From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752468AbbDBLGQ (ORCPT ); Thu, 2 Apr 2015 07:06:16 -0400 Received: from 8bytes.org ([81.169.241.247]:50069 "EHLO theia.8bytes.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751058AbbDBLGK (ORCPT ); Thu, 2 Apr 2015 07:06:10 -0400 Date: Thu, 2 Apr 2015 13:06:08 +0200 From: Joerg Roedel To: "Li, Zhen-Hua" Cc: dwmw2@infradead.org, indou.takao@jp.fujitsu.com, bhe@redhat.com, vgoyal@redhat.com, dyoung@redhat.com, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, kexec@lists.infradead.org, alex.williamson@redhat.com, ddutile@redhat.com, ishii.hironobu@jp.fujitsu.com, bhelgaas@google.com, doug.hatch@hp.com, jerry.hoemann@hp.com, tom.vaden@hp.com, li.zhang6@hp.com, lisa.mitchell@hp.com, billsumnerlinux@gmail.com, rwright@hp.com Subject: Re: [PATCH v9 07/10] iommu/vt-d: enable kdump support in iommu module Message-ID: <20150402110608.GL4441@8bytes.org> References: <1426743388-26908-1-git-send-email-zhen-hual@hp.com> <1426743388-26908-8-git-send-email-zhen-hual@hp.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1426743388-26908-8-git-send-email-zhen-hual@hp.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Mar 19, 2015 at 01:36:25PM +0800, Li, Zhen-Hua wrote: > +#ifdef CONFIG_CRASH_DUMP > + if (is_kdump_kernel()) > + __iommu_update_old_root_entry(iommu, bus); > +#endif All the is_kdump_kernel checks in this patch (and maybe in other patches too) should really be checks whether translation on the IOMMU was enabled or not when the kernel booted. You might also boot from a kernel that had translation disabled into a kdump kernel that wants to enable it. In this case these checks would break. Speaking of booting from kernels with translation disabled, there is a valid use of is_kdump_enabled(), to omit iommu initialization in the kdump kernel when translation was disabled before. But the other checks should depend on the state the iommu had when booting the kdump kernel. Joerg