RE: [PATCH v2 6/6] net/vhost: perform SW checksum in Tx path

["Jiang, Cheng1" <cheng1.jiang@intel.com>]

Hi Maxime,

> -----Original Message-----
> From: Xia, Chenbo <chenbo.xia@intel.com>
> Sent: Friday, June 10, 2022 11:50 AM
> To: Maxime Coquelin <maxime.coquelin@redhat.com>; dev@dpdk.org;
> jasowang@redhat.com; david.marchand@redhat.com; Matz, Olivier
> <olivier.matz@6wind.com>; Ma, WenwuX <wenwux.ma@intel.com>; Zhang,
> Yuying <yuying.zhang@intel.com>; Singh, Aman Deep
> <aman.deep.singh@intel.com>
> Subject: RE: [PATCH v2 6/6] net/vhost: perform SW checksum in Tx path
> 
> +Cheng for review
> 
> > -----Original Message-----
> > From: Maxime Coquelin <maxime.coquelin@redhat.com>
> > Sent: Wednesday, June 8, 2022 8:50 PM
> > To: dev@dpdk.org; jasowang@redhat.com; Xia, Chenbo
> > <chenbo.xia@intel.com>; david.marchand@redhat.com; Matz, Olivier
> > <olivier.matz@6wind.com>; Ma, WenwuX <wenwux.ma@intel.com>;
> Zhang,
> > Yuying <yuying.zhang@intel.com>; Singh, Aman Deep
> > <aman.deep.singh@intel.com>
> > Cc: Maxime Coquelin <maxime.coquelin@redhat.com>
> > Subject: [PATCH v2 6/6] net/vhost: perform SW checksum in Tx path
> >
> > Virtio specification supports guest checksum offloading for L4, which
> > is enabled with VIRTIO_NET_F_GUEST_CSUM feature negotiation.
> However,
> > the Vhost PMD does not advertise Tx checksum offload capabilities.
> >
> > Advertising these offload capabilities at the ethdev level is not
> > enough, because we could still end-up with the application enabling
> > these offloads while the guest not negotiating it.
> >
> > This patch advertises the Tx checksum offload capabilities, and
> > introduces a compatibility layer to cover the case
> > VIRTIO_NET_F_GUEST_CSUM has not been negotiated but the application
> > does configure the Tx checksum offloads. This function performs the L4
> > Tx checksum in SW for UDP and TCP.
> > Compared to Rx SW checksum, the Tx SW checksum function needs to
> > compute the pseudo-header checksum, as we cannot know whether it was
> > done before.
> >
> > This patch does not advertise SCTP checksum offloading capability for
> > now, but it could be handled later if the need arises.
> >
> > Reported-by: Jason Wang <jasowang@redhat.com>
> > Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
> > ---

Reviewed-by: Cheng Jiang <cheng1.jiang@intel.com>