From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from 8bytes.org ([81.169.241.247] helo=theia.8bytes.org) by casper.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1YAhWI-0003wv-91 for kexec@lists.infradead.org; Mon, 12 Jan 2015 16:07:10 +0000 Date: Mon, 12 Jan 2015 17:06:46 +0100 From: Joerg Roedel 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-Disposition: inline In-Reply-To: <20150112152919.GA16162@redhat.com> 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" Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: Vivek Goyal Cc: alex.williamson@redhat.com, indou.takao@jp.fujitsu.com, bhe@redhat.com, tom.vaden@hp.com, rwright@hp.com, dwmw2@infradead.org, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, lisa.mitchell@hp.com, jerry.hoemann@hp.com, iommu@lists.linux-foundation.org, "Li, Zhen-Hua" , ddutile@redhat.com, doug.hatch@hp.com, ishii.hironobu@jp.fujitsu.com, linux-pci@vger.kernel.org, bhelgaas@google.com, billsumnerlinux@gmail.com, li.zhang6@hp.com, dyoung@redhat.com 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 _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joerg Roedel Subject: Re: [PATCH v8 02/10] iommu/vt-d: Items required for kdump Date: Mon, 12 Jan 2015 17:06:46 +0100 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" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20150112152919.GA16162-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Vivek Goyal Cc: bhe-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, tom.vaden-VXdhtT5mjnY@public.gmane.org, rwright-VXdhtT5mjnY@public.gmane.org, dwmw2-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org, kexec-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, lisa.mitchell-VXdhtT5mjnY@public.gmane.org, iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, "Li, Zhen-Hua" , doug.hatch-VXdhtT5mjnY@public.gmane.org, ishii.hironobu-+CUm20s59erQFUHtdCDX3A@public.gmane.org, linux-pci-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, bhelgaas-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org, billsumnerlinux-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, li.zhang6-VXdhtT5mjnY@public.gmane.org, dyoung-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org List-Id: iommu@lists.linux-foundation.org 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 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