Re: [RFC PATCH 00/15] Prepare for new Intel family models

From: Sohil Mehta
Date: Mon Dec 23 2024 - 14:44:39 EST


On 12/20/2024 4:29 PM, Andrew Cooper wrote:
>>
>> A dump of the microcode file 06-03-02 shows:
>> 001/001: sig 0x00001632, pf_mask 0x00, 1998-06-10, rev 0x0002, size 2048
>> An archived CPUID dump [3] also says:
>> CPUID 00000001: 00001632-00000000-00000000-0183FBFF
>>
>> That would translate to a family number of 22 (0x16). This aberration is
>> not explicitly handled anywhere in the kernel so the platform might already
>> be broken. This series might make it worse for the platform if the latest
>> kernel works on it by chance.
>
> Are you sure?  Bits 13:12 are the type field, and the 0x1 you've got is
> for an OverDrive processor.
>

You are right. This is indeed the processor type field. I should have
spent more time reading the specification than Wikipedia :)


> x86_family() will consider this to be family 6 as far as I can see.
>

On the bright side, we don't have to worry about breaking this CPU.

Sohil