Re: [tip:x86/urgent] x86, AMD: Disable wrongly set X86_FEATURE_LAHF_LM CPUID bit

Borislav Petkov
2009-08-25T05:52:21Z

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.

--
Regards/Gruss,
Boris.