libvirt supports KVM PCI device assignment since Fedora 11, but we do not support hotplug. Patches to add this support have been committed upstream now: http://libvirt.org/git/?p=libvirt.git;a=commitdiff;h=7636ef4630 http://libvirt.org/git/?p=libvirt.git;a=commitdiff;h=0c5b7b93a3
Mark added this in rawhide * Wed Aug 19 2009 Mark McLoughlin <markmc> - 0.7.0-5 - Add PCI host device hotplug support