virsh, implicit use of kvm?

[Mihamina Rakotomandimby (R12y)]

Hi,
Following this documentation:
https://help.ubuntu.com/community/KVM
and having kvm kernel modle loaded.
When launching the virtual machine, will it automagically use KVM?
Optionnaly, how to know?

I ask, because when using manual launching (without those libvirt 
related stuff), I use explicitely "kvm" or "qemu" according to wat I 
want to do.

My hardware: AMD Phenom (virtualization capable).