Re: [gentoo-user] Microcode update AMD

[Volker Armin Hemmann]

On Monday 17 January 2011 10:48:36 Mark Knecht wrote:
> On Mon, Jan 17, 2011 at 10:10 AM, BRM <bm_witness@×××××.com> wrote:
> > ----- Original Message ----
> >
> >> I have two questions:
> >>
> >>  1) Do I have to enable microcode  updates in the BIOS of my Crosshair
> >>     IV Formula to activate  microcodes push in the CPU by the module
> >>     "microcode" ? (AMD  Phenom X6 1090T)
> >
> > Not sure about BIOS, but the Linux Kernel you are running will certainly
> > need support enabled too.
> >
> >>  2) Does anyone know, what these microcodes do? They are  fixes for...
> >>     ...what?
> >
> > The Intel and AMD processors are more abstract than physical now. With
> > i486 and earlier the processors were typically hard wired; hardware
> > "bug" fixes could not be pushed out.
> > Intel's Pentium (and I don't know which AMD) started using micro-code to
> > program the processor. This enabled them to push out "hardware" bug
> > fixes for the processors.
> >
> > So what happens is the x86 instruction (e.g. mov ax, bx) gets translated
> > to micro-code first, then it gets processed, and the result translated
> > back to the expected instruction result - essentially, emulating the
> > x86 instruction set in the processor. That's the simple version.
> >
> > So now when they discover a bug in the hardware they can push out a
> > micro-code update to either fix the "hardware"  (microcode) bug or work
> > around a hardware (physical hardware) bug.
> >
> > Ben
>
> Ben,
>    Do you know how security on these updates is handled? Seems to me
> this is an area rife for exploitation so I've been very hesitant to
> use them until I understood more.

you can not not use them because alsmost all bios load the microcode 
automatically.