@@ -198,6 +198,28 @@ virtqueue_enqueue_recv_refill(struct virtqueue *vq, struct rte_mbuf *cookie)
 	return 0;
 }
 
+static void
+virtqueue_enqueue_offload(struct virtqueue *txvq, struct rte_mbuf *m,
+			uint16_t idx, uint16_t hdr_sz)
+{
+	struct virtio_net_hdr *hdr = (struct virtio_net_hdr *)(uintptr_t)
+				(txvq->virtio_net_hdr_addr + idx * hdr_sz);
+
+	if (m->tso_segsz != 0 && m->ol_flags & PKT_TX_TCP_SEG) {
+		if (m->ol_flags & PKT_TX_IPV4) {
+			if (!vtpci_with_feature(txvq->hw, VIRTIO_NET_F_HOST_TSO4))
+				return;
+			hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
+		} else if (m->ol_flags & PKT_TX_IPV6) {
+			if (!vtpci_with_feature(txvq->hw, VIRTIO_NET_F_HOST_TSO6))
+				return;
+			hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
+		}
+		hdr->gso_size = m->tso_segsz;
+		hdr->hdr_len = m->l2_len + m->l3_len + m->l4_len;
+	}
+}
+
 static int
 virtqueue_enqueue_xmit(struct virtqueue *txvq, struct rte_mbuf *cookie)
 {

@@ -221,6 +243,7 @@ virtqueue_enqueue_xmit(struct virtqueue *txvq, struct rte_mbuf *cookie)
 	dxp->cookie = (void *)cookie;
 	dxp->ndescs = needed;
 
+	virtqueue_enqueue_offload(txvq, cookie, idx, head_size);
 	start_dp = txvq->vq_ring.desc;
 	start_dp[idx].addr =
 		txvq->virtio_net_hdr_mem + idx * head_size;