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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 74109CCA47C for ; Thu, 23 Jun 2022 18:18:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236777AbiFWSSn (ORCPT ); Thu, 23 Jun 2022 14:18:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41808 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237351AbiFWSSP (ORCPT ); Thu, 23 Jun 2022 14:18:15 -0400 Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1D487B62A1; Thu, 23 Jun 2022 10:24:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1656005081; x=1687541081; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=HyD7sZmGzSIHx03CaYUHtjWHrLaftO9PYHM6NFaUHG0=; b=cInEJ/OfBt/UerM5ZmBpBAYpdjXlp8Pl5hgIau9o+rmZD0trj3DNdFTj Elc0NoqWhXqRDs8S9JYSwRWmYTFUJnnRZ0M1HX7qh8K/YAqRSA99TbFNF pbaCPW6yEXh8SKluG0EC4ERGk0aLroTh8zzfGNIWAsKrF4mh7k4plSk5z Pv27dABxFNTthbzw5uo/Ueg8kTPFwjlkFBL/TpkvjlpboQvl3GvwZJ6Ql k0Kv33RDJayG2+wz38jG+aD7/OrWuRonHo899k1bBukNZ2c5N5bGpykhA MqMo+0Z7cEz4JPINsuoJJb8P11GqMA/gm2JHBtHO6rM7+R7/47QXvsN0H Q==; X-IronPort-AV: E=McAfee;i="6400,9594,10387"; a="269511427" X-IronPort-AV: E=Sophos;i="5.92,216,1650956400"; d="scan'208";a="269511427" Received: from orsmga006.jf.intel.com ([10.7.209.51]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 Jun 2022 10:24:26 -0700 X-IronPort-AV: E=Sophos;i="5.92,216,1650956400"; d="scan'208";a="563531696" Received: from ckeane-mobl1.amr.corp.intel.com (HELO [10.209.81.98]) ([10.209.81.98]) by orsmga006-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 Jun 2022 10:24:25 -0700 Message-ID: <6be29d38-5c93-7cc9-0de7-235d3f83773c@intel.com> Date: Thu, 23 Jun 2022 10:23:59 -0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.9.1 Subject: Re: [PATCHv7 11/14] x86: Disable kexec if system has unaccepted memory Content-Language: en-US To: "Kirill A. Shutemov" , Borislav Petkov , Andy Lutomirski , Sean Christopherson , Andrew Morton , Joerg Roedel , Ard Biesheuvel Cc: Andi Kleen , Kuppuswamy Sathyanarayanan , David Rientjes , Vlastimil Babka , Tom Lendacky , Thomas Gleixner , Peter Zijlstra , Paolo Bonzini , Ingo Molnar , Varad Gautam , Dario Faggioli , Mike Rapoport , David Hildenbrand , marcelo.cerri@canonical.com, tim.gardner@canonical.com, khalid.elmously@canonical.com, philip.cox@canonical.com, x86@kernel.org, linux-mm@kvack.org, linux-coco@lists.linux.dev, linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org, Eric Biederman , kexec@lists.infradead.org References: <20220614120231.48165-1-kirill.shutemov@linux.intel.com> <20220614120231.48165-12-kirill.shutemov@linux.intel.com> From: Dave Hansen In-Reply-To: <20220614120231.48165-12-kirill.shutemov@linux.intel.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-efi@vger.kernel.org ... adding kexec folks On 6/14/22 05:02, Kirill A. Shutemov wrote: > On kexec, the target kernel has to know what memory has been accepted. > Information in EFI map is out of date and cannot be used. > > boot_params.unaccepted_memory can be used to pass the bitmap between two > kernels on kexec, but the use-case is not yet implemented. > > Disable kexec on machines with unaccepted memory for now. ... > +static int __init unaccepted_init(void) > +{ > + if (!boot_params.unaccepted_memory) > + return 0; > + > +#ifdef CONFIG_KEXEC_CORE > + /* > + * TODO: Information on memory acceptance status has to be communicated > + * between kernel. > + */ > + pr_warn("Disable kexec: not yet supported on systems with unaccepted memory\n"); > + kexec_load_disabled = 1; > +#endif This looks to be the *only* in-kernel user tweaking kexec_load_disabled. It doesn't feel great to just be disabling kexec like this. Why not just fix it properly? What do the kexec folks think?