From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.13]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 20D9C30DD1B; Wed, 2 Sep 2026 17:43:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=198.175.65.13 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788371000; cv=fail; b=jgiGUDlZ5OAdx9f9GrS7zFRv8PxCU54fDFDSYT2kd9w3E7XtftW2oGTmJ70ohK/Y9SPz0QolxVP13xQ0FP/B+auP0ofEDl0cwVOky5NE+gjCZfz0SyySyugH7Ltf98xiRw6NAfwPzSy+qbyqokA4hNQ5wcDCDZzSX6jK/05Ll5k= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788371000; c=relaxed/simple; bh=aSj2FrfjcZ7K8SFyJCD1GfKBgaLVPM7QvZwbcgvze1E=; h=Message-ID:Date:Subject:To:CC:References:From:In-Reply-To: Content-Type:MIME-Version; b=fmCDH1CNxyR4MYyX/ffjD6g0cZKmStLFJlxUD/hwYaRv70vezoz2oGO97p0WxDHCS3FzKsV3/ATINNDkXHxJ0glYrMX9SM9iKmHJHDDK+RpAWS6tBVEUDteHOITSS7Cc4otZNG3lyOng2YGFg7lw0b3kR6EP9oKHbzgBtvDA4PA= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=Lg5rjhos; arc=fail smtp.client-ip=198.175.65.13 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="Lg5rjhos" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1788370998; x=1819906998; h=message-id:date:subject:to:cc:references:from: in-reply-to:content-transfer-encoding:mime-version; bh=aSj2FrfjcZ7K8SFyJCD1GfKBgaLVPM7QvZwbcgvze1E=; b=Lg5rjhosaHkIJzyZxWS22RBvW6la8i26j2sgsBaI0+tLsw/YRmrN1mBm r6OpYeoc9yYfnms2bwGGxG/TZ+/Sr29GBRShQCRmrjRlacG0pDtXllL6w s+Vvj1YyH4y3dtvwuo/pIHWa8N3Fgk8mz2E1s/hXlFFTlPr7LnjsfnYD7 bM9mx6vUXdP7GSSX3NXN/YyyTOdMkuOSvOx4+pKa9cWK+vXiOqRyDpFAG pg33AlcU5gebriAP752IcxCfbJlczxlL0O0zZwRS1PRJYdWiKNoeuJcp3 5Jr6oO4Ye+SfQ79y8o6LyKYzEomfeoLaG2k+5WI5VH9yz2kKpTaVx7+hZ g==; X-CSE-ConnectionGUID: idDkMGzYTZWMYpiXrgrQBA== X-CSE-MsgGUID: LO8imfMNQBy/yU84RW8TVQ== X-IronPort-AV: E=McAfee;i="6800,10657,11894"; a="100000138" X-IronPort-AV: E=Sophos;i="6.25,258,1779174000"; d="scan'208";a="100000138" Received: from orviesa005.jf.intel.com ([10.64.159.145]) by orvoesa105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Sep 2026 10:43:17 -0700 X-CSE-ConnectionGUID: XDlUbs0NSJ6qYJaQntRwcg== X-CSE-MsgGUID: x/SdNNQKQzuG4FyjkjWd1g== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.25,258,1779174000"; d="scan'208";a="273635616" Received: from orsmsx901.amr.corp.intel.com ([10.22.229.23]) by orviesa005.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Sep 2026 10:43:17 -0700 Received: from ORSMSX901.amr.corp.intel.com (10.22.229.23) by ORSMSX901.amr.corp.intel.com (10.22.229.23) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.46; Wed, 2 Sep 2026 10:43:16 -0700 Received: from ORSEDG902.ED.cps.intel.com (10.7.248.12) by ORSMSX901.amr.corp.intel.com (10.22.229.23) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.46 via Frontend Transport; Wed, 2 Sep 2026 10:43:16 -0700 Received: from SN4PR0501CU005.outbound.protection.outlook.com (40.93.194.40) by edgegateway.intel.com (134.134.137.112) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.46; Wed, 2 Sep 2026 10:43:15 -0700 ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=MXGgqFa0n4WZ/EcDRI1pMu775Mo0Jh5wPt8ujgkbEX9Q7Ja3ydGLp8W2G4jpB3d/5iiUCW3YAYTxlMN/vUjDrBTfdymhDHxDeUTRwFJGnlh5tpcJpaGNQy5qyxFAV6ixKzRS0B87sDdPU0F5H19bMBKk0suBfWGVkIu+00fDCNf7CnVcoU60CbV6TIeGbfr1rH4lLnS55RCJb6GQVm5OlLI2QfYR61ZLZFfRLoAJWN75ZPZlgRycHeZ9EbDAkz2W0QjXJWTLoef7IQ/wz1+Fp3IDlMKRf+bIj49iLsP6fEjtleskoN/tXf9g8Xsuwf4aFv2H8ecSUQKcvMj4FGm5Jg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector10001; 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=/iGKexsKBiwjeIdQ3dqjEmCwUOGcekxxlCciwnmIgec=; b=YEeTVUWyuxO88PZ3evDLYNnGGoL/GXPDHm7GYGjfRGEqPbFxOAUG3b+BdrptQIrlAFOwLqxODUWVTHl9ub8O7OqZCDWqQhgWDT3CzidRtCi0TzM++LyKgI1FYet9yCN9LRwxkWzAlwPy0gYv5t1n8XWHGuxHz6KLhCJBK90XIhEVtkjM6CK+53JxGCvmXXCAfeyrd5wV+F/Zuw8hnVotgvELKUcv1IjlElDGP0eyPEx5TGjbZuWrkQK7Ef9AgdkeI1HAxOASKVvv9UTMffXCnJepsXhbUtwaw1XiMR41HBPkrl8/QrBAe0yx4SIP4cvVk1/unBEN2sapXH9JXhP9Vg== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=intel.com; dmarc=pass action=none header.from=intel.com; dkim=pass header.d=intel.com; arc=none Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=intel.com; Received: from DS0PR11MB8050.namprd11.prod.outlook.com (2603:10b6:8:117::5) by CH0PR11MB8213.namprd11.prod.outlook.com (2603:10b6:610:18b::11) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.21.360.13; Wed, 2 Sep 2026 17:43:12 +0000 Received: from DS0PR11MB8050.namprd11.prod.outlook.com ([fe80::f099:a504:2ad6:1d12]) by DS0PR11MB8050.namprd11.prod.outlook.com ([fe80::f099:a504:2ad6:1d12%5]) with mapi id 15.21.0360.008; Wed, 2 Sep 2026 17:43:12 +0000 Message-ID: <73beeef9-3ecf-49fc-87e3-6fa30f8f56d3@intel.com> Date: Wed, 2 Sep 2026 10:43:09 -0700 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 2/4] KVM: TDX: Report CORE_CAPABILITIES as configurable To: Binbin Wu , , CC: , , , , , , , , References: <20260827031837.2863609-1-binbin.wu@linux.intel.com> <20260827031837.2863609-3-binbin.wu@linux.intel.com> Content-Language: en-US From: Kishen Maloor In-Reply-To: <20260827031837.2863609-3-binbin.wu@linux.intel.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-ClientProxiedBy: MW4PR04CA0328.namprd04.prod.outlook.com (2603:10b6:303:82::33) To DS0PR11MB8050.namprd11.prod.outlook.com (2603:10b6:8:117::5) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: DS0PR11MB8050:EE_|CH0PR11MB8213:EE_ X-MS-Office365-Filtering-Correlation-Id: a5c75483-4a07-4fe4-b071-08df0919a897 X-LD-Processed: 46c98d88-e344-4ed4-8496-4ed7712e255d,ExtAddr X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|366016|1800799024|23010399003|376014|10067099003|6133799003|11063799006|4143699003|56012099006|22082099003|18002099003; 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:DS0PR11MB8050.namprd11.