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=-8.4 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 BCCB9C04AB1 for ; Thu, 9 May 2019 07:01:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8D65F2173C for ; Thu, 9 May 2019 07:01:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726702AbfEIHBS (ORCPT ); Thu, 9 May 2019 03:01:18 -0400 Received: from mx1.redhat.com ([209.132.183.28]:56846 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725908AbfEIHBR (ORCPT ); Thu, 9 May 2019 03:01:17 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 997EB3097035; Thu, 9 May 2019 07:01:17 +0000 (UTC) Received: from localhost (ovpn-12-17.pek2.redhat.com [10.72.12.17]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 7B97A5D9D1; Thu, 9 May 2019 07:01:13 +0000 (UTC) Date: Thu, 9 May 2019 15:01:11 +0800 From: Baoquan He To: linux-kernel@vger.kernel.org Cc: tglx@linutronix.de, mingo@kernel.org, bp@alien8.de, hpa@zytor.com, kirill.shutemov@linux.intel.com, x86@kernel.org, dyoung@redhat.com Subject: Re: [PATCH v4 2/3] x86/kexec/64: Error out if try to jump to old 4-level kernel from 5-level kernel Message-ID: <20190509070111.GE24922@MiWiFi-R3L-srv> References: <20190509013644.1246-1-bhe@redhat.com> <20190509013644.1246-3-bhe@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190509013644.1246-3-bhe@redhat.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.43]); Thu, 09 May 2019 07:01:17 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05/09/19 at 09:36am, Baoquan He wrote: > If the running kernel has 5-level paging activated, the 5-level paging > mode is preserved across kexec. If the kexec'ed kernel does not contain > support for handling active 5-level paging mode in the decompressor, the > decompressor will crash with #GP. > > Prevent this situation at load time. If 5-level paging is active, check the > xloadflags whether the kexec kernel can handle 5-level paging at least in > the decompressor. If not, reject the load attempt and print out error > message. > > Signed-off-by: Baoquan He > Acked-by: Kirill A. Shutemov > --- > arch/x86/kernel/kexec-bzimage64.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/arch/x86/kernel/kexec-bzimage64.c b/arch/x86/kernel/kexec-bzimage64.c > index 22f60dd26460..858cc892672f 100644 > --- a/arch/x86/kernel/kexec-bzimage64.c > +++ b/arch/x86/kernel/kexec-bzimage64.c > @@ -321,6 +321,11 @@ static int bzImage64_probe(const char *buf, unsigned long len) > return ret; > } > > + if (!(header->xloadflags & XLF_5LEVEL) && pgtable_l5_enabled()) { > + pr_err("Can not jump to old 4-level kernel from 5-level kernel.\n"); Check the old thread again, found Thomas also had comment about this error message. Just forgot updating it. Will update it with a new one. > + return ret; > + } > + > /* I've got a bzImage */ > pr_debug("It's a relocatable bzImage64\n"); > ret = 0; > -- > 2.17.2 >