From owner-freebsd-questions@FreeBSD.ORG Wed Oct 23 00:07:46 2013 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTP id 02EFFCE5 for ; Wed, 23 Oct 2013 00:07:46 +0000 (UTC) (envelope-from tg@gmplib.org) Received: from shell.gmplib.org (gmplib-02.nada.kth.se [130.237.222.242]) by mx1.freebsd.org (Postfix) with ESMTP id BFEE32281 for ; Wed, 23 Oct 2013 00:07:44 +0000 (UTC) Received: by shell.gmplib.org (Postfix, from userid 1001) id 28D0222204; Wed, 23 Oct 2013 02:02:25 +0200 (CEST) To: freebsd-questions@freebsd.org Subject: MULX on haswell triggers ILLOP From: Torbjorn Granlund Sender: tg@gmplib.org Date: Wed, 23 Oct 2013 02:02:25 +0200 Message-ID: <86wql4onvy.fsf@shell.gmplib.org> User-Agent: Gnus/5.11 (Gnus v5.11) Emacs/22.3 (berkeley-unix) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 23 Oct 2013 00:07:46 -0000 I have an Intel Haswell system which runs Xen/NetBSD with Debian 7.2, NetBSD 6.1.2 and FreeBSD 9.2 guests. The FreeBSD guest casts an ILLOP when fed with the new MULX instruction. This is a plain integer register based instruction which should require zero kernel support. MULX is part of the BMI2 extensions. The instruction works fine in the other guest systems. What is going on? How can FreeBSD reject this instruction? I have not tried to run FreeBSD on the bare metal, so I cannot tell if BMI2 works as expected there. --=20 Torbj=C3=B6rn