From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.17]) (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 1645A139E for ; Sat, 7 Dec 2024 00:25:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=198.175.65.17 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733531125; cv=fail; b=TvJVp8KeY7BX9w4/1wo8yMRI3c5tAtRLlauadGsJrDSCSwAzYtuyH8msuIhlkXhkcKJ/dJN/xHwHUN+eD7SK+D6q2D/XW6Hh5ok/rSkItcIO4mpMzjXFMlfmfAd7XXHrSCMoNwbtQfqORL8+i3cB2sDEWxKv4CUW/GbRoWQ2yyA= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733531125; c=relaxed/simple; bh=aGfVeJ/RNOfmOswwiQmcyCJqVBWdG84mAWw2/aFx95c=; h=Message-ID:Date:Subject:To:CC:References:From:In-Reply-To: Content-Type:MIME-Version; b=cQxZl29QEnq9EamUN6BvgzA442ZFlz8w6nTkl3nlsODJRA+EGFSRR37kfrUag4kgi74TdU0v5jsO8PPy0SP2BihbXe5cBW+KU3i65Cr4Ks5yZD41XKw+Knborn/koe5sBgrjE4Rx8qCYMjtI/RtjlCAxMhYSysn5bfPEwlPIY9k= 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=mt0elPjB; arc=fail smtp.client-ip=198.175.65.17 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="mt0elPjB" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1733531123; x=1765067123; h=message-id:date:subject:to:cc:references:from: in-reply-to:content-transfer-encoding:mime-version; bh=aGfVeJ/RNOfmOswwiQmcyCJqVBWdG84mAWw2/aFx95c=; b=mt0elPjBzVGT79bdkwDkn5Ug6l55JYaVLNSavSIePldrw+fviO7W24ek qgmkM45iual/6l+N9+tS53r/3LNmYW2rzzHpTIBYxxHWH1Raw1uIIFnFY OQGFhLepsn0B/2Mtk0GUkSaeYPYfLDqqrwgLERffnQenppB12x5LKgfyr o8/9OG9SAAGPTnRawz+XhRhS7wsDmfBPFtlUPeMaCLsARbpBRIO0aWiKl Pff+yTc4TvkOzPq7e1kv7nELrJwEX5NVMlojJFsO9BMl4xqvn5SbgxhCP QiE5H11U/HPo0bdBLYz2k8+JPPZ65RUnG8H/lLiaUdHbLkI5olDPkvnwD g==; X-CSE-ConnectionGUID: rLUr4gNbRYewihxfJ+Fv3A== X-CSE-MsgGUID: Jh2jhw5jSQ6nYhVQWsUXPg== X-IronPort-AV: E=McAfee;i="6700,10204,11278"; a="33952937" X-IronPort-AV: E=Sophos;i="6.12,214,1728975600"; d="scan'208";a="33952937" Received: from orviesa001.jf.intel.com ([10.64.159.141]) by orvoesa109.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 06 Dec 2024 16:25:22 -0800 X-CSE-ConnectionGUID: GzpFRhyFSWG77RQ/Jh66lQ== X-CSE-MsgGUID: sGA9uFeSQgaT5EsHQqZW0g== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.12,214,1728975600"; d="scan'208";a="131950367" Received: from orsmsx603.amr.corp.intel.com ([10.22.229.16]) by orviesa001.jf.intel.com with ESMTP/TLS/AES256-GCM-SHA384; 06 Dec 2024 16:25:22 -0800 Received: from orsmsx603.amr.corp.intel.com (10.22.229.16) by ORSMSX603.amr.corp.intel.com (10.22.229.16) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.39; Fri, 6 Dec 2024 16:25:22 -0800 Received: from ORSEDG602.ED.cps.intel.com (10.7.248.7) by orsmsx603.amr.corp.intel.com (10.22.229.16) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.39 via Frontend Transport; Fri, 6 Dec 2024 16:25:22 -0800 Received: from NAM11-BN8-obe.outbound.protection.outlook.com (104.47.58.174) by edgegateway.intel.com (134.134.137.103) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.1.2507.39; Fri, 6 Dec 2024 16:25:21 -0800 ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=cbt3svrOHR7PcEncgVzU5bNgtLE5utbYebazAiaCKmlFcG5zkoiv9mQXhMJS7dan6M2FgPDOoDWMQ3MkTsQ9U7npAd0cchQnT8h8z97f4w0l0ld8+FBtfuegktwtJONctdxRuoeMU713GPsRzE9MmHXrZ6MGtGJhBy7CuccSXPKFNOp9RzG91nGPxqEZwsDDfSMA3/plmMg8MVd7WP2VwgtLD/cEKEOdRTDXVw1ifrhq/xzWcgql3zJ4/qkANFwmnQ9Pj9mMunHMVURhS2AMC98bVKxPmu7a/AgMzrSSEMMqbCUMJFUiFRmQ/mOAMu6JY8RozOZ2oX3JM6JNvbMNHw== 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=yV4yLAmZCS8ZICFZhEvr1O1TdfG4km/yvrZuBbCJ1cI=; b=GszNqBmQXXAmFx9y7wO4dXI8E1pEqovzlcF9A516sP74nLNVPEjVVzm4vsf00SsPUfNkwIff5dyGk45sTsIAttDv8Epx3fkjdsjiLwqg5xJIOsxc+DBlHIDv2Zt0SpKCI4S7o7A6qRj1KNmrUPt/2l5O6Kpwz2+Q3oaPsZzkW4JGVgiD2CsSvH8nuQEYHEml6B52cCiKEctCtWqWt6WFmBVcFXnSZuYb5QfTQk6MZYBxq1MgeKWajecn/oos1tWzZgYptFN5xkvOkpRC0TQY1CDXnOL168o634xwkDQp7WC3DAtUm02chJXBPSSJvYsG8wvc/XQoEFx3mjWlAoQ7Qw== 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 SJ2PR11MB7573.namprd11.prod.outlook.com (2603:10b6:a03:4d2::10) by CO1PR11MB4978.namprd11.prod.outlook.com (2603:10b6:303:91::18) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.8230.12; Sat, 7 Dec 2024 00:25:18 +0000 Received: from SJ2PR11MB7573.namprd11.prod.outlook.com ([fe80::61a:aa57:1d81:a9cf]) by SJ2PR11MB7573.namprd11.prod.outlook.com ([fe80::61a:aa57:1d81:a9cf%7]) with mapi id 15.20.8207.017; Sat, 7 Dec 2024 00:25:18 +0000 Message-ID: <3c8fa312-e6d4-41d3-8912-b35ecdf93eb9@intel.com> Date: Fri, 6 Dec 2024 16:25:16 -0800 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2] x86/resctrl: Disallow mongroup rename on MPAM To: Peter Newman , Fenghua Yu CC: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , , "H . Peter Anvin" , Babu Moger , James Morse , Shaopeng Tan , Tony Luck , , References: <20241205153845.394714-1-peternewman@google.com> Content-Language: en-US From: Reinette Chatre In-Reply-To: <20241205153845.394714-1-peternewman@google.