It might not exist on all platforms and according to the man page:
The kvm wrapper script is used to provide compatibility with old
qemu-kvm package which has been merged into qemu as of version 1.3.
The script executes
qemu-system-x86_64 -enable-kvm
passing all other command-line arguments to the qemu binary.
Closesstrongswan/strongswan#385.
A new global option enables sending this vendor ID to prevent Cisco
devices from narrowing the initiator's local traffic selector to the
requested virtual IP, so e.g. 0.0.0.0/0 can be used instead.
This has been tested with a "tunnel mode ipsec ipv4" Cisco template but
should also work for GRE encapsulation.
Closesstrongswan/strongswan#180.
Noel Kuntze