1. An apparatus, comprising: a graphics processing unit (GPU) comprising a plurality of storage locations; wherein, for each one of a plurality of virtual GPUs implemented by the GPU, a corresponding one of the plurality of storage locations includes: first and second storage areas respectively configured to store intermediate results including intermediate vertex-processing results and intermediate pixel-processing results that correspond to that virtual GPU; wherein the intermediate results in the first and second storage areas are usable to resume execution of one or more incomplete vertex-processing operations and one or more incomplete pixel-processing operations for that virtual GPU.