From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759204AbaGCPwm (ORCPT ); Thu, 3 Jul 2014 11:52:42 -0400 Received: from one.firstfloor.org ([193.170.194.197]:46869 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759171AbaGCPwk (ORCPT ); Thu, 3 Jul 2014 11:52:40 -0400 Date: Thu, 3 Jul 2014 17:52:37 +0200 From: Andi Kleen To: Peter Zijlstra Cc: kan.liang@intel.com, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, andi@firstfloor.org Subject: Re: [PATCH V2 2/3] perf protect LBR when Intel PT is enabled. Message-ID: <20140703155237.GQ5714@two.firstfloor.org> References: <1404324855-15166-1-git-send-email-kan.liang@intel.com> <1404324855-15166-2-git-send-email-kan.liang@intel.com> <20140703073321.GU19379@twins.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140703073321.GU19379@twins.programming.kicks-ass.net> 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 > If there's active LBR users out there, we should refuse to enable PT and > vice versa. This doesn't work, e.g. hardware debuggers can take over at any time. -Andi -- ak@linux.intel.com -- Speaking for myself only.