[libvirt-users] Passing "migratable=no" to qemu in domain's XML

Hi, I want to use Invariant TSC with qemu, and to do that qemu must get the following args: "-cpu host,migratable=no,+invtsc". invtsc works only if migratable=no is passed too. The "+invtsc" part is sucessfully handled by using <feature name="invtsc"/> inside domain's XML, however I don't how/where to put the "migratable=no" there. Is there an elegant way to pass "migratable=no" to qemu via domain's XML without using <qemu:arg/> tags?