Shadow command ring for graphics processor virtualization

A non-transitory computer-readable medium having instructions that when operated on by the computer cause the computer to perform operations comprising:

• loading a command batch from a virtual machine of a general purpose processor into a physical command ring of a graphics processor;
• setting a physical tail pointer register of the graphics processor for the command ring based on the size of the command batch;
• trapping the command batch and the physical tail pointer at a mediator;
• copying the trapped command batch and the physical tail pointer in a shadow command ring of the mediator;
• setting a virtual tail pointer at the mediator based on the trapped physical tail pointer;
• executing the physical command ring by the graphics processor;
• monitoring the execution of the physical command ring;
• and
• clearing the physical command ring and reloading the physical command ring of the graphics processor using the shadow command ring if there is a determined error in executing the command batch.

An apparatus comprising:

• a general purpose processor having a memory and supporting a plurality of virtual machines and a mediator for the virtual machines;
• and
• a graphics processor having a physical command ring,
• wherein a virtual machine of the general purpose processor loads a command batch into the physical command ring of the graphics processor, and sets a physical tail pointer register of the graphics processor for the command ring based on the size of the command batch,
• wherein the mediator traps the command batch and the physical tail pointer, copies the trapped command batch and the physical tail pointer in a shadow command ring of the mediator, and sets a virtual tail pointer based on the trapped physical tail pointer,
• wherein the graphics processor executes the physical command ring by monitoring and monitors the execution of the physical command ring, and
• wherein the mediator clears the physical command ring and reloads the physical command ring of the graphics processor using the shadow command ring if there is a determined error in executing the command batch.