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 53CB8C43334 for ; Mon, 18 Jul 2022 06:08:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233284AbiGRGII (ORCPT ); Mon, 18 Jul 2022 02:08:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35792 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233351AbiGRGID (ORCPT ); Mon, 18 Jul 2022 02:08:03 -0400 Received: from EUR02-VE1-obe.outbound.protection.outlook.com (mail-eopbgr20069.outbound.protection.outlook.com [40.107.2.69]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 097871400E; Sun, 17 Jul 2022 23:08:01 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=ETYOJfMeDxXpPQEfRSnLKM4quMgV14NEImj3h+j9Gbp3N+t+uiRmEHQscelc9vpREj0j+G4e2VLCut+qyaNi7BV53OcyJwJknnm58IA5H63NmZ732JF0zQTman9SEMeheZ5jGXfWJJcwCyw/h0p2Gn2tHokVVhBZOGeXsSPdf9O0Vh3UHLZR+BMV63BWn8xUyDOhxKhVK+awqOre0cFvmq16HIo8KbWzYwWGE3aFsQMOee/aBelwtsnc4pKHnUnNc+6EdvxtZRolUOjU44+HOleK68vSG8PeNeGaRL6A+K6WvHLj1yXuos32jr0zAnF0zItCxyOnUCRNsidl4hXczg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=1IXuJHho9OSOXl7UV/zLebNmFWmzinEovfcnOoaOWdg=; b=E3rE0F3WSLSYgPteSKr1Xg4uEOw/Tp6UZ/Oi1Q0bTKs/NGyDj9XPKgx0r7Rth77WY6WxBTgnK1vSx9W+Y1xvSJUXXjFZUUnTkNfGKD40GlWTjVSl2ggiMkYhhE/TtbmDiQy8UpvOC/aFhi8gp08z7omG6PczezOpxHRTZu5QZrc+v+ps9LsrA1TYH+yaBBgoN7iCPbIgbGAFgqPoCnvK8NBav5ZuOUVDiXnBDLfvGl7ut8UXv/TB5rDBkXzV3fRHmwr/7Obb8Cn4LmWx6QHEMC0iiZ+dxV5Yy2q4m1t4wYOMbk77ccuRiV9GSM+KIHqxcujBc59vMnaGP02FCUOn5w== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=suse.com; dmarc=pass action=none header.from=suse.com; dkim=pass header.d=suse.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=selector1; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=1IXuJHho9OSOXl7UV/zLebNmFWmzinEovfcnOoaOWdg=; b=YXnzq6b7PQOkppzmoYhYAaxWI0o4IGdlFtLExcAfLKh3pBkyv4JC15JI/q7/GJ20SKI40uAHLAOazgkl0B9Fcmk4KTpf/05Uf0t7jWFKczFardOYca2o23FDH9zRMAUFI7wYcgo41yiWBpkKeL5d+7bWj8GKGuvK2f/TeWHisz/4qn+ZMlpbrwC2eU6jXY1IfVPf/9i7OM16pugfk8xvCCkj1Vmd3C7p/L1cdWVw73WeLN8wMWd5JDNTd9GsDM5tbJe4RKh3h9SuanYJqlyvJMas1JD335GkHljfQuNIE9sphd2XX9UrQUbva//0iJZQhBpNtOd08820AJU+eHC5cg== Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=suse.com; Received: from VE1PR04MB6560.eurprd04.prod.outlook.com (2603:10a6:803:122::25) by DBBPR04MB8026.eurprd04.prod.outlook.com (2603:10a6:10:1ed::6) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.5438.21; Mon, 18 Jul 2022 06:07:56 +0000 Received: from VE1PR04MB6560.eurprd04.prod.outlook.com ([fe80::60ad:4d78:a28a:7df4]) by VE1PR04MB6560.eurprd04.prod.outlook.com ([fe80::60ad:4d78:a28a:7df4%4]) with mapi id 15.20.5438.021; Mon, 18 Jul 2022 06:07:56 +0000 Message-ID: <764ea65f-269a-6f32-c780-cbdd7cf09120@suse.com> Date: Mon, 18 Jul 2022 08:07:56 +0200 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.11.0 Subject: Re: [PATCH v2] Subject: x86/PAT: Report PAT on CPUs that support PAT without MTRR Content-Language: en-US