From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756401AbZA2QQH (ORCPT ); Thu, 29 Jan 2009 11:16:07 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752386AbZA2QPz (ORCPT ); Thu, 29 Jan 2009 11:15:55 -0500 Received: from mx2.mail.elte.hu ([157.181.151.9]:49468 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751864AbZA2QPy (ORCPT ); Thu, 29 Jan 2009 11:15:54 -0500 Date: Thu, 29 Jan 2009 17:15:46 +0100 From: Ingo Molnar To: Jack Steiner Cc: suresh.b.siddha@intel.com, linux-kernel@vger.kernel.org Subject: Re: Possible x2apic breakage Message-ID: <20090129161546.GB28984@elte.hu> References: <20090129154146.GA2694@sgi.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090129154146.GA2694@sgi.com> User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Jack Steiner wrote: > Suresh - > > This popped up in Ingo's x86 tree yesterday. This appears to be breaking > on our simulator running in x2apic mode. If I understand the code, > this is a real breakage and not a problem in our simulator: > > > arch/x86/include/asm/genapic.h > > static inline unsigned int read_apic_id(void) > { > unsigned int reg; > > reg = *(u32 *)(APIC_BASE + APIC_ID); > return apic->get_apic_id(reg); > } > > > As expected, the failure occurs right after: > > Enabling x2apic > Enabled x2apic and interrupt-remapping > > The next reference to apicid tries to read from mem instead of MSRs. yes - Suresh sent a fix earlier today. Could you please check latest tip/master (v2.6.29-rc3-1212-g69f3c6d or later), does it work fine in your simulator? And i'll also merge struct apic_ops into struct genapic - now that genapic is unified there's no reason for the two to be separate. Ingo