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 lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 8C91AC02194 for ; Fri, 7 Feb 2025 12:54:19 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1tgNrc-0001Pd-G1; Fri, 07 Feb 2025 07:53:44 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1tgNrH-0001Ko-Ri; Fri, 07 Feb 2025 07:53:26 -0500 Received: from mail-bn7nam10on20610.outbound.protection.outlook.com ([2a01:111:f403:2009::610] helo=NAM10-BN7-obe.outbound.protection.outlook.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1tgNrF-0000mF-Ia; Fri, 07 Feb 2025 07:53:23 -0500 ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=s8KQBuBB2nDXDXvBFx1rLNOMzUcB51eTQ/gAR4HcLQ20AKfIXjwUiBh7KUAgJkOkYFh79pm/Dp9B9NyrcC2b30MUI4GZE92x1ZhZbgb+Vg05c794PSI4TfKBKQgR49hOhNaoQxR/WFEDy81TNE+tzUgoFJr1CGHWjlWGTERSOlgOHqOM4iOoXKxWRAJxnqJIbocSkH/1qxqsP704yjDHq/GvqjwMAuUHeXYTqpymSUNOZkOY24C20rMUkh7pWn+eBZkxEVzh3Qcxl+nOzWmusFGx/+pDBCg4pCj7x+VFrTgjFHoFFs8xirDVmU6qkHw234nMwrbQVJQCqecOOio1EA== 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=cuk/dfmyJA2/jcB2matVzFgwpGssMj6j/DoBaiPkRME=; b=olP9uTWNYrhok52VejduVZEgw0S8UWSNoGD24+fyA9kFQZ7eiQt9cVVZ21Bo2eyV85phCH/Rwi3/wkKO1wa5IdME2CIUdJqA9RZAkrxciiEoWa1e4DIzHPahKdq3XSyIt5diQWEw9S/6G3A39verVqTIrgrnGauHLjFQPe9g9TnMOSn46a3ZN0awGC3ipyJwpWe08p76g2IjBE1hz9Fhw+xNhcs5t6gMmm8mjzTXzaXf+9omGk2h5munzpAjeFa02HP48kpBxB9fsm9aIt8IdG3tiWGqpsktaxmhgnLJomxdw8vs/kTkJYiDbzJ0qPbPoMXiFyacd6fbv0m3iTTobw== 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=cuk/dfmyJA2/jcB2matVzFgwpGssMj6j/DoBaiPkRME=; b=mSMpvPlOeFt2uIR7MmHUaB3lVpgfypiAdHjVB2sb5zfoSyerQmXtG7jdOP2WIiKfg2vW3xsLOslMB4Ai8A6/KPHe73In1SlQCVHqMW5SGRjrQNCYpoY41pXxtA0DYiPUVkw1MfS4KovsXMIVJTwIeYPC6YWKVMh+YXofgp462Ma79Z+Y4wBR4LBRLEczMDvBO/aNDUZ5hbWeUVtTGIg8mGW8V8yv4LyZZzCVJQmZobYjGNaPE9Mueq9NVvIjBz/F2aacGHm+iCvpo0H1cYtJ7bKerI5Q6ibkbIP4wfYxaslucUBw7siFIk78m4hGXtmcFTlC+TkTQCBp1i+uROx2Ig== Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=nvidia.com; Received: from CH3PR12MB8659.namprd12.prod.outlook.com (2603:10b6:610:17c::13) by CH3PR12MB8512.namprd12.prod.outlook.com (2603:10b6:610:158::19) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.8422.11; Fri, 7 Feb 2025 12:53:08 +0000 Received: from CH3PR12MB8659.namprd12.prod.outlook.com ([fe80::6eb6:7d37:7b4b:1732]) by CH3PR12MB8659.namprd12.prod.outlook.com ([fe80::6eb6:7d37:7b4b:1732%6]) with mapi id 15.20.8422.011; Fri, 7 Feb 2025 12:53:08 +0000 