From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from 8bytes.org ([81.169.241.247]:46328 "EHLO theia.8bytes.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751608AbbALQGr (ORCPT ); Mon, 12 Jan 2015 11:06:47 -0500 Date: Mon, 12 Jan 2015 17:06:46 +0100 From: Joerg Roedel To: Vivek Goyal Cc: "Li, Zhen-Hua" , dwmw2@infradead.org, indou.takao@jp.fujitsu.com, bhe@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 v8 02/10] iommu/vt-d: Items required for kdump Message-ID: <20150112160646.GF6343@8bytes.org> References: <1421046388-27925-1-git-send-email-zhen-hual@hp.com> <1421046388-27925-3-git-send-email-zhen-hual@hp.com> <20150112152207.GC6343@8bytes.org> <20150112152919.GA16162@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20150112152919.GA16162@redhat.com> Sender: linux-pci-owner@vger.kernel.org List-ID: On Mon, Jan 12, 2015 at 10:29:19AM -0500, Vivek Goyal wrote: > Kdump has the notion of backup region. Where certain parts of old kernels > memory can be moved to a different location (first 640K on x86 as of now) > and new kernel can make use of this memory now. > > So we will have to just make sure that no parts of this old page table > fall into backup region. Uuh, looks like the 'iommu-with-kdump-issue' isn't complicated enough yet ;) Sadly, your above statement is true for all hardware-accessible data structures in IOMMU code. I think about how we can solve this, is there an easy way to allocate memory that is not in any backup region? Thanks, Joerg