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

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

Hi Maxime,

> -----Original Message-----
> From: Maxime Coquelin [mailto:maxime.coquelin@redhat.com]
> Sent: Thursday, January 18, 2018 5:04 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
> 
> Hi Zhiyong,
> 
> Sorry for the late reply, please find my comments inline:
> 
> On 01/11/2018 12:13 PM, Yang, Zhiyong wrote:
> > Hi Maxime, all,
> >
> 
> ...
> 
> >>> Zhiyong Yang (11):
> >>>     drivers/net: add vhostpci PMD base files
> >>>     net/vhostpci: public header files
> >>>     net/vhostpci: add debugging log macros
> >>>     net/vhostpci: add basic framework
> >>>     net/vhostpci: add queue setup
> >>>     net/vhostpci: add support for link status change
> >>>     net/vhostpci: get remote memory region and vring info
> >>>     net/vhostpci: add RX function
> >>>     net/vhostpci: add TX function
> >>>     net/vhostpci: support RX/TX packets statistics
> >>>     net/vhostpci: update release note
> >>>
> >>>    MAINTAINERS                                       |    6 +
> >>>    config/common_base                                |    9 +
> >>>    config/common_linuxapp                            |    1 +
> >>>    doc/guides/rel_notes/release_18_02.rst            |    6 +
> >>>    drivers/net/Makefile                              |    1 +
> >>>    drivers/net/vhostpci/Makefile                     |   54 +
> >>>    drivers/net/vhostpci/rte_pmd_vhostpci_version.map |    3 +
> >>>    drivers/net/vhostpci/vhostpci_ethdev.c            | 1521
> >> +++++++++++++++++++++
> >>>    drivers/net/vhostpci/vhostpci_ethdev.h            |  176 +++
> >>>    drivers/net/vhostpci/vhostpci_logs.h              |   69 +
> >>>    drivers/net/vhostpci/vhostpci_net.h               |   74 +
> >>>    drivers/net/vhostpci/vhostpci_pci.c               |  334 +++++
> >>>    drivers/net/vhostpci/vhostpci_pci.h               |  240 ++++
> >>>    mk/rte.app.mk                                     |    1 +
> >>>    14 files changed, 2495 insertions(+)
> >>>    create mode 100644 drivers/net/vhostpci/Makefile
> >>>    create mode 100644
> >> drivers/net/vhostpci/rte_pmd_vhostpci_version.map
> >>>    create mode 100644 drivers/net/vhostpci/vhostpci_ethdev.c
> >>>    create mode 100644 drivers/net/vhostpci/vhostpci_ethdev.h
> >>>    create mode 100644 drivers/net/vhostpci/vhostpci_logs.h
> >>>    create mode 100644 drivers/net/vhostpci/vhostpci_net.h
> >>>    create mode 100644 drivers/net/vhostpci/vhostpci_pci.c
> >>>    create mode 100644 drivers/net/vhostpci/vhostpci_pci.h
> >>>
> >>
> >> 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.
> >>
> >
> > I'm trying to reuse  librte_vhost RX/TX logic  and it seems feasible,
> > However, I have to expose many internal data structures in librte_vhost
> such as virtio_net, vhost_virtqueue , etc to PMD layer.
> 
> I don't really like it, it looks like a layer violation.
> 
> > Since vhostpci PMD is using one virtio pci device (vhostpci device) in guest,
> Memory allocation and release should be done in driver/net/vhostpci as
> virtio PMD does that.
> 
> If you talk about mbuf alloc/release, then Vhost PMD also does it.
> So I'm not sure to get the point.
> 
> > Vhostpci and vhost can share struct  virtio_net to manage the different
> drivers, since they are very similar.
> > The features for example zero copy feature, make rarp packets don't need
> to be supported for vhostpci, we can always disable them.
> > How do you think about the thoughts?
> 
> Why not put vhost-pci wrappers in virtio-net?
> Maybe TX/RX functions should be reworked to extract the common bits
> between vhost-user and vhost-pci, taking care of not degrading performance
> of vhost-user.
> 
> I don't know if this is feasible, what do you think?
> 

make sense, thanks for your useful suggestions. :)

Thanks
Zhiyong

> Thanks,
> Maxime
> > thanks
> > Zhiyong
> >
> >> Cheers,
> >> Maxime
> >
> >