1. A storage device comprising: a storage medium having a memory capacity; and virtual storage device firmware configured to directly respond to commands from a first guest operating system in a virtual machine for accesses to a first subset of the memory capacity of the storage medium when a first virtual storage device is enabled, wherein the first virtual storage device comprises the first subset of the memory capacity of the storage medium, and wherein data stored in the first subset of the memory capacity of the storage medium is read-only when the first virtual storage device is disabled.