Funny that I am seeing this now, because last Fall I had Daniel Genkin as my Intro to Cyber Security Professor (co-author of this result). Interesting class, but I remember him mentioning that they were working on a speculative attack for Apple CPUs after seeing the results of spectre and meltdown on Intel CPUs. I remember how he seemed almost paranoid about security, and I suppose I see why now (security is almost never guaranteed).
Especially now that I have just bought an M4 mac