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(366016)(1800799024)(23010399003)(376014)(10067099003)(6133799003)(11063799006)(4143699003)(56012099006)(22082099003)(18002099003);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?NkFGKytQYWhyT0QzN0VsYndtU3g5cWcvdC9UT1NaN1hnZFJpN3p0d3lMU2JS?= =?utf-8?B?MTVwVHhWbzlmczB2dVVmWmJYT1lwSlVNWWVYcE9uMTJQZkdIVjQ0VjV2eDJL?= =?utf-8?B?R0gzcDNYc1dEVm9yOVlFUll0SW5RYTV0bDg1OElkWjZpTUlPZzNpNzcxcHJN?= =?utf-8?B?S2U5TXdwem52dTYwTTNVTVovYjA4N3pXamdycFJZV2dCQ2krc2ZXekhlN0ty?= =?utf-8?B?amFpVXhsNGpTbkswL01nUG0ySVBvdzEzR3BBN1NYZ1JFNnNqeDVLQnUvVGR2?= =?utf-8?B?SmlpL0FKMXFuOGJycEhKOXJVN2dOSnJOeEJZYkdZVDE2TFh4eHo3VlBFQ1Nz?= =?utf-8?B?YW5JVlVhWk5BZ0FLQ1pHWWt0WGg0dEVBcDZCTmw5QUszYmkraVBLYXVqRnRP?= =?utf-8?B?bHJ0dzF5akFaa0hXZEdwWXJuYU56ZVpGZElWTGE5c0s1S2NRK1RWdkZ4aGp5?= =?utf-8?B?c2twV05GL0tLYmppNnJFR0NYeDZjR0JiZStHNlVWaVpKWkFldmc3cW1DK1lz?= =?utf-8?B?azhsbXhRQ3RpR1IrTi9kT1NGdkpBdXlvdDdzcjhkbkszSUhQUW5zUHYvZ2dW?= =?utf-8?B?eWduWTdPZFBKYlRGdUNaWTdVYnZKQ2xRRWVybXhNcTlkZFpRMExQaUxqRU9n?= =?utf-8?B?ZSs0d0ZlRDVMNC9tMVNWaFNxTjMya2NrdG1KeEdsdHkvemxKWWZjWmpVOVdi?= =?utf-8?B?Y0JUTDc1Z3RJZzc2N3R6WU1adlNveEhLbE9vUGpGbjYvMm04d1YvbHlueUwx?= =?utf-8?B?elY4RWZPRHBwTG9iNnpuM1haRW5Od0licllhSXJKM2V4RUw2VWpxZjUzTEgy?= =?utf-8?B?OXpNcnNQNWRYUmYrVHY5QUJUaWZPR1BvbUNiKzZZZlk4VHhPMVJNK25XQUFs?= =?utf-8?B?UDlLR3BxZGpjZzRtVmtCTWEremkzUlIzRUNuSmNCRXB5VzVKRDNra2NuRDhv?= =?utf-8?B?SHBXNGlsMmRrYmpYVXNvNHlpVzhuTmM5U2prckg4c1dPZVFWVWcvblhpTCta?= =?utf-8?B?aCtsQlUwb0N0ZmZDYzhZT0dhNkRRdUxPRzlBR1dRMzllWnZxVW96dkJ0L3N4?= =?utf-8?B?OUo3d2lCS2U0eUhidjZZeXhVUWJYdnRlaGtOU1prTkJFNnZMamYwcmxlay9Z?= =?utf-8?B?cC9BRE1xd0hSeWJmVlowQkdxRjhuamRmWnRsNm5lV0NTSXh5WWNNT1JhT0tC?= =?utf-8?B?RlhtMXQ2RHRic3luc1poZENab1pLL3g1RTUzUUJ3aHRVTGk0VGRUek5JcUU4?= =?utf-8?B?U2hxdFJrMUpZZU80Vnh3SnhDSm02NzF5VmJDL3ZEZTZpdFNFeFlYSUR0OCtu?= =?utf-8?B?L05kalZTeE9FYXRoem1wWUJSbWVUZGw1YkF5MzB3ZDhGUkdOY3E4TDUvTjI4?= =?utf-8?B?VDVqeExnQ3FrYXJvZU9pUm9ZZkxPbWVybDlWcjBjeTNEWG1BaFBsYXA2SzVS?= =?utf-8?B?L3ZjZkhrRlBycmRDNGNvOXA0UUcrbUhFY25ES2VnS250dnBGelFwdUloQTJM?= =?utf-8?B?OEdJWHpUWExiazJUbjVOb2x2R2cwUWVnNmtaSVhkcmxSRU83TjBUSTdmVzRK?= =?utf-8?B?YXZqcUFQSGhQMkZMU0dsb2JUUkFiU2NUVnFMN0xHVUg4enNQVjRQYXZxNmxC?= =?utf-8?B?ZDJUeUxRMUs1d3U0YytZdk5jSTh0K3Q5OHJxeGF2eCtBeFpZcGhkcmNqSDFC?= =?utf-8?B?UFBwb1RPUWFreUpqNm1HOEpGNkxHQ2Q2ejJtcElmTmw5V2lhWkNzZUZOVWpp?= =?utf-8?B?aE5ub3ZabDNzeitFLzZxWEhWYjhvRXVGa05IYWdCc0g0bENibnB6YzVPai84?= =?utf-8?B?bXBEN0owcGJrRXhIK2Q1L1pNV0tNU0xSUmxSUW11YTBXWnd0QmdIZFlHK0VS?= =?utf-8?B?OE1WQWhVNjFwT0cydDhROGdLV0pLbmZVZUo5bVNRRkxRZTdtVGdOQlVLUG9J?