Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933248AbaD2OGz (ORCPT ); Tue, 29 Apr 2014 10:06:55 -0400 Received: from cdptpa-outbound-snat.email.rr.com ([107.14.166.228]:23542 "EHLO cdptpa-oedge-vip.email.rr.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S932647AbaD2OGy (ORCPT ); Tue, 29 Apr 2014 10:06:54 -0400 Date: Tue, 29 Apr 2014 10:06:52 -0400 From: Steven Rostedt To: "H. Peter Anvin" Cc: Jiri Kosina , Linus Torvalds , linux-kernel@vger.kernel.org, x86@kernel.org, Salman Qazi , Ingo Molnar , Michal Hocko , Borislav Petkov , Vojtech Pavlik , Petr Tesarik , Petr Mladek Subject: Re: 64bit x86: NMI nesting still buggy? Message-ID: <20140429100652.56c8c07f@gandalf.local.home> In-Reply-To: <535FA920.9080503@linux.intel.com> References: <535FA920.9080503@linux.intel.com> X-Mailer: Claws Mail 3.9.3 (GTK+ 2.24.22; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-RR-Connecting-IP: 107.14.168.130:25 X-Cloudmark-Score: 0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 29 Apr 2014 06:29:04 -0700 "H. Peter Anvin" wrote: > > [2] "A special case can occur if an SMI handler nests inside an NMI > > handler and then another NMI occurs. During NMI interrupt > > handling, NMI interrupts are disabled, so normally NMI interrupts > > are serviced and completed with an IRET instruction one at a > > time. When the processor enters SMM while executing an NMI > > handler, the processor saves the SMRAM state save map but does > > not save the attribute to keep NMI interrupts disabled. > > Potentially, an NMI could be latched (while in SMM or upon exit) > > and serviced upon exit of SMM even though the previous NMI > > handler has still not completed." > > I believe [2] only applies if there is an IRET executing inside the SMM > handler, which should not normally be the case. It might also have been > addressed since that was written, but I don't know. Bad behaving BIOS? But I'm sure there's no such thing ;-) -- Steve -- 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/