You want a simple way for your virtual machine to access to the host, to the internet or to resources available on your local network. You don't need to access your guest from the network or from another guest. You are ready to take a huge performance hit. Warning: User networking does not support a number of networking features like ICMP.
Defining an static IP using the Default network Nat-based networking. We will use the default network crated on the KVM instalation process. Using virsh. You can create, exclude, execute, stop and manage your virtual machines from the command line, using a tool called virsh.