[coreboot] FYI: Reverse Engineering x86 Processor Microcode

[Andrey Korolyov]

> In this paper, we reverse engineer the microcode semantics
> and inner workings of its update mechanism of conventional
> COTS CPUs on the example of AMD’s K8 and
> K10 microarchitectures.
>

Still wondering what was engineering reasons for these families behind
such a practice as non-verified microcode updates. Also these families
had very interesting uop-update behavior that could be called 'mu-ops
cache', where under certain conditions malicious micro-ops could be
cached forever, even if the 'good' update has been loaded afterwards.