Re: Death of DRM on PC platforms??
"And the 'ret-poline' seems to be an adequate defense against at least SOME of it, by not using the speculative execution thingy in the first place."
Retpoline doesn't get in the way of most speculative execution; that would make the penalty of the Meltdown mitigation look positively light-weight in comparison. Instead, it tricks the processor into treating simple jumps as function calls, which are handled differently(though our buddies at Intel have managed to screw up that bit of security: in the right circumstances, newer models can starting reading from the vulnerable branch buffer rather than the secure return buffer).
This post from Stack Overflow explains it a lot better than I ever could.