RE: [v2 1/3] x86/microcode/intel: Check microcode revision before updating sibling threads

[Van De Ven, Arjan]

> > In the past the only guidance was to not load microcode at the same time to
> the
> > thread siblings of a core. We now have new guidance that the sibling must be
> > spinning and not doing other things that can introduce instability around
> loading
> > microcode.
> 
> Document that properly in the Intel SDM, *please*.

yes we will update the SDM, just that is a much longer process than sending code out.

> 
> While at it, please verify with the microcode teams that the requirement
> for 16-byte alignment of the microcode update as present in the Intel
> SDM still stands.  

I'd be surprised if it did not. 

>Linux does not enforce it on the early microcode
> update loader when using an initramfs (but userspace can work around
> that, and iucode_tool --early-fw does so).  If that 16-byte alignment is
> important, I could dust off some patches that fix it.

hmm wonder what those tools do nowadays; Intel publishes the microcode in the linux native format since some time (and the .dat format is about to go away entirely)