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=-3.8 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,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 C0D6AC433E6 for ; Mon, 31 Aug 2020 15:22:32 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 904A120767 for ; Mon, 31 Aug 2020 15:22:32 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=citrix.com header.i=@citrix.com header.b="aqVvdrQN" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 904A120767 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=citrix.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1kCldV-00052B-R7; Mon, 31 Aug 2020 15:22:21 +0000 Received: from all-amaz-eas1.inumbo.com ([34.197.232.57] helo=us1-amaz-eas2.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1kCldU-00051y-2E for xen-devel@lists.xenproject.org; Mon, 31 Aug 2020 15:22:20 +0000 X-Inumbo-ID: 65c78666-5994-40e0-8a44-b034db121f4b Received: from esa6.hc3370-68.iphmx.com (unknown [216.71.155.175]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTPS id 65c78666-5994-40e0-8a44-b034db121f4b; Mon, 31 Aug 2020 15:22:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=citrix.com; s=securemail; t=1598887339; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=F8ZyoyWPK6N2FdpDmcHFDdIkhC3kihjRqos6ChwY3dI=; b=aqVvdrQNTAbgXCsmaaFizBsy9nZVhxoO/LXCizRJAcusrqBna3JcdxzK BHUUpA+Z592kfQBukp5BSkTlqjwiZbjJ0EwhPlzCs6ccjDgtRpH7bKV74 rMN2tDv3hBIRYUKvFyW0PhewFN2w9cI1skSnnC5zzjYmf638Pigps6QO0 g=; Authentication-Results: esa6.hc3370-68.iphmx.com; dkim=none (message not signed) header.i=none IronPort-SDR: yvY5E6LBUMcOvWUguoBTSl+nIx8oQ/rRDbusaQmtptcwfrsFoXYJkMvpkiYk9xj77Ipj+wIXUZ 394VpSrh5Rz/uXub+nhnwFfC6Cj86XRK4kft21qlGnDou8dOUIgGzta6savrhhCljgYsnPI9rX gapXcN3JfkuiPNGt2cH2KeummWT/s+0bC5E8Oe7dglenfjhktgCe3O+TDPQacChMEX+VvWE3N7 N1fMdcFjIAmZXKReula2cRBnnAiJwSH/eFrhcquNIihGsmSyxzCvxJHomsaexxxhkhdaHEiYfl wuw= X-SBRS: 2.7 X-MesageID: 25959238 X-Ironport-Server: esa6.hc3370-68.iphmx.com X-Remote-IP: 162.221.158.21 X-Policy: $RELAYED X-IronPort-AV: E=Sophos;i="5.76,376,1592884800"; d="scan'208";a="25959238" Date: Mon, 31 Aug 2020 17:22:10 +0200 From: Roger Pau =?utf-8?B?TW9ubsOp?= To: Jan Beulich CC: Andrew Cooper , , Wei Liu Subject: Re: [PATCH v2 8/8] x86/msr: Drop compatibility #GP handling in guest_{rd,wr}msr() Message-ID: <20200831152210.GG753@Air-de-Roger> References: <20200820150835.27440-1-roger.pau@citrix.com> <20200820150835.27440-9-roger.pau@citrix.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Disposition: inline In-Reply-To: X-ClientProxiedBy: AMSPEX02CAS02.citrite.net (10.69.22.113) To FTLPEX02CL06.citrite.net (10.13.108.179) X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" On Fri, Aug 28, 2020 at 10:55:29AM +0200, Jan Beulich wrote: > On 20.08.2020 17:08, Roger Pau Monne wrote: > > Now that the main PV/HVM MSR handlers raise #GP for all unknown MSRs, there is > > no need to special case these MSRs any more. > > I agree, yet I'd like to point out (based on past backporting of > security fixes) that this change may end up being a good source > of backporting mistakes, as 4.14 may need chunks added here which > on master / staging have no place anymore. Even if we leave this chunk out, patches for > 4.14 won't need to add anything to make a MSR return a #GP, so it's likely that the chunk will have to be added for backports anyway. I really have no idea of how to help with backporting with such change in place. Thanks, Roger.