= =?utf-8?B?RXc2WS8vSXFDeS9GK2RwSjB0WkdUREFIMTQ0YzI0SkhiUXZIL0M2SisxK0Nn?= =?utf-8?B?YWFQN2hkZGNRamcyMUNQYlBIMVJSeG5zelRQL2xWbm16dnNmaWo0V2MwdTJX?= =?utf-8?B?ais3Y2dPMmJjeFpaSjdUcGsvcHExMWlvWUV3V2xnYVNFM1pSRTdrUUlNR1Nx?= =?utf-8?B?VXhtTlJETFhQNUdlMDZPTjJObFdyRVp1TWQzS0hXRHQ1eDVWSHB1TU1pblh2?= =?utf-8?B?SXhDSkZaN3VsK0FQYnV2YmxyN0pGTER5ZVVtVHlhVGRFMitEY1BsZnRFVjEw?= =?utf-8?B?Zmt0elBNN3NHVmtTWlUwVjBNZm8yNzRPSWhjWGJwblgzcGYrL1RHWW90NkJS?= =?utf-8?B?cW5Hd2VySUhOUjZPNUpXR3JRN3pDVnh5dmtBY084WU15WTBXYVMyUT09?= X-Exchange-RoutingPolicyChecked: OzfjPE+o03SFtO4LZhZ5TFwzGXzCWOXIDHca5fpGmcfubxWXLk1xSnlpLr6K5PjCDcD+F+R+a5zHWM1R+p9/g1TeJ3pklLH0DujgzzVpiJhPMR28bV5R78WEBGU+l7/EIkfp+zlSU2yHcNxUF7S5vx05Pba4viAGBAdcXaTswhgNyOG1lLtesqnRivufdp+/PfUycH6MvBEpdD+uZP3esl9YYARjk+yKSl5dsyOZ7iivhoTYHT87n/lc2OLmNuiV0ebHStEohZ/JInp2I1W/5o1vbfPS1f6ZIGPE2+NaQWAWzUkVMHAb0eCeEZtnEyTS7TyiuAaKWTFzIuMPSuX57A== X-MS-Exchange-CrossTenant-Network-Message-Id: a5c75483-4a07-4fe4-b071-08df0919a897 X-MS-Exchange-CrossTenant-AuthSource: DS0PR11MB8050.namprd11.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 02 Sep 2026 17:43:11.9185 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 46c98d88-e344-4ed4-8496-4ed7712e255d X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: rKMq9xkIT1IiURYpNUrTZq/UCpcM9/srgu9Gv1vfypKrfA+8fx5K1A3VUBIYuc8sFhh+jhIYxM/ew00h8OFbBg== X-MS-Exchange-Transport-CrossTenantHeadersStamped: CH0PR11MB8213 X-OriginatorOrg: intel.com On 8/26/26 8:18 PM, Binbin Wu wrote: > Reporting CORE_CAPABILITIES as configurable keeps userspace able to enable > the bit across the fixed-1 => configurable transition, and lets userspace > infer that the bit is no longer fixed-1 so it can adjust its expectations. > ... > @@ -147,6 +147,12 @@ static void __init tdx_initialize_cpu_cfg_caps(void) > + /* > + * KVM does not support MSR_IA32_CORE_CAPS, but older TDX specs > + * define this bit as fixed-1. Report it as configurable so > + * userspace can know the feature is no longer a fixed-1 bit. > + */ > + TDX_CFG_EXTRA_F(CORE_CAPABILITIES), Would a mask of the bits that are fixed-1 across the modules KVM supports today be worth carrying, or adding to the allowed set? I assume it would be hardcoded, just as the allowed list is. If a module update later made one of them configurable, userspace would keep the ability to set it -- something it has today with the denylist. And since such bits are already enabled in every TD running now, continuing to accept them can't turn on anything that isn't already on. A bit that becomes fixed-1 in the future and configurable after a subsequent module update would still need a patch to the mask, just as this patch does. Is CORE_CAPABILITIES the only fixed-1 case so far?