From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753309Ab3KRCRn (ORCPT ); Sun, 17 Nov 2013 21:17:43 -0500 Received: from mx1.redhat.com ([209.132.183.28]:23203 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751377Ab3KRCRg (ORCPT ); Sun, 17 Nov 2013 21:17:36 -0500 Date: Mon, 18 Nov 2013 10:16:41 +0800 From: Dave Young To: Matt Fleming Cc: linux-kernel@vger.kernel.org, linux-efi@vger.kernel.org, x86@kernel.org, mjg59@srcf.ucam.org, hpa@zytor.com, James.Bottomley@HansenPartnership.com, vgoyal@redhat.com, ebiederm@xmission.com, horms@verge.net.au, kexec@lists.infradead.org, bp@alien8.de Subject: Re: [patch 5/7 v2] export efi runtime memory mapping to sysfs Message-ID: <20131118021641.GC4025@dhcp-16-126.nay.redhat.com> References: <20131105082007.872550445@dhcp-16-126.nay.redhat.com> <20131105082718.185728964@dhcp-16-126.nay.redhat.com> <20131113155027.GC17248@console-pimps.org> <20131114015047.GD4081@dhcp-16-126.nay.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20131114015047.GD4081@dhcp-16-126.nay.redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > > > +/* > > > + * These are default attributes that are added for every memmap entry. > > > + */ > > > +static struct attribute *def_attrs[] = { > > > + &map_type_attr.attr, > > > + &map_phys_addr_attr.attr, > > > + &map_virt_addr_attr.attr, > > > + &map_num_pages_attr.attr, > > > + &map_attribute_attr.attr, > > > + NULL > > > +}; > > > > If the UEFI spec ever releases an update for the memory descriptor > > structure, and bumps 'memmap.desc_version', how are we going to signal > > the incompatibility to legacy versions of kexec tools? > > Hmm, that is a problem. I will consider to export memmap according to > what firmware provided with extra desc_version instead of using attrs from kernel > data structure efi_memory_desc_t > Matt, desc_version is already in boot_params.efi_info, so kexec-tools can get the version from there. I do not need to export it as another file. I think for now we do not need worry much about the compatibility issue, do you think I need add version checking in kexec-tools currently? like below? if (desc_version != 1) /* current version is 1? */ error out it is not supported -- Thanks Dave