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-ClientProxiedBy: MW3PR05CA0002.namprd05.prod.outlook.com (2603:10b6:303:2b::7) To SJ2PR11MB7573.namprd11.prod.outlook.com (2603:10b6:a03:4d2::10) 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: SJ2PR11MB7573:EE_|CO1PR11MB4978:EE_ X-MS-Office365-Filtering-Correlation-Id: 2639b7b2-a5cc-4c67-395d-08dd1655a0a4 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|376014|1800799024|366016|7416014|7053199007; X-Microsoft-Antispam-Message-Info: =?utf-8?B?MmpsRTB1ZmtKeldMdmp0ZjJhalhZRUREcEFOOWFsZUpSZlNYWkNkZktHcXJY?= =?utf-8?B?clQweE4xVWFmODBiNmF4NGNsNExZNHJlbEZQSGlZZnJjUURnMnE4WkowY0Fs?= =?utf-8?B?d1lFWFZjTnpFNU9RdGduUyt0THVZT1J5bDZOa3dETDJCbGszOUoxNzNrWnhE?= =?utf-8?B?OGNDYTZsYTRBVFluNmFrYWVsY0RTRzhLQXdVWk5aN09VUXVwLzJwUjUza0tU?= =?utf-8?B?aGJTT2k2cnVLbkRSdFVma3A1cU5iNDVPb3ZudllGWU1vQncvTWU5ZTJNNWMz?= =?utf-8?B?NmRHLzcyWXRTZWdmN3BhNFZmYXp1RGZrK0FkcnBjamZWdFVaT2c5NzRQM3lH?= =?utf-8?B?NGR6SXBsaE0waDNxcTVCem5mdWt4RXAraE50YTRab2JhSzNpR3dkeEF2WUo3?= =?utf-8?B?K2hTdlZ5UzZFWVIzRk5sRVFuQWNyaXpWQTFhbHp0THlBdERIeEIwdnhNWkFn?= =?utf-8?B?a20zTXNmQXNwZ1gvb0xSMEdqU1B4ZkRXUWlzcXlkOTVOU0ZuakFLT0pkckhR?= =?utf-8?B?UlpXV2o4ZnpISEQ5eGF5MEIzNHVROWIzOHg0ODNQZUY2VVNjdHR1YUxyRURK?= =?utf-8?B?RkhGeCtoMHJLRU5NNlJIck55UzExYXU5QU5GdWxQcVlOblpRbkJJNDlKVmJj?= =?utf-8?B?dHhZVkY0aEdGVnFmSU5WMjlJVVZwR0NPYlJnY2QraDI3azJLV1RBZlpGdDli?= =?utf-8?B?UmNzbkxwdXpvZ0FoZWhrYk95ZW5wRFErcU9EZURIM1JXRkJ0QnZoNjBJUGJ6?= =?utf-8?B?dmtuc2RYUlRuNmEvbEhrUWRhVm5PVDRMRERhWUdFMFNHTGhYcS83NlFXTHQv?= =?utf-8?B?MWp2R1N5WTFaOUdZWlpGU3QveGxKRUU2YVllNDZUa1RCQ3pCTUtLekRYbVg2?= =?utf-8?B?TDh5a09oSmQwY2dvOTk0MkpHRmhPS2pMVThXZXVuZ2dhT25qRmdoaFVNQ3hj?= =?utf-8?B?K0xqUHpVYlplTEJXRk8xQkU4QjhQTkFlV3FWTUUyNEZyZU9tTFF6dGMraDFH?= =?utf-8?B?NTR6M0F4MDlBUVZTeG0zRXBMcHNFaWxPQzk0RFNvZjNTSWt6NTdjNjhac1BV?= =?utf-8?B?UDhaRWJDYy9hWXNPVHppbnJPMEJDK0dmMGk4QVZzWkRZcVRCTTRua1g0Uzdu?= =?utf-8?B?T1hYY25tV3JjOG8zdm9PZ0RzWWx4enZiQUs3RTd0R0lDZnVwV0cxcjBYR001?= =?utf-8?B?RDVMYjZhSnJYMjNRRlRyTEkwZ1FFVWJkZ3JLUk1hUHlNUnYrWEFFT1lEZlFm?= =?utf-8?B?aWpXRzM2SGZ5QVRNTDlyWktVK3RtcGZBaSs3eUZPbUd2dURIbVJoMk1Ncnk1?= =?utf-8?B?dlhPdFpadSt6VWV3My9RNzEraGtqcmE4LzRWYnN5a1Vyc0ZPRnQ2eUlzMzVC?= =?utf-8?B?akxxWTM5TXJmQnhjMUwxUitCN0R3T1h2NlFqeWJiODlHN3A4TWUzZXhrMjRP?= =?utf-8?B?OUt2NmtBTUZNRk9CQVdmZzM4ckh1Q2dmYlVVcHZVY3pzK0Zxb0lzVlhVcDdR?