18 ms·
This one is going to be much more difficult to defeat. I suspect we will see more dangerous local exploits based on power side channels. Mitigating those will
by xenadu02 8y ago
This one is going to be much more difficult to defeat. I suspect we will see more dangerous local exploits based on power side channels.
Mitigating those will be bad for power usage and performance. We can imagine future processors will manage cache state differently, keeping all changes local to the core until the relevant instructions retire. I have no idea how you would mitigate functional unit power up / power down without destroying the usefulness of the feature itself.
- Eit4Choh 8y agoMaybe just don't speculate across power domains? I.e. if a speculative execution would require bringing up the AVX2 unit that might be a bad idea anyway because it slows down everything else even if the branch is mispredicted. Or at least execute it on the slow path if the unit is not up (lower execution width) without triggering the ramp-up as long as it is speculative. Only ramp-up when the instruction is committed.