linux-kernel - RE: early microcode: how to disable at runtime?

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Message-ID: <3E5A0FA7E9CA944F9D5414FEC6C712205A666A7F@ORSMSX106.amr.corp.intel.com>
Date:	Thu, 4 Sep 2014 18:37:05 +0000
From:	"Yu, Fenghua" <fenghua.yu@...el.com>
To:	Borislav Petkov <bp@...en8.de>,
	Henrique de Moraes Holschuh <hmh@....eng.br>
CC:	"H. Peter Anvin" <hpa@...or.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: early microcode: how to disable at runtime?

> From: Borislav Petkov [mailto:bp@...en8.de]
> > What I did claim is that it is going to be a far more user-friendly
> > stop gap than the "boot from rescue media" option.
> 
> Ok, we have it now and we can use it if needed. All is good.

Quoted comment from commit 65cef1311d5d212fd3d48a43678536dc878ca288:
"...This is useful mostly in debugging situations where we want to turn off microcode
    loading, both early from the initrd and late, ...."

In case this comment may cause confusion, I need to confirm that:

The parameter "dis_ucode_ldr" only turns off early microcode loading from the initrd.
It does not trun off loading microcode later during run time.

Thanks.

-Fenghua