Commit 011531f7 authored by Mauro Carvalho Chehab's avatar Mauro Carvalho Chehab Committed by David S. Miller

docs: networking: device drivers: convert microsoft/netvsc.txt to ReST

- add SPDX header;
- adjust titles and chapters, adding proper markups;
- mark code blocks and literals as such;
- adjust identation, whitespaces and blank lines where needed;
- add to networking/index.rst.
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent c81f1957
......@@ -41,6 +41,7 @@ Contents:
freescale/gianfar
intel/ipw2100
intel/ipw2200
microsoft/netvsc
.. only:: subproject and html
......
.. SPDX-License-Identifier: GPL-2.0
======================
Hyper-V network driver
======================
......@@ -10,15 +13,15 @@ Windows 10.
Features
========
Checksum offload
----------------
Checksum offload
----------------
The netvsc driver supports checksum offload as long as the
Hyper-V host version does. Windows Server 2016 and Azure
support checksum offload for TCP and UDP for both IPv4 and
IPv6. Windows Server 2012 only supports checksum offload for TCP.
Receive Side Scaling
--------------------
Receive Side Scaling
--------------------
Hyper-V supports receive side scaling. For TCP & UDP, packets can
be distributed among available queues based on IP address and port
number.
......@@ -32,30 +35,37 @@ Features
hashing. Using L3 hashing is recommended in this case.
For example, for UDP over IPv4 on eth0:
To include UDP port numbers in hashing:
To include UDP port numbers in hashing::
ethtool -N eth0 rx-flow-hash udp4 sdfn
To exclude UDP port numbers in hashing:
To exclude UDP port numbers in hashing::
ethtool -N eth0 rx-flow-hash udp4 sd
To show UDP hash level:
To show UDP hash level::
ethtool -n eth0 rx-flow-hash udp4
Generic Receive Offload, aka GRO
--------------------------------
Generic Receive Offload, aka GRO
--------------------------------
The driver supports GRO and it is enabled by default. GRO coalesces
like packets and significantly reduces CPU usage under heavy Rx
load.
Large Receive Offload (LRO), or Receive Side Coalescing (RSC)
-------------------------------------------------------------
Large Receive Offload (LRO), or Receive Side Coalescing (RSC)
-------------------------------------------------------------
The driver supports LRO/RSC in the vSwitch feature. It reduces the per packet
processing overhead by coalescing multiple TCP segments when possible. The
feature is enabled by default on VMs running on Windows Server 2019 and
later. It may be changed by ethtool command:
later. It may be changed by ethtool command::
ethtool -K eth0 lro on
ethtool -K eth0 lro off
SR-IOV support
--------------
SR-IOV support
--------------
Hyper-V supports SR-IOV as a hardware acceleration option. If SR-IOV
is enabled in both the vSwitch and the guest configuration, then the
Virtual Function (VF) device is passed to the guest as a PCI
......@@ -70,8 +80,8 @@ Features
flow direction is desired, these should be applied directly to the
VF slave device.
Receive Buffer
--------------
Receive Buffer
--------------
Packets are received into a receive area which is created when device
is probed. The receive area is broken into MTU sized chunks and each may
contain one or more packets. The number of receive sections may be changed
......@@ -83,8 +93,8 @@ Features
will use slower method to handle very large packets or if the send buffer
area is exhausted.
XDP support
-----------
XDP support
-----------
XDP (eXpress Data Path) is a feature that runs eBPF bytecode at the early
stage when packets arrive at a NIC card. The goal is to increase performance
for packet processing, reducing the overhead of SKB allocation and other
......@@ -99,7 +109,8 @@ Features
overwritten by setting of synthetic NIC.
XDP program cannot run with LRO (RSC) enabled, so you need to disable LRO
before running XDP:
before running XDP::
ethtool -K eth0 lro off
XDP_REDIRECT action is not yet supported.
......@@ -7867,7 +7867,7 @@ S: Supported
T: git git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux.git
F: Documentation/ABI/stable/sysfs-bus-vmbus
F: Documentation/ABI/testing/debugfs-hyperv
F: Documentation/networking/device_drivers/microsoft/netvsc.txt
F: Documentation/networking/device_drivers/microsoft/netvsc.rst
F: arch/x86/hyperv
F: arch/x86/include/asm/hyperv-tlfs.h
F: arch/x86/include/asm/mshyperv.h
......
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