From: Olaf Hering <olaf@aepfle.de>
Subject: Re: [PATCH v3] new config option vtsc_tolerance_khz to
 avoid TSC emulation
Date: Tue, 6 Mar 2018 13:11:26 +0100
Message-ID: <20180306131126.23f86a32.olaf@aepfle.de>
References: <20180306104133.22106-1-olaf@aepfle.de>
 <af47cc31-d3cb-023a-1229-ab9eb013f985@citrix.com>
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To: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>, Wei Liu <wei.liu2@citrix.com>, George Dunlap <George.Dunlap@eu.citrix.com>, Tim Deegan <tim@xen.org>, Ian Jackson <ian.jackson@eu.citrix.com>, Marek =?UTF-8?B?TWFy?= =?UTF-8?B?Y3p5a293c2tpLUfDs3JlY2tp?= <marmarek@invisiblethingslab.com>, xen-devel@lists.xen.org, Julien Grall <julien.grall@arm.com>, Jan Beulich <jbeulich@suse.com>, Daniel De Graaf <dgdegra@tycho.nsa.gov>
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Am Tue, 6 Mar 2018 11:07:54 +0000
schrieb Andrew Cooper <andrew.cooper3@citrix.com>:

> We should see about using better sources of information.=C2=A0 For one, m=
any
> Intel systems actually expose the TSC frequency in the bottom of the
> PLATFORM_INFO MSR, although this isn't architectural, and has been
> replaced with CPUID information in Skylake.

I'm not familiar with that.
Is it what arch/x86/kernel/tsc_msr.c:cpu_khz_from_msr()
gets from MSR_PLATFORM_INFO + MSR_FSB_FREQ?

Olaf

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