[Cryptography] Speculation re Intel HW cockup; reqs. OS rewrites & slow execution

[jamesd at echeque.com]

On 1/5/2018 2:38 PM, Bill Frantz wrote:
> I can imagine speculative execution which does not proceed if the needed 
> data is not already in the cache.

Indeed loading stuff into cache on speculative execution increases your 
working set, so arguably there are efficiency grounds for not 
speculatively hitting the cache.

If you need to load stuff into cache, your speculative execution is 
going to be delayed, does not buy you much.  Worst case, your 
speculative execution is delayed by a cache miss, and then turns out to 
be wrong, then you take the the correct path - and it has a cache miss 
again because your speculative execution ejected the needed value from 
cache.