From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932549AbbERTe0 (ORCPT ); Mon, 18 May 2015 15:34:26 -0400 Received: from www.linutronix.de ([62.245.132.108]:50729 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932270AbbERTeY (ORCPT ); Mon, 18 May 2015 15:34:24 -0400 Date: Mon, 18 May 2015 21:34:32 +0200 (CEST) From: Thomas Gleixner To: Dave Hansen cc: linux-kernel@vger.kernel.org, x86@kernel.org, dave.hansen@linux.intel.com Subject: Re: [PATCH 01/19] x86, mpx, xsave: fix up bad get_xsave_addr() assumptions In-Reply-To: <20150508185948.01B91DEB@viggo.jf.intel.com> Message-ID: References: <20150508185948.4C19F4B0@viggo.jf.intel.com> <20150508185948.01B91DEB@viggo.jf.intel.com> User-Agent: Alpine 2.11 (DEB 23 2013-08-11) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001,URIBL_BLOCKED=0.001 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 8 May 2015, Dave Hansen wrote: > From: Dave Hansen > > get_xsave_addr() assumes that if an xsave bit is present in the > hardware (pcntxt_mask) that it is present in a given xsave > buffer. Due to an bug in the xsave code on all of the systems > that have MPX (and thus all the users of this code), that has > been a true assumption. > > But, the bug is getting fixed, so our assumption is not going > to hold any more. > > It's quite possible (and normal) for an enabled state to be > present on 'pcntxt_mask', but *not* in 'xstate_bv'. We need > to consult 'xstate_bv'. > > Signed-off-by: Dave Hansen Reviewed-by: Thomas Gleixner