To: Chuck Zmudzinski Cc: Dave Hansen , Andy Lutomirski , Peter Zijlstra , Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org, "H. Peter Anvin" , Dan Williams , "Kirill A. Shutemov" , Tom Lendacky , Jane Chu , Tianyu Lan , Randy Dunlap , Sean Christopherson , Juergen Gross , xen-devel@lists.xenproject.org, stable@vger.kernel.org, Thorsten Leemhuis , linux-kernel@vger.kernel.org References: <9d5070ae4f3e956a95d3f50e24f1a93488b9ff52.1657671676.git.brchuckz.ref@aol.com> <9d5070ae4f3e956a95d3f50e24f1a93488b9ff52.1657671676.git.brchuckz@aol.com> <5ea45b0d-32b5-1a13-de86-9988144c0dbe@leemhuis.info> <56a6ab5f-06fb-fa11-5966-cb23cb276fa6@netscape.net> <1309c3f5-86c7-e4f8-9f35-e0d430951d49@netscape.net> From: Jan Beulich In-Reply-To: <1309c3f5-86c7-e4f8-9f35-e0d430951d49@netscape.net> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-ClientProxiedBy: FR0P281CA0037.DEUP281.PROD.OUTLOOK.COM (2603:10a6:d10:48::19) To VE1PR04MB6560.eurprd04.prod.outlook.com (2603:10a6:803:122::25) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: 8789e7cb-adcd-486e-ee7e-08da6883db80 X-MS-TrafficTypeDiagnostic: DBBPR04MB8026:EE_ X-LD-Processed: f7a17af6-1c5c-4a36-aa8b-f5be247aa4ba,ExtFwd X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:VE1PR04MB6560.eurprd04.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230016)(366004)(346002)(376002)(39850400004)(396003)(136003)(6486002)(6916009)(4744005)(2906002)(41300700001)(83380400001)(8936002)(7416002)(66556008)(5660300002)(86362001)(2616005)(31696002)(54906003)(478600001)(53546011)(38100700002)(6506007)(31686004)(36756003)(6512007)(26005)(316002)(8676002)(4326008)(66946007)(186003)(66476007)(45980500001)(43740500002);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?d2tkN3d1d0JGNkM0YUp3RlhReDM0cFpMQjVCZXNaYWlESUwxdkZCeXZhU1Zv?= =?utf-8?B?NWpkK0pqQ0V6bmExRnFHSCttQUxzS1dGbE1uc215RzJ4ZFoyMUU2RmZkM3RK?= =?utf-8?B?MytKbXYvQXhGdmxCMUZjcVRLSGhCZlhLU0R5N21RSzhKQUVtMHVyRE85dThk?= =?utf-8?B?dWQ4azU2N3BscXZoYndVem9QMmtLR29GUmlzcGs5eC91M21GU1ZtTWx5VzRs?= =?utf-8?B?Q3pPNkUwenJFQzNHZXE3V2k5blB2Rm50YUs4Sys1N0xhdUJFTFEyYlV6em5Q?= =?utf-8?B?cU9FYmlYWHMzTitGRkpNdnhLZFYzZXdPdm1oRks0Q0R1ZDAvYlVYbzhXTm1Y?= =?utf-8?B?d2VJREp5eFc0WVEwU1AxV2FDMU9tSGxSZG5hdVNOMTZSbEtYVGtxdlQwMXJ4?= =?utf-8?B?QXh1OWx4Vm9pM1pHQmEzb2hTVmlIODMwWlR4UW15S1I3SVpNRE9jZEJGQkFZ?= =?utf-8?B?VWxQcmJCWlZ5cDlCdHlDSXgzM0FjQWJUbkY5ZE1VY1BuQjhlKzNKNmtsSUda?= =?utf-8?B?QWdwRVFQOSt1K1d1VzhBMXdpYmMvMGZFa045UE1QNkFvNzFBTXJBcXk0Qll5?= =?utf-8?B?SlVtVnhZL2R4K1NiM3p2RHN6d0FhbVZsVkloUjc2d2x6R0xuMTAvaUxManZ5?= =?utf-8?B?Zml0S3FZNkg1WVd4TTBDYUpJazhoSUlWTWRPRm9lU1pTS01zNHMyaHQvRDU5?= =?utf-8?B?bnNLWmd4MFJTK1Q0MUhxMnVpOCsra3RJZnN5VUY0Z0RIUm9wcUdxbGZsQjhW?= =?utf-8?B?b2lCK0pSNGh2dlJ1VlB4Sjh5eXJTNlU4SEhLRkpLTy9MMGRoTXNoTitvdEsv?= =?utf-8?B?WWMwWkVjcm9CVEg3MGRSOEZ6OENuYk5MWmJENzBtWUJ3aXNya1lVMERsVklR?= =?utf-8?B?d203enVWeVNPSjJBMnJhenNRQTdOc2pkTjd4RWdZckZKL0xySVhoUHhSWk1n?