differences between KVM_GET_API_VERSION and KVM_CREATE_VM which both call _IO

Hi,

I try to figure out how this 2 calls:
KVM_GET_API_VERSION
KVM_CREATE_VM
differ from each other because here:
http://www.cs.fsu.edu/~baker/devices/lxr/http/source/linux/include/linux/kvm.h#L351
i see that both call _IO and as far i understood the _IO function only shifts 8 bits from the given address 0xAE which in fact if i open /dev/kvm always returns 12. I guess that i missed something or I misunderstood it. It would be nice to be able to clarify it.

Thank you for your time!

Beste Regards!
Frank :-)