[dpdk-dev] [PATCH 00/11] net/vhostpci: A new vhostpci PMD supporting VM2VM scenario

[Yang, Zhiyong]

Hi Jianfeng,

> -----Original Message-----
> From: Tan, Jianfeng
> Sent: Thursday, December 21, 2017 1:52 PM
> To: Yang, Zhiyong <zhiyong.yang at intel.com>; Maxime Coquelin
> <maxime.coquelin at redhat.com>; dev at dpdk.org; yliu at fridaylinux.org
> Cc: Wang, Wei W <wei.w.wang at intel.com>
> Subject: RE: [PATCH 00/11] net/vhostpci: A new vhostpci PMD supporting
> VM2VM scenario
> 
> Hi,
> 
> > -----Original Message-----
> > From: Yang, Zhiyong
> > Sent: Wednesday, December 20, 2017 9:52 AM
> > To: Maxime Coquelin; dev at dpdk.org; yliu at fridaylinux.org
> > Cc: Wang, Wei W; Tan, Jianfeng
> > Subject: RE: [PATCH 00/11] net/vhostpci: A new vhostpci PMD supporting
> > VM2VM scenario
> >
> > Hi Maxime,
> >
> > > -----Original Message-----
> > > From: Maxime Coquelin [mailto:maxime.coquelin at redhat.com]
> > > Sent: Tuesday, December 19, 2017 7:15 PM
> > > To: Yang, Zhiyong <zhiyong.yang at intel.com>; dev at dpdk.org;
> > > yliu at fridaylinux.org
> > > Cc: Wang, Wei W <wei.w.wang at intel.com>; Tan, Jianfeng
> > > <jianfeng.tan at intel.com>
> > > Subject: Re: [PATCH 00/11] net/vhostpci: A new vhostpci PMD
> > > supporting VM2VM scenario
> > >
> >
> > <snip>
> >
> > > Thanks for the RFC.
> > > It seems there is a lot of code duplication between this series and
> > > libvhost-
> > user.
> > >
> > > Does the non-RFC would make reuse of libvhost-user? I'm thinking of
> > > all
> > the
> > > code copied from virtio-net.c for example.
> > >
> > > If not, I think this is problematic as it will double the maintenance cost.
> >
> > Thank you for paying attention to the patchset . TX/RX logic basically
> > comes from vhost user code.
> > but some function interfaces and data structures are different,  So
> > can not reuse them directly, code duplicate should be removed, I'm
> > aware of this point too, when I was writing the vhostpci PMD.
> >  But We should modify the  libvhost-user firstly,  let libvhostuser
> > become more generic.
> > It looks like that more and more PMDs are becoming the member of
> > virtio family or are on the road.
> 
> Trying to draw a conclusion here, there are two kinds of code duplication in
> net/vhost-pci.
> - For pci operations in guest driver, it has some duplicated code with virtio-net
> pmd.
> - For the enqueue/dequeuer operations, it has some duplicated code with vhost-
> user lib.
> 
> Right?

Right. If the existing code in DPDK can become more generic, we can avoid the duplication. 

Thanks
Zhiyong

> Thanks,
> Jianfeng
> 
> > >
> > > Cheers,
> > > Maxime