From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.8]) (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 4F7AC1B87EB; Tue, 4 Nov 2025 06:07:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=192.198.163.8 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762236451; cv=fail; b=kpjt/mcsK5OuYoh9xDvHD1CmH1q203Db8ouGPaFffCFsUmJ0fWw+HIN6G3O9j1GK8P/PsFDLohXD7EjEKeKaQwQXh72v3CO/8G9aa3zDEImWtw/C9bt6IUauYUg27doZb7DCIEgKb11NDChyY1FprcKg2xek92j/qJ0OGfTeSe0= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762236451; c=relaxed/simple; bh=jEZnekfTsQjoA0QFXtAen8IU/DyG8IbFIMJ/jwgt0HM=; h=Date:From:To:CC:Subject:Message-ID:References:Content-Type: Content-Disposition:In-Reply-To:MIME-Version; b=VOguHfxatbziE2bqpT1AIXYheK5ISpypfGu5SfGHHES9P/SM7Qlu8sDcz8yRI+7+VMPNYLxZmCqp5vLf9LgAy9PGFM3Zf2XyC3lJ1v9/pJe192TCHbHjWSV8BtFrWA42iusGDFaNIrjoinADVAS8ZYs9XI6d+Z5UhYLf+7UgJP0= 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=Jqjr38se; arc=fail smtp.client-ip=192.198.163.8 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="Jqjr38se" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1762236450; x=1793772450; h=date:from:to:cc:subject:message-id:references: in-reply-to:mime-version; bh=jEZnekfTsQjoA0QFXtAen8IU/DyG8IbFIMJ/jwgt0HM=; b=Jqjr38seV/emvV+mCn1u7R5y8phoqOizSP7xL+mQTEonjiFXPp3wLQJ0 wb28ZE3pKQJBnUbrlE7/G5KwTAsD4o7sjnjVj89W3S0945OGY71bwC7Tw SBSxAnZkDF6+pn47Q45vmt8fYAnaBAPpbfbfwU0fU15ezGA0TgoxMzoH1 behtVB85kBalbyZGfr5UgrI08N4CbERd2hJZGFPaeREWMr/uiYphdpGM9 uOclEDCPuUCBbF6QsZKIZQLXpQyWFp0dA2o9oOcqmJ4q7rqxfVn5fxw7n EAv725Ufkl2RRQmuQGACf50cMQ7Ov/KVazUVBQ0CzqW+1nEp7Q4k0I7yK w==; X-CSE-ConnectionGUID: ExwtnqBFSgSqzeFEWYBP5Q== X-CSE-MsgGUID: JAbJs3oiSLaF5JkBQHczRA== X-IronPort-AV: E=McAfee;i="6800,10657,11602"; a="81952473" X-IronPort-AV: E=Sophos;i="6.19,278,1754982000"; d="scan'208";a="81952473" Received: from fmviesa009.fm.intel.com ([10.60.135.149]) by fmvoesa102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Nov 2025 22:07:30 -0800 X-CSE-ConnectionGUID: koCDbcB5Q7COC5abHe42IQ== X-CSE-MsgGUID: KNHYAOJdTd2Qu0x/tFXyAg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.19,278,1754982000"; d="scan'208";a="187518095" Received: from orsmsx902.amr.corp.intel.com ([10.22.229.24]) by fmviesa009.