From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id BB8AEC43441 for ; Tue, 20 Nov 2018 04:07:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8154E206B2 for ; Tue, 20 Nov 2018 04:07:35 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8154E206B2 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731033AbeKTOeh (ORCPT ); Tue, 20 Nov 2018 09:34:37 -0500 Received: from mx1.redhat.com ([209.132.183.28]:49482 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730180AbeKTOeh (ORCPT ); Tue, 20 Nov 2018 09:34:37 -0500 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 66D8A3082141; Tue, 20 Nov 2018 04:07:33 +0000 (UTC) Received: from localhost.localdomain (ovpn-12-61.pek2.redhat.com [10.72.12.61]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 3BAFE5D75E; Tue, 20 Nov 2018 04:07:22 +0000 (UTC) Subject: Re: [PATCH 1/2 v6] x86/kexec_file: add e820 entry in case e820 type string matches to io resource name To: Borislav Petkov Cc: Bjorn Helgaas , linux-kernel@vger.kernel.org, kexec@lists.infradead.org, x86@kernel.org, tglx@linutronix.de, mingo@redhat.com, akpm@linux-foundation.org, dyoung@redhat.com, bhe@redhat.com References: <20181114072926.13312-1-lijiang@redhat.com> <20181114072926.13312-2-lijiang@redhat.com> <20181114112600.GD13926@zn.tnic> <9eb61523-7a08-24c4-ac15-050537bd9203@redhat.com> <20181115103959.GB26448@zn.tnic> <20181118115251.GB19380@zn.tnic> From: lijiang Message-ID: Date: Tue, 20 Nov 2018 12:07:18 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20181118115251.GB19380@zn.tnic> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.42]); Tue, 20 Nov 2018 04:07:33 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 在 2018年11月18日 19:52, Borislav Petkov 写道: > On Fri, Nov 16, 2018 at 11:25:55AM +0800, lijiang wrote: >> For the pci mmconfig issue, it should be good enough that the e820 reserved region >> [mem 0x0000000078000000-0x000000008fffffff] is only passed to the second kernel, but >> the pci mmconfig region is not the same in another machine. > > Yes. And now the question is, *which* reserved regions need to be mapped > for the second kernel to function properly? How do we figure that out? > >> A simple case, hotplug a pci network card and use the ssh/nfs to dump the vmcore. >> If the pci mmconfig region is not reserved in kdump kernel, the pci hotplug device >> could not be recognized. So the pci network card won't work. > > Yes that's a good example; put *that* example in your commit message. > >> Here, there is an example about SME kdump. Maybe it can help to better understand. > > You keep pasting that and I've read it already. And you keep repeating > that the reserved regions need to be mapped in the second kernel and I'm > asking, how do we determine *which* regions should we pass to the second > kernel? > > If we should pass *all* reserved regions, why? > > IOW, I'm looking for the *why* first. > > Thx. > I guess you have gotten the answer what you want from Dave's reply. Thank you, Boris. Also thanks for Dave's explanation in detail. Regards, Lianbo