_index = (data >> 8ULL) & 0xFF;
     uint8_t ctl = (data >> 16ULL) & 0xFF;
+    uint8_t conn_id = (data >> 24ULL) & 0xFF;
 
     switch (ctl) {
     case HV_TEST_DEV_SINT_ROUTE_CREATE:
@@ -111,6 +260,18 @@ static void hv_test_dev_control(void *opaque, hwaddr addr, uint64_t data,
     case HV_TEST_DEV_SINT_ROUTE_SET_SINT:
         sint_route_set_sint(dev, vp_index, sint);
         break;
+    case HV_TEST_DEV_MSG_CONN_CREATE:
+        msg_conn_create(dev, vp_index, sint, conn_id);
+        break;
+    case HV_TEST_DEV_MSG_CONN_DESTROY:
+        msg_conn_destroy(dev, conn_id);
+        break;
+    case HV_TEST_DEV_EVT_CONN_CREATE:
+        evt_conn_create(dev, vp_index, sint, conn_id);
+        break;
+    case HV_TEST_DEV_EVT_CONN_DESTROY:
+        evt_conn_destroy(dev, conn_id);
+        break;
     default:
         break;
     }
@@ -130,6 +291,8 @@ static void hv_test_dev_realizefn(DeviceState *d, Error **errp)
     MemoryRegion *io = isa_address_space_io(isa);
 
     QLIST_INIT(&dev->sint_routes);
+    QLIST_INIT(&dev->msg_conns);
+    QLIST_INIT(&dev->evt_conns);
     memory_region_init_io(&dev->sint_control, OBJECT(dev),
                           &synic_test_sint_ops, dev,
                           "hyperv-testdev-ctl", 4);