Date: Fri, 7 Feb 2025 08:53:07 -0400 From: Jason Gunthorpe To: Shameerali Kolothum Thodi Cc: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= , Nicolin Chen , "qemu-arm@nongnu.org" , "qemu-devel@nongnu.org" , "eric.auger@redhat.com" , "peter.maydell@linaro.org" , "ddutile@redhat.com" , Linuxarm , "Wangzhou (B)" , jiangkunkun , Jonathan Cameron , "zhangfei.gao@linaro.org" , "nathanc@nvidia.com" Subject: Re: [RFC PATCH 0/5] hw/arm/virt: Add support for user-creatable nested SMMUv3 Message-ID: <20250207125307.GQ2960738@nvidia.com> References: <20250206175843.GI2960738@nvidia.com> <13b1d8b97a314cb28b87563fa9b45299@huawei.com> <20250206181306.GK2960738@nvidia.com> <02a0080a4a1642d69b7f5dd4707a5b3d@huawei.com> <20250206182201.GL2960738@nvidia.com> <9112ba0694bd42199e279e37fbfc9dd0@huawei.com> <64a4431fca6f429782a78c9740eadbe2@huawei.com> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <64a4431fca6f429782a78c9740eadbe2@huawei.com> X-ClientProxiedBy: BN0PR04CA0177.namprd04.prod.outlook.com (2603:10b6:408:eb::32) To CH3PR12MB8659.namprd12.prod.outlook.com (2603:10b6:610:17c::13) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: CH3PR12MB8659:EE_|CH3PR12MB8512:EE_ X-MS-Office365-Filtering-Correlation-Id: 8dbf6ad0-e344-4df8-d841-08dd47765ef9 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|366016|1800799024|7416014|376014; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?IyPx9GSHkDA+0d9AT3aHqjWVlcKilWlrxuy2M1LZfHZDuaqSe4IK2+ai/k6B?= =?us-ascii?Q?yu6CAqA2wp5KeqxGQmpcoBuLr73Y3Cu12TzuVq3M6eX1UMDCxWlTvvOaNr9J?= =?us-ascii?Q?/NlECPXgiFgvDayrDBD80xRuST/TMP0JNssDm+YK3em4VW29Mm/Gr1PpJlv7?= =?us-ascii?Q?8agNIsp91fQ5IgFpsnpHW9ZDvjWLSLEoBhd6VdBl2G6uXIXd2dnd3aIH4D42?= =?us-ascii?Q?3Ba50Z4zsFFKIaeSyx2+vk8+voFxSS1H9ElkZL39QsNmUNsSa/MttA0OzXFu?= =?us-ascii?Q?GPrepc2P7WPB/C33f62hoMgHVAibE9qRArXnOPcYuu4bb641Xv/zpWeTja7A?= =?us-ascii?Q?06wIDhpw6+j5W+KYytCCeRmiTesb3QkXmHiRczgH29zihcwsiiZsnEoYTdOL?= =?us-ascii?Q?gyB8eEJ+0zOy4J+FULyoAw2e3814VSa1X42ILYrygFV+e/de+a5Z+FHH/5mW?= =?us-ascii?Q?BAaEeo0vREHUxlKZhuj0NLyVK/XtCWJA6l/4yph5p3KS8YGvGUscGyE5H4kb?= =?us-ascii?Q?gIMl+sjJNcX2RGbJLlzmioNYmb01gFXVPZdyw0940OhI5gOAcXfxCPudFTZb?= =?us-ascii?Q?jWaxT1LZWDq0QgIc//tYHu3/VzSkvR+GnyRDiGorBafl1u4pgY334GrUvWja?= =?us-ascii?Q?hn5ls7Tnf5wpe5Ca7AOwwQQ+KMPa5XtXZYcx3vkhnxM51lnbWk2a4N4W589s?= =?us-ascii?Q?wmkUJ2VcR6b5iQdhM1ZTCYXxnI3LgwHYTNasmrAXSgSDNWVc8D/LCBELJzX2?