From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from NAM12-DM6-obe.outbound.protection.outlook.com (mail-dm6nam12on2064.outbound.protection.outlook.com [40.107.243.64]) (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 25EC31A0BF3; Tue, 3 Sep 2024 23:40:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=40.107.243.64 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725406828; cv=fail; b=iLHBhLnj3aZdKC2Qo45W2m5eAxOJU9HuETdgCLXtJk03ySw3ITmlO7SyhOBNsbfQmLKhOvDAlrXc20aOc2R+JyTvI6K2gbqeJzgbCljnfd5V0XEqbRbz9RmWcPGFdKxIf6BEjSynqWswNPscbOajI/AoUI7aphHXj4vn0/8oC5w= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725406828; c=relaxed/simple; bh=2e3WShGXJ8Y8Phf7wELQT36rTqUpsFm4bRlmz4VkpYk=; h=Date:From:To:Cc:Subject:Message-ID:References:Content-Type: Content-Disposition:In-Reply-To:MIME-Version; b=GLT5oKl6y5TTI5WV+7nSEx+7RiPv7kU1tW3n9SzjbHZ/Co9E8skq1LMF86QDEdTvG/cqVb6GGUIx35EFp4INy5n82LMQahHOw4ostsleCDmElGgHU2NfZCc4T8HXd1lrGLKjOguAu6qAiVhI8J1wXUeRxydpJTdTqoiTO6EoddM= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=nvidia.com; spf=fail smtp.mailfrom=nvidia.com; dkim=pass (2048-bit key) header.d=Nvidia.com header.i=@Nvidia.com header.b=CYBWDvd9; arc=fail smtp.client-ip=40.107.243.64 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=nvidia.com Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=nvidia.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=Nvidia.com header.i=@Nvidia.com header.b="CYBWDvd9" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=OJPOt3JPDhTJ/0qmJn16TaOXBumPckb+/z1G6LssnL6AnZPkSWkOG6IL0v3eie0ctkwhoudM5rmdqP6GIxYvbtezmJ6Nzvn7nCGsnu1F3PIlMZnl+J8rojnf3y7G8u7drEyFcEh8XXXzEVEXJO4bVYMU2AZb9YETu/QiLgmCizZ2dU02TENL6UHW/wXv2hTfvIgyGJ3su/nhkL/QmFEMMLSb2jE+3K83NUG9vJ9GEw+LVU7CdO9fbYY6fEYcKwWBt0j//Tdtuv/0wOYIkjZJtwbPh2MJPUVbxAkwt52XsP7Ahqxse+4CY8scZ0t/0kz4HXw520pFp0GqCCqKZvfnpA== 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=kLfkaWwhL0u0HoesGrlpfpS4OFom8Xrl30Mci1SwY5M=; b=psJTHrKdjd0XoEno6pQl0VGKu9xBSzkPsGSHTZJVJyM9IR5iNdUOPCJvjiHTK0B+2GJrQMTmL2lqPHKg1iRuLmotNVyEQlrYS3N/3S0R1W09tZJZfcKCBcAXDuZOeUlA+xoAmbfydcbsK9TG+beApmFCWGiLitswPS96JHFxlFPSJdkxGkKgUErdQflZj5FbUzafUNsTDHIj8EuRWZZoW/Px06hS7FgHcEH3TByM0GHBuxkz6gB+eDhmgyMmY4rQ9W5Tq1DLHXVZeganz1LFv5HVxiUaLdWEmki9KMjMTZrZMPRo2HaxsN1/3kyGVnFWuiHYu90W/QWZJ7ClUd2Aog== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=nvidia.com; dmarc=pass action=none header.from=nvidia.com; dkim=pass header.d=nvidia.