diff --git a/drivers/net/ethernet/netronome/nfp/flower/cmsg.c b/drivers/net/ethernet/netronome/nfp/flower/cmsg.c
index baaea6f1a9d8..3735c09d2112 100644
--- a/drivers/net/ethernet/netronome/nfp/flower/cmsg.c
+++ b/drivers/net/ethernet/netronome/nfp/flower/cmsg.c
@@ -104,7 +104,8 @@ nfp_flower_cmsg_mac_repr_add(struct sk_buff *skb, unsigned int idx,
 	msg->ports[idx].phys_port = phys_port;
 }
 
-int nfp_flower_cmsg_portmod(struct nfp_repr *repr, bool carrier_ok)
+int nfp_flower_cmsg_portmod(struct nfp_repr *repr, bool carrier_ok,
+			    unsigned int mtu, bool mtu_only)
 {
 	struct nfp_flower_cmsg_portmod *msg;
 	struct sk_buff *skb;
@@ -118,7 +119,11 @@ int nfp_flower_cmsg_portmod(struct nfp_repr *repr, bool carrier_ok)
 	msg->portnum = cpu_to_be32(repr->dst->u.port_info.port_id);
 	msg->reserved = 0;
 	msg->info = carrier_ok;
-	msg->mtu = cpu_to_be16(repr->netdev->mtu);
+
+	if (mtu_only)
+		msg->info |= NFP_FLOWER_CMSG_PORTMOD_MTU_CHANGE_ONLY;
+
+	msg->mtu = cpu_to_be16(mtu);
 
 	nfp_ctrl_tx(repr->app->ctrl, skb);
 
@@ -146,6 +151,34 @@ int nfp_flower_cmsg_portreify(struct nfp_repr *repr, bool exists)
 	return 0;
 }
 
+static bool
+nfp_flower_process_mtu_ack(struct nfp_app *app, struct sk_buff *skb)
+{
+	struct nfp_flower_priv *app_priv = app->priv;
+	struct nfp_flower_cmsg_portmod *msg;
+
+	msg = nfp_flower_cmsg_get_data(skb);
+
+	if (!(msg->info & NFP_FLOWER_CMSG_PORTMOD_MTU_CHANGE_ONLY))
+		return false;
+
+	spin_lock_bh(&app_priv->mtu_conf.lock);
+	if (!app_priv->mtu_conf.requested_val ||
+	    app_priv->mtu_conf.portnum != be32_to_cpu(msg->portnum) ||
+	    be16_to_cpu(msg->mtu) != app_priv->mtu_conf.requested_val) {
+		/* Not an ack for requested MTU change. */
+		spin_unlock_bh(&app_priv->mtu_conf.lock);
+		return false;
+	}
+
+	app_priv->mtu_conf.ack = true;
+	app_priv->mtu_conf.requested_val = 0;
+	wake_up(&app_priv->mtu_conf.wait_q);
+	spin_unlock_bh(&app_priv->mtu_conf.lock);
+
+	return true;
+}
+
 static void
 nfp_flower_cmsg_portmod_rx(struct nfp_app *app, struct sk_buff *skb)
 {
@@ -269,6 +302,10 @@ void nfp_flower_cmsg_rx(struct nfp_app *app, struct sk_buff *skb)
 		/* We need to deal with stats updates from HW asap */
 		nfp_flower_rx_flow_stats(app, skb);
 		dev_consume_skb_any(skb);
+	} else if (cmsg_hdr->type == NFP_FLOWER_CMSG_TYPE_PORT_MOD &&
+		   nfp_flower_process_mtu_ack(app, skb)) {
+		/* Handle MTU acks outside wq to prevent RTNL conflict. */
+		dev_consume_skb_any(skb);
 	} else {
 		skb_queue_tail(&priv->cmsg_skbs, skb);
 		schedule_work(&priv->cmsg_work);
diff --git a/drivers/net/ethernet/netronome/nfp/flower/cmsg.h b/drivers/net/ethernet/netronome/nfp/flower/cmsg.h
index 3f46d836d1b8..96bc0e33980c 100644
--- a/drivers/net/ethernet/netronome/nfp/flower/cmsg.h
+++ b/drivers/net/ethernet/netronome/nfp/flower/cmsg.h
@@ -397,6 +397,7 @@ struct nfp_flower_cmsg_portmod {
 };
 
