Fri, Apr 27, 2018 at 07:06:59PM CEST, sridhar.samudr...@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
Why? Both datapaths could be enabled at a time. Why the loop on hypervisor side would be a problem. This in not an issue for bonding/team as well. >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 "reset the MAC filter of the VF" - you mean "set the VF mac"? >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. > >It uses the generic failover framework that provides 2 functions to create >and destroy a master failover netdev. When STANDBY feature is enabled, an >additional netdev(failover 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 'standby' netdev and a passthru device with the same MAC is >registered as 'primary' netdev. > >This patch is based on the discussion initiated by Jesse on this thread. >https://marc.info/?l=linux-virtualization&m=151189725224231&w=2 [...]
