Index: head/sys/dev/hyperv/netvsc/hv_net_vsc.h
===================================================================
--- head/sys/dev/hyperv/netvsc/hv_net_vsc.h
+++ head/sys/dev/hyperv/netvsc/hv_net_vsc.h
@@ -261,7 +261,7 @@
 struct hn_send_ctx;
 
 void netvsc_linkstatus_callback(struct hn_softc *sc, uint32_t status);
-int hv_nv_on_device_add(struct hn_softc *sc);
+int hv_nv_on_device_add(struct hn_softc *sc, int mtu);
 int hv_nv_on_device_remove(struct hn_softc *sc);
 int hv_nv_on_send(struct vmbus_channel *chan, uint32_t rndis_mtype,
 	struct hn_send_ctx *sndc, struct vmbus_gpa *gpa, int gpa_cnt);
Index: head/sys/dev/hyperv/netvsc/hv_net_vsc.c
===================================================================
--- head/sys/dev/hyperv/netvsc/hv_net_vsc.c
+++ head/sys/dev/hyperv/netvsc/hv_net_vsc.c
@@ -61,7 +61,7 @@
 static int  hv_nv_init_rx_buffer_with_net_vsp(struct hn_softc *);
 static int  hv_nv_destroy_send_buffer(struct hn_softc *sc);
 static int  hv_nv_destroy_rx_buffer(struct hn_softc *sc);
-static int  hv_nv_connect_to_vsp(struct hn_softc *sc);
+static int  hv_nv_connect_to_vsp(struct hn_softc *sc, int mtu);
 static void hn_nvs_sent_none(struct hn_send_ctx *sndc,
     struct hn_softc *, struct vmbus_channel *chan,
     const void *, int);
@@ -526,10 +526,9 @@
  * Net VSC connect to VSP
  */
 static int
-hv_nv_connect_to_vsp(struct hn_softc *sc)
+hv_nv_connect_to_vsp(struct hn_softc *sc, int mtu)
 {
 	int ret = 0;
-	struct ifnet *ifp = sc->hn_ifp;
 	struct hn_nvs_ndis_init ndis;
 
 	ret = hn_nvs_init(sc);
@@ -541,7 +540,7 @@
 	 * This needs to be right after the NVSP init message per Haiyang
 	 */
 	if (sc->hn_nvs_ver >= HN_NVS_VERSION_2)
-		ret = hv_nv_send_ndis_config(sc, ifp->if_mtu);
+		ret = hv_nv_send_ndis_config(sc, mtu);
 
 	/*
 	 * Initialize NDIS.
@@ -583,13 +582,13 @@
  * Callback when the device belonging to this driver is added
  */
 int
-hv_nv_on_device_add(struct hn_softc *sc)
+hv_nv_on_device_add(struct hn_softc *sc, int mtu)
 {
 
 	/*
 	 * Connect with the NetVsp
 	 */
-	return (hv_nv_connect_to_vsp(sc));
+	return (hv_nv_connect_to_vsp(sc, mtu));
 }
 
 /*
Index: head/sys/dev/hyperv/netvsc/hv_netvsc_drv_freebsd.c
===================================================================
--- head/sys/dev/hyperv/netvsc/hv_netvsc_drv_freebsd.c
+++ head/sys/dev/hyperv/netvsc/hv_netvsc_drv_freebsd.c
@@ -528,7 +528,6 @@
 	ifp->if_flags = IFF_BROADCAST | IFF_SIMPLEX | IFF_MULTICAST;
 	ifp->if_ioctl = hn_ioctl;
 	ifp->if_init = hn_ifinit;
-	/* needed by hv_rf_on_device_add() code */
 	ifp->if_mtu = ETHERMTU;
 	if (hn_use_if_start) {
 		int qdepth = hn_get_txswq_depth(&sc->hn_tx_ring[0]);
@@ -565,7 +564,7 @@
 	if (sc->hn_xact == NULL)
 		goto failed;
 
-	error = hv_rf_on_device_add(sc, &device_info, &ring_cnt);
+	error = hv_rf_on_device_add(sc, &device_info, &ring_cnt, ETHERMTU);
 	if (error)
 		goto failed;
 	KASSERT(ring_cnt > 0 && ring_cnt <= sc->hn_rx_ring_inuse,
@@ -1584,7 +1583,8 @@
 		hn_chan_attach(sc, sc->hn_prichan); /* XXX check error */
 
 		ring_cnt = sc->hn_rx_ring_inuse;
-		error = hv_rf_on_device_add(sc, &device_info, &ring_cnt);
+		error = hv_rf_on_device_add(sc, &device_info, &ring_cnt,
+		    ifr->ifr_mtu);
 		if (error) {
 			NV_LOCK(sc);
 			sc->temp_unusable = FALSE;
Index: head/sys/dev/hyperv/netvsc/hv_rndis_filter.h
===================================================================
--- head/sys/dev/hyperv/netvsc/hv_rndis_filter.h
+++ head/sys/dev/hyperv/netvsc/hv_rndis_filter.h
@@ -43,7 +43,8 @@
 void hv_rf_on_receive(struct hn_softc *sc, struct hn_rx_ring *rxr,
     const void *data, int dlen);
 void hv_rf_channel_rollup(struct hn_rx_ring *rxr, struct hn_tx_ring *txr);
-int hv_rf_on_device_add(struct hn_softc *sc, void *additl_info, int *nchan);
+int hv_rf_on_device_add(struct hn_softc *sc, void *additl_info, int *nchan,
+    int mtu);
 int hv_rf_on_device_remove(struct hn_softc *sc);
 int hv_rf_on_open(struct hn_softc *sc);
 int hv_rf_on_close(struct hn_softc *sc);
Index: head/sys/dev/hyperv/netvsc/hv_rndis_filter.c
===================================================================
--- head/sys/dev/hyperv/netvsc/hv_rndis_filter.c
+++ head/sys/dev/hyperv/netvsc/hv_rndis_filter.c
@@ -1012,7 +1012,7 @@
  */
 int
 hv_rf_on_device_add(struct hn_softc *sc, void *additl_info,
-    int *nchan0)
+    int *nchan0, int mtu)
 {
 	int ret;
 	netvsc_device_info *dev_info = (netvsc_device_info *)additl_info;
@@ -1031,7 +1031,7 @@
 	 * (hv_rf_on_receive()) before this call is completed.
 	 * Note:  Earlier code used a function pointer here.
 	 */
-	ret = hv_nv_on_device_add(sc);
+	ret = hv_nv_on_device_add(sc, mtu);
 	if (ret != 0)
 		return (ret);