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Nov 2025 22:07:30 -0800 Received: from ORSMSX903.amr.corp.intel.com (10.22.229.25) by ORSMSX902.amr.corp.intel.com (10.22.229.24) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.27; Mon, 3 Nov 2025 22:07:29 -0800 Received: from ORSEDG903.ED.cps.intel.com (10.7.248.13) by ORSMSX903.amr.corp.intel.com (10.22.229.25) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.27 via Frontend Transport; Mon, 3 Nov 2025 22:07:29 -0800 Received: from SN4PR2101CU001.outbound.protection.outlook.com (40.93.195.47) by edgegateway.intel.com (134.134.137.113) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.27; Mon, 3 Nov 2025 22:07:29 -0800 ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=D5AjpaBPlsWtPF+yaMQO7oh8j6f8yeSzEDyHbuT8YScDFT3FWTr+5DINwFhvvY09L1TfP+GERHPylnnEo88GsA9IA3TmF+dKz3s9BYuJT7arw39YFabkzIxNhjQAghnOBWinyZCmPQxOf83EkMenMQQL85nRqd6F9D0NRQDnQQgyT5iRhIUtRl9EXvag3Xmjv5Gf4zJRPz41cLzOdlTnFuOJlkSoenSSxAVQlHaCvJcjGY4gnkF6bk5Tr2mg1by114dJa9LlnT9OKG0iRNVByZrVVMTytHGZZmK6c8XiW7iqTTxzhyxrMplrqeNyecZvkTfUz41HcQK/ak5sRBSdAQ== 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=zbePZNboU+QMf41nG2XXPQCT9qYKSTiNheRQ3Cbt6AI=; b=Bqs21ahXNoUG5BpKU/zo3BAd3YZgI59W95hjZkfS6T+g48xMzTiPTyOgaHw7qiytR9G396HTiYRdXv4imueW24ba9AcQmV72M7DUsLEz8FOxY5kymDotmm+XJIIOqte7qZqz3Bkv4jzrAey6JKE/lGeqswTdnTn8ddUNg/uSXlBRWbPcqRLW/XIES4CpVI0uoGEkcIT1LjAFuVXYkH7NjP844u7Tl9e5VTqk6fIhLJE1i31cSLEBpF+iAFYVeQRxSCEnHK+RFaUYl0vcLlJK8UBN9wIOaRfNqc8bnij6yUlUVN79ZiSYSO7+Hd7l94VrtcaKTQC85/ahbAGFhRm9aA== 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 CH3PR11MB8660.namprd11.prod.outlook.com (2603:10b6:610:1ce::13) by CYXPR11MB8756.namprd11.prod.outlook.com (2603:10b6:930:d6::14) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9275.16; Tue, 4 Nov 2025 06:07:27 +0000 Received: from CH3PR11MB8660.namprd11.prod.outlook.com ([fe80::cfad:add4:daad:fb9b]) by CH3PR11MB8660.namprd11.prod.outlook.com ([fe80::cfad:add4:daad:fb9b%4]) with mapi id 15.20.9275.015; Tue, 4 Nov 2025 06:07:27 +0000 Date: Tue, 4 Nov 2025 14:07:19 +0800 From: Chao Gao To: Sean Christopherson CC: Paolo Bonzini , , , Alexander Potapenko Subject: Re: [PATCH 2/2] KVM: x86: Harden KVM against imbalanced load/put of guest FPU state Message-ID: References: <20251030185802.3375059-1-seanjc@google.com> <20251030185802.3375059-3-seanjc@google.com> Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <20251030185802.3375059-3-seanjc@google.com> X-ClientProxiedBy: SG2P153CA0042.APCP153.PROD.OUTLOOK.COM (2603:1096:4:c6::11) To CH3PR11MB8660.namprd11.prod.outlook.com (2603:10b6:610:1ce::13) Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: CH3PR11MB8660:EE_|CYXPR11MB8756:EE_ X-MS-Office365-Filtering-Correlation-Id: 32c29ac2-b98d-40bd-bd9d-08de1b686e35 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|376014|1800799024|366016|7053199007; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?ozbqDPZMg1+4qqa6MEaXy/20jJk8b9NbT3hNl6bTOeTD+lWMcv9YvuANw/Op?