Red Hat Bugzilla – Bug 526472
libvirt fails to enable IFF_VNET_HDR on tap fds for qemu-kvm
Last modified: 2009-10-06 23:08:45 EDT
See bug #522994
It seems that on F11, if you run a KVM guest with a virtio_net NIC using libvirt, GSO support is not enabled
Simplest way to check is to log in to the guest and run 'ethtool -k eth0' - if IFF_VNET_HDR is enabled, you'll see e.g. 'tcp-segmentation-offload: on'
The problem is that the code in libvirt-0.6.2 will only enable IFF_VNET_HDR if the qemu -help output displays something like:
QEMU PC emulator version 0.9.1 (kvm-74)
whereas in F-11 it displays:
QEMU PC emulator version 0.10.6 (qemu-kvm-0.10.6)
This was fixed upstream by the following commits:
I'm going to backport those to F-11
* Wed Sep 30 2009 Mark McLoughlin <email@example.com> - 0.6.2-18
- Fix qemu-kvm version detection so GSO is enabled for virtio_net (#526472)
libvirt-0.6.2-18.fc11 has been submitted as an update for Fedora 11.
libvirt-0.6.2-18.fc11 has been pushed to the Fedora 11 testing repository. If problems still persist, please make note of it in this bug report.
If you want to test the update, you can install it with
su -c 'yum --enablerepo=updates-testing update libvirt'. You can provide feedback for this update here: http://admin.fedoraproject.org/updates/F11/FEDORA-2009-10123
libvirt-0.6.2-18.fc11 has been pushed to the Fedora 11 stable repository. If problems still persist, please make note of it in this bug report.