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 ECA28ECDE46 for ; Sat, 27 Oct 2018 02:57:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9A9C02082B for ; Sat, 27 Oct 2018 02:57:59 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9A9C02082B 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 S1727682AbeJ0Lgs (ORCPT ); Sat, 27 Oct 2018 07:36:48 -0400 Received: from mx1.redhat.com ([209.132.183.28]:59482 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726501AbeJ0Lgs (ORCPT ); Sat, 27 Oct 2018 07:36:48 -0400 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 mx1.redhat.com (Postfix) with ESMTPS id 8923C307D992; Sat, 27 Oct 2018 02:57:21 +0000 (UTC) Received: from localhost.localdomain (ovpn-12-142.pek2.redhat.com [10.72.12.142]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 647A56714C; Sat, 27 Oct 2018 02:57:12 +0000 (UTC) Subject: Re: [PATCH] kdump, vmcoreinfo: Export sme_me_mask value to vmcoreinfo To: Borislav Petkov , Petr Tesarik Cc: linux-kernel@vger.kernel.org, bhe@redhat.com, x86@kernel.org, kexec@lists.infradead.org, mingo@redhat.com, tglx@linutronix.de, dyoung@redhat.com References: <20181026093630.8520-1-lijiang@redhat.com> <053CC83A-9A95-4C12-9627-AABD1427DA9C@alien8.de> <1263471c-a27d-a698-15f0-b5947f13ea93@redhat.com> <20181026182440.20a4b107@ezekiel.suse.cz> <20181026222517.GB26927@nazgul.tnic> From: lijiang Message-ID: Date: Sat, 27 Oct 2018 10:57:08 +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: <20181026222517.GB26927@nazgul.tnic> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.48]); Sat, 27 Oct 2018 02:57:21 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 在 2018年10月27日 06:25, Borislav Petkov 写道: > On Fri, Oct 26, 2018 at 06:24:40PM +0200, Petr Tesarik wrote: >> But we need the MSR value from the panic kernel environment, not while >> the production kernel is still running, right? > > Actually, we need only the encryption bit number (and it should be 0 > otherwise to denote SME wasn't enabled). > Thanks for your comment. For this patch, it really needs only the encryption bit number. For the AMD machine with SME feature, the OS or HV sets bit 47 of a physical address to 1 in the page table entry to indicate the page should be encrypted. Thanks. Lianbo > I guess something like > > VMCOREINFO_NUMBER(sme_mask); > > which gets written by the kexec-ed kernel. > >> If so, then this reminds me that I have wanted for a long time to store >> more of the hardware state in a vmcore NOTE after a kernel crash ... >> control registers, MSRs and whatnot. Of course, this would be a >> long-term project, but I wonder what other people think about it in >> general. > > I guess that sounds like a good idea - the more relevant hw info for > debugging, the better. Determining the important MSRs to save would need > a bit of a pondering over though. For example, some MSRs are per-core, > some per-socket, etc... >