[RFC 1/2] vhost: add ingress API for port mirroring datapath

[Jiang, Cheng1]

Hi,

> -----Original Message-----
> From: Stephen Hemminger <stephen at networkplumber.org>
> Sent: Sunday, August 14, 2022 10:58 PM
> To: Jiang, Cheng1 <cheng1.jiang at intel.com>
> Cc: maxime.coquelin at redhat.com; Xia, Chenbo <chenbo.xia at intel.com>;
> dev at dpdk.org; Hu, Jiayu <jiayu.hu at intel.com>; Ding, Xuan
> <xuan.ding at intel.com>; Ma, WenwuX <wenwux.ma at intel.com>; Wang,
> YuanX <yuanx.wang at intel.com>; Yang, YvonneX <yvonnex.yang at intel.com>
> Subject: Re: [RFC 1/2] vhost: add ingress API for port mirroring datapath
> 
> On Sun, 14 Aug 2022 12:49:19 +0000
> Cheng Jiang <cheng1.jiang at intel.com> wrote:
> 
> > From: Wenwu Ma <wenwux.ma at intel.com>
> >
> > Similar to the port mirroring function on the switch or router, this
> > patch also implements an ingress function on the Vhost lib. When data
> > is sent to a front-end, it will also send the data to its mirror
> > front-end.
> >
> > Signed-off-by: Cheng Jiang <cheng1.jiang at intel.com>
> > Signed-off-by: Wenwu Ma <wenwux.ma at intel.com>
> 
> We already have rte_flow, packet capture, and rx/tx callbacks.
> This seems like re-invention.

Sorry that I didn't make it clear in the v1 commit message. This port mirror function is based on async vhost which is accelerated by DMA device. Compared with other mirror implements: 1. It's targeted for vhost. 2. The performance is really good. Its use scenario is to let one front-end(mirror-VM) monitor the traffic of another front-end(VM). It's different from the things you mentioned above. So, IMO I don't think it's re-invention.

Thanks,
Cheng