From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr0-f179.google.com ([209.85.128.179]:35582 "EHLO mail-wr0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1422939AbeCBIgH (ORCPT ); Fri, 2 Mar 2018 03:36:07 -0500 Received: by mail-wr0-f179.google.com with SMTP id l43so9232162wrc.2 for ; Fri, 02 Mar 2018 00:36:06 -0800 (PST) Date: Fri, 2 Mar 2018 09:36:05 +0100 From: Jiri Pirko To: Sridhar Samudrala Cc: mst@redhat.com, stephen@networkplumber.org, davem@davemloft.net, netdev@vger.kernel.org, virtio-dev@lists.oasis-open.org, jesse.brandeburg@intel.com, alexander.h.duyck@intel.com, kubakici@wp.pl Subject: Re: [PATCH v4 2/2] virtio_net: Extend virtio to use VF datapath when available Message-ID: <20180302083605.GD2099@nanopsycho> References: <1519934923-39372-1-git-send-email-sridhar.samudrala@intel.com> <1519934923-39372-3-git-send-email-sridhar.samudrala@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1519934923-39372-3-git-send-email-sridhar.samudrala@intel.com> Sender: netdev-owner@vger.kernel.org List-ID: Thu, Mar 01, 2018 at 09:08:43PM CET, sridhar.samudrala@intel.com wrote: >This patch enables virtio_net to switch over to a VF datapath when a VF >netdev is present with the same MAC address. It allows live migration >of a VM with a direct attached VF without the need to setup a bond/team >between a VF and virtio net device in the guest. > >The hypervisor needs to enable only one datapath at any time so that >packets don't get looped back to the VM over the other datapath. When a VF >is plugged, the virtio datapath link state can be marked as down. The >hypervisor needs to unplug the VF device from the guest on the source host >and reset the MAC filter of the VF to initiate failover of datapath to >virtio before starting the migration. After the migration is completed, >the destination hypervisor sets the MAC filter on the VF and plugs it back >to the guest to switch over to VF datapath. > >When BACKUP feature is enabled, an additional netdev(bypass netdev) is >created that acts as a master device and tracks the state of the 2 lower >netdevs. The original virtio_net netdev is marked as 'backup' netdev and a >passthru device with the same MAC is registered as 'active' netdev. > >This patch is based on the discussion initiated by Jesse on this thread. >https://marc.info/?l=linux-virtualization&m=151189725224231&w=2 > >Signed-off-by: Sridhar Samudrala >Signed-off-by: Alexander Duyck >Reviewed-by: Jesse Brandeburg >--- > drivers/net/virtio_net.c | 683 ++++++++++++++++++++++++++++++++++++++++++++++- As I wrote to the discussion of the other version of this patchset, I strongly believe you need to have a common part in net/core/ that will be shared by both virtio_net and netvsc. There there should be explicit limits for this in-driver bonding solution, like max 1 vf slave, etc.