linux-kernel - Re: [PATCH] x86/rapl: Do not load in a guest

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Message-ID: <20151204182807.GN21177@pd.tnic>
Date:	Fri, 4 Dec 2015 19:28:07 +0100
From:	Borislav Petkov <bp@...en8.de>
To:	Jacob Pan <jacob.jun.pan@...ux.intel.com>
Cc:	Ingo Molnar <mingo@...nel.org>,
	Paolo Bonzini <pbonzini@...hat.com>,
	"H. Peter Anvin" <hpa@...or.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Amy Wiles <amy.l.wiles@...el.com>,
	"Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
	LKML <linux-kernel@...r.kernel.org>,
	Arnaldo Carvalho de Melo <acme@...nel.org>,
	Ingo Molnar <mingo@...hat.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Hannes Reinecke <hare@...e.de>
Subject: Re: [PATCH] x86/rapl: Do not load in a guest

On Fri, Dec 04, 2015 at 10:16:10AM -0800, Jacob Pan wrote:
> CPU model detection is the first level checking.

And in the case of RAPL, the only checking you can do. This is why it
should've had a CPUID bit.

> The error is about no valid domains (e.g. counters not working). So
> the error on minnowboard board could be a real problem if you expect
> to use RAPL.

Right, and if you need to disable it there, you would need to add a
quirk table looking at DMI strings or so. A CPUID bit might've been a
bit better if BIOS update would clear it on those boards. Then, sw won't
even try to load there.

-- 
Regards/Gruss,
    Boris.

ECO tip #101: Trim your mails when you reply.
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