From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from out02.mta.xmission.com ([166.70.13.232]) by bombadil.infradead.org with esmtp (Exim 4.69 #1 (Red Hat Linux)) id 1NyNNW-00028h-Hp for kexec@lists.infradead.org; Sun, 04 Apr 2010 10:48:31 +0000 Subject: Re: [PATCH 3/4] Revert "x86: disable IOMMUs on kernel crash" References: <20100403012751.834020949@sous-sol.org> <20100403012820.229410717@sous-sol.org> <20100403174128.GQ24846@8bytes.org> <4BB83EAE.5090609@bwalle.de> From: ebiederm@xmission.com (Eric W. Biederman) Date: Sun, 04 Apr 2010 00:51:10 -0700 In-Reply-To: <4BB83EAE.5090609@bwalle.de> (Bernhard Walle's message of "Sun\, 04 Apr 2010 09\:24\:30 +0200") Message-ID: MIME-Version: 1.0 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: kexec-bounces@lists.infradead.org Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: Bernhard Walle Cc: nhorman@redhat.com, nhorman@tuxdriver.com, Joerg Roedel , 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 Bernhard Walle writes: > 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. I have been rather pleasantly surprised at how well that works. Although I am still glad I insisted that using the same kernel version not be a hard requirement. It allowed us to specify a good solid interface. How to cope with GART in that situation without having to manually specify iommu=off in the configuration I find a more compelling question. I expect I will have a look at that in the coming months if someone doesn't get there before I do. Eric _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec