Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752260AbaJVOQJ (ORCPT ); Wed, 22 Oct 2014 10:16:09 -0400 Received: from bombadil.infradead.org ([198.137.202.9]:53195 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751511AbaJVOQH (ORCPT ); Wed, 22 Oct 2014 10:16:07 -0400 Date: Wed, 22 Oct 2014 16:15:47 +0200 From: Peter Zijlstra To: Alexander Shishkin Cc: Ingo Molnar , linux-kernel@vger.kernel.org, Robert Richter , Frederic Weisbecker , Mike Galbraith , Paul Mackerras , Stephane Eranian , Andi Kleen , kan.liang@intel.com, adrian.hunter@intel.com, acme@infradead.org Subject: Re: [PATCH v5 11/20] x86: perf: Intel PT and LBR/BTS are mutually exclusive Message-ID: <20141022141547.GO12706@worktop.programming.kicks-ass.net> References: <1413207948-28202-1-git-send-email-alexander.shishkin@linux.intel.com> <1413207948-28202-12-git-send-email-alexander.shishkin@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1413207948-28202-12-git-send-email-alexander.shishkin@linux.intel.com> User-Agent: Mutt/1.5.22.1 (2013-10-16) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Oct 13, 2014 at 04:45:39PM +0300, Alexander Shishkin wrote: > Intel PT cannot be used at the same time as LBR or BTS and will cause a > general protection fault if they are used together. In order to avoid > fixing up GPs in the fast path, instead we use flags to indicate that > that one of these is in use so that the other avoids MSR access altogether. > Yeah, don't like this. Like I've said many times before we should simply disallow creating PT events when there are LBR events and vice versa. -- 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/