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=Nvidia.com; s=selector2; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=kLfkaWwhL0u0HoesGrlpfpS4OFom8Xrl30Mci1SwY5M=; b=CYBWDvd9y3lA4a2rq7YO7nwlUo6XKElDrrnxaMHDRcp5cmIAPr1vqpMXi5YdnsC2ZVfYS2qRKHu/QJ2fVnhyJwiG0tcD8O99JxIVO60prGojHqOvHXIwiS94Q1AbPiLjAQz+pIC38KKmO7AYI60D8XJ37nQiFpluucH2L8XRrKMBRRAxoEg2mhVRLCR00Qn6fuPxxyFxw7E87aifQeK1cCXzqkzlPYJPYeyyThqgy8G95Y7IKMCj7cOrtnoRJhacI/EKz1hyVYrjsdCPvPeMbw1T4RVai0plnnIo+7brGtX3TRF6qm3QD1bzcNfmAOp6ismCtZrR/ihW+tqWKhMkhA== Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=nvidia.com; Received: from CH3PR12MB7763.namprd12.prod.outlook.com (2603:10b6:610:145::10) by CYXPR12MB9278.namprd12.prod.outlook.com (2603:10b6:930:e5::11) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.7897.27; Tue, 3 Sep 2024 23:40:19 +0000 Received: from CH3PR12MB7763.namprd12.prod.outlook.com ([fe80::8b63:dd80:c182:4ce8]) by CH3PR12MB7763.namprd12.prod.outlook.com ([fe80::8b63:dd80:c182:4ce8%3]) with mapi id 15.20.7918.024; Tue, 3 Sep 2024 23:40:19 +0000 Date: Tue, 3 Sep 2024 20:40:19 -0300 From: Jason Gunthorpe To: Mostafa Saleh Cc: acpica-devel@lists.linux.dev, Hanjun Guo , iommu@lists.linux.dev, Joerg Roedel , Kevin Tian , kvm@vger.kernel.org, Len Brown , linux-acpi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Lorenzo Pieralisi , "Rafael J. Wysocki" , Robert Moore , Robin Murphy , Sudeep Holla , Will Deacon , Alex Williamson , Eric Auger , Jean-Philippe Brucker , Moritz Fischer , Michael Shavit , Nicolin Chen , patches@lists.linux.dev, Shameerali Kolothum Thodi Subject: Re: [PATCH v2 6/8] iommu/arm-smmu-v3: Support IOMMU_GET_HW_INFO via struct arm_smmu_hw_info Message-ID: <20240903234019.GI3773488@nvidia.com> References: <0-v2-621370057090+91fec-smmuv3_nesting_jgg@nvidia.com> <6-v2-621370057090+91fec-smmuv3_nesting_jgg@nvidia.com> <20240830171602.GX3773488@nvidia.com> <20240903001654.GE3773488@nvidia.com> Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-ClientProxiedBy: BLAPR03CA0130.namprd03.prod.outlook.com (2603:10b6:208:32e::15) To CH3PR12MB7763.namprd12.prod.outlook.com (2603:10b6:610:145::10) 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: CH3PR12MB7763:EE_|CYXPR12MB9278:EE_ X-MS-Office365-Filtering-Correlation-Id: ec7053fb-b25d-4d6d-a08b-08dccc71c588 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|7416014|1800799024|376014|366016; X-Microsoft-Antispam-Message-Info: =?utf-8?B?TVNXb1lucmdQM09JS2JHMXBad1ZvNEtzc1B6M0pkVnBXbEt1d3RNOUZ4RHo2?