Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757013Ab0HQHFZ (ORCPT ); Tue, 17 Aug 2010 03:05:25 -0400 Received: from mail.skyhub.de ([78.46.96.112]:34467 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756825Ab0HQHFY (ORCPT ); Tue, 17 Aug 2010 03:05:24 -0400 Date: Tue, 17 Aug 2010 09:05:20 +0200 From: Borislav Petkov To: "H. Peter Anvin" Cc: akataria@vmware.com, the arch/x86 maintainers , Greg KH , "greg@kroah.com" , "ksrinivasan@novell.com" , LKML , borislav.petkov@amd.com Subject: Re: [Patch] Skip cpu_calibrate for kernel running under hypervisors. Message-ID: <20100817070520.GD32714@liondog.tnic> Mail-Followup-To: Borislav Petkov , "H. Peter Anvin" , akataria@vmware.com, the arch/x86 maintainers , Greg KH , "greg@kroah.com" , "ksrinivasan@novell.com" , LKML , borislav.petkov@amd.com References: <1281986754.23253.32.camel@ank32.eng.vmware.com> <4C69D02F.6090601@zytor.com> <1282024311.20786.2.camel@ank32.eng.vmware.com> <4C6A2C98.4060605@zytor.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <4C6A2C98.4060605@zytor.com> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1347 Lines: 34 From: "H. Peter Anvin" Date: Mon, Aug 16, 2010 at 11:30:48PM -0700 > On 08/16/2010 10:51 PM, Alok Kataria wrote: > >> > >> I'm somewhat reluctant to take this one, since it assumes all the > >> hypervisors act the same. This seems rather inherently wrong. In fact, > >> the whole statement is fishy as heck... instead of being dependent on > >> AMD and so on, > > > > The check about being on AMD is something that was already there. > > > > I know it was... and calibrate_cpu() seems to be an AMD-specific > function, but that's rather crappy. I'm thinking that perhaps we should > make it an x86_init function, then the AMD CPU detection can install it > and the vmware hypervisor detection can uninstall it. Btw, can we revisit this AMD-specific issue? IIUC, Alok you're seeing a mismatch between the calibrated TSC value and the cpu frequency even on cpus which have the CONSTANT_TSC bit set, i.e. their TSC is counting with P0 frequency. Can you please elaborate more on what systems you're seeing this (cpu family, chipset, etc)? Thanks. -- Regards/Gruss, Boris. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/