From: Stephen Hemminger <sthem...@microsoft.com> Matching documentation for new netvsc device. Includes a brief note about the restart issue.
Signed-off-by: Stephen Hemminger <sthem...@microsoft.com> --- doc/guides/nics/features/netvsc.ini | 23 ++++++ doc/guides/nics/index.rst | 1 + doc/guides/nics/netvsc.rst | 101 +++++++++++++++++++++++++ doc/guides/rel_notes/known_issues.rst | 20 +++++ doc/guides/rel_notes/release_18_08.rst | 6 ++ 5 files changed, 151 insertions(+) create mode 100644 doc/guides/nics/features/netvsc.ini create mode 100644 doc/guides/nics/netvsc.rst diff --git a/doc/guides/nics/features/netvsc.ini b/doc/guides/nics/features/netvsc.ini new file mode 100644 index 000000000000..2ff6042bf47b --- /dev/null +++ b/doc/guides/nics/features/netvsc.ini @@ -0,0 +1,23 @@ +; +; Supported features of the 'netvsc' network poll mode driver. +; +; Refer to default.ini for the full list of available PMD features. +; +[Features] +Speed capabilities = P +Link status = Y +Queue start/stop = Y +Scattered Rx = Y +Promiscuous mode = Y +Allmulticast mode = Y +Basic stats = Y +Stats per queue = Y +Extended stats = Y +Multiprocess aware = Y +Other kdrv = Y +ARMv7 = Y +ARMv8 = Y +x86-32 = Y +x86-64 = Y +Usage doc = Y +MTU update = Y diff --git a/doc/guides/nics/index.rst b/doc/guides/nics/index.rst index ddb9eb7a922e..d4eae2b8f046 100644 --- a/doc/guides/nics/index.rst +++ b/doc/guides/nics/index.rst @@ -33,6 +33,7 @@ Network Interface Controller Drivers mlx4 mlx5 mvpp2 + netvsc nfp octeontx qede diff --git a/doc/guides/nics/netvsc.rst b/doc/guides/nics/netvsc.rst new file mode 100644 index 000000000000..0f033e3a3d63 --- /dev/null +++ b/doc/guides/nics/netvsc.rst @@ -0,0 +1,101 @@ +.. SPDX-License-Identifier: BSD-3-Clause + Copyright(c) Microsoft Corporation. + +Netvsc poll mode driver +======================= + +The Netvsc Poll Mode driver (PMD) provides support for the paravirtualized +network device for Microsoft Hyper-V. It can be used with +Window Server 2008/2012/2016, Windows 10 and Azure cloud. +The device offers multi-queue support (if kernel and host support it), +checksum and segmentation offloads. + + +Features and Limitations of Hyper-V PMD +--------------------------------------- + +In this release, the hyper PMD driver provides the basic functionality of packet reception and transmission. + +* It supports merge-able buffers per packet when receiving packets and scattered buffer per packet + when transmitting packets. The packet size supported is from 64 to 65536. + +* The PMD supports multicast packets and promiscuous mode subject to restrictions on the host. + In order to this to work, the guest network configuration on Hyper-V must be configured to allow MAC address + spoofing. This option is not available on Azure. + +* The device has only a single MAC address. + Hyper-V driver does not support MAC or VLAN filtering because the Hyper-V host does not support it. + +* VLAN tags are always stripped and presented in mbuf tci field. + +* The Hyper-V driver does not use or support Link State or Rx interrupt. + +* The maximum number of queues is limited by the host (currently 64). + When used with 4.16 kernel only a single queue is available. + +* This driver is intended for use with synthetic path only. + Accelerated Networking (SR-IOV) acceleration is not supported yet. + Use the VDEV_NETVSC device for accelerated networking instead. + + +Installation +------------ + +The Netvsc PMD is a standalone driver, similar to virtio and vmxnet3. +Using Netvsc PMD requires that the associated VMBUS device be bound to the userspace +I/O device driver for Hyper-V (uio_hv_generic). By default, all netvsc devices +will be bound to the Linux kernel driver; in order to use netvsc PMD the +device must first be overridden. + +The first step is to identify the network device to override. +VMBUS uses Universal Unique Identifiers +(`UUID`_) to identify devices on the bus similar to how PCI uses Domain:Bus:Function. +The UUID associated with a Linux kernel network device can be determined +by looking at the sysfs information. To find the UUID for eth1 and +store it in a shell variable: + + .. code-block:: console + + DEV_UUID=$(basename $(readlink /sys/class/net/eth1/device)) + + +.. _`UUID`: https://en.wikipedia.org/wiki/Universally_unique_identifier + +There are several possible ways to assign the uio device driver for a device. +The easiest way (but only on 4.18 or later) +is to use the `driverctl Device Driver control utility`_ to override +the normal kernel device. + + .. code-block:: console + + driverctl -b vmbus set-override $DEV_UUID uio_hv_generic + +.. _`driverctl Device Driver control utility`: https://gitlab.com/driverctl/driverctl + +Any settings done with driverctl are by default persistent and will be reapplied +on reboot. + +On older kernels, the same effect can be had by manual sysfs bind and unbind +operations: + + .. code-block:: console + + NET_UUID="f8615163-df3e-46c5-913f-f2d2f965ed0e" + modprobe uio_hv_generic + echo $NET_UUID > /sys/bus/vmbus/drivers/uio_hv_generic/new_id + echo $DEV_UUID > /sys/bus/vmbus/drivers/hv_netvsc/unbind + echo $DEV_UUID > /sys/bus/vmbus/drivers/uio_hv_generic/bind + +.. Note:: + + The dpkd-devbind.py script should not be used. It only handles PCI devices. + + +Prerequisites +------------- + +The following prerequisites apply: + +* Linux kernel support for UIO on vmbus is done with the uio_hv_generic driver. + Full support of multiple queues requires the 4.17 kernel. It is possible + to use the netvsc PMD with 4.16 kernel but it is limited to a single queue. diff --git a/doc/guides/rel_notes/known_issues.rst b/doc/guides/rel_notes/known_issues.rst index 716bd7360949..95e4ce693e45 100644 --- a/doc/guides/rel_notes/known_issues.rst +++ b/doc/guides/rel_notes/known_issues.rst @@ -739,3 +739,23 @@ Linux kernel 4.10.0 iommu attribute read error **Driver/Module**: ``vfio-pci`` module. + +Netvsc driver and application restart +------------------------------------- + +**Description**: + The Linux kernel uio_hv_generic driver does not completely shutdown and clean up + resources properly if application using Netvsc PMD exits. + +**Implication**: + When application using Netvsc PMD is restarted it can not complete initialization + handshake sequence with the host. + +**Resolution/Workaround**: + Either reboot the guest or remove and reinsert the hv_uio_generic module. + +**Affected Environment/Platform**: + Linux Hyper-V. + +**Driver/Module**: + ``uio_hv_generic`` module. diff --git a/doc/guides/rel_notes/release_18_08.rst b/doc/guides/rel_notes/release_18_08.rst index 5bc23c537371..41ad33e227f8 100644 --- a/doc/guides/rel_notes/release_18_08.rst +++ b/doc/guides/rel_notes/release_18_08.rst @@ -41,6 +41,12 @@ New Features Also, make sure to start the actual text at the margin. ========================================================= +* **Added support for Hyper-V netvsc PMD.** + + The new ``netvsc`` poll mode driver provides native support for + networking on Hyper-V. See the :doc:`../nics/netvsc` NIC driver guide + for more details on this new driver. + API Changes ----------- -- 2.17.1