[Pkg-libvirt-maintainers] Bug#664124: libvirt: should not use type=ioemu for any emulated NIC

[Stefan Bader]

Package: libvirt
Version: 0.9.8-2
Severity: normal
Tags: patch
User: ubuntu-devel at lists.ubuntu.com
Usertags: origin-ubuntu precise ubuntu-patch

Dear Maintainer,

libvirt uses xend (xm stack) to manage Xen instances. Even when using
any emulated NIC, there will always be a paravirt NIC in parallel if the
pci-platform device is present. Newer guests will unplug the emulated
NIC on boot. However there is a bug in the stack that will cause the
paravirt NIC to have no MAC address when "type=ioemu" is used in the
vif definition. On the other hand, even without this keyword, the
emulated NIC will be provided.

Current libvirt already has a quirk to drop this when using no specific
NIC model (defaulting to rtl8139). But the problem exists as well when
using any other emulated NIC.

So currently, when booting a 3.0+ kernel after setting up the instance
with the default NIC model, everything works. Changing the model to
something like e1000, then the guest cannot use the paravirt interface
after unplugging the emulated one. Ending up with no network.

*** /tmp/tmpay_5Gn/bug_body
In Ubuntu, the attached patch was applied to achieve the following:

The parch replicates the quirk used to prevent the usage of "type=ioemu"
to be used for the case of using a NIC model name explicitely.
I think it should be useful/working for Debian as well. Sorry if this
is not the ideal justification. Since this is the first time I use
submittodebian, I am not sure how this exactly should be done.


  [ Stefan Bader ]
  * Never use type=ioemu for NIC definitions. It is not needed
    and actually breaks the paravirt interface which always gets
    created in parallel.


Thanks for considering the patch.


-- System Information:
Debian Release: wheezy/sid
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  APT policy: (500, 'precise-updates'), (500, 'precise-security'), (500, 'precise-proposed'), (500, 'precise')
Architecture: amd64 (x86_64)

Kernel: Linux 3.2.0-18-generic (SMP w/2 CPU cores)
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