Contrary to popular sentiment, Meltdown is also not an Intel-unique bug, it also affected POWER and ARM processors.
AMD essentially got lucky on this one - their neural-network based branch predictor is difficult for an attacker to train to follow specific code paths, which is a necessary component of Meltdown/Spectre style attacks. Pretty much every other processor that does speculation is affected.
The potential for cache timing to serve as a side-channel leak was not widely appreciated in the industry, although it was theoretically described as far back as the early 90s.
AMD essentially got lucky on this one - their neural-network based branch predictor is difficult for an attacker to train to follow specific code paths, which is a necessary component of Meltdown/Spectre style attacks. Pretty much every other processor that does speculation is affected.
The potential for cache timing to serve as a side-channel leak was not widely appreciated in the industry, although it was theoretically described as far back as the early 90s.