No segmentation should be performed if gso type is
VIRTIO_NET_HDR_GSO_NONE even if ECN bit is set.

Fixes: e263cd49c7 ("Packet abstraction for VMWARE network devices")
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1544
Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
---
 hw/net/net_tx_pkt.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/hw/net/net_tx_pkt.c b/hw/net/net_tx_pkt.c
index cb606cc84b..efe80b1a80 100644
--- a/hw/net/net_tx_pkt.c
+++ b/hw/net/net_tx_pkt.c
@@ -796,11 +796,13 @@ bool net_tx_pkt_send_custom(struct NetTxPkt *pkt, bool offload,
 {
     assert(pkt);
 
+    uint8_t gso_type = pkt->virt_hdr.gso_type & ~VIRTIO_NET_HDR_GSO_ECN;
+
     /*
      * Since underlying infrastructure does not support IP datagrams longer
      * than 64K we should drop such packets and don't even try to send
      */
-    if (VIRTIO_NET_HDR_GSO_NONE != pkt->virt_hdr.gso_type) {
+    if (VIRTIO_NET_HDR_GSO_NONE != gso_type) {
         if (pkt->payload_len >
             ETH_MAX_IP_DGRAM_LEN -
             pkt->vec[NET_TX_PKT_L3HDR_FRAG].iov_len) {
@@ -808,7 +810,7 @@ bool net_tx_pkt_send_custom(struct NetTxPkt *pkt, bool offload,
         }
     }
 
-    if (offload || pkt->virt_hdr.gso_type == VIRTIO_NET_HDR_GSO_NONE) {
+    if (offload || gso_type == VIRTIO_NET_HDR_GSO_NONE) {
         if (!offload && pkt->virt_hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
             net_tx_pkt_do_sw_csum(pkt, &pkt->vec[NET_TX_PKT_L2HDR_FRAG],
                                   pkt->payload_frags + NET_TX_PKT_PL_START_FRAG - 1,
-- 
2.39.2