= =?us-ascii?Q?s7K95JDDfr1RNVnPVc7XsYYUL8PjYCzzYOYxRC/xO3aMKIMU6nhpvPDfpx3V?= =?us-ascii?Q?x8fJZpLlaBOl3vSaSW3d7Su6TaiDYt2uLNM6MREDwy7+RHs5BuGj/2Z94g/B?= =?us-ascii?Q?05v2UEqTSO8ZFsUvtgnaN15f7FKAgxSc1UV9S4A+jbcy+nVzCXjz0Z+unHg7?= =?us-ascii?Q?pBO1kI2TarijKMOQ1EydT6j6TIm7+L4nA/Wwkzzc3zfuAwX952jnonnDO+wh?= =?us-ascii?Q?MoYkgveJtpbfwCeG37EQgQhXuXEVkvk+yLbaM0NL3ckffq88Q0SpMrW4FOI5?= =?us-ascii?Q?/dXfCJOUVSzrsa0goPdTxccUrCu3KLp/h2/Fqbj3051h/u2ml8+m3c4/g3bS?= =?us-ascii?Q?ytRIx/z2LL3LUSEgwYQM/+ify/Dn36K/VFZdkGJLwjuofBDl7UbAzCVL1Tde?= =?us-ascii?Q?Zub2z9DwZZeFqEwWDBF8yyxod68h23z4h6RRN7k4HmRTIkQhjd2YDTZR8Jvv?= =?us-ascii?Q?HQPHK70TrOP1P7MMDi0mtBSSBHz/FdZQeU0QSvRYgbPvxtxGY17SLHJpwrju?= =?us-ascii?Q?ei3ZAI2xglz7fhWixaQm332uizMrw4/ltGvYRgfU215BplzMkH1jv1Z5WDBz?= =?us-ascii?Q?f3XPS8MDMyUmFVpPEkJ+Z1V0/J7G?= X-Forefront-Antispam-Report: CIP:255.255.255.255; CTRY:; LANG:en; SCL:1; SRV:; IPV:NLI; SFV:NSPM; H:CH3PR12MB8659.namprd12.prod.outlook.com; PTR:; CAT:NONE; SFS:(13230040)(366016)(1800799024)(7416014)(376014); DIR:OUT; SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?06hwFRpIOhYILH8TY6xVzxmtZmGvuUZFzQEUUl6YZaPhAZdkuFRpulklFzJv?= =?us-ascii?Q?2ChFKUIJYcRD4gCOhnOZhMPY/esKUAyxQLU+27TnJ3Hm2VBQ2Imz+2aJ/U+z?= =?us-ascii?Q?dKV4TGBDCv0tseogweRSQ9TEDM5VEBr0ktTwNvs0jhkHnMnVIxleJMsD8JqM?= =?us-ascii?Q?HzybouFxBwaUnnJh3WaTlapaFiFW+NOiF82VLYWXepGfLWx0dEUPA/u5Rism?= =?us-ascii?Q?Xao8ShiwsgHwlkviWM8uJCV9hSFfoVgjpzzJlQj2V0h/RarP8ciKYqvy2C/B?= =?us-ascii?Q?97/Ik15KUcr+xPnS3DaZa4nzyHa3ItbzvBGYSkvSHxuhrl2jWEdRTCgnXRwD?= =?us-ascii?Q?5xLzvDTm1xh7vtnXmXyeyb0JpdTGNR8ydXnRYXv6gcTThs+sML35piuPwszb?= =?us-ascii?Q?Qq5XC778WFhicScuG67bGesnV9S4keoH4BhLhPpaPawQuX90xA5JtSckdWnS?= =?us-ascii?Q?l0/zcEOCjyUGId/S9Et7O/pnkt4bZv9be5gYgBU2NoFZovFZUc/72EGmldcK?= =?us-ascii?Q?OavEL2ozQzoifbFO9DaotYHOatyGCnQoJzix7Ge+v5LaiC7sYaFohF+h/K3k?= =?us-ascii?Q?UQujJ7VlohNoltmdPrEb4Ye26MHhkisqAO83OiVp3VR1ar6o9zuSuarVdq2N?= =?us-ascii?Q?KQ3J9SpTlnZU+gGqblj3Amb3bfc+l7WIEm47RVRxWiuZYJ+S8lKVXciWDBNE?= =?us-ascii?Q?CY16dpGmJO2OzBO6Ww9td7tOgqXB031TG4vSJSt1Ek7OJ7pxc4whH3d66QbD?= =?us-ascii?Q?rTUyr/IwxVEx1c1hoQux8XRsAAbW04SoKaQoBLXdqoXQ/Pa0keAmSKPel+0W?= =?us-ascii?Q?31gw0LrBY+q1iVMShUCOquh4ucywIf71wKC6ASwnU+hj6WTcWVNVtNiON/ag?= =?us-ascii?Q?5yYNaMey3PMtjUyLspbiXQXETiLXPUAV+oOv3ZiuQlg/F5TTy/fBlV9Jo14p?= =?us-ascii?Q?uM0Yy4SPBs/Q7hR5QkYqVRDSiz6EgQ6T70pkrRKQrPNHZk2Fcb20xXTHXYya?= =?us-ascii?Q?Rj17aLSKCLt9RuxEpgwFwS4fBMm2MQ+IX9QK/CjE6W7URMrixoV7J+kV3KhJ?