Convert the vdi image to raw
$ vboxmanage clonehd /media/some/virtualbox-guest.vdi /media/some/x-virtualbox-guest.img --format raw
virt-install --connect qemu:///system --description x-virtualbox-guest -r 4096 --os-type=linux --disk /home/vm/jira/jira.img,device=disk --network=bridge:br0 --hvm --vnc --noautoconsole --name= x-virtualbox-guest--import
Notes on migrating a virtualbox guest to KVM
