Re: [libvirt] Re: [Qemu-devel] [PATCH 1/6] Allow multiple monitor devices (v2)

On Tue, Apr 14, 2009 at 12:15:23PM +0300, Avi Kivity wrote: > Daniel P. Berrange wrote: >> Yes indeed its a little crazy :-) As anthony mentioned if libvirt were >> able to be notified of changes a user makes in the monitor, there's no >> reason we could not allow end users to access the monitor of a VM >> libvirt is managing. We just need to make sure libvirt doesn't miss >> changes like attaching or detaching block devices, etc, because that'll >> cause crash/data loss later when libvirt migrates or does save/restore, >> etc because it'll launch QEMU with wrong args >> > You still have an inherent race here. > > user: plug in disk > libvirt: start migration, still without disk > qemu: libvirt, a disk has been plugged in. That is true, but we'd still be considering direct monitor access to be a 'expert' user mode of use. If they wish to shoot themselves in the foot by triggering a migration at same time they are hotplugging I'm fine if their whole leg gets blown away.