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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 576BCC7618F for ; Mon, 15 Jul 2019 16:34:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2A1772081C for ; Mon, 15 Jul 2019 16:34:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731189AbfGOQeC (ORCPT ); Mon, 15 Jul 2019 12:34:02 -0400 Received: from mga02.intel.com ([134.134.136.20]:8134 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729533AbfGOQeC (ORCPT ); Mon, 15 Jul 2019 12:34:02 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by orsmga101.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 15 Jul 2019 09:34:01 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.63,493,1557212400"; d="scan'208";a="175145375" Received: from tassilo.jf.intel.com (HELO tassilo.localdomain) ([10.7.201.137]) by FMSMGA003.fm.intel.com with ESMTP; 15 Jul 2019 09:34:00 -0700 Received: by tassilo.localdomain (Postfix, from userid 1000) id 9AA04301AE9; Mon, 15 Jul 2019 09:34:00 -0700 (PDT) From: Andi Kleen To: Juergen Gross Cc: xen-devel@lists.xenproject.org, x86@kernel.org, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, Andy Lutomirski , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , Boris Ostrovsky , Stefano Stabellini , Alok Kataria Subject: Re: [PATCH 0/2] Remove 32-bit Xen PV guest support References: <20190715113739.17694-1-jgross@suse.com> Date: Mon, 15 Jul 2019 09:34:00 -0700 In-Reply-To: <20190715113739.17694-1-jgross@suse.com> (Juergen Gross's message of "Mon, 15 Jul 2019 13:37:37 +0200") Message-ID: <87y30zfe9z.fsf@linux.intel.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Juergen Gross writes: > The long term plan has been to replace Xen PV guests by PVH. The first > victim of that plan are now 32-bit PV guests, as those are used only > rather seldom these days. Xen on x86 requires 64-bit support and with > Grub2 now supporting PVH officially since version 2.04 there is no > need to keep 32-bit PV guest support alive in the Linux kernel. > Additionally Meltdown mitigation is not available in the kernel running > as 32-bit PV guest, so dropping this mode makes sense from security > point of view, too. Normally we have a deprecation period for feature removals like this. You would make the kernel print a warning for some releases, and when no user complains you can then remove. If a user complains you can't. -Andi