I agree that this should be at an OS level, and coarse-grained.
Direct access to fine-grained cycle counters are well-known to be used for timing-based attacks. (Not just Spectre and Meltdown but also for reducing the time to guess passwords, encryption keys, etc, etc.). A whole field of “constant time algorithms” has arisen to combat it, which is a bit unnecessary IMHO.
- This reply was modified 1 week ago by Findecanor.