Re: runtime regression with "x86/mm/pat: Emulate PAT when it is disabled"

[Borislav Petkov]

On Thu, Mar 10, 2016 at 02:04:29PM -0500, Paul Gortmaker wrote:
> So, I guess that is a qemu bug?  If there is no real silicon out there
> that has no MTRR but does claim PAT, then qemu32 is a flawed CPU type?

Well, AFAICT, "qemu32" is emulating something PPRO-like:

#define PPRO_FEATURES (CPUID_FP87 | CPUID_DE | CPUID_PSE | CPUID_TSC | \
          CPUID_MSR | CPUID_MCE | CPUID_CX8 | CPUID_PGE | CPUID_CMOV | \
          CPUID_PAT | CPUID_FXSR | CPUID_MMX | CPUID_SSE | CPUID_SSE2 | \
	  ^^^^^^^^^

and that one advertizes PAT but not MTRRs.

I need to go dig into history to find out what PPRO actually supported.

-- 
Regards/Gruss,
    Boris.

SUSE Linux GmbH, GF: Felix ImendÃrffer, Jane Smithard, Graham Norton, HRB 21284 (AG NÃrnberg)
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