OK, so this works on AMD Jaguar according to the README. That's a architecture from 2013. There's notes about Zen 3 having a different base address for the memory controller registers, but that's it. What newer CPUs does attack actually work on?
CPU designers have been aware of this attack vector for a while, so many (maybe all) have controls to lock these registers. They are written and locked by vendor firmware before it hands off to the operating system.
You would have first break the firmware or locks before an attack like this on a modern CPU
Zen has completely different memory controller IP (UMC), that's configured at boot by AGESA/PSP. I doubt this exploit applies to modern Zen CPUs, however AMD are the only ones who could really confirm this.
Yes, a hurdle to effective security research. Something hidden only appears to have no vulnerabilities. By raising the bar on a mass market product of this sort you ensure that in the event well funded actors develop exploits in secret they won't be inadvertently discovered by the public.
Then publishing it in this incomplete state is just pointless fearmongering and will just make others fill in this information within the next couple of days. And the good guys likely won't be the first ones to do that.
