Oracle licensing policies screw you if you are using VMWare. You need to license the whole server host and not just what is partitioned for use by the application server VM.
From Oracle Partitioning policy, http://www.oracle.com/us/corporate/pricing/partitioning-070609.pdf
Found on this page: http://www.oracle.com/us/corporate/pricing/specialty-topics/index.html
Soft partitioning segments the operating system using OS resource managers. The operating system limits the number of CPUs where an Oracle database is running by creating areas where CPU resources are allocated to applications within the same operating system. This is a flexible way of managing data processing resources since the CPU capacity can be changed fairly easily, as additional resource is needed. Examples of such partitioning type include: Solaris 9 Resource containers, AIX Workload Manager, HP Process Resource Manager, Affinity Management, Oracle VM, and VMware.Soft partitioning is not permitted as a means to determine or limit the number of software licenses required for any given server.
It does say that if you are using Solaris Zones that is Hard partitioning and that is ok. Also if you are using Oracles own VM Server, that is also Hard Partitioning and that is ok.