Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2992530AbXEBCr7 (ORCPT ); Tue, 1 May 2007 22:47:59 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S2992549AbXEBCr7 (ORCPT ); Tue, 1 May 2007 22:47:59 -0400 Received: from outbound-mail-53.bluehost.com ([69.89.20.33]:40714 "HELO outbound-mail-53.bluehost.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S2992530AbXEBCr5 (ORCPT ); Tue, 1 May 2007 22:47:57 -0400 X-Greylist: delayed 399 seconds by postgrey-1.27 at vger.kernel.org; Tue, 01 May 2007 22:47:57 EDT From: Jesse Barnes To: Olivier Galibert Subject: Re: [RFC PATCH] PCI MMCONFIG: add validation against ACPI motherboard resources Date: Tue, 1 May 2007 19:41:06 -0700 User-Agent: KMail/1.9.6 Cc: Robert Hancock , linux-kernel , Andi Kleen , Chuck Ebbert , Len Brown References: <4635510D.4060103@shaw.ca> <20070430225916.GA39223@dspnet.fr.eu.org> In-Reply-To: <20070430225916.GA39223@dspnet.fr.eu.org> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200705011941.07438.jbarnes@virtuousgeek.org> X-Identified-User: {642:box128.bluehost.com:virtuous:virtuousgeek.org} {sentby:smtp auth 67.161.73.10 authed with jbarnes@virtuousgeek.org} Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1869 Lines: 38 On Monday, April 30, 2007, Olivier Galibert wrote: > On Sun, Apr 29, 2007 at 08:14:37PM -0600, Robert Hancock wrote: > > -Validate that the area is reserved even if we read it from the > > chipset directly and not from the MCFG table. This catches the case > > where the BIOS didn't set the location properly in the chipset and > > has mapped it over other things it shouldn't have. This might be > > overly pessimistic - we might be able to instead verify that no > > other reserved resources (like chipset registers) are inside this > > memory range. > > I have a fundamental problem with that: you don't validate a higher > reliability information against a lower one. The chipset registers > are high reliability. Modulo unknown hardware erratas and bugs in the > code (and accepting f0000000 is in practice a bug in the code, the > docs are starting to catch up with it too), the chipset *will* decode > mmconfig at the looked up address no matter what. On the other side, > the ACPI data is bios generated, and that is well known to be horribly > unreliable. Hell, if it was reliable we could just use the MFCG ACPI > table without questions. Now that I've read his patch closely I think you're right. Robert, it looks like you'll trust acpi_table_parse if pci_mmcfg_check_hostbridge returns a failure. I think it should be treated with a higher priority. If pci_mmcfg_check_hostbridge returns a failure, there's no way MCFG space can work, so we should disable it unconditionally in that case (even if ACPI says "trust me, when have I ever lied to you?"). I'm testing it now on my 965... Thanks, Jesse - 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/