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=-6.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 D5B73C433E1 for ; Tue, 18 Aug 2020 14:12:08 +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 A156E207DE for ; Tue, 18 Aug 2020 14:12:08 +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="H7KHVumh" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A156E207DE 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 1k82LG-0003A6-Jg; Tue, 18 Aug 2020 14:11:58 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1k82LF-00039y-Pr for xen-devel@lists.xenproject.org; Tue, 18 Aug 2020 14:11:57 +0000 X-Inumbo-ID: b693b1bd-dc68-407d-89fa-7763a048eaea Received: from esa4.hc3370-68.iphmx.com (unknown [216.71.155.144]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id b693b1bd-dc68-407d-89fa-7763a048eaea; Tue, 18 Aug 2020 14:11:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=citrix.com; s=securemail; t=1597759916; h=date:from:to:cc:subject:message-id:references: mime-version:content-transfer-encoding:in-reply-to; bh=XjFFh43jOwM5Rzoopsx8W0Ju3mUyoUkOMqPRtyKRLrc=; b=H7KHVumh3ahOg2CSCt+RhYB/e48L/QpSLSGw7HMmZwGXqNUTvbai1T7q BAJvNnKHJB+35IowXXudc8wSiuMI7bwxDlFxnTnpvWkinISXnotC2awEs 55Ogc2i3mmULF8QIaTUfT7IYnDj9uaCz/q9uSAMXM/tsQl1SZggkcs8NV I=; Authentication-Results: esa4.hc3370-68.iphmx.com; dkim=none (message not signed) header.i=none IronPort-SDR: QJwo+YKeBCb/M2HsxxLhjLKtT+G249eJwtMwvRUQt8lTdtpAjZ85xf/VkK7+oJPMIR8U3W77/M wIErd+966wLAuCj7CsHct4Nzwuvx6uLpgO00GiqmGTKbpTck3pksQ183zs+re/WIPlGwO5xj71 aMH3Ma359F56lDL1d4vTkdKcLMm3ywhktu7B4g3DcyC/DODw52nGyBlY6Ly/4A5QoAoew+BPVi hnct1Wh5LT0TqPjYBQBDF15gQENTvTYwH4VChlwb0oADTbupr+tFECVkxTB4i8IEpTUw0ZQvBd /QE= X-SBRS: 2.7 X-MesageID: 25699118 X-Ironport-Server: esa4.hc3370-68.iphmx.com X-Remote-IP: 162.221.158.21 X-Policy: $RELAYED X-IronPort-AV: E=Sophos;i="5.76,327,1592884800"; d="scan'208";a="25699118" Date: Tue, 18 Aug 2020 16:11:50 +0200 From: Roger Pau =?utf-8?B?TW9ubsOp?= To: Andrew Cooper CC: , Jan Beulich , Wei Liu Subject: Re: [PATCH 4/8] x86/pv: handle reads to the PAT MSR Message-ID: <20200818141150.GN828@Air-de-Roger> References: <20200817155757.3372-1-roger.pau@citrix.com> <20200817155757.3372-5-roger.pau@citrix.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-ClientProxiedBy: AMSPEX02CAS01.citrite.net (10.69.22.112) To AMSPEX02CL02.citrite.net (10.69.22.126) 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 Tue, Aug 18, 2020 at 02:50:24PM +0100, Andrew Cooper wrote: > On 17/08/2020 16:57, Roger Pau Monne wrote: > > The value in the PAT MSR is part of the ABI between Xen and PV guests, > > and there's no reason to not allow a PV guest to read it. > > This is faster than using RDMSR to find the constant. > > > Signed-off-by: Roger Pau Monné > > Acked-by: Andrew Cooper > > (Can fix up on commit) Sure, I didn't write it down because I assumed it would be obvious, but worth writing down. Thanks, Roger.