Date: Tue, 25 Apr 2017 14:59:13 +0200
From: Borislav Petkov <bp@alien8.de>
To: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Ingo Molnar <mingo@redhat.com>, Andy Lutomirski <luto@kernel.org>,
        Brian Gerst <brgerst@gmail.com>, Peter Zijlstra <peterz@infradead.org>,
        "H. Peter Anvin" <hpa@linux.intel.com>, x86@kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] x86, msr: Better document AMD "tweak MSRs", rename
 MSR_F15H_IC_CFG
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On Tue, Apr 25, 2017 at 02:16:55PM +0200, Denys Vlasenko wrote:
> However, all IBS registers are in this range.

I knew you were gonna say that. But IBS registers are architectural too
in the sense that they are behind a CPUID bit.

> DRi_ADDR_MASK are in this range - and these are very useful, likely to
> stay.

Those are too behind a CPUID bit.

> In the arch/x86/include/asm/msr-index.h file we already have
> three "tweak" MSRs defined with "AMD64":
> 
> #define MSR_AMD64_LS_CFG               0xc0011020
> #define MSR_AMD64_DC_CFG               0xc0011022
> #define MSR_AMD64_BU_CFG2              0xc001102a
> 
> I just noticed that we have a fourth one in
> arch/x86/kernel/cpu/amd.c:
> 
> #define MSR_AMD64_DE_CFG       0xC0011029

That's wrong. I think we should call those something else but not
"AMD64". Perhaps the families for which the workaround is being applied.
In the last case, MSR_F12H_DE_CFG, for example. And yes, I should've
paid attention to that but ...

-- 
Regards/Gruss,
    Boris.

Good mailing practices for 400: avoid top-posting and trim the reply.