Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752970Ab0DDKBI (ORCPT ); Sun, 4 Apr 2010 06:01:08 -0400 Received: from 8bytes.org ([88.198.83.132]:38399 "EHLO 8bytes.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752469Ab0DDKBD (ORCPT ); Sun, 4 Apr 2010 06:01:03 -0400 Date: Sun, 4 Apr 2010 12:01:01 +0200 From: Joerg Roedel To: "Eric W. Biederman" Cc: Bernhard Walle , nhorman@redhat.com, nhorman@tuxdriver.com, Joerg Roedel , kexec@lists.infradead.org, linux-kernel@vger.kernel.org, Chris Wright , hbabu@us.ibm.com, iommu@lists.linux-foundation.org, vgoyal@redhat.com Subject: Re: [PATCH 3/4] Revert "x86: disable IOMMUs on kernel crash" Message-ID: <20100404100101.GW24846@8bytes.org> References: <20100403012751.834020949@sous-sol.org> <20100403012820.229410717@sous-sol.org> <20100403174128.GQ24846@8bytes.org> <4BB83EAE.5090609@bwalle.de> <20100404085338.GU24846@8bytes.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1265 Lines: 32 On Sun, Apr 04, 2010 at 02:44:36AM -0700, Eric W. Biederman wrote: > Joerg Roedel writes: > > > On Sun, Apr 04, 2010 at 09:24:30AM +0200, Bernhard Walle wrote: > >> Am 03.04.10 19:49, schrieb Eric W. Biederman: > >> > Not a problem. We require a lot of things of the kdump kernel, > >> > and it is immediately apparent in a basic sanity test. > >> > >> Also, in most cases (for example: distribution kernels), the kdump > >> kernel nowadays is identical to the running kernel. So, if the running > >> kernel has IOMMU support, the kdump kernel also has. > > > > Yes, I know. But is that a requirement for kexec? > > For normal kexec no. That path is expected to do a clean hardware > shutdown. > > For kexec on panic aka kdump the requirement is that your your crash > kernel be able to initialize your hardware from any state it can be > put in. Ok, if you show me where this is documented for everybody then I am probably convinced :-) We should fixup the gart initialization anyway. Joerg -- 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/