 #define NFP_FLOWER_CMSG_PORTMOD_INFO_LINK	BIT(0)
+#define NFP_FLOWER_CMSG_PORTMOD_MTU_CHANGE_ONLY	BIT(1)
 
 /* NFP_FLOWER_CMSG_TYPE_PORT_REIFY */
 struct nfp_flower_cmsg_portreify {
@@ -464,7 +465,8 @@ void
 nfp_flower_cmsg_mac_repr_add(struct sk_buff *skb, unsigned int idx,
 			     unsigned int nbi, unsigned int nbi_port,
 			     unsigned int phys_port);
-int nfp_flower_cmsg_portmod(struct nfp_repr *repr, bool carrier_ok);
+int nfp_flower_cmsg_portmod(struct nfp_repr *repr, bool carrier_ok,
+			    unsigned int mtu, bool mtu_only);
 int nfp_flower_cmsg_portreify(struct nfp_repr *repr, bool exists);
 void nfp_flower_cmsg_process_rx(struct work_struct *work);
 void nfp_flower_cmsg_rx(struct nfp_app *app, struct sk_buff *skb);
diff --git a/drivers/net/ethernet/netronome/nfp/flower/main.c b/drivers/net/ethernet/netronome/nfp/flower/main.c
index 742d6f1575b5..6357e0720f43 100644
--- a/drivers/net/ethernet/netronome/nfp/flower/main.c
+++ b/drivers/net/ethernet/netronome/nfp/flower/main.c
@@ -52,6 +52,8 @@
 
 #define NFP_FLOWER_ALLOWED_VER 0x0001000000010000UL
 
+#define NFP_FLOWER_FRAME_HEADROOM	158
+
 static const char *nfp_flower_extra_cap(struct nfp_app *app, struct nfp_net *nn)
 {
 	return "FLOWER";
@@ -157,7 +159,7 @@ nfp_flower_repr_netdev_open(struct nfp_app *app, struct nfp_repr *repr)
 {
 	int err;
 
-	err = nfp_flower_cmsg_portmod(repr, true);
+	err = nfp_flower_cmsg_portmod(repr, true, repr->netdev->mtu, false);
 	if (err)
 		return err;
 
@@ -171,7 +173,7 @@ nfp_flower_repr_netdev_stop(struct nfp_app *app, struct nfp_repr *repr)
 {
 	netif_tx_disable(repr->netdev);
 
-	return nfp_flower_cmsg_portmod(repr, false);
+	return nfp_flower_cmsg_portmod(repr, false, repr->netdev->mtu, false);
 }
 
 static int
@@ -521,6 +523,9 @@ static int nfp_flower_init(struct nfp_app *app)
 	INIT_WORK(&app_priv->cmsg_work, nfp_flower_cmsg_process_rx);
 	init_waitqueue_head(&app_priv->reify_wait_queue);
 
+	init_waitqueue_head(&app_priv->mtu_conf.wait_q);
+	spin_lock_init(&app_priv->mtu_conf.lock);
+
 	err = nfp_flower_metadata_init(app);
 	if (err)
 		goto err_free_app_priv;
@@ -552,6 +557,81 @@ static void nfp_flower_clean(struct nfp_app *app)
 	app->priv = NULL;
 }
 
+static int
+nfp_flower_check_mtu(struct nfp_app *app, struct net_device *netdev,
+		     int new_mtu)
+{
+	/* The flower fw reserves NFP_FLOWER_FRAME_HEADROOM bytes of the
+	 * supported max MTU to allow for appending tunnel headers. To prevent
+	 * unexpected behaviour this needs to be accounted for.
+	 */
+	if (new_mtu > netdev->max_mtu - NFP_FLOWER_FRAME_HEADROOM) {
+		nfp_err(app->cpp, "New MTU (%d) is not valid\n", new_mtu);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static bool nfp_flower_check_ack(struct nfp_flower_priv *app_priv)
+{
+	bool ret;
+
+	spin_lock_bh(&app_priv->mtu_conf.lock);
+	ret = app_priv->mtu_conf.ack;
+	spin_unlock_bh(&app_priv->mtu_conf.lock);
+
+	return ret;
+}
+
+static int
+nfp_flower_repr_change_mtu(struct nfp_app *app, struct net_device *netdev,
+			   int new_mtu)
+{
+	struct nfp_flower_priv *app_priv = app->priv;
+	struct nfp_repr *repr = netdev_priv(netdev);
+	int err, ack;
+
+	/* Only need to config FW for physical port MTU change. */
+	if (repr->port->type != NFP_PORT_PHYS_PORT)
+		return 0;
+
+	if (!(app_priv->flower_ext_feats & NFP_FL_NBI_MTU_SETTING)) {
+		nfp_err(app->cpp, "Physical port MTU setting not supported\n");
+		return -EINVAL;
+	}
+
+	spin_lock_bh(&app_priv->mtu_conf.lock);
+	app_priv->mtu_conf.ack = false;
+	app_priv->mtu_conf.requested_val = new_mtu;
+	app_priv->mtu_conf.portnum = repr->dst->u.port_info.port_id;
+	spin_unlock_bh(&app_priv->mtu_conf.lock);
+
+	err = nfp_flower_cmsg_portmod(repr, netif_carrier_ok(netdev), new_mtu,
+				      true);
+	if (err) {
+		spin_lock_bh(&app_priv->mtu_conf.lock);
+		app_priv->mtu_conf.requested_val = 0;
+		spin_unlock_bh(&app_priv->mtu_conf.lock);
+		return err;
+	}
+
+	/* Wait for fw to ack the change. */
+	ack = wait_event_timeout(app_priv->mtu_conf.wait_q,
+				 nfp_flower_check_ack(app_priv),
+				 msecs_to_jiffies(10));
+
+	if (!ack) {
+		spin_lock_bh(&app_priv->mtu_conf.lock);
+		app_priv->mtu_conf.requested_val = 0;
+		spin_unlock_bh(&app_priv->mtu_conf.lock);
+		nfp_warn(app->cpp, "MTU change not verified with fw\n");
+		return -EIO;
+	}
+
+	return 0;
+}
+
 static int nfp_flower_start(struct nfp_app *app)
 {
 	return nfp_tunnel_config_start(app);
@@ -574,6 +654,9 @@ const struct nfp_app_type app_flower = {
 	.init		= nfp_flower_init,
 	.clean		= nfp_flower_clean,
 
+	.check_mtu	= nfp_flower_check_mtu,
+	.repr_change_mtu  = nfp_flower_repr_change_mtu,
+
 	.vnic_alloc	= nfp_flower_vnic_alloc,
 	.vnic_init	= nfp_flower_vnic_init,
 	.vnic_clean	= nfp_flower_vnic_clean,
diff --git a/drivers/net/ethernet/netronome/nfp/flower/main.h b/drivers/net/ethernet/netronome/nfp/flower/main.h
index c5cebf6fb1d3..e030b3ce4510 100644
--- a/drivers/net/ethernet/netronome/nfp/flower/main.h
+++ b/drivers/net/ethernet/netronome/nfp/flower/main.h
@@ -65,6 +65,7 @@ struct nfp_app;
 
 /* Extra features bitmap. */
 #define NFP_FL_FEATS_GENEVE		BIT(0)
+#define NFP_FL_NBI_MTU_SETTING		BIT(1)
 
 struct nfp_fl_mask_id {
 	struct circ_buf mask_id_free_list;
@@ -78,6 +79,22 @@ struct nfp_fl_stats_id {
 	u8 repeated_em_count;
 };
 
+/**
+ * struct nfp_mtu_conf - manage MTU setting
+ * @portnum:		NFP port number of repr with requested MTU change
+ * @requested_val:	MTU value requested for repr
+ * @ack:		Received ack that MTU has been correctly set
+ * @wait_q:		Wait queue for MTU acknowledgements
+ * @lock:		Lock for setting/reading MTU variables
+ */
+struct nfp_mtu_conf {
+	u32 portnum;
+	unsigned int requested_val;
+	bool ack;
+	wait_queue_head_t wait_q;
+	spinlock_t lock;
+};
+
 /**
  * struct nfp_flower_priv - Flower APP per-vNIC priv data
  * @app:		Back pointer to app
@@ -106,6 +123,7 @@ struct nfp_fl_stats_id {
  * @reify_replies:	atomically stores the number of replies received
  *			from firmware for repr reify
  * @reify_wait_queue:	wait queue for repr reify response counting
+ * @mtu_conf:		Configuration of repr MTU value
  */
 struct nfp_flower_priv {
 	struct nfp_app *app;
@@ -133,6 +151,7 @@ struct nfp_flower_priv {
 	struct notifier_block nfp_tun_neigh_nb;
 	atomic_t reify_replies;
 	wait_queue_head_t reify_wait_queue;
+	struct nfp_mtu_conf mtu_conf;
 };
 
 struct nfp_fl_key_ls {