On Wed, Nov 12, 2025 at 12:04 PM David Marchand <[email protected]> wrote:
> A bug in the vhost library for VDUSE devices resulted in multi-segments > mbufs being treated by OVS. > > This hard to debug situation resulted in incorrectly segmented packets > with mlx5 nics, as the DPDK driver handles multi-segments mbufs fine > even without requiring RTE_ETH_TX_OFFLOAD_MULTI_SEGS. > > While the bug is fixed in the vhost library, we could still hit similar > situations with "normal" DPDK ports: for example, > RTE_ETH_RX_OFFLOAD_SCATTER is requested for jumbo frames and a bug could > be hidden there. > > Enforce only mono-segment mbufs are received. > > Link: > https://patchwork.dpdk.org/project/dpdk/patch/[email protected]/ > Reported-at > <https://patchwork.dpdk.org/project/dpdk/patch/[email protected]/Reported-at>: > https://issues.redhat.com/browse/FDP-2121 > Signed-off-by: David Marchand <[email protected]> > --- > lib/netdev-dpdk.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/lib/netdev-dpdk.c b/lib/netdev-dpdk.c > index 3704145a57..0cb9fae9f0 100644 > --- a/lib/netdev-dpdk.c > +++ b/lib/netdev-dpdk.c > @@ -2598,6 +2598,9 @@ netdev_dpdk_batch_init_packet_fields(struct > dp_packet_batch *batch) > struct dp_packet *packet; > > DP_PACKET_BATCH_FOR_EACH (i, packet, batch) { > + /* Datapath does not support multi-segment buffers. */ > + ovs_assert(packet->mbuf.nb_segs == 1); > Would this assert ever be hit in a case that wasn't a bug in a DPDK driver? -M + > dp_packet_reset_cutlen(packet); > packet->packet_type = htonl(PT_ETH); > packet->has_hash = !!(packet->mbuf.ol_flags & > RTE_MBUF_F_RX_RSS_HASH); > -- > 2.51.0 > > _______________________________________________ dev mailing list [email protected] https://mail.openvswitch.org/mailman/listinfo/ovs-dev
