if (efx_ef100_has_cap(nic_data->datapath_caps2, TX_TSO_V3)) {
                struct net_device *net_dev = efx->net_dev;
                netdev_features_t tso = NETIF_F_TSO | NETIF_F_TSO6 | NETIF_F_GSO_PARTIAL |
-                                       NETIF_F_GSO_UDP_TUNNEL | NETIF_F_GSO_UDP_TUNNEL_CSUM;
+                                       NETIF_F_GSO_UDP_TUNNEL | NETIF_F_GSO_UDP_TUNNEL_CSUM |
+                                       NETIF_F_GSO_GRE | NETIF_F_GSO_GRE_CSUM;
 
                net_dev->features |= tso;
                net_dev->hw_features |= tso;
                net_dev->hw_enc_features |= tso;
+               /* EF100 HW can only offload outer checksums if they are UDP,
+                * so for GRE_CSUM we have to use GSO_PARTIAL.
+                */
+               net_dev->gso_partial_features |= NETIF_F_GSO_GRE_CSUM;
        }
        efx->num_mac_stats = MCDI_WORD(outbuf,
                                       GET_CAPABILITIES_V4_OUT_MAC_STATS_NUM_STATS);
 
        u16 vlan_tci = skb_vlan_tag_get(skb);
        u32 mss = skb_shinfo(skb)->gso_size;
        bool encap = skb->encapsulation;
+       bool udp_encap = false;
        u16 vlan_enable = 0;
        struct tcphdr *tcp;
        bool outer_csum;
                outer_l4_offset = skb_transport_offset(skb);
                ip_offset = skb_inner_network_offset(skb);
                tcp_offset = skb_inner_transport_offset(skb);
+               if (skb_shinfo(skb)->gso_type &
+                   (SKB_GSO_UDP_TUNNEL | SKB_GSO_UDP_TUNNEL_CSUM))
+                       udp_encap = true;
        } else {
                ip_offset =  skb_network_offset(skb);
                tcp_offset = skb_transport_offset(skb);
                              ESF_GZ_TX_TSO_ED_INNER_IP_LEN, 1,
                              ESF_GZ_TX_TSO_OUTER_L3_OFF_W, outer_ip_offset >> 1,
                              ESF_GZ_TX_TSO_OUTER_L4_OFF_W, outer_l4_offset >> 1,
-                             ESF_GZ_TX_TSO_ED_OUTER_UDP_LEN, encap && !gso_partial,
+                             ESF_GZ_TX_TSO_ED_OUTER_UDP_LEN, udp_encap && !gso_partial,
                              ESF_GZ_TX_TSO_ED_OUTER_IP_LEN, encap && !gso_partial,
                              ESF_GZ_TX_TSO_ED_OUTER_IP4_ID, encap ? mangleid :
                                                                     ESE_GZ_TX_DESC_IP4_ID_NO_OP,