Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757759Ab0DWVl0 (ORCPT ); Fri, 23 Apr 2010 17:41:26 -0400 Received: from mx1.redhat.com ([209.132.183.28]:50727 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757541Ab0DWVlX (ORCPT ); Fri, 23 Apr 2010 17:41:23 -0400 Message-ID: <4BD213FE.2000800@redhat.com> Date: Fri, 23 Apr 2010 11:41:18 -1000 From: Zachary Amsden User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.8) Gecko/20100301 Fedora/3.0.3-1.fc12 Thunderbird/3.0.3 MIME-Version: 1.0 To: Jeremy Fitzhardinge CC: Avi Kivity , Glauber Costa , Peter Zijlstra , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Marcelo Tosatti Subject: Re: [PATCH 1/5] Add a global synchronization point for pvclock References: <1271675100.1674.818.camel@laptop> <4BCC3A3E.9070909@redhat.com> <20100419142158.GD14158@mothafucka.localdomain> <4BCC69D5.3050209@redhat.com> <1271688411.1488.248.camel@laptop> <4BCC8246.9040202@goop.org> <4BCD748E.7080007@redhat.com> <4BCDF12C.1020702@goop.org> <4BCDF85C.3000004@redhat.com> <4BCE0399.2010708@goop.org> <20100422131113.GA3364@mothafucka.localdomain> <4BD0FB92.4060301@redhat.com> <4BD169B5.4000409@redhat.com> <4BD211B9.5080707@redhat.com> <4BD212BF.60707@goop.org> In-Reply-To: <4BD212BF.60707@goop.org> Content-Type: text/plain; charset=UTF-8; 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: 888 Lines: 22 On 04/23/2010 11:35 AM, Jeremy Fitzhardinge wrote: > On 04/23/2010 02:31 PM, Zachary Amsden wrote: > >> Does lfence / mfence actually serialize? I thought there was some >> great confusion about that not being the case on all AMD processors, >> and possibly not at all on Intel. >> >> A trap, however is a great way to serialize. >> >> I think, there is no serializing instruction which can be used from >> userspace which does not trap, at least, I don't know one off the top >> of my head. >> > rsm is not technically privileged... but not quite usable from usermode ;) > rsm under hardware virtualization makes my head hurt -- 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/