Type:	host
	host reference
Name:	affinity
	a host which the VM has some affinity for (or NULL). This is used as a hint to the start call when it decides where to run the VM. Implementations are free to ignore this field.

Field is read-write

• host get_affinity (session session_id, VM self)

  Get the affinity field of the given VM.

• void set_affinity (session session_id, VM self, host value)

  Set the affinity field of the given VM.