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

["Yang, Zhiyong" <zhiyong.yang@intel.com>]

> -----Original Message-----
> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Yang, Zhiyong
> Sent: Thursday, December 21, 2017 2:21 PM
> To: Tan, Jianfeng <jianfeng.tan@intel.com>; Maxime Coquelin
> <maxime.coquelin@redhat.com>; dev@dpdk.org; yliu@fridaylinux.org
> Cc: Wang, Wei W <wei.w.wang@intel.com>
> Subject: Re: [dpdk-dev] [PATCH 00/11] net/vhostpci: A new vhostpci PMD
> supporting VM2VM scenario
> 
> Hi Jianfeng,
> 
> > -----Original Message-----
> > From: Tan, Jianfeng
> > Sent: Thursday, December 21, 2017 1:52 PM
> > To: Yang, Zhiyong <zhiyong.yang@intel.com>; Maxime Coquelin
> > <maxime.coquelin@redhat.com>; dev@dpdk.org; yliu@fridaylinux.org
> > Cc: Wang, Wei W <wei.w.wang@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@dpdk.org; yliu@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@redhat.com]
> > > > Sent: Tuesday, December 19, 2017 7:15 PM
> > > > To: Yang, Zhiyong <zhiyong.yang@intel.com>; dev@dpdk.org;
> > > > yliu@fridaylinux.org
> > > > Cc: Wang, Wei W <wei.w.wang@intel.com>; Tan, Jianfeng
> > > > <jianfeng.tan@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.
> 

BTW,  wonder why vhost user enqueue/dequeue are put in lib layer,not in driver/net/vhost  like virtio PMD?

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