1. A method of managing a self-virtualizing input/output (IO) resource in a logically partitioned data processing system comprising a plurality of logical partitions, the method comprising: interfacing an adjunct partition associated with the self-virtualizing input/output (IO) resource with a hypervisor through a vendor-independent Adjunct Management Channel (AMC) interface, wherein the adjunct partition includes a partition AMC device driver and the hypervisor includes a hypervisor AMC device driver configured to interface with the partition AMC device driver over the AMC interface, and wherein the AMC interface comprises a virtual interface implemented using paired virtual adapters resident respectively in the adjunct partition and the hypervisor; and in the hypervisor, managing the adjunct partition by communicating a configuration command from the hypervisor to vendor-specific adjunct management program code in the adjunct partition over the AMC interface using the partition AMC device driver and the hypervisor AMC device driver to enable the adjunct partition to configure the self-virtualizing IO resource for access by the plurality of logical partitions or to allow access to the self-virtualizing IO resource by at least one of the plurality of logical partitions, wherein the adjunct partition includes a separate dispatchable state and employs virtual address space donated from a logical partition in the plurality of logical partitions or the hypervisor of the data processing system.