= =?utf-8?B?VEFUbzlzVCsreGdDbmdDQkcrcHo4Ym1CT2NHaHErVmtPM0VlWlZBZ3VsOHBL?= =?utf-8?B?V1BNOEsyWjJ3SjJSY2NiMGgrL2JJWUFVVmxaV3FSeWNNbFhUd0tzNWxZMWNL?= =?utf-8?B?cnkxTDdWdHExdmZyNW1xR09Tc2EvZi84cTM4bVJTRUwyTTZhLzhWVk9xNWd2?= =?utf-8?B?NUs1bmdDL2FCWHM1WmZyV0VsU1dXZUlua3hLbCtZRnV0MXA5cHhNR04zZFVm?= =?utf-8?B?TE14Z29ab2E1c1FLdjhRalYzQk1mS0k5eCttT2FzUHVtNmZXeWtrMkFyOWsv?= =?utf-8?B?TVhHUkFPazMraXd0Z3NoUVhmT3hsSGZqdUEvd0l1R2pKTTh1Tlk5QWhiZ0Zk?= =?utf-8?B?QmFtY2I2V2RZOWhaN2pYSFB6Mis1Yld1ZEhpNXhva2tsdHV0ckZaQ2VJdm1K?= =?utf-8?B?ZS9WTnQvbVkwa1EzQ2dEcTdtSUF5amQvV3YvL283UXA2b2tPYlZJaTVpUFcv?= =?utf-8?B?Q0RORm4vODBKVHpHTDIxREVGOFE4SnZPdlBnU3p0NzlwQVE0OTVBWjdrVTdi?= =?utf-8?B?UmtkQ0VGZXNHM0ZuQWJvb0RXOEpHYnBBbHg4VE80ZCtJdTVrTG50djhSLzJh?= =?utf-8?B?R3pldzhuS3J4U2JTWVJINzQ0MXI1UnMza0ZHa3d3ZWFyc3RLYis2TEx5Y2hv?= =?utf-8?B?SG1JV0tPSytZRnpQT2hydUxmQ1ZEMWdwYTZKa3lQbE9mblJuRC9TakdqSlho?= =?utf-8?B?UVludmFmRWo3UWYxbWFVWHFiU09IMGtaRjd0Tzg5K0tiQS9TMDliSHB4RDlm?= =?utf-8?B?cXUwN0hpN2hWVU5xa3lZRFZzMVF0TEFsT1k1RE9pdlF6WjIzbEg4dkZjRVNF?= =?utf-8?B?ektlK3l6d084QVVFWDc1cjJWUzQ4d00va3FzVWFoVm5iQVpyU2NQSnpBMEJr?= =?utf-8?B?RmdaSDBrVlBvS3pFY2Y2TFhMaDNlTzVNUmsyUkQ0ME5iSkZDSld1ZFVoWUN6?= =?utf-8?B?L2FjT3NkaU9ISTcwc1lETHJSUmcxUTFOQklyL1M1OWJ4N3ZCRVl3elpmQkMz?= =?utf-8?B?Yzhya2lOdndpTzRVSzZzNVpzcFlsSzhJbXdsMEE2R0hsbjBuRk1zZFhJUVRY?= =?utf-8?B?OUN2VnIwcGs0RUtKb0pPZUxlY2V6eWhqd28zM3Y2UFVNK2p4RTJTUEFQRnI0?= =?utf-8?Q?xANokraIXdPXr3Re9SC36O35v?= X-OriginatorOrg: suse.com X-MS-Exchange-CrossTenant-Network-Message-Id: 8789e7cb-adcd-486e-ee7e-08da6883db80 X-MS-Exchange-CrossTenant-AuthSource: VE1PR04MB6560.eurprd04.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 18 Jul 2022 06:07:56.0885 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: f7a17af6-1c5c-4a36-aa8b-f5be247aa4ba X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: SfWz5ydNitlLQuAlzLNOK2GMnbdeziDfGDNQS5pRtK23635iJbDj/oVy06/IJuWwOkIHZDQ92ALvOOlmvWwXoA== X-MS-Exchange-Transport-CrossTenantHeadersStamped: DBBPR04MB8026 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 15.07.2022 21:53, Chuck Zmudzinski wrote: > Two things I see here in my efforts to get a patch to fix this regression: > > 1. Does Xen have plans to give Linux running in Dom0 write-access to the > PAT MSR? No, as this is not technically feasible (all physical CPUs should run with the same value in the MSR, or else other issues arise). > 2. Does Xen have plans to expose MTRRs to Linux running in Dom0? Yen does expose MTRRs to PV Dom0, but via a hypercall mechanism. I don't think there are plans on the Xen side to support the MSR interface (and hence to expose the CPUID bit), and iirc there are no plans on the Linux side to use the MTRR interface. This also wouldn't really make sense anymore now that it has become quite clear that Linux wants to have PAT working without depending on MTRR. Jan