Hector Martin

Allow me to summarize x86 side channel attacks: Spectre v1: speculation is insecure by design Spectre v2: secure branch prediction matters Meltdown: Intel are dumbasses L1TF: Intel are monumental, inexcusable dumbasses PortSmash: hyperthreading is insecure by design

And yes, Spectre v1 and PortSmash aren't going away. Anyone who knows anything about CPUs knew PortSmash was theoretically possible for years (just someone bothered to finally implement it). Disable HT or petition OSes to do security-domain-aware HT by default.

Also PortSmash should be adaptable to AMD systems with HT (i.e. Zen) and also all the POWER stuff. And it gets worse, because under more specific circumstances and with cleverer exploits, the side channels go beyond HT and to shared caches too.

Ultimately, computing needs to come to terms with the fact that any time there is *any* shared resource, that's ripe for side channels. This includes main memory and peripheral devices. It's worse and more insidious the lower level and more tightly coupled you make it, like HT.