I don't think Meltdown depends on eager (both-branch) speculative execution. I think you are being overly gentle responding to this flaw in the explanation. N

I don't think Meltdown depends on eager (both-branch) speculative execution. I think you are being overly gentle responding to this flaw in the explanation. Not only does the bug not depend on both-branch speculative execution, I don't think there even exist any x64 processors that do both-branch speculative execution. I'm almost certain that all modern Intel x64 processors do branch-prediction and speculatively execute only the branch that they predict as most likely. If that guess is later proved wrong, they throw away the executed but not-yet-retired instructions and execute the correct path. Am I wrong about this?