To use a SmartCard or CAC with kvm/qemu, you'll need to install remote-viewer on the machine that will run remote-viewer to connect to the remote VM. The VM will need the Smartcard hardware installed and set to Passthrough. A CCID controller will be required as well.
The command to connect to the VM with the smartcard is
remote-viewer --spice-smartcard spice://<ip or hostname of VM host>:5900