= =?us-ascii?Q?LQcuxWakTy15FR4U5su7B+bk1K8OuKp9EwwA3zmp1O/mDAM9Be+yxNp4yoDz?= =?us-ascii?Q?V1XHzSOrVJCcEbcbbriHLktggzB/yLk/CJxv5aBwYNwTB++K1bjiUA+Y328/?= =?us-ascii?Q?mGjU5p6FJUfIwQXcIH0sYd6mIDVa4LAxC0gPgFSO6uWZDMiWyxs7Qubhf1TT?= =?us-ascii?Q?NV5nWn2z0GhDpVgxLw/J7+2/ZRxwUCQzOpW0+3c89PyzkXr4Z52DGLcSOzzF?= =?us-ascii?Q?1YeMFT8PdG2XsOz69gA8UwZzjWhyPvnWa/NkIpz0w1qrWnhNrbd11NESTEmq?= =?us-ascii?Q?Ep37NZr+D0NdtjEO7G9y0neUrTDNClyRLSWMVEarehC4yB+YDmIFDmehMJBI?= =?us-ascii?Q?xY0/ogiCxPyG7ole1ArcFv4AWBvECtc9lqs4GZYy/MM1r2RdJ8UP2vUaDHL3?= =?us-ascii?Q?mTDre/3Lrkue0rmDZacawVGY+HFVYhPb8enTwxOpTgmlQYNtI/aZt12mVCfY?= =?us-ascii?Q?80y74KTDu11ub+XYLJxKlveMNILgrjvEqwULoLU4WEZsZwzgMDEI7nRN1p8e?= =?us-ascii?Q?UA0VfosQyUdwCaP+FnQwc+cU0jPJX+fjhBVY+Ov0JBf1rFXGkUU50N17juAp?= =?us-ascii?Q?W9KTmolU9s75aegBxzF4v0khkZwvF6nMOJvPFuvGE22Tsa5gGm88h+cgE3Q0?= =?us-ascii?Q?FlXbRxe5+fiquwH7FV9/K8JHB/JoI0Y1bYfGPLnPm7TEC+nmyeaOWUjftmE/?= =?us-ascii?Q?YagU7Wt0yvDTp4U5ntoy+rDGF5LPGqmzda8S5X8gJ8z3ed3FhEkU0h0I/9dr?= =?us-ascii?Q?OU2eAX3Sj9UjfsyORnudMFzjOBW4z8HWPxrBSWX+dHqLuTVcOaI3Od44St4X?= =?us-ascii?Q?dZH4nkqaekq/879MJo6Q7LJK7LW+n7cJun6100z+hr24091lsLmDqVgHzzB2?= =?us-ascii?Q?kiT0MnPkrgQAah7+VLH+pfBctbVx019ea1VNEtJw8YQfZcM0PLJPe0OKYLKk?= =?us-ascii?Q?CAVE09q6zR95ubYZznykUcBidghITlr2mrbldfaMPkhDHUidwHyi5+kq3/Dw?= =?us-ascii?Q?rF4Q1bpelJULD4TsoV4A0rpG5gfqFgZ868iv/6gcrLplQHyLJSFDyzUZ8T2O?= =?us-ascii?Q?Ss5RLqVCx3ZdI0p//l4a+r2SjIfD8BHZgyLrDJBjikTbDkK1eCnUvyByUVNZ?= =?us-ascii?Q?9kund5PC+qV7+gmD46/Ew902TVWosjDE+xW2xK4TJDRyyilylQUxhWvzWwOV?= =?us-ascii?Q?sP0/fTJrSKRow/h24CgtVo7ohl1OEA8U3IKEjoB2O5u8mJakBaMa6ZNBNEO0?= =?us-ascii?Q?BYCyOr1Y7tBbzTe5OCWzWWtcQzAopYXLIOp+tQI50CLvM9/VfI9sVI7hqjbN?= =?us-ascii?Q?dlKeC3Y9IuO99kQc8vt73p+t+gEQ06Ir80aB1rXDiryfusA06KbY1E2FzC3r?= =?us-ascii?Q?51EQ7sYkLBAkLaQeMlzypjrHNG7Fw63r?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:CH3PR11MB8660.namprd11.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(376014)(1800799024)(366016)(7053199007);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?wKIFSVnHB/pCZfcmm2aJ/wRMD1qtYbYQRBCqEFnzjcQFJzaqRpXMHVUpokrU?= =?us-ascii?Q?0LQ4yJMKCkM8HXaqIfPI37p8hmofWKlgU0mWxyAahdGLiD3hVl48LkR5oerZ?= =?us-ascii?Q?+lQ7M1yjJpik/oMdt/TAlkdPkRz+C8ecMYbCdgLAK+MTQ0alauVbInNl9qO0?= =?us-ascii?Q?Haa7M6WOEYRENxcujT5eNIPAMIrTvilX8eplO++eIP9kHwjvZ89AO10W7N3Z?= =?us-ascii?Q?5qdrP7wRNI+xe0MSvpO0Iix3AkjZjWMqILLuEeK0pTjQxi3kqveI8KsK0uwL?= =?us-ascii?Q?17cjubxJPLXAsMV9zbdwzoSqKm06Tl1+SqNdTXertQYGOxdZEoyV5JT+D+hX?