Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754321Ab1EQLsL (ORCPT ); Tue, 17 May 2011 07:48:11 -0400 Received: from mx1.redhat.com ([209.132.183.28]:62917 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753664Ab1EQLsJ (ORCPT ); Tue, 17 May 2011 07:48:09 -0400 Message-ID: <4DD2605A.90506@redhat.com> Date: Tue, 17 May 2011 14:47:38 +0300 From: Avi Kivity User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.17) Gecko/20110428 Fedora/3.1.10-1.fc14 Lightning/1.0b3pre Thunderbird/3.1.10 MIME-Version: 1.0 To: Ingo Molnar CC: "H. Peter Anvin" , Fenghua Yu , Thomas Gleixner , Asit K Mallick , Linus Torvalds , Arjan van de Ven , Andrew Morton , Andi Kleen , linux-kernel , Pekka Enberg Subject: Re: [PATCH v2 0/4] Enable SMEP CPU Feature References: <1305581685-5144-1-git-send-email-fenghua.yu@intel.com> <4DD19C81.8000902@zytor.com> <20110517070527.GD22305@elte.hu> <4DD23CB6.3050503@redhat.com> <20110517092903.GJ22093@elte.hu> <4DD2409F.4030800@redhat.com> <20110517104654.GN22093@elte.hu> <4DD25D29.9040008@redhat.com> <20110517113851.GD13475@elte.hu> <4DD25FA4.7030307@redhat.com> In-Reply-To: <4DD25FA4.7030307@redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1063 Lines: 30 On 05/17/2011 02:44 PM, Avi Kivity wrote: > On 05/17/2011 02:38 PM, Ingo Molnar wrote: >> > >> > Depends if the guest uses a read-modify-write pattern or not. We >> could do it >> > transparently in kvm.ko, since the real cr4 need not corresponds >> to the guest >> > notion (for example, we often set cr0.wp or cr0.ts even though the >> guest >> > wants them clear). >> >> Oh, being transparent is a nice touch when it comes to security measures >> (catching attackers who think there's no SMEP and such) - but that >> would need >> KVM support and a new ioctl to configure it, right? > > Yes. > btw, KVM support is required anyway, you can't set random bits in cr4 (from either the guest or host userspace) - kvm needs to understand them. -- error compiling committee.c: too many arguments to function -- 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/