Re: [virtio-comment] RE: [PATCH v13] virtio-net: support inner header hash

[Heng Qi <hengqi@linux.alibaba.com>]

å 2023/4/26 äå9:47, Parav Pandit åé:
> > From: Heng Qi <hengqi@linux.alibaba.com>
> > Sent: Wednesday, April 26, 2023 9:43 AM
> > > "With that no need to define two fields at two different places in
> > > config area and also in cvq."
> > I'm not sure if this is sufficiently motivated, RSS also has supports_hash_types
> > in config space.
> There are many fields grown to MMIO config space because 0.9.5 has config space there.
> These are usually one time read or rarely used; hence it doesnât need to come from this area of the device to be _always_ available.

Yes.

supported_tunnel_hash_types If in cvq, each GET command needs to return 
supported_tunnel_hash_types and hash_tunnel_types,
but users may only need the hash_tunnel_types "SET" by themselves.

>   
> > We don't actually need cvq and config to sync on
> > supported_tunnel_hash_types, since it doesn't need to change (meaning
> > supported_tunnel_hash_types doesn't send configuration change
> > notifications).
> It doesnât but device is expected to publish the value at two places.

Yes, but that seems like a tiny cost, and the cvq command-related 
structure is much simpler.

> > > > +For scenarios with sufficient external entropy or no internal
> > > > hashing requirements, inner header hash may not be needed:
> > > > +A tunnel is often expected to isolate the external network from the
> > > > internal one. By completely ignoring entropy
> > > > +in the external header and replacing it with entropy from the
> > > > internal header, for hash calculations, this expectation
> > > You wanted to say inner here like rest of the places.
> > >
> > > s/internal header/inner header
> > I want to make the 'external' and 'internal' correspond, but avoid the internal
> > header, and use a unified 'inner header' is also reasonable.:)
> Since in rest of other description, we refer to it as "outer", it is better to keep it consistent as outer instead of external here.

Totally agree.

Thanks.