= =?us-ascii?Q?s4HZcfgqcjhUUVm4JHl+NHFZuoP/OrW9RexYotfC9vdNbSGMcfsJ9iqjIs2t?= =?us-ascii?Q?IWMOUqfSlnq+rzAZKIbGuvhc4nROq5ypLfge560hZPE1VsH9vT5kdOWRa2Xn?= =?us-ascii?Q?EEkiAxbho+EG2Mxj+iCnWl61T2lw62ypRLnduSouV68DDuVm3mAaCYeDbClk?= =?us-ascii?Q?ceXaw/WFLYjO76J080eeJ8REvsEB4noVz83cuc4xXuA9IcKj+m9ok3AmpZWY?= =?us-ascii?Q?WLxqZctl1t5hpkmfLyTisqRdcTYv/SgFEz22i0R/jnCFZGZ3QGGtwmv/vQTT?= =?us-ascii?Q?CyhVtu8/h0FuaK5TrF64YpTHoyJ6DGVSAivW8T+/TxuPEPiwOuQTtoCEgFZv?= =?us-ascii?Q?/hVG+44A024getKQlSJRAnIzlzkm+9oNoZp7ig2PFLbP9eWuxa9xK/+YEuDK?= =?us-ascii?Q?IkVXE0cMSkEnEHBuehEhK0rg+deZjJEBXTDXdMdnnSUQaE3ThSpkz5Flmp1j?= =?us-ascii?Q?PwuBsKRzDJLryHVXMtt9MsQs6LyQANo9DdFIdWvnu9LqofsqcJVdaLaMEDsz?= =?us-ascii?Q?Rmbp553VUCCyYIooICSUCTKrLmPf4cQWemS8bBzRjpwWcmTPd/YWnuQuFtKp?= =?us-ascii?Q?mjychFeiqKp7NVEa781OUqhxdW2A6IvySPM84SurTDmSSiP4M+SDjmtfD9wH?= =?us-ascii?Q?mVZbU269Tkxw2plgoCuCmHLwHn/zrc93/PdtWEW2tZsXvtMu7+vHmXMe3Zp7?= =?us-ascii?Q?kOwOvSWK82rSDBkLMVJ90ZmWI5wIGt8L5spfaxZ0oy9oC4jnSJWR6h2R3DK6?= =?us-ascii?Q?QWmD9IoWiDUDIryQHH2elY23HR2a3olLcvYgsQHh42pbGyDg3k5h8luF8Ofv?= =?us-ascii?Q?SFzS2gxhE6qE/EFXx0WfRYqBl7TnhqwxFCalWGS3tXgqnru8rNL4B2HQ+lsh?= =?us-ascii?Q?QoIw1Po3h7jvPuf4vGraTrnTwkA/VLYi4kR5iGxozXXcRMsVgve+dVeKFnTl?= =?us-ascii?Q?1siNpQ+LypRwqm/ZCbtJwDU+rikaAKEue+oHwaFMSBG0Oc8dPnbbBTn6RvGz?= =?us-ascii?Q?YeBB4NWJennpoEGT60f9i5vVrbTbjah+MMkyE5/29A9myGjq0cpPoku1/D+5?= =?us-ascii?Q?KVAeV3ucgtNwkpLyZn4JS6zkZimdqtuYILv1vF0Km7xcik8Z6ZtMTdmhpWFS?= =?us-ascii?Q?1LERwrTodDBwO9nmM1HMXBKAIyGgpVl7vU/Onbkvfk/QH5bi1gw/fp7+geRZ?= =?us-ascii?Q?qmHP0O8UQLt3CUWIusFnEJhf17JQU52Pojb93k0O?= X-MS-Exchange-CrossTenant-Network-Message-Id: 32c29ac2-b98d-40bd-bd9d-08de1b686e35 X-MS-Exchange-CrossTenant-AuthSource: CH3PR11MB8660.namprd11.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 04 Nov 2025 06:07:27.4597 (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: uy+Pu5bmnHjPossSPv2FQoWGB9R26BxGHLiqP79hGPVGk0LbXWkW6YHimXKxEvJy16eBERTeRl2T7V1RzDbhow== X-MS-Exchange-Transport-CrossTenantHeadersStamped: CYXPR11MB8756 X-OriginatorOrg: intel.com On Thu, Oct 30, 2025 at 11:58:02AM -0700, Sean Christopherson wrote: >Assert, via KVM_BUG_ON(), that guest FPU state isn't/is in use when >loading/putting the FPU to help detect KVM bugs without needing an assist >from KASAN. If an imbalanced load/put is detected, skip the redundant >load/put to avoid clobbering guest state and/or crashing the host. > >Note, kvm_access_xstate_msr() already provides a similar assertion. > >Signed-off-by: Sean Christopherson Reviewed-by: Chao Gao