Re: [PATCH 2/2] x86, microcode: Make reload interface per system

From: H. Peter Anvin
Date: Fri Jun 22 2012 - 14:23:37 EST


On 06/22/2012 09:26 AM, Nix wrote:
> On 20 Jun 2012, Borislav Petkov uttered the following:
>> I know, right. Whose idea was it to do it like that I don't know.
>> AFAICT, Intel delivers ucode as a single blob too, so why split it? The
>> driver picks out the right blob anyway.
>
> Only if supplied over the old interface. Over the new interface,
> we just see
>
> microcode: error! Bad data in microcode data file
>
> in the log. So clearly the driver doesn't know how to split up the
> microcode.bin that Intel provides, and (until Henrique's iucode-tool or
> something like it becomes ubiquitous) the old interface, and
> microcode_ctl, cannot be removed.
>

Even more importantly, to do early microcode updates we need to stash
away not just the current CPU's microcode but any compatible CPU's
microcode, so just loading a single one is not going to work...

Oif.

-hpa

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