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 446CFCA0ECE for ; Tue, 12 Sep 2023 07:48:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231783AbjILHsF (ORCPT ); Tue, 12 Sep 2023 03:48:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58368 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231222AbjILHsD (ORCPT ); Tue, 12 Sep 2023 03:48:03 -0400 Received: from mgamail.intel.com (mgamail.intel.com [134.134.136.100]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E5122E73; Tue, 12 Sep 2023 00:47:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1694504879; x=1726040879; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=myILytDdutAkJHoVsjGJrHjJI0XRaM5nA9tqDHz8FOQ=; b=BRsrZzgwiMKZTkvrgrCGhPincsWUsGdarkRTiUcBK2aExbWudOuW8yrc SWYr2RstRa/XyLcivhmZe30gUWfauyFIF6oUPWdyqoX71tzahL7eUdgd6 iny/Rjssqlf3KO6RAZKvq2LCIxZV0kGtIjf0NyqxPDo+PpAjRvale1vyP 64NDT+WQ4RNvAK/4aGY7vDlSYYbIcKyR74pbl/fQKPIbgBeXnKuLHBguU M6y7SjkXQCNxVkuvcZu0C9E9EzPGz/9IH3EVdRw1GoOOb0K1UGuXcGEAL GtT1RZ/jbsgqHmgyPZBBqRtwBuTUQmZSkZsWv/2rUXM0r0x55aWgfFRgT w==; X-IronPort-AV: E=McAfee;i="6600,9927,10830"; a="444742371" X-IronPort-AV: E=Sophos;i="6.02,245,1688454000"; d="scan'208";a="444742371" Received: from orsmga004.jf.intel.com ([10.7.209.38]) by orsmga105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Sep 2023 00:47:59 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10830"; a="867283368" X-IronPort-AV: E=Sophos;i="6.02,245,1688454000"; d="scan'208";a="867283368" Received: from ahunter6-mobl1.ger.corp.intel.com (HELO [10.0.2.15]) ([10.249.45.152]) by orsmga004-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Sep 2023 00:47:53 -0700 Message-ID: <1c736ca3-36e2-3225-2f98-e51149c468ef@intel.com> Date: Tue, 12 Sep 2023 10:47:49 +0300 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Firefox/102.0 Thunderbird/102.15.0 Subject: Re: [PATCH V2 1/2] efi/unaccepted: Do not let /proc/vmcore try to access unaccepted memory Content-Language: en-US To: David Hildenbrand , Adrian Hunter , "Kirill A. Shutemov" , Borislav Petkov , Andrew Morton , Ard Biesheuvel Cc: Dave Hansen , Vlastimil Babka , Mike Rapoport , Lorenzo Stoakes , Tom Lendacky , Baoquan He , Vivek Goyal , Dave Young , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-coco@lists.linux.dev, linux-efi@vger.kernel.org, kexec@lists.infradead.org References: <20230911112114.91323-1-adrian.hunter@intel.com> <20230911112114.91323-2-adrian.hunter@intel.com> <96f124d6-c1f2-adb3-1d3b-8329e85ff099@redhat.com> From: Adrian Hunter Organization: Intel Finland Oy, Registered Address: PL 281, 00181 Helsinki, Business Identity Code: 0357606 - 4, Domiciled in Helsinki In-Reply-To: <96f124d6-c1f2-adb3-1d3b-8329e85ff099@redhat.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/09/23 10:19, David Hildenbrand wrote: > On 11.09.23 13:21, Adrian Hunter wrote: >> Support for unaccepted memory was added recently, refer commit dcdfdd40fa82 >> ("mm: Add support for unaccepted memory"), whereby a virtual machine may >> need to accept memory before it can be used. >> >> Do not let /proc/vmcore try to access unaccepted memory because it can >> cause the guest to fail. > > Oh, hold on. What are the actual side effects of this? > > Once we're in the kdump kernel, any guest is already dead. So failing a guest doesn't apply, no? > Unaccepted Memory is used by virtual machines. In this case the guest has kexec'ed to a dump-capture kernel, so the virtual machine is still alive and running the dump-capture kernel.