Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757861Ab2EaHjV (ORCPT ); Thu, 31 May 2012 03:39:21 -0400 Received: from nat28.tlf.novell.com ([130.57.49.28]:48071 "EHLO nat28.tlf.novell.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751323Ab2EaHjT convert rfc822-to-8bit (ORCPT ); Thu, 31 May 2012 03:39:19 -0400 Message-Id: <4FC73C430200007800087137@nat28.tlf.novell.com> X-Mailer: Novell GroupWise Internet Agent 12.0.0 Date: Thu, 31 May 2012 08:39:15 +0100 From: "Jan Beulich" To: "Borislav Petkov" Cc: "Andre Przywara" , "Jacob Shin" , , , , , "Konrad Rzeszutek Wilk" , , "H. Peter Anvin" Subject: Re: [Xen-devel] [PATCH] x86/amd: fix crash as Xen Dom0 on AMD Trinity systems References: <4FC63DAF0200007800086DC5@nat28.tlf.novell.com> <4FC62888.9010407@amd.com> <20120530144851.GA12184@jshin-Toonie> <20120530145005.GI3207@phenom.dumpdata.com> <20120530150334.GA13349@jshin-Toonie> <20120530171754.GA5115@phenom.dumpdata.com> <20120530173247.GC15635@x1.osrc.amd.com> <4FC65D34.1060803@zytor.com> <20120530175150.GE15438@x1.osrc.amd.com> <4FC66037.6020506@zytor.com> <20120530181722.GF15438@x1.osrc.amd.com> In-Reply-To: <20120530181722.GF15438@x1.osrc.amd.com> 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 Content-Length: 1166 Lines: 25 >>> On 30.05.12 at 20:17, Borislav Petkov wrote: > On Wed, May 30, 2012 at 11:00:23AM -0700, H. Peter Anvin wrote: > The other place where we use the amd_safe variants is an obscure K8, > revC and earlier fix for _some_ BIOSen and this hasn't bitten us yet > so I'm assuming people haven't run xen on such boxes yet. Does it need > fixing? Probably, if we really really have to. This again is something that shouldn't even be attempted under Xen. The hypervisor, unless really old, does this (and wouldn't allow the write by any domain - privileged or not - anyway). There's one more user though - the code triggered by the "show_msr=" command line option. This one indeed requires rdmsr_safe_regs to be functional (albeit under Xen, once again, this won't work currently anyway for those MRS on old CPUs where the special key in %edi is required, which the emulation code in Xen doesn't support). Jan -- 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/