= =?us-ascii?Q?YaX9033/08BpoVuOT+W0ujO6OhF09BAxDH6PdMeNEIoIw85H3PAaApP1iVpd?= =?us-ascii?Q?81au7Csy77KWgZkdqAOM5tJEXbTnZzkiF8FefqKaOiU4KHAatVsKKTLoWjBj?= =?us-ascii?Q?VX5+N01uEc7spo+x01L7XApIgtnpZq/edidlyqTL6AJXnUrGVWOM+YVSBlSy?= =?us-ascii?Q?rhaGQn0wSuifWLwv13IUf+dkiLdf7/SJcY/jwg8Ppc2hqZIRbzvmyMc6SHrY?= =?us-ascii?Q?zdFqLNvmsydWyDd+rkjHxK3zfhv6o4WH8idqHnXePGXsK0b/qcCjIsDWtIGc?= =?us-ascii?Q?MoKImC9/BHzQCG3varMeSW+9hF2SqXroBh82vabwZN4Z6ghmsOjmWSGwxucg?= =?us-ascii?Q?wJ8FbUE/cVPnLBBvXEKO1NMLr/jS0pI6LBQ+Zv5GVA6HfB+ouElU9V9MAj2C?= =?us-ascii?Q?oYqsUHSiFNa+CVTehy2+2fo699aUYqY9nNa61Xl4zziKCOpqbau12UNkZm3u?= =?us-ascii?Q?z2j4plRktvcKwzMkzOP7IJGp1rh9tgwDd4hn8nf7?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 8dbf6ad0-e344-4df8-d841-08dd47765ef9 X-MS-Exchange-CrossTenant-AuthSource: CH3PR12MB8659.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 07 Feb 2025 12:53:08.3588 (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: f7VlUJ0D/NUTb8XgIwWzEyHRgiUuzsAY4McOoTvq4CGdKIVnJzPBHYJfXgWfywXE X-MS-Exchange-Transport-CrossTenantHeadersStamped: CH3PR12MB8512 Received-SPF: softfail client-ip=2a01:111:f403:2009::610; envelope-from=jgg@nvidia.com; helo=NAM10-BN7-obe.outbound.protection.outlook.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Fri, Feb 07, 2025 at 12:21:54PM +0000, Shameerali Kolothum Thodi wrote: > Just wondering whether we can have something like the > vfio_register_iommu_driver() for iommufd subsystem by which it can directly > access iommu drivers ops(may be a restricted set). I very much want to try hard to avoid that. AFAICT you do not need a VFIO device, or access to the HW_INFO of the smmu to start up a SMMU driver. Yes, you cannot later attach a VFIO device with a pSMMU that materially differs from vSMMU setup, but that is fine. qemu has long had a duality where you can either "inherit from host" for an easy setup or be "fully specified" and support live migration/etc. CPUID as a simple example. So, what the smmu patches are doing now is "inherit from host" and that requires a VFIO device to work. I think that is fine. If you want to do full hotplug then you need to "fully specified" on the command line so a working vSMMU can be shown to the guest with no devices, and no kernel involvement. Obviously this is a highly advanced operating mode as things like IIDR and errata need to be considered, but I would guess booting with no vPCI devices is already abnormal. Jason