Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757504Ab0DBBYf (ORCPT ); Thu, 1 Apr 2010 21:24:35 -0400 Received: from sous-sol.org ([216.99.217.87]:39812 "EHLO sequoia.sous-sol.org" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1757155Ab0DBBYc (ORCPT ); Thu, 1 Apr 2010 21:24:32 -0400 Date: Thu, 1 Apr 2010 18:23:53 -0700 From: Chris Wright To: Joerg Roedel Cc: Chris Wright , Neil Horman , Neil Horman , kexec@lists.infradead.org, linux-kernel@vger.kernel.org, hbabu@us.ibm.com, iommu@lists.linux-foundation.org, "Eric W. Biederman" , Vivek Goyal Subject: [PATCH 1/2] x86/amd-iommu: enable iommu before attaching devices Message-ID: <20100402012353.GY29241@sequoia.sous-sol.org> References: <20100331191811.GD13406@hmsreliant.think-freely.org> <20100331202745.GE13406@hmsreliant.think-freely.org> <20100401142902.GF24846@8bytes.org> <20100401144736.GA14069@shamino.rdu.redhat.com> <20100401155643.GG24846@8bytes.org> <20100401171149.GH13603@shamino.rdu.redhat.com> <20100401201433.GK24846@8bytes.org> <20100402000012.GA8930@hmsreliant.think-freely.org> <20100402003034.GX29241@sequoia.sous-sol.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100402003034.GX29241@sequoia.sous-sol.org> User-Agent: Mutt/1.5.19 (2009-01-05) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1503 Lines: 42 Hit another kdump problem as reported by Neil Horman. When initializaing the IOMMU, we attach devices to their domains before the IOMMU is fully (re)initialized. Attaching a device will issue some important invalidations. In the context of the newly kexec'd kdump kernel, the IOMMU may have stale cached data from the original kernel. Because we do the attach too early, the invalidation commands are placed in the new command buffer before the IOMMU is updated w/ that buffer. This leaves the stale entries in the kdump context and can renders device unusable. Simply enable the IOMMU before we do the attach. Cc: Neil Horman Cc: Vivek Goyal Signed-off-by: Chris Wright --- arch/x86/kernel/amd_iommu_init.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/arch/x86/kernel/amd_iommu_init.c +++ b/arch/x86/kernel/amd_iommu_init.c @@ -1288,6 +1288,8 @@ static int __init amd_iommu_init(void) if (ret) goto free; + enable_iommus(); + if (iommu_pass_through) ret = amd_iommu_init_passthrough(); else @@ -1300,8 +1302,6 @@ static int __init amd_iommu_init(void) amd_iommu_init_notifier(); - enable_iommus(); - if (iommu_pass_through) goto out; -- 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/