OASIS Mailing List ArchivesView the OASIS mailing list archive below
or browse/search using MarkMail.


Help: OASIS Mailing Lists Help | MarkMail Help

virtio-dev message

[Date Prev] | [Thread Prev] | [Thread Next] | [Date Next] -- [Date Index] | [Thread Index] | [List Home]

Subject: Re: [PATCH net-next v9 3/4] virtio_net: Extend virtio to use VF datapath when available

On 4/28/2018 1:24 AM, Jiri Pirko wrote:
Fri, Apr 27, 2018 at 07:06:59PM CEST, 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
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.

Somehow the hypervisor needs to make sure that the broadcasts/multicasts from the VM
sent over the VF datapath don't get looped back to the VM via the virtio-net datapth.
This can happen if both datapaths are enabled at the same time.

I would think this is an issue even with bonding/team as well when virtio-net and
VF are backed by the same PF.

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"?

Yes.  the PF should take away the MAC address assigned to the VF so that the PF
starts receiving those packets.

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.

[Date Prev] | [Thread Prev] | [Thread Next] | [Date Next] -- [Date Index] | [Thread Index] | [List Home]