Re: [dpdk-dev] [PATCH 5/5] vhost: fix offload flags in Rx path

[Flavio Leitner <fbl@sysclose.org>]

On Thu, Apr 01, 2021 at 11:52:43AM +0200, David Marchand wrote:
> The vhost library current configures Tx offloading (PKT_TX_*) on any
> packet received from a guest virtio device which asks for some offloading.
> 
> This is problematic, as Tx offloading is something that the application
> must ask for: the application needs to configure devices
> to support every used offloads (ip, tcp checksumming, tso..), and the
> various l2/l3/l4 lengths must be set following any processing that
> happened in the application itself.
> 
> On the other hand, the received packets are not marked wrt current
> packet l3/l4 checksumming info.
> 
> Copy virtio rx processing to fix those offload flags.
> 
> The vhost example needs a reworking as it was built with the assumption
> that mbuf TSO configuration is set up by the vhost library.
> This is not done in this patch for now so TSO activation is forcibly
> refused.
> 
> Fixes: 859b480d5afd ("vhost: add guest offload setting")

There is change that before ECN was ignored and now it is invalid.
I think that's the right way to go, but not sure if virtio blocks
the negotiation of that feature.

Reviewed-by: Flavio Leitner <fbl@sysclose.org>

fbl