[jawnv6]

you should probably check the Programmer's Reference Manual (PRM)

i mean, they don't try to hide this information? Section 8.1.3 gives two options that are guaranteed to work across future iterations of hardware. the sibling comment that assumes a heavy serializing like CPUID is the ONLY method is shooting from the hip and only really appropriate if you're playing tricks with what LA you're using for the write/read.

you'll probably want to skim "11.6 Self-Modifying Code" as well. SMC is guaranteed to work, not work fast. Most folks want that second one and blasting out icache entries is going to put a damper on that.