= =?utf-8?B?Y0dETnMwNy9wVDcyT2lyVWxBMVRuYmk0dEhoVlhBVXZGMFNManlqM2p4MnlP?= =?utf-8?B?WUJkS0x2ZTlQbFFZODhnWDdmUTBENDVSZWlrQVlMYnZFRTZYU2VKVWJ1OHo4?= =?utf-8?B?dnUvUllxTFNhWFo0UlA3STRoOGw3azNNNmdaZ0ZiaHJYWVoxbkdsY1IvME9v?= =?utf-8?B?bk1FMkplL1NvbnJHc2lMd1UrQXViczJHcmszaE04WTZZMzhDSEhCWVZ4UXZo?= =?utf-8?B?VlNuVWtpcGw3bWR0ZEZjY3RTdVNIM1BRc051ZVVXcERHUzF3NHJwQTR4U2wx?= =?utf-8?B?T2czMGxQc0NWRGdwRDJrakxhMjdnckpLTGRyRHhzdHJDQUErMFpFTHpoUXN5?= =?utf-8?B?aGFDdjUwa1ZTNkpNcHRTWGxiR1k5NGdpWDRxa0tycTlyaDZRaGxXaU44TWFz?= =?utf-8?B?REdKUmQ4NGY4VVJxUmJiRGQ0dlBoWG5tbm1hUEZRWWtXam1BaWtiUHhGYlZk?= =?utf-8?B?aHZFQlRtR3QrZmpSSFJwM2VORFlGNG82R3RZNU5vayt1Y0hRV1luTGVJQVUr?= =?utf-8?B?eWZ0eFBXeFk2dlBqdm53M3hvNTZuYk9JY1RydUNqZG0wUTV3VkpxRWlBcjZh?= =?utf-8?B?RUpteE92ek53cmNlZElGU3NkaFN2TDZINnh2Q0VBdFMyaExUa2dUd1dzMm0w?= =?utf-8?B?TXY3Lzd5RU41d2pLa0VnR21kNDJhU3Z1UlI5cmFVemIrbVFQbXZIT1IwS3Rh?= =?utf-8?B?dWVSOENpM1UyajhyaWpBazUwWEQyR0dnVXFFOE9aUW1ObGNxRGpDdHk5SVkr?= =?utf-8?B?SENaQmdISHlTdStTQk1EL3I0NjdsWnRQQVhxQ0F0WXVrUzgxYWtlVHRSYlpa?= =?utf-8?B?aVFMNmd4OHRwZVZzajMvamdpNkdDV2VYRFBQMlVyRmJmMGVGbTE1czYvWHkw?= =?utf-8?B?RUFtK2pCNHdacWNJa1VINmk0aUI2aCtuSklGMWE4NWEyUkwwZTVUcVZrZml5?= =?utf-8?B?bWNVMjRqVEpBMFhIYWFyVmx0Rk9idlhZWEhIblc4ZWU4a0l0YnJaMWNPbUpp?= =?utf-8?B?bFMwekNTdVIxNGtVK0djOU9hOEovNVBJdXcxcFc1YzB5WXFYZ2pyb3B4dHBl?= =?utf-8?B?cU9FSEVMNXJSOFdrYkZRTXc3ZERzY1d1eklybVJMZXBaRHhFdFFycWppRWVN?= =?utf-8?B?cGFFVldKSHFKREFPZVJneVBPOTZQTzNheEJERUdrT2tJcFJZZEJFNzZhOWkx?= =?utf-8?B?dnJNRVJGSkNja3Z2TWhlMml2VjJ3SENVVDU4ZmhaSk4xZzFkamFwNzBCZWRI?= =?utf-8?B?TDBiM1lvZVhESnZ3R1F0VWhpZzg2RmdDRkNzOXc4SzQ0Z09wYWRUL2c5Vjhz?= =?utf-8?B?ZnZoSk56aXlodTlLVGhxVEtDUzZxemIxTWVKdEk3aGhsZkEvQ3FXSGhLQ0hz?= =?utf-8?B?VmV4SjVZZFFCNVBwRmlScDJoSXRmWEUwbWxEQkxZaHlCOUQxanZzM2hYM0VJ?= =?utf-8?B?b0Rlcy92ZStIS0ptU0FyOFBJb09ZMGtPeFFkcmFSOU1tbDRzdTF5V2R1aVJK?= =?utf-8?B?dWR5K0FjcndraTRZSlREd3RjNllTSERGcUR4SEw5cXlaTm5Gc1lpd1hCaEpR?= =?utf-8?B?TC9RVUpnemVlN2hvRnRDK0cyak5HN1NFSkwyRjZPc1h3akFVTmNLdnFNWUwx?= =?utf-8?B?VzZ0R0ttUXd4TUZoK2JjQ0t3TzJxcHN4ZU5NVnBTSndYaTN1TXhVTUNvOUVB?