From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756393Ab3AHTqj (ORCPT ); Tue, 8 Jan 2013 14:46:39 -0500 Received: from mail-vb0-f44.google.com ([209.85.212.44]:61931 "EHLO mail-vb0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756209Ab3AHTqi (ORCPT ); Tue, 8 Jan 2013 14:46:38 -0500 Date: Tue, 8 Jan 2013 14:46:34 -0500 From: Konrad Rzeszutek Wilk To: "H. Peter Anvin" Cc: Fenghua Yu , Ingo Molnar , Thomas Gleixner , Asit K Mallick , Tigran Aivazian , Yinghai Lu , Andreas Herrmann , Borislav Petkov , linux-kernel , x86 Subject: Re: [PATCH v5 00/12] x86/microcode: Early load microcode Message-ID: <20130108194633.GA15194@phenom.dumpdata.com> References: <1356075872-3054-1-git-send-email-fenghua.yu@intel.com> <20130103174455.GA7350@localhost.localdomain> <50E5C47B.6060707@zytor.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <50E5C47B.6060707@zytor.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jan 03, 2013 at 09:48:43AM -0800, H. Peter Anvin wrote: > On 01/03/2013 09:44 AM, Konrad Rzeszutek Wilk wrote: > > > >A couple of questions - why the usage of native_[read|write]_msr? I get the > >__native_cpuid variant, but I am not sure I understand why you are using > >the native_* variants. Especially as this code ends up being called on > >Xen and lguest (at least on 64-bit) and probably should go through the > >paravirt interfaces. > > > > For Xen, the early microcode update should be done in the hypervisor launch. Right. That is the plan. > > However, if you have a more specific flow in mind please clarify. > Keep in mind Xen is largely a black box to non-Xen developers > (#include ). OK. I am trying to figure out whether this usage of native_* for the MSRs was done on purpose - and it sounds like the answer is no. If so - can it be done using the normal 'safe_rdmsr' and 'wrmsr'? That would allow at least in the case of Xen, to omit a whole bunch of MSR writes/reads during the boot that are not neccessary as we would not trap in the hypervisor - but could use the pvops version of read/write MSR calls to just do a nop. > > -hpa > > P.S. Since when is lguest 64-bit? Did I miss something? Oh, I assumed it could do it. > > -- > H. Peter Anvin, Intel Open Source Technology Center > I work for Intel. I don't speak on their behalf. > > -- > 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/ >