Method and apparatus for direct virtual memory address caching

A method for direct memory access, comprising:

• receiving a request for direct memory access comprising an I/O virtual address;
• querying a mapping table to obtain a virtual-to-physical address mapping;
• obtaining a physical address using the virtual-to-physical address mapping;
• forwarding the physical address to a direct virtual memory access engine;
• and
• transferring data to physical memory located at the physical address,
• wherein, prior to receiving the request for direct memory access:
• pre-allocating the physical memory and a virtual memory,
• generating the virtual-to-physical address mapping to associate the physical memory to the virtual memory,
• populating at least one entry in the mapping table with the virtual-to-physical address mapping, and
• generating at least one tracking structure associated with the at least one entry, and
• wherein the at least one entry and the at least one tracking structure persist for at least two direct memory access requests.

A computer system for performing direct memory access, comprising:

• a processor;
• a memory;
• a storage device;
• and
• software instructions stored in the memory for enabling the computer system under control of the processor to:
• receive a request for direct memory access comprising an I/O virtual address;
• query a mapping table to obtain a physical address to I/O virtual address mapping;
• obtain the physical address using the virtual-to-physical address mapping;
• forward the physical address to a direct virtual memory access engine;
• and
• transfer data to physical memory located at the physical address,
• wherein, prior to the software instructions to receive the request for direct memory access, the computer system executes software instructions to:
• pre-allocate the physical memory and a virtual memory,
• generate the virtual-to-physical address mapping to associate the physical memory to the virtual memory,
• populate at least one entry in the mapping table with the virtual-to-physical address mapping, and
• generate at least one tracking structure associated with the at least one entry,
• wherein the at least one entry and the at least one tracking structure persists for at least two direct memory access requests.