On Thu, Feb 7, 2019 at 1:24 PM Andy Lutomirski <l...@amacapital.net> wrote: > > How bad would it be to set CR0.CD while fiddling with the page tables rather > than masking the address?
I would suggest against it. When you disable caching, things don't just go "slightly slower". Everything comes to a screeching halt, with instruction fetch etc becoming a serious problem. So disabling caching for a few instructions in a very simple asm snippet might be reasonable (particularly since you could pre-fetch the cache and just rely on CR0.CD not fetching *new* lines). But doing it in C code that might have things like tracing enabled etc? I'd be very very leery. Linus