One trick computer processors use for improving performance is speculative execution.Basically, the processor tries to "look ahead" into the code of the currently running program, and execute things that might not even end up getting executed – for example, if between the line of code in the prediction and the line currently being executed, an error (such as attempting to read memory you're not allowed to access) happens. In such a scenario, the changes by the processor are supposed to be "rolled back", and the code is supposed to continue running as if this prediction never happened.However, as discovered by researchers, observable side effects from code that was not supposed to be executed remain, which is what vulnerabilities like Meltdown and Spectre rely on.The most common scenario where speculative execution comes into play is branching – moments where code can diverge into multiple scenarios, with things like if statements.With that taken into account, @xor...
