Re: [dpdk-dev] [PATCH v1 0/3] Introduce virtual PMD for Hyper-V/Azure platforms

[Stephen Hemminger <stephen@networkplumber.org>]

On Mon, 18 Dec 2017 17:46:19 +0100
Adrien Mazarguil <adrien.mazarguil@6wind.com> wrote:

> Virtual machines hosted by Hyper-V/Azure platforms are fitted with
> simplified virtual network devices named NetVSC that are used for fast
> communication between VM to VM, VM to hypervisor, and the outside.
> 
> They appear as standard system netdevices to user-land applications, the
> main difference being they are implemented on top of VMBUS [1] instead of
> emulated PCI devices.
> 
> While this reads like a case for a standard DPDK PMD, there is more to it.
> 
> To accelerate outside communication, NetVSC devices as they appear in a VM
> can be paired with physical SR-IOV virtual function (VF) devices owned by
> that same VM [2]. Both netdevices share the same MAC address in that case.
> 
> When paired, egress and most of the ingress traffic flow through the VF
> device, while part of it (e.g. multicasts, hypervisor control data) still
> flows through NetVSC. Moreover VF devices are not retained and disappear
> during VM migration; from a VM standpoint, they can be hot-plugged anytime
> with NetVSC acting as a fallback.
> 
> Running DPDK applications in such a context involves driving VF devices
> using their dedicated PMDs in a vendor-independent fashion (to benefit from
> maximum performance without writing dedicated code) while simultaneously
> listening to NetVSC and handling the related hot-plug events.
> 
> This new virtual PMD (referred to as "hyperv" from this point on)
> automatically coordinates the Hyper-V/Azure-specific management part
> described above by relying on vendor-specific, failsafe and tap PMDs to
> expose a single consolidated Ethernet device usable directly by existing
> applications.
> 
>          .------------------.
>          | DPDK application |
>          `--------+---------'
>                   |
>            .------+------.
>            | DPDK ethdev |
>            `------+------'       Control
>                   |                 |
>      .------------+------------.    v    .------------.
>      |       failsafe PMD      +---------+ hyperv PMD |
>      `--+-------------------+--'         `------------'
>         |                   |
>         |          .........|.........
>         |          :        |        :
>    .----+----.     :   .----+----.   :
>    | tap PMD |     :   | any PMD |   :
>    `----+----'     :   `----+----'   : <-- Hot-pluggable
>         |          :        |        :
>  .------+-------.  :  .-----+-----.  :
>  | NetVSC-based |  :  | SR-IOV VF |  :
>  |   netdevice  |  :  |   device  |  :
>  `--------------'  :  `-----------'  :
>                    :.................:
> 
> Note this diagram differs from that of the original RFC [3], with hyperv no
> longer acting as a data plane layer.
> 
> This initial version of the driver only works in whitelist mode. Users have
> to provide the --vdev net_hyperv EAL option at least once to trigger it.
> 
> Subsequent work will add support for blacklist mode based on automatic
> detection of the host environment.
> 
> [1] http://dpdk.org/ml/archives/dev/2017-January/054165.html
> [2] https://docs.microsoft.com/en-us/windows-hardware/drivers/network/overview-of-hyper-v
> [3] http://dpdk.org/ml/archives/dev/2017-November/082339.html
> 
> Adrien Mazarguil (3):
>   net/hyperv: introduce MS Hyper-V platform driver
>   net/hyperv: implement core functionality
>   net/hyperv: add "force" parameter
> 
>  MAINTAINERS                                   |   6 +
>  config/common_base                            |   6 +
>  config/common_linuxapp                        |   1 +
>  doc/guides/nics/features/hyperv.ini           |  12 +
>  doc/guides/nics/hyperv.rst                    | 119 +++
>  doc/guides/nics/index.rst                     |   1 +
>  drivers/net/Makefile                          |   1 +
>  drivers/net/hyperv/Makefile                   |  58 ++
>  drivers/net/hyperv/hyperv.c                   | 799 +++++++++++++++++++++
>  drivers/net/hyperv/rte_pmd_hyperv_version.map |   4 +
>  mk/rte.app.mk                                 |   1 +
>  11 files changed, 1008 insertions(+)
>  create mode 100644 doc/guides/nics/features/hyperv.ini
>  create mode 100644 doc/guides/nics/hyperv.rst
>  create mode 100644 drivers/net/hyperv/Makefile
>  create mode 100644 drivers/net/hyperv/hyperv.c
>  create mode 100644 drivers/net/hyperv/rte_pmd_hyperv_version.map
> 

Please don't call this drivers/net/hyperv/
that name conflicts with the real netvsc PMD that I am working on.

Maybe vdev-netvsc?