On Wed, Jul 21, 2010 at 11:15:05AM +0100, Daniel P. Berrange wrote: > A Linux software bridge will assume the MAC address of the enslaved > interface with the numerically lowest MAC addr. When the bridge > changes MAC address there is a period of network blackout, so a > change should be avoided. The kernel gives TAP devices a completely > random MAC address. Occassionally the random TAP device MAC is lower > than that of the physical interface (eth0, eth1etc) that is enslaved, > causing the bridge to change its MAC. Ah, that's the reason why it was hiding ! > This change sets an explicit MAC address for all TAP devices created > using the configured MAC from the XML, but with the high byte set > to 0xFE. This should ensure TAP device MACs are higher than any > physical interface MAC. > > * src/qemu/qemu_conf.c, src/uml/uml_conf.c: Pass in a MAC addr > for the TAP device with high byte set to 0xFE > * src/util/bridge.c, src/util/bridge.h: Set a MAC when creating > the TAP device to override random MAC > --- > src/qemu/qemu_conf.c | 11 +++++++++-- > src/uml/uml_conf.c | 11 +++++++++-- > src/util/bridge.c | 42 ++++++++++++++++++++++++++++++++++++++++++ > src/util/bridge.h | 3 ++- > 4 files changed, 62 insertions(+), 5 deletions(-) Patch looks fine, ACK, Daniel -- Daniel Veillard | libxml Gnome XML XSLT toolkit http://xmlsoft.org/ daniel@xxxxxxxxxxxx | Rpmfind RPM search engine http://rpmfind.net/ http://veillard.com/ | virtualization library http://libvirt.org/ -- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list