Don't know if it will fully work like that, but it will probably work like a normal mouse without the extra buttons working. I could be wrong, but mice that are made for either usually come with a USB to PS/2 adapter. Do you not have a USB port or what? Get a USB hub if you don't have any open ones, and you shouldn't have that mouse if your PC doesn't have a USB port... If you got open USB ports, why do you want to use PS/2 when USB is better?
EDIT: just re read and found out what a KVM was... Maybe you should get a KVM with a USB port...