[dpdk-dev] [PATCH v1 0/3] Introduce virtual PMD for Hyper-V/Azure platforms
Stephen Hemminger
stephen at networkplumber.org
Mon Dec 18 19:23:04 CET 2017
On Mon, 18 Dec 2017 17:46:19 +0100
Adrien Mazarguil <adrien.mazarguil at 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?
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