From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752471AbaEUJqu (ORCPT ); Wed, 21 May 2014 05:46:50 -0400 Received: from mail.skyhub.de ([78.46.96.112]:60401 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751023AbaEUJqt (ORCPT ); Wed, 21 May 2014 05:46:49 -0400 Date: Wed, 21 May 2014 11:46:26 +0200 From: Borislav Petkov To: Andy Lutomirski Cc: Steven Rostedt , "linux-kernel@vger.kernel.org" , "H. Peter Anvin" , Linus Torvalds , Ingo Molnar , Thomas Gleixner , Andi Kleen Subject: Re: [RFC] x86_64: A real proposal for iret-less return to kernel Message-ID: <20140521094626.GB21205@pd.tnic> References: <1400639227.9759.21.camel@pippen.local.home> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, May 20, 2014 at 07:39:31PM -0700, Andy Lutomirski wrote: > So the issue here is that we can have an NMI followed immediately by > an MCE. That part might need clarification for me: #MC is higher prio interrupt than NMI so a machine check exception can interrupt the NMI handler at any point. But you're talking only about the small window when nmi_mce_nest_count hasn't been incremented yet, right? I.e., this: "The result is that the only interrupt that can happen with `nmi_mce_nest_count == 0` in NMI context is an MCE at the beginning or end of the NMI handler." Correct? -- Regards/Gruss, Boris. Sent from a fat crate under my desk. Formatting is fine. --