Bug 526472

Summary: libvirt fails to enable IFF_VNET_HDR on tap fds for qemu-kvm
Product: [Fedora] Fedora Reporter: Mark McLoughlin <markmc>
Component: libvirtAssignee: Mark McLoughlin <markmc>
Status: CLOSED ERRATA QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: medium Docs Contact:
Priority: high    
Version: 11CC: berrange, clalance, crobinso, itamar, veillard, virt-maint
Target Milestone: ---   
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: 0.6.2-18.fc11 Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2009-10-06 23:08:45 EDT Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: ---
Bug Depends On:    
Bug Blocks: 480594    

Description Mark McLoughlin 2009-09-30 10:12:13 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:

  http://libvirt.org/git/?p=libvirt.git;a=commitdiff;h=04cbe68797
  http://libvirt.org/git/?p=libvirt.git;a=commitdiff;h=56ecebf22d

I'm going to backport those to F-11
Comment 1 Mark McLoughlin 2009-09-30 10:20:23 EDT
* Wed Sep 30 2009 Mark McLoughlin <markmc@redhat.com> - 0.6.2-18
- Fix qemu-kvm version detection so GSO is enabled for virtio_net (#526472)
Comment 2 Fedora Update System 2009-09-30 10:37:09 EDT
libvirt-0.6.2-18.fc11 has been submitted as an update for Fedora 11.
http://admin.fedoraproject.org/updates/libvirt-0.6.2-18.fc11
Comment 3 Fedora Update System 2009-09-30 20:02:07 EDT
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
Comment 4 Fedora Update System 2009-10-06 23:08:33 EDT
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.