Goal

Enable the Windows virtio driver to support GRE and other general tunnelling protocols by allowing the driver to deliver packets to the correct queues and provide the calculated hash for each packet following the virtio spec (VIRTIO_NET_F_RSS and VIRTIO_NET_F_HASH_REPORT).

This enhancement would improve RSS performance, optimize load balancing, and increase overall throughput in tunnelling scenarios.

Current Status

GRE: At the moment, the netkvm driver does not declare support of the GRE to Windows and does not support it; this means both RX direction (RSS and checksum validation) and TX direction (LSO and checksum offloads). Support for the GRE also involves dedicated certification tests.

Upstream issue: https://github.com/virtio-win/kvm-guest-drivers-windows/issues/978