Download a tar ball with CentOS VM into /tmp and extract its content into KVM directory:
tar -zxvf /tmp/CentOS7_VM.tgz
Copy the xml file with VM configuration into directory /etc/libvirt/qemu as shown below;
the img file with the VM root file system stays in KVM directory.
Assign hostadm user and group ownership on the both, xml and img, files: