In a CPU of the combined CPU / APD architecture
system, the CPU having multiple CPU cores, each core having a first
machine specific register for receiving a physical
page table / page
directory base address, a second
machine specific register for receiving a
physical address pointing to a location controlled by an IOMMUv2 that is communicatively coupled to an APD, and
microcode which when executed causes a write notification to be issued to the
physical address contained in the second
machine specific register; receiving in the first machine specific register of a CPU core, a physical
page table / page
directory base address, receiving in the second machine specific register of the CPU core, a
physical address pointing to a location controlled by the IOMMUv2, determining that a
control register of the CPU core has been updated, and responsive to the determination that the
control register has been updated, executing
microcode in the CPU core that causes a write notification to be issued to the physical address contained in the second machine specific register, wherein the physical address is able to receive writes that affect IOMMUv2
page table invalidations.