Hi Konstantin, > -----Original Message----- > From: Ananyev, Konstantin > Sent: Monday, February 15, 2016 9:16 PM > To: Thomas Monjalon; Lu, Wenzhuo > Cc: dev at dpdk.org > Subject: RE: [dpdk-dev] [PATCH v2 5/6] ixgbe: support VxLAN & NVGRE TX > checksum off-load > > Hi lads, > > > -----Original Message----- > > From: Thomas Monjalon [mailto:thomas.monjalon at 6wind.com] > > Sent: Monday, February 15, 2016 10:03 AM > > To: Lu, Wenzhuo > > Cc: dev at dpdk.org; Ananyev, Konstantin > > Subject: Re: [dpdk-dev] [PATCH v2 5/6] ixgbe: support VxLAN & NVGRE TX > > checksum off-load > > > > 2016-02-15 05:32, Lu, Wenzhuo: > > > From: Ananyev, Konstantin > > > > From reading X550 spec, I don't really understand what for we need > > > > to specify is it GRE or VXLAN packet, so probably we don't need that > > > > flag > for now at all? > > > The reason is we need to set the tunnel type in the Advanced Transmit Data > Descriptor. > > Yes, I saw that in x550 spec, though I really doubt it is needed to calculate > etiher > outer IP, or inner IP/L4 checksum. > After all TUNNELLEN includes all tunnel headers plus inner L2 length. > The only reason I can think it might be useful for HW is when packets are > sent > from one VF to another. > In that case, HW probably would try to avoid extra packet scanning and rely on > information from SW. > As mentioned in x550 spec, section's note: > "...In virtualization mode, packets might be received from other local VMs. > The > X550 does not check the L5 header for these packets and does not report NFS > header. If such packets carry IP tunneling (IPv4 - IPv6), they are reported as > IPV4E. The packets received from local VM are indicated by the LB bit in the > status field. To be identified, the CC bit in the transmit descriptor must be > set > and if it is a tunnel packet, the TUNNEL.OUTERIPCS must be set also." > Though I am not sure we do need to support that case. > That's why probably the easiest way would be to avoid setting 'Tunnel Type' > field > at all. Many thanks for your suggestion. I think you're right. For outer IP header checksum offload, we need not to set the tunnel type bit. I'll choose this option and remove this vxlan ol_flag.
> > > > > Why don't we use packet type? > > Yes, that's probably another possible way, if we really decide to setup this > info > at TX descriptor. > > BTW, reading x550 spec, I think ixgbe RX code that setups packet_type need to > be updated too. > Right now it can't handle vxlan/gre tunnelling case. > > Konstantin > > > > > > > If we really do, might bw worth to organise it like KT_TX_L4_CKSUM > > > > (as enum) and reserve few values for future expansion (2 or 3 bits?). > > > Now there're only VxLAN and NVGRE supported. So, only 1 bit is > > > occupied for that. Not sure if more types will be supported in the > > future. Any suggestions? Thanks. > > > > Yes there can be a lot of tunnel types. > > Please check RTE_PTYPE_TUNNEL_* > >
