Re: [tip:x86/urgent] x86, AMD: Disable wrongly setX86_FEATURE_LAHF_LM CPUID bit

From: Borislav Petkov
Date: Tue Aug 25 2009 - 01:52:48 EST

On Mon, Aug 24, 2009 at 01:34:07PM -0700, H. Peter Anvin wrote:
> Looks reasonable... although part of me wonders if having a pointer to
> an array containing the entire register file in and out is even better,
> of if I'm just overengineering at this point.

Hmm, let's have necessity determine that. I can only think of %edi being
used as an input reg to rd/wrmsr beside %ecx but it could be very well
that some other x86 hardware uses other regs too. Do we actually need
all regs or a two should suffice?

> Note that the only difference between "rdmsr" and "wrmsr" is the actual
> opcode being executed at this point...

... which means even less code with macro magic.

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