As an alternative to this approach, I wonder if it's possible to push all sensitive computations into a few small components, and rewrite those components carefully to obscure any information that could be obtained from timing?
Of course.
Branchless code equivalents can be written for practically anything, and you can force-prefetch memory regardless of branch(its an intrinsic in most C compilers), though this loses performance and branch prediction benefits.
It would require doing this for any new/existing code exposing timing information, the current timing fixes/isolation patches are much smaller.
It would make more sense in user code, like browsers/media players/etc to remove influence of branch prediction regardless of host OS, just like GCC does with retpoline insertion.