= =?utf-8?B?cndiVytRYlgycEpzVkNCZTNSRmg5OTdtM1FKM2JpeXVLYVRWaFo0ODZPVVJD?= =?utf-8?B?OFZWZUhaQnA4NGdCWTllR0VpMFUrMGZKak5BWWZQRnlJQWhxZE55cXJiUk10?= =?utf-8?B?MHhDNG5PZGdJUFU5aE5RMlRmNlpJUWV1TVJad09mTjJZcGpuRU1PeTh4K1RY?= =?utf-8?B?MmtwdGRvYk13N2ZHUEVoWjBpeHF6dDBlT05MS0FaQUJiOHpxMWY2T2wvQ1Bq?= =?utf-8?B?WUJwMnpXSHRjV2Eza3J3UitoZ09lMUNHOUYzYUJKUHN5TGVnNXlzQnJEZVJ2?= =?utf-8?Q?cZn41ZzbFL+CmBR3UbtZASoL2hCcx39IGyZaI=3D?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:SJ2PR11MB7573.namprd11.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(376014)(1800799024)(366016)(7416014)(7053199007);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?VVA2MUZxa0JDenQ0VjhHcyt4YlZFakczbWRxRW5wMXk5cFVUL2FEeGdrNUor?= =?utf-8?B?SlBkNFNzS1d1MGp4R0hHN1I5ZngwMTQ3MDk3d29qb0ZHWE5wRE91enNQb3cr?= =?utf-8?B?TW9KNjU4cW1JWkJtZTRPa3ZjV0E0WmFsNVNSSCthUm1QbDJQMjU0Qk9hbFVW?= =?utf-8?B?cGwwREFIZmdjN2hSWk0xWGJ2eEI2U2dsQlFvYis1K2dmSFM1NVlEYkdKMzU4?= =?utf-8?B?Nm5MS2tpc1JQVFlaT3d6SWlON2lOaE9HSEFLR2VUMlRUblRpbkE2bGJOdlNB?= =?utf-8?B?MjlkMXhJc2dnMlQxU2FxVDdQc1JhMzQ2bTVWNlFUV1ZrbWJ4QmtjdEpPWlNI?= =?utf-8?B?N09JS3o2OTFNenVCRGE4S0hMUVBBT3BhODRSb0ptM2dZbWVhSVBhUWw3SURQ?= =?utf-8?B?OFgxTWs3UTZWOGxQWldEM3NkNTFNQ3dCMUhBeDhSTzBublRmbkZ3NUVDV2Nz?= =?utf-8?B?YUxaa2dBSUtQMmhaMWN1dTRxSlU5UHd4eEtzUUZyTDBnaVp3ekdxK2FlK0x6?= =?utf-8?B?RHBHR1lPV0ZoOVFNSzFoWTk1ZTREaElaYnVaYWk1c3R1Z1Mwd0kwVm9zWVNK?= =?utf-8?B?a0pCSWpWTlNxcGxpUEpZaEhkVDFPd0QxaEFqSEkrYnJrNjFJbXdTaTBuVUQz?= =?utf-8?B?Sm5VWXNjYTRXQ1pNeGJncXIwVDl6OXVablB0RWR4TFo4RUxsa3ljME1QcUI4?= =?utf-8?B?Q0JKZzcwejBBcEtrbkxMK2toMzBCM3dDM0lreW1JZGFvYXgwYmlQY3RXcTJH?= =?utf-8?B?K2tzbmd4YXh0emRpK1RYSHlqY0pmb0NPTjdyVlpYZDAwZ28vRHZPY0x5cXZJ?= =?utf-8?B?R01YR2NLQ1NJdnBFbTRTeUdWbjZnU01RR2Rpa09NUEwxakNlcEdGTTZ4NStE?= =?utf-8?B?d3k3U09RbDhMYUlNR2hDZGhNTk5FeFl2ckdpUkhXRXhrZzFsRnllaitGWTl5?= =?utf-8?B?RDhNTDA0SWlmUFMyaVF5b0MvMlNBTDJyYmhmNCt1bC9QV3pGQm5iNDUwQjI3?= =?utf-8?B?MEYyblRGK3RDbTdPUlJSS2Jkd0llOVRpdVZGd1NHYmlsZHVpNytVY3BjTE5E?= =?utf-8?B?WkVOVXNTTFdxeU00RnQySUNNYk5IQUhaUjNNaGZQb1VhOVFuYmZLWkNCYzkz?= =?utf-8?B?Vml4VnFFelE2WUZnOUxzWUJHdnNHUW1veEVsRjZDQmlVZWlNVmg2UHExV0Jl?= =?utf-8?B?ZWgxekFFL05ZbTUzTHpvdUh6Y2JFUDQvNFhpSVBIdEVDK3dGWVRJT1VISG04?= =?utf-8?B?QVhqNzhTaHJ2c1dxcVpaQzhUeDVzSUx1enI1Y0FoVjJLR0V4ZHlwMDY4cFZW?= =?utf-8?B?NjltR3ZGK2FSMjBYQklaK0dhRmRQMzZuck9RNCtwcFdCazg4dVU5V1N5Nm5J?