From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754907Ab2CLMKd (ORCPT ); Mon, 12 Mar 2012 08:10:33 -0400 Received: from nat28.tlf.novell.com ([130.57.49.28]:59618 "EHLO nat28.tlf.novell.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754715Ab2CLMKb convert rfc822-to-8bit (ORCPT ); Mon, 12 Mar 2012 08:10:31 -0400 Message-Id: <4F5DF5C30200007800077A5B@nat28.tlf.novell.com> X-Mailer: Novell GroupWise Internet Agent 12.0.0 Date: Mon, 12 Mar 2012 12:10:27 +0000 From: "Jan Beulich" To: "Steven Rostedt" Cc: , "Peter Zijlstra" , , Subject: recent x86-64 nested NMI adjustments Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 8BIT Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Steven, the explanation of 45d5a1683c04be28abdf5c04c27b1417e0374486 seems bogus to me: When arriving from user mode, %rsp won't point to the user stack anymore, as it gets switched away from during the processing of the exception (the more that the IDT entry specifies a separate stack anyway, which even guarantees this for kernel mode entries). Further, a38449ef596b345e13a8f9b7d5cd9fedb8fcf921 makes the (presumably superfluous) compare a 4-byte one, while the documentation isn't really stating that selectors get pushed zero- extended. Hence, if not reverting the first change altogether, I'd minimally recommend converting the compare to a 2-byte one. Jan