On Wed, Apr 07, 2010 at 10:41:08AM +0800, Xin, Xiaohui wrote: > Michael, > > >> Qemu needs a userspace write, is that a synchronous one or > >>asynchronous one? > > >It's a synchronous non-blocking write. > Sorry, why the Qemu live migration needs the device have a userspace write? > how does the write operation work? And why a read operation is not cared here? > > Thanks > Xiaohui Roughly, with ethernet bridges, moving a device from one location in the network to another makes forwarding tables incorrect (or incomplete), until outgoing traffic from the device causes these tables to be updated. Since there's no guarantee that guest will generate outgoing traffic, after migration qemu sends out several dummy packets itself. -- MST -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
