Earlier quoted context omitted.
I do not understand how you want to mitigate this issue by using the "context" given that the attack demonstration is done with a source code that makes use of the "context". The attack is fully context-agnostic since the "PACMAN gadget" in victim's code is injecting the "context" by itself. The root of the problem is the small hash size and the fact that you can "suppress" failed hash check effects to bruteforce the…
Speculative exec ruins everything again. I get the performance gainz, but when are we going to get past the formal fallacy that executing any instruction we don't need to based on actual flow is de facto a complete violation of user expectations and therefore completely unsafe to do. Like every lay person I explain speculative execution seems to be able to recognize that a pipeline stall to figure out what a value ac…
Speculative execution today (within modern high-end processor) does not execute both sides of a conditional branch.
It would indeed be a waste of power and it would be a much more complex micro-architecture.
Modern speculative OoO processors execute a single path and simply relies on the branch predictor accuracy. And they are pretty accurate, on the order of 3 misspredictions every 1000 instructions. The power consumption in unnecessary work due to a missprediction is quite low.
Modern processors consume much of their power in Out-of-Order instruction scheduling.