A data processing system comprising an accelerator that acts as a common shared resource for plural applications executing in respective virtual machines. The data processing system includes an interface mapping unit that facilitates the submission of tasks from applications to the accelerator. The interface mapping unit includes physical registers that act as physical register input/output interfaces for the accelerator. The interface mapping unit exposes a plurality of virtual accelerator input/output interfaces to the applications that are then dynamically mapped to the physical register input/output interfaces by the interface mapping unit to allow applications to access, and thereby submit a task to, a given physical register input/output interface.