Turning off prefetching while running crypto code would be a performance gain before you can implement the algorithms safely without even more expensive and fra

Turning off prefetching while running crypto code would be a performance gain before you can implement the algorithms safely without even more expensive and fragile software mitigations. Just give me the option of configuring parts of the caches (at least data + instructions + TLBs) as scratchpad and and a "run without timing side-channels pretty please" bit with a clearly defined API contract and accessible (by default) to unprivileged userspace code. Lots of cryptographic algorithms have such small working sets that they would profit from a constant-time accessible scratchpad in the L1d cache if they get to use data dependent addresses into it again.