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=-0.8 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 54089C6778A for ; Tue, 3 Jul 2018 11:25:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 141B724BE1 for ; Tue, 3 Jul 2018 11:25:39 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 141B724BE1 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 S1753038AbeGCLZe (ORCPT ); Tue, 3 Jul 2018 07:25:34 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:40094 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752596AbeGCLZa (ORCPT ); Tue, 3 Jul 2018 07:25:30 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 5110A72634; Tue, 3 Jul 2018 11:25:30 +0000 (UTC) Received: from localhost.localdomain (ovpn-12-173.pek2.redhat.com [10.72.12.173]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 2EA4C2026D76; Tue, 3 Jul 2018 11:25:24 +0000 (UTC) Subject: Re: [PATCH 1/5 V5] Add a function(ioremap_encrypted) for kdump when AMD sme enabled To: Borislav Petkov Cc: linux-kernel@vger.kernel.org, mingo@redhat.com, tglx@linutronix.de, hpa@zytor.com, ebiederm@xmission.com, joro@8bytes.org, thomas.lendacky@amd.com, dyoung@redhat.com, kexec@lists.infradead.org, iommu@lists.linux-foundation.org, bhe@redhat.com References: <20180702072639.10110-1-lijiang@redhat.com> <20180702072639.10110-2-lijiang@redhat.com> <20180702101451.GB28730@zn.tnic> <4ae1cfb5-0a4b-2aac-2575-024e2c74826f@redhat.com> <20180703093924.GA5748@zn.tnic> From: lijiang Message-ID: <55b86851-4978-9289-8a1f-012c6114ec9e@redhat.com> Date: Tue, 3 Jul 2018 19:25:21 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.4.0 MIME-Version: 1.0 In-Reply-To: <20180703093924.GA5748@zn.tnic> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.78 on 10.11.54.4 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.2]); Tue, 03 Jul 2018 11:25:30 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.2]); Tue, 03 Jul 2018 11:25:30 +0000 (UTC) for IP:'10.11.54.4' DOMAIN:'int-mx04.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'lijiang@redhat.com' RCPT:'' Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 在 2018年07月03日 17:39, Borislav Petkov 写道: > On Tue, Jul 03, 2018 at 10:17:19AM +0800, lijiang wrote: >> for example, the elfcorehdr. In fact, the elfcorehdr and notes > > You mean this? > > ssize_t __weak elfcorehdr_read_notes(char *buf, size_t count, u64 *ppos) > { > - return read_from_oldmem(buf, count, ppos, 0); > + return read_from_oldmem(buf, count, ppos, 0, sme_active()); > > That looks encrypted to me. > The elf notes is an old memory, it is encrypted. But the elf header is a crash kernel reserved memory, which is unencrypted. ssize_t __weak elfcorehdr_read(char *buf, size_t count, u64 *ppos) { - return read_from_oldmem(buf, count, ppos, 0); + return read_from_oldmem(buf, count, ppos, 0, false); } They call the same function(read_from_oldmem->ioremap_cache), so it is hard to properly remap the memory if we don't use the parameter to distinguish. Regards, Lianbo >> call the same function(read_from_oldmem->ioremap_cache), in this case, >> it is very difficult to properly remap the memory if the caller don't >> care whether the memory is encrypted. > > So beef up the logic in __ioremap_caller() to figure out based on the > address whether to access the memory encrypted or not. You can find out > the elfcorehdr address in the capture kernel. >