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=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 503E8C433DF for ; Tue, 30 Jun 2020 03:30:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 26239206A5 for ; Tue, 30 Jun 2020 03:30:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="d1hMDAEh" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729105AbgF3Dar (ORCPT ); Mon, 29 Jun 2020 23:30:47 -0400 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:48659 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1729037AbgF3Daq (ORCPT ); Mon, 29 Jun 2020 23:30:46 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1593487844; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=B5CWu0YTtNLLeEFzddhpFxvlgHTZraP4ByG++eJey7I=; b=d1hMDAEhTSibcunVhDsipfoIM5gKAng5VOXEWU3zm+iBdk8PfU6Z2a3eGJ1FRdfchYsCSu twVOk7hB+u9wYPjmUVmykbCPu4rCeQQoDT2R7RHZIEKfxT5NM0tvGEUrW1aB/aPO30qgN7 IOI+rrqK2NJWLPMteKIaemy2dqu7uOM= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-502-MtJI14wRPq6V8I8u-UWGKg-1; Mon, 29 Jun 2020 23:30:40 -0400 X-MC-Unique: MtJI14wRPq6V8I8u-UWGKg-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 4F9911009600; Tue, 30 Jun 2020 03:30:38 +0000 (UTC) Received: from [10.72.8.19] (ovpn-8-19.pek2.redhat.com [10.72.8.19]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 1917160BF3; Tue, 30 Jun 2020 03:30:29 +0000 (UTC) Subject: Re: [PATCH 04/11] ppc64/kexec_file: avoid stomping memory used by special regions To: Hari Bathini , Michael Ellerman , Andrew Morton References: <159319825403.16351.7253978047621755765.stgit@hbathini.in.ibm.com> <159319831192.16351.17443438699302756548.stgit@hbathini.in.ibm.com> <9cfda789-0747-a67a-b825-5ea6f15099b8@redhat.com> Cc: Kexec-ml , Petr Tesarik , Mahesh J Salgaonkar , Sourabh Jain , lkml , linuxppc-dev , Mimi Zohar , Vivek Goyal , Dave Young , Thiago Jung Bauermann , Eric Biederman From: piliu X-Enigmail-Draft-Status: N1110 Message-ID: <283fc181-2331-7c2f-db66-5e02e5ffb2e4@redhat.com> Date: Tue, 30 Jun 2020 11:30:26 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 06/29/2020 01:55 PM, Hari Bathini wrote: > > > On 28/06/20 7:44 am, piliu wrote: >> Hi Hari, > > Hi Pingfan, > >> >> After a quick through for this series, I have a few question/comment on >> this patch for the time being. Pls see comment inline. >> >> On 06/27/2020 03:05 AM, Hari Bathini wrote: >>> crashkernel region could have an overlap with special memory regions >>> like opal, rtas, tce-table & such. These regions are referred to as >>> exclude memory ranges. Setup this ranges during image probe in order >>> to avoid them while finding the buffer for different kdump segments. > > [...] > >>> + /* >>> + * Use the locate_mem_hole logic in kexec_add_buffer() for regular >>> + * kexec_file_load syscall >>> + */ >>> + if (kbuf->image->type != KEXEC_TYPE_CRASH) >>> + return 0; >> Can the ranges overlap [crashk_res.start, crashk_res.end]? Otherwise >> there is no requirement for @exclude_ranges. > > The ranges like rtas, opal are loaded by f/w. They almost always overlap with > crashkernel region. So, @exclude_ranges is required to support kdump. f/w passes rtas/opal as service, then must f/w mark these ranges as fdt_reserved_mem in order to make kernel aware not to use these ranges? Otherwise kernel memory allocation besides kdump can also overwrite these ranges. Hmm, revisiting reserve_crashkernel(). It seems not to take any reserved memory into consider except kernel text. Could it work based on memblock allocator? Thanks, Pingfan > >> I guess you have a design for future. If not true, then it is better to >> fold the condition "if (kbuf->image->type != KEXEC_TYPE_CRASH)" into the >> caller and rename this function to better distinguish use cases between >> kexec and kdump > > Yeah, this condition will be folded. I have a follow-up patch for that explaining > why kexec case should also be folded. Will try to add that to this series for v2. > > Thanks > Hari >