This patch series extends virtio_net to take over VF datapath by simulating a transparent bond without creating any additional netdev. I understand that there are some comments suggesting an alternate model that is based on 3 driver model(virtio_net, VF driver, a new driver virt_bond that acts as a master to virtio_net and VF). Would like to get some feedback on the right way to solve the live migration problem with direct attached devices in KVM environment. Stephen, Is the netvsc transparent bond implemenation robust enough and deployed in real environments? Or would netvsc switch over to a 3-driver model if that solution becomes available? Can we start with this implementation that is similar to netvsc and if needed we can move to the 3 driver model later? This patch series enables virtio 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 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. It is based on netvsc implementation and it should be possible to make this code generic and move it to a common location that can be shared by netvsc and virtio. This patch series is based on the discussion initiated by Jesse on this thread. https://marc.info/?l=linux-virtualization&m=151189725224231&w=2 v2: - Changed VIRTIO_NET_F_MASTER to VIRTIO_NET_F_BACKUP (mst) - made a small change to the virtio-net xmit path to only use VF datapath for unicasts. Broadcasts/multicasts use virtio datapath. This avoids east-west broadcasts to go over the PCI link. - added suppport for the feature bit in qemu Sridhar Samudrala (2): virtio_net: Introduce VIRTIO_NET_F_BACKUP feature bit virtio_net: Extend virtio to use VF datapath when available drivers/net/virtio_net.c | 309 +++++++++++++++++++++++++++++++++++++++- include/uapi/linux/virtio_net.h | 3 + 2 files changed, 309 insertions(+), 3 deletions(-) Sridhar Samudrala (1): qemu: Introduce VIRTIO_NET_F_BACKUP feature bit to virtio_net hw/net/virtio-net.c | 2 ++ include/standard-headers/linux/virtio_net.h | 3 +++ 2 files changed, 5 insertions(+) -- 2.14.3 _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
