Windows 7 in format is a virtual disk image typically used for running the legacy operating system within KVM/QEMU hypervisors. Because Windows 7 has reached its end of life, using it in a virtualized environment is often the only safe way to access legacy software. Technical Performance Virtualization Support
qemu-img convert -O qcow2 -c windows7.qcow2 windows7_compacted.qcow2
Enable Hyper-V Enlightenments Windows 7 benefits from paravirtualization flags. Add to your libvirt XML: Windows 7 Qcow2
qemu-img command to create a new Qcow2 image: