Hi! I have connected my kvm guest using a macvtap interface and configured a macvlan interface in bridge mode on the host to allow host to guest communication. If using virtio_net in the guest, host to guest transfer works fine. But in guest to host direction large tcp segments do not arrive at the host and are retransmitted using smaller segment sizes. (See iperf-virtio-guest2host_guest.pcap and iperf-virtio-guest2host_host.pcap. [1]) Disabling tcp segmentation offload at the guest nic fixes that problem. If I switch to different nics (e1000, rtl8139, etc), checksum offloading also seems to interfere. The checksum errors go away after disabling TX checksumming on the underlying host interface but that's a performance killer. Checksum errors also occur on other connections, not only on host to guest traffic. Does macvlan/macvtap networking only work with virtio-net or are there any tweakings for other guest NICs? Thanks, --leo [1] http://leo.kloburg.at/tmp/kvm-macvtap/ -- e-mail ::: Leo.Bergolth (at) wu.ac.at fax ::: +43-1-31336-906050 location ::: IT-Services | Vienna University of Economics | Austria -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