= =?utf-8?B?UjZBZStqRXhPTVgwbVBMYVNTOFZjM1EvUmEwQWdUSWpGaGxuM1lTWjJSai9m?= =?utf-8?B?NllyZGljU29XdldvODk0dFpycmZ4b1ZIQ1hPL0pkVnRWR2FtSmt1VTY1VkZ4?= =?utf-8?B?Zm8rd01sdXV6N0hOSXp6eUdrMnEzOFU2UVFqUG0zcS96K3gxTGl5M3YxN2p2?= =?utf-8?B?T2haUnlodGl4QlFaOVhtWDd1V25BV0NOeWNVQ1JtSTc2aVU4SnRvMENMRWpL?= =?utf-8?B?aEpjWUl2Rkw3bDB1UGlMU2pHd2d0QjJzTjErcnB4M3FRbnNralRFbTNUNmpF?= =?utf-8?B?Q3BtaWNMN0hzTlNBTXpuZnZyUDQ5eUV6WTRnRDZiWWVScTVEOXFrTVBLZk9o?= =?utf-8?B?LzVJbXlDaWdHRkM0V2lWOUVzZWV0TDlXSmJpTXBYSHViU2VIVE9QeVFzT21V?= =?utf-8?B?OVRkK05lTDN5bGRTYUFlV0xpcVZ1dFF5VUdvTVlheTU4bmhjYXRPNnFLZi9w?= =?utf-8?B?bnBsOGdqNEs4UytZZG9HK2VYbUc1S2lJRUFpN2lIRWxWbHJ3ZVRxOHN0ZGdT?= =?utf-8?B?bHdOcnJaS1VsZmpOR3c4TnZjQlJSWTg2UjZlNlZibVJMbG5kVFVKLyt5NHBP?= =?utf-8?B?ZzF4VUszTlhNMWkxdE1DVGpkSDU5aFp6U05yYkZSMS9nbTJQemwycGdZb1d0?= =?utf-8?B?NTRyVGJ5TnJwM29ZZXZ4QjNqOFdmTmRyT2ZSWVNLZXVyNFVxUjd0K0hOWTNa?= =?utf-8?B?TTdUQTJqZlhObXhHUld6SFFTTWg5b0xCZk5kcU1DeUNsNk50cUlpai9TLzV5?= =?utf-8?B?d0E9PQ==?= X-MS-Exchange-CrossTenant-Network-Message-Id: 2639b7b2-a5cc-4c67-395d-08dd1655a0a4 X-MS-Exchange-CrossTenant-AuthSource: SJ2PR11MB7573.namprd11.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 07 Dec 2024 00:25:18.1497 (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: D9aTkouHwewt3EUZi1JjSkvnMUKHdIOci8ZzBP84cfAtoYr3UWY/cBupPoNchNRNgjLm3rkeodjutShrTxebQ2AJDDWZdwM6gteBD9kWNo0= X-MS-Exchange-Transport-CrossTenantHeadersStamped: CO1PR11MB4978 X-OriginatorOrg: intel.com Hi Peter, On 12/5/24 7:38 AM, Peter Newman wrote: > Moving a monitoring group to a different parent control assumes that the Should "parent control" perhaps be "parent control group"? > monitors will not be impacted. This is not the case on MPAM where the > PMG is an extension of the PARTID. > > Detect this situation by requiring the change in CLOSID not to affect > the result of resctrl_arch_rmid_idx_encode(), otherwise return > -EOPNOTSUPP. I think it is potentially confusing how the changelog jumps between different architectural acronyms without introduction and without noting how these architectural acronyms relate to resctrl. Consider something like below: On x86 the hardware monitoring id (the x86 RMID) is independent from the hardware control id (the x86 CLOSID). On Arm the hardware monitoring id (the MPAM PMG) is dependent on the hardware control id (the MPAM PARTID). resctrl associates the hardware monitoring id with