Intel has a cache-as-ram (CAR) mode / Non-Eviction Mode, which is what you wanted but it is only available before DRAM is brought up via core initialization. Not sure about AMD.
AFAIK AMD doesn’t do this because it’s a pain in the butt to do from a hardware and firmware perspective. They basically have their equivalent of the intel ME do RAM for training and then the main cpu comes on with DRAM already up. At least it was like that five years ago when I last worked on an AMD part.
epolanski · · focus · HN ↗
Edit: dug in it, no, because cache isn't addressable and it's directly managed by the cpu.
stevefan1999 · · focus · HN ↗
matthewfcarlson · · focus · HN ↗