= =?utf-8?B?SXR3S3JRNDFIV3VLb2FkOTRwY0srOThFdzNqTnlUcndCMWozYWQweGsrRTJq?= =?utf-8?B?Uzk0UjFYRmE0MGUwbFZoUT09?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:CH3PR12MB7763.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(7416014)(1800799024)(376014)(366016);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?UGgzSURRVjJNV1REUTNzaGJieWxPcGFBazB4RHIrKy8wUUVyTVM1SHorR05F?= =?utf-8?B?aG95MHRUblJYUWEyNS9lSFVGUG1xWVdGYUdFZmFiQVh5WmZCQjdUWmFpOURi?= =?utf-8?B?VkxsdW0zVm1tYU1Vb2NBOFdBc1gwbjRPQW9sclR5OWNBU282d3RiYkQ5RTBs?= =?utf-8?B?SG9NRld5Y1ZFSGpPaWtZUzRSeHpub29HM0hMbG1PTTROTFI3b3c4Z3YvM1dw?= =?utf-8?B?UmhJelhoZExSdldIaWw4M3AyNHNtdEVjNlJxcVJlWVVWdHBSQUNuNVpVaFE2?= =?utf-8?B?Mkw3U1JiR1dqVUcvRHdldi9VNzFoSXJzT2QvSkFlV1NSaDlJWnRsdUcvYmhP?= =?utf-8?B?alFmRCtlekZwR2lNQmRQL3pIcWxPVjhESHJzOEM3dlBjNVJ0SDd1STlZMHY5?= =?utf-8?B?emp6WkdlNzlRMkFwMThWaTNHVk01YWQrd3hzeTdLaDJGNGE0RlRQdi92VmpF?= =?utf-8?B?bnlrMTB1Ym5KM2NpdE1PS0dTcTRhYitTM1k0aDAwNnJNQnVOcENRcVJ3L29O?= =?utf-8?B?eG1XRzJkSkZYUU8yWldKeU1SaDMxazVtam8waVRqbVo5akNlSUgzUk9PZ2lN?= =?utf-8?B?MmJSWWJtTC9UajZ6K3Q1eEtZK3ZxZGhvUCtEQm9yRTA5bDV6TG95SlZlaDY5?= =?utf-8?B?WVY4U0FHQUNhY085RHh4UUpjRFZCMTl4emhlWWlXR051cXovdk04TkVnaWZI?= =?utf-8?B?TmhDdjNTVElRY2FWQ0RZa1FocDRZelRIc0RzbFFPVlJoYzdGbFNLZ2s2bnov?= =?utf-8?B?YlJlVnlhM3lDd0RXV1JSdDcvcVp1aU1uWlVlaG5RSDNTLzFYcFJJR3RvRHgz?= =?utf-8?B?SDJ3Y0laczVndmZDRzBZbEZhMHFDNlc5TnpDcFVIV2ptd21yanVWMituUGhZ?= =?utf-8?B?cXJXV2c1cjREQjZVZWwzS2ViYUdpaGtTQ0ZWNmJIOEo2ZnN2b3RLWmVrUUJ4?= =?utf-8?B?WVJUcm9NTGx2QTRhQjl0U0FuUzUrRGhKRXBwcS9jVDNlMlJ3WkJ6QVZ0U2I1?= =?utf-8?B?T2xHU0QrVnNjbnNVeFpvSGN2Tkg5RlhabDhMdWNvdGtVUEpEanZWaWhhSzhh?= =?utf-8?B?RFkwSHRpQ0YzdUJRUlBUNm1SVnVKbGVkWTZGTlIwNEF0bHJlSjZaa3pKV290?= =?utf-8?B?STJHbitkVmc1L0d3MUFMOG5MRmlteUJvYXk3dkt4eHRxVlRPU3luL1dPV1g3?= =?utf-8?B?N0ExdHlrZU8rbU4vRmM5a1FRZWlFQ3NkcDNUcG84dUE5ZGo2cU1nUGUvUnd3?= =?utf-8?B?NjMyd0Q3VHhJOGphTks3aVIvcDRuejl2Z0loZ3hhZkFRZGFPZTVZbW9uVkI1?= =?utf-8?B?RWM1NTVZaUVLejBTOG1kaFJjQjMzd2N2UWtteTdOSU9kdWFrK2FsaDhVdkNN?= =?utf-8?B?aUs3ck4rQ3YxSmY2RGd2ODR0ekFjd1hhWVladXJwY25YbVZ2K2xYbGVBUGkz?= =?utf-8?B?SXEwMld3MlZ5aFhHN3NJTTRKZlhRaHJDTWhsV2ZCTmR0QVRwT1h1TE4wRkhi?= =?utf-8?B?eXlDWjhTQml5N2hzeUVMcEVYSFBMSE9iejAxTGNJQmdUZkZaaUdZZVNDOE4y?= =?utf-8?B?Q3pieXJnMUhYMThmcFliUERsK3ZxekVuNE80b25aNEtDQ1dPdlNDMjZ3WmFB?= =?utf-8?B?amVOakdqbUJBR3dab2lWN0tHQitMbXlzNTRCR0ppaEdKc0hIVjJJSEhYa2kx?