[libvirt] Multpile network interfaces have same MAC address

Daniel P. Berrange berrange at redhat.com
Thu Apr 16 16:28:24 UTC 2009

On Wed, Apr 15, 2009 at 10:39:42AM -0700, David Mueller wrote:
> On Wed, 25 Feb 2009, Daniel P. Berrange wrote:
> >On Tue, Feb 24, 2009 at 01:29:41PM -0800, David Mueller wrote:
> >>I remember seeing this problem before, but I can't remember what the
> >>resolution was, nor can I find a discussion of the issue in
> >>the list archives or Bugzilla.
> >>
> >>I've had my setup working for a while now, on both Fedora 8 and Fedora 10.
> >>Now I'm trying to get it to work with CentOS 5 and
> >>running into an old bug.  My guest VM has multiple virtual network
> >>interfaces, with the MAC address defined in the XML file used to
> >>define the VM.  However, I'm seeing each network interface getting the
> >>same MAC addrss (the last one defined in the XML file) on
> >>all if the interfaces when I run ifconfig in the guest.
> >>
> >>Was there a workaround for this, or do I need to upgrade libvirt?  CentOS
> >>5.2 is what I'm working with; they haven't released 5.3
> >>yet so I don't know if that will have a newer version.
> >
> >Last time I saw this was with QEMU and the rtl8139 nic, where there was
> >a bug setting up the MMIO space, so all NICs were reading their mac
> >from the first NIC's region instead of their own.
> Does anyone know if the patch for this is going to be rolled into RHEL5 at 
> some point?  I'm still having this problem with CentOS 5.3.  For 
> reference, I found the original Fedora 7 bug as well as filed one for 
> CentOS:
> https://bugzilla.redhat.com/show_bug.cgi?id=247641
> http://bugs.centos.org/bug_view_page.php?bug_id=3466

We don't ship QEMU or KVM in RHEL yet, so there's nothing to fix in RHEL
for QEMU/KVM, and I don't believe Xen suffers from it, since it uses a
different way of handling MMIO memory registration.

Whereever that CentOS  user got their qemu & kvm RPMs from, they weren't
a standard part of RHEL & those versions are absolutely ancient too.

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