Circuits, methods, and apparatus that reduce or eliminate system memory
accesses to retrieve address translation information. In one example,
these accesses are reduced or eliminated by pre-populating a graphics TLB
with entries that are used to translate virtual addresses used by a GPU
to physical addresses used by a system memory. Translation information is
maintained by locking or restricting entries in the graphics TLB that are
needed for display access. This may be done by limiting access to certain
locations in the graphics TLB, by storing flags or other identifying
information in the graphics TLB, or by other appropriate methods. In
another example, memory space is allocated by a system BIOS for a GPU,
which stores a base address and address range. Virtual addresses in the
address range are translated by adding them to the base address.