1. A method of pinning a logical memory area to physical memory in a shared memory partition data processing system, the method comprising: receiving by a hypervisor of the shared memory partition data processing system a request to register a logical memory area with the hypervisor; and responsive to receipt of the request, transparently determining by the hypervisor whether the logical memory area is a critical memory area for access by the hypervisor, and if so, automatically pinning by the hypervisor the logical memory area to physical memory of the shared memory partition data processing system to ensure availability thereof to the hypervisor by preventing the logical memory area from being paged-out from the physical memory to external storage.