Re: [net-next PATCH v2 5/9] octeontx2-af: Add packet path between representor and VF

[Sunil Kovvuri Goutham]

> -----Original Message-----
> From: Jiri Pirko <jiri@xxxxxxxxxxx>
> Sent: Tuesday, April 23, 2024 6:39 PM
> To: Geethasowjanya Akula <gakula@xxxxxxxxxxx>
> Cc: netdev@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; kuba@xxxxxxxxxx;
> davem@xxxxxxxxxxxxx; pabeni@xxxxxxxxxx; edumazet@xxxxxxxxxx; Sunil
> Kovvuri Goutham <sgoutham@xxxxxxxxxxx>; Subbaraya Sundeep Bhatta
> <sbhatta@xxxxxxxxxxx>; Hariprasad Kelam <hkelam@xxxxxxxxxxx>
> Subject: [EXTERNAL] Re: [net-next PATCH v2 5/9] octeontx2-af: Add packet
> path between representor and VF
> 
> Mon, Apr 22, 2024 at 11:53:57AM CEST, gakula@xxxxxxxxxxx wrote:
> >This patch installs tcam rules to stree traffic representors and VF
> >when swicthdev mode is set. To support this a HW loopback channel is
> >reserved. Through this channel packet are routed between representor
> >and VFs. "ESW_CFG" mbox is defined to notify AF for installing rules.
> 
> This sounds very wrong. In switchdev mode, there is no implicit packet
> forwarding. User configures that, either by setting up TC filters to
> match/forward packets, putting representors in a bridge, etc.
> Basically the driver offloads whatever configuration on representors the user
> does, in case it supports it.
> 
> Please make sure you follow that.

In our HW, there is no in-built switch which will forward pkts between representee and representor.
When representor is put under a bridge and pkts needs to be sent to representee, then pkts from
representor are sent on a HW internal loopback channel, which again will be punted to ingress
pkt parser. Now the rules that this patch installs are the MCAM filters/rules which will match against
these pkts and forward them to representee.

To be more clear the rules that this patch installs are for basic representor <-=> representee path
similar to Tun/TAP between VM and Host. Now for any further offloads (eg: L2 or ConnTrk)
user will have to install explicit rules via TC filters.

Thanks,
Sunil.