1. A method in a logical partitioned data processing system that includes a plurality of different logical partitions for dynamically sharing adapter resources among a plurality of operating system instances, wherein each one of the plurality of operating system instances is included in a different one of the plurality of different logical partitions, comprising: locating, by a hypervisor, available resources in a peripheral computer interface input/output adapter, the available resources comprising resources that have not been allocated; allocating, by the hypervisor, a first part of the available adapter resources in the adapter to a first one of the plurality of operating system instances; allocating, by the hypervisor, a second part of the available adapter resources in the adapter to a second one of the plurality of operating system instances; notifying the adapter, by the hypervisor, of the adapter resource allocation to the first one of the plurality of operating system instances; updating, by the adapter, an internal structure of the adapter to reflect the allocation; wherein a resource context of the internal structure of the adapter includes a plurality of fields, wherein each one of the plurality of fields defines a mapping of an address of the first part of the available adapter resources to a permitted accessing address range, and wherein each one of the plurality of fields includes an access permission attribute for the permitted accessing address range defined in the one of the plurality of fields; wherein the access permission attribute identifies an allowed type of access; wherein the resource context can only be accessed via an address space that has been allocated to the adapter, wherein the resource context is stored outside of the adapter; and wherein the adapter is accessed using the address space.