= =?utf-8?B?c1UxbzkyalhUbktIT2hPRys4SWhNMlhEa0J2eVZkUkpKTnVyTXJPZldjemxl?= =?utf-8?B?eWJyTExBNGxuWHM5SnVFM2pNaG1lQXlUbTVuVUw1UmhNbm5GN0JPMFg1MTVq?= =?utf-8?B?bGU2VHk0K21VMThjMHdqYlZwZGhmVVBmOVdKM3RKd1RWeFozR0t2Mk1sbStl?= =?utf-8?B?VHNDd1RTdnU4YmxtTGYxdDQ1WTVRUkVtYm1RQXBkaUtHNW1CdTlCd2tRM0ph?= =?utf-8?B?QmNWSUJPZkYyMGFLWVpaMGpMZlNLTGRKSlFxcTFTM1V5NEtwSnZLR1pJU2x4?= =?utf-8?B?bm1NeEM5NzRxQTZVbktadk5FZ1FmM3ZoK25odWtpeDR3ZFIxVDcrc1FBVDlH?= =?utf-8?B?elBJNVJSV1h5QnlOby9RN1A1YXR4eEd2cy9KcUtWU1A3c0V0SDBCZWJoQU5Y?= =?utf-8?Q?5GQrjPvi3uSiZzcBhEc3L7tzi?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: ec7053fb-b25d-4d6d-a08b-08dccc71c588 X-MS-Exchange-CrossTenant-AuthSource: CH3PR12MB7763.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 03 Sep 2024 23:40:19.8362 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: T9gkTZtcuyVxFv+wkDD52Pahk4GttFPpL1VtWGXgnEwajjklL9CwZyZDrCABa9We X-MS-Exchange-Transport-CrossTenantHeadersStamped: CYXPR12MB9278 On Tue, Sep 03, 2024 at 08:34:17AM +0000, Mostafa Saleh wrote: > > > For example, KVM doesn’t allow reading reading the CPU system > > > registers to know if SVE(or other features) is supported but hides > > > that by a CAP in KVM_CHECK_EXTENSION > > > > Do you know why? > > I am not really sure, but I believe it’s a useful abstraction It seems odd to me, unpriv userspace can look in /proc/cpuinfo and see SEV, why would kvm hide the same information behind a CAP_SYS_ADMIN/whatever check? > I don’t have a very strong opinion to sanitise the IDRs (specifically > many of those are documented anyway per IP), but at least we should have > some clear requirement for what userspace needs, I am just concerned > that userspace can misuse some of the features leading to a strange UAPI. We should probably have a file in Documentation/ that does more explaining of this. The design has the kernel be very general, the kernel's scope is bigger than just providing a vSMMU. It is the VMM's job to take the kernel tools and build the vSMMU para virtualization. It is like this because the configuration if the vSMMU is ultimately a policy choice that should be configured by the operator. When we consider live migration the vSMMU needs to be fully standardized and consistent regardless of what the pSMMU is. We don't want policy in the kernel. Jason