a resctrl monitoring group using the x86 "rmid" term and associates the hardware control id with the resctrl control group using the x86 "closid" term. User space can move a monitoring group to a different parent control group. This results in the monitoring group's control id changed to the new parent control group's id. This is safe to do on x86 because the monitoring and control ids are independent, but not safe on Arm where the ids are dependent. On Arm the destination control group may not have the original monitoring id available for use, and if it does, the monitoring counters associated with the new control and monitoring id pair will not reflect the original monitoring group's data. Use resctrl_arch_rmid_idx_encode() to detect if a change in the control group id impacts the monitoring id and prevent moving a monitor group to a new control group if it does. Please do correct and feel free to improve. > > Signed-off-by: Peter Newman > --- It may be helpful to add in the maintainer notes that there is no Fixes: tag needed because MPAM is not yet supported and thus this issue cannot be encountered at this time. > v1->v2: > - separated out from earlier series > - fixed capitalization in error message > > [v1] https://lore.kernel.org/lkml/20240325172707.73966-4-peternewman@google.com/ > > --- > arch/x86/kernel/cpu/resctrl/rdtgroup.c | 13 +++++++++++++ > 1 file changed, 13 insertions(+) > > diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c > index d906a1cd84917..8c77496b090cd 100644 > --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c > +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c > @@ -3888,6 +3888,19 @@ static int rdtgroup_rename(struct kernfs_node *kn, > goto out; > } > > + /* > + * If changing the CLOSID impacts the RMID, this operation is not > + * supported. > + */ > + if (resctrl_arch_rmid_idx_encode(rdtgrp->mon.parent->closid, > + rdtgrp->mon.rmid) != > + resctrl_arch_rmid_idx_encode(new_prdtgrp->closid, > + rdtgrp->mon.rmid)) { > + rdt_last_cmd_puts("Changing parent control group not supported\n"); > + ret = -EOPNOTSUPP; > + goto out; > + } > + > /* > * If the MON group is monitoring CPUs, the CPUs must be assigned to the > * current parent CTRL_MON group and therefore cannot be assigned to > > base-commit: 40384c840ea1944d7c5a392e8975ed088ecf0b37 The change looks good to me. Thank you. Reinette