Re: CPU microcode reported wrong in /proc/cpuinfo

[Brian Inglis <Brian.Inglis@SystematicSw.ab.ca>]

On 2020-06-10 14:23, Lavrentiev, Anton (NIH/NLM/NCBI) [C] via Cygwin wrote:
>> I'll have to recheck how Linux handles these
> 
> JFYI I was in correspondence with the cpuid utility team lately, and they told me that Linux uses vendor-specific MSRs to pull that info out:
> 
>> Check out:
>>
>>    MSR_IA32_UCODE_REV
>>    MSR_AMD64_PATCH_LEVEL
>>
>> Both reference MSR 0x8b.

As does MS, as I also tracked down some older MS Windows microcode registry
values used, whose names also appear to be based on the earlier MSR names.
Using MSRs are not an option, as MS Windows appears to provide no documented
access to those register values, and they are only accessible from kernel level
drivers, which are not available for latest MS Windows (i.e. I don't trust
offered drivers that claim to provide MSR access!)

I have applied a patch for this, and rebuilt cygwin, but are having problems
testing with the new dll (as are some others), so need some time to figure out
what are the minimum synced pieces now required to be able to test!

-- 
Take care. Thanks, Brian Inglis, Calgary, Alberta, Canada

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