Return-path: Received: from sous-sol.org ([216.99.217.87] helo=x200.localdomain) by bombadil.infradead.org with esmtps (Exim 4.69 #1 (Red Hat Linux)) id 1Nxs9u-0003qk-W4 for kexec@lists.infradead.org; Sat, 03 Apr 2010 01:28:24 +0000 Message-Id: <20100403012814.543517900@sous-sol.org> Date: Fri, 02 Apr 2010 18:27:52 -0700 From: Chris Wright Subject: [PATCH 1/4] x86/amd-iommu: enable iommu before attaching devices References: <20100403012751.834020949@sous-sol.org> Content-Disposition: inline; filename=amd-enable-iommu-earlier.patch List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 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: Joerg Roedel Cc: nhorman@redhat.com, nhorman@tuxdriver.com, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, hbabu@us.ibm.com, iommu@lists.linux-foundation.org, ebiederm@xmission.com, vgoyal@redhat.com 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 | 5 +++-- 1 file changed, 3 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; @@ -1315,6 +1315,7 @@ out: return ret; free: + disable_iommus(); amd_iommu_uninit_devices(); _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec