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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 7DED7C46475 for ; Sat, 27 Oct 2018 14:51:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F33172085B for ; Sat, 27 Oct 2018 14:51:47 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F33172085B Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=alien8.de 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 S1728753AbeJ0XdA (ORCPT ); Sat, 27 Oct 2018 19:33:00 -0400 Received: from mail.skyhub.de ([5.9.137.197]:39252 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728629AbeJ0XdA (ORCPT ); Sat, 27 Oct 2018 19:33:00 -0400 X-Virus-Scanned: Nedap ESD1 at mail.skyhub.de Received: from mail.skyhub.de ([127.0.0.1]) by localhost (blast.alien8.de [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id BiYLkZVQrnPA; Sat, 27 Oct 2018 16:51:44 +0200 (CEST) Received: from nazgul.tnic (x2f7f1ca.dyn.telefonica.de [2.247.241.202]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.skyhub.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id 1855C1EC0496; Sat, 27 Oct 2018 16:51:43 +0200 (CEST) Date: Sat, 27 Oct 2018 16:51:51 +0200 From: Borislav Petkov To: lijiang Cc: Baoquan He , Petr Tesarik , linux-kernel@vger.kernel.org, x86@kernel.org, kexec@lists.infradead.org, mingo@redhat.com, tglx@linutronix.de, dyoung@redhat.com Subject: Re: [PATCH] kdump, vmcoreinfo: Export sme_me_mask value to vmcoreinfo Message-ID: <20181027145151.GA7338@nazgul.tnic> References: <1263471c-a27d-a698-15f0-b5947f13ea93@redhat.com> <20181026182440.20a4b107@ezekiel.suse.cz> <20181026222517.GB26927@nazgul.tnic> <20181027081343.GA1884@MiWiFi-R3L-srv> <20181027091007.GB1046@nazgul.tnic> <20181027093917.GA14493@MiWiFi-R3L-srv> <20181027101221.GC1046@nazgul.tnic> <20181027110858.GB14493@MiWiFi-R3L-srv> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.6.0 (2016-04-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Oct 27, 2018 at 10:41:56PM +0800, lijiang wrote: > Actually, the value of 'sme_me_mask' is 0x800000000000 when SME is > enabled, otherwise it is 0. That is to say, if the bit 47 is set, the > bit number is also 0x800000000000 (1 << 47UL); Yes, and you can simply copy the mask into your variable and export that. Thinking about it more, though, it might be better if you instead export a smaller value - not an u64 - and construct the mask in userspace. I.e., a u8 which should be enough for your current purposes. I say current because if it turns out we need to export more SME-related info to userspace, exporting an u64 and then OR-ing in more information in it would allow that. u8 not so much. So doing something like: [ misc ][ enc bit ][ other misc SME info ] 0000_0000_0000_0000_1000_0000_0000_0000_0000_0000_0000_0000_0000_0000_0000_0000 63 59 55 51 47 43 39 35 31 27 23 19 15 11 7 3 would allow for exporting that additional info. Especially if we want to use VMCOREINFO for more than kexec things. -- Regards/Gruss, Boris. ECO tip #101: Trim your mails when you reply. --