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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 05E32C3ABBC for ; Wed, 7 May 2025 02:33:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:CC:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=uUATeyaFCWFUopb4n5zW3zLd+Y3fITC5gTACDpMQ2N0=; b=VrOhqh/1p8kRplf32Sd3bruPHw EM5sKlgzqLDb+TrBb9VefgmtTvtLPrM1FdZhPCpENU+6VKugDyyxKJ+AYOfExGVeHAuVDworKViYT a/yn6mSiOKP41ZVc61fdJ8Pk0+J67w2qLkloehdbn06DJBxxsNFbH0+CtkDDT0q6mZSKLjeIKZfvX U5emd3eyeo/GEzNeVtJt33QsTQfSZbmMc5setdL2KgH6R12abmlfFf76E0BzY0F+od7crGO+Chfxq PBw+HXX0IJbV3weM6N4SGhczA6iLEBpGE6vTWkCG9tl9PiwhJ+SogEF+RhI5Y9WBwR/Mtm4OJTlXI Y08LA0gw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1uCUaV-0000000DuUC-2HBA; Wed, 07 May 2025 02:32:47 +0000 Received: from mail-dm6nam12on20602.outbound.protection.outlook.com ([2a01:111:f403:2417::602] helo=NAM12-DM6-obe.outbound.protection.outlook.com) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1uCOO8-0000000DHzC-1bST for linux-arm-kernel@lists.infradead.org; Tue, 06 May 2025 19:55:37 +0000 ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=fYRPm2focz7LNC3oUHp1Ti806Rtu8X5B0zErqmz+dC1Lw2k9CZGx45VEtaPeBEi2nwCIGgn4EDLCroLrzGiq3tZG8T4Aj2is46vpGS+jq5s39MrMTJ9b6gECuEukWlL0A296388NAipVEXqveAGCBu7fKsghlKsqymaUAPstgjxlR4QFCTAxSD4nOtP81Y+Qa5lgs24QXzVDfd2mxN4CPARyTQPey/OnP4paRdB1CHV2c43qim42hEod79ej6ljM0LMbAuuCy7kBf1DHjsbrGIQagCn644lW/xOGPik3vUUmos2MsTiw46zmtft5qX6JoBf2kn//aUuTtWOlvWRNTg== 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=uUATeyaFCWFUopb4n5zW3zLd+Y3fITC5gTACDpMQ2N0=; b=qRlRFab7KdS5sMu7hf7Xm3t0Yh5zGXVLrXOg4pCpP1wuVMAkUvsldm1rfFO1SGjoGtG1jRH/+eDvlS+AP2NhinyCvOxjX1Nbqztdkl0gFS0oTj/ILSJ1MyAtYpN6PmF3UiEgKQoajxV8SLoUMadJiwSa95o5bkWoxR0sYd5VXqLjcSuw9hcBQcE6rLf42cufirg/N+G9UhPNC44Pu9URubtVl/+Icl84rC0nIXeiDWi0fdCX1xe4OBoyZdUViUxPeUvMBw/hYkdYkjPnoIyYbixfRX7S14kbj3pQ+Tc6N2VaJDYlIOyE7ol59uPdG4+trbYbiKqj3mcT8X5mpcBTvQ== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass (sender ip is 216.228.117.160) smtp.rcpttodomain=huawei.com smtp.mailfrom=nvidia.com; dmarc=pass (p=reject sp=reject pct=100) action=none header.from=nvidia.com; dkim=none (message not signed); arc=none (0) 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=uUATeyaFCWFUopb4n5zW3zLd+Y3fITC5gTACDpMQ2N0=; b=oF4Nauc1o0D4xGayY1G89L9hh2RO9O0O/4zdAYLsNlrfd9Dg+lycfwfjSSXja30z/KDgJF8euQZz9d/Pva841+k7b4YZZWcjFN0MdIJp+Iyf7V/jSrWvPyp1z4OtdxDe3JfDK0hoC8qaYD61ffdPngKxPO58AHVsrf99/r1BKj38l6SjABVUZCsj7DKZYU8Xl9U3us2XcBE702COGjE1zsJYDz0z5hMMMDKkmkIY3hKUMR5cdhve5vrJ7viBQbWy6e+Plr5qEO7phUL5YIPJKHPpizOGuahsE/PubvbyD3Dn57FQegHnYu81+WKKEmRt0jMOmGhtSIah4rrnBNJmjA== Received: from MW4PR04CA0127.namprd04.prod.outlook.com (2603:10b6:303:84::12) by SA1PR12MB7248.namprd12.prod.outlook.com (2603:10b6:806:2be::12) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.8699.23; Tue, 6 May 2025 19:55:28 +0000 Received: from SJ5PEPF000001F5.namprd05.prod.outlook.com (2603:10b6:303:84:cafe::b4) by MW4PR04CA0127.outlook.office365.com (2603:10b6:303:84::12) with Microsoft SMTP Server (version=TLS1_3, cipher=TLS_AES_256_GCM_SHA384) id 15.20.8699.31 via Frontend Transport; Tue, 6 May 2025 19:55:27 +0000 X-MS-Exchange-Authentication-Results: spf=pass (sender IP is 216.228.117.160) smtp.mailfrom=nvidia.com; dkim=none (message not signed) header.d=none;dmarc=pass action=none header.from=nvidia.com; Received-SPF: Pass (protection.outlook.com: domain of nvidia.com designates 216.228.117.160 as permitted sender) receiver=protection.outlook.com; client-ip=216.228.117.160; helo=mail.nvidia.com; pr=C Received: from mail.nvidia.com (216.228.117.160) by SJ5PEPF000001F5.mail.protection.outlook.com (10.167.242.73) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.8722.18 via Frontend Transport; Tue, 6 May 2025 19:55:26 +0000 Received: from rnnvmail205.nvidia.com (10.129.68.10) by mail.nvidia.com (10.129.200.66) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.4; Tue, 6 May 2025 12:55:16 -0700 Received: from rnnvmail204.nvidia.com (10.129.68.6) by rnnvmail205.nvidia.com (10.129.68.10) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.14; Tue, 6 May 2025 12:55:08 -0700 Received: from nvidia.com (10.127.8.14) by mail.nvidia.com (10.129.68.6) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.14 via Frontend Transport; Tue, 6 May 2025 12:55:05 -0700 Date: Tue, 6 May 2025 12:55:02 -0700 From: Nicolin Chen To: Jason Gunthorpe CC: Alexey Kardashevskiy , , , , , , , , , , , , , , , , , , , Subject: Re: [PATCH v2 06/19] iommufd/viommu: Add IOMMU_VIOMMU_SET/UNSET_VDEV_ID ioctl Message-ID: References: <6348cc7a72ce9f2ac0e9caf9737e70177a01eb74.1724776335.git.nicolinc@nvidia.com> <35701c5e-030a-4f52-b6f6-ed18368fb2cd@amd.com> <20241004114147.GF1365916@nvidia.com> <95ab62fa-bb1c-4e4a-a210-b0bdba0d4ad2@amd.com> <20250505170807.GP2260709@nvidia.com> <20250506125847.GA2260709@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <20250506125847.GA2260709@nvidia.com> X-NV-OnPremToCloud: AnonymousSubmission X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: SJ5PEPF000001F5:EE_|SA1PR12MB7248:EE_ X-MS-Office365-Filtering-Correlation-Id: fb43138a-a590-47e3-49c8-08dd8cd7f27f X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|82310400026|376014|7416014|36860700013|1800799024; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?8hMP+V7PxnIlYAytle0gPB1mbkVAYDGOTEkwM8k2LKr7mg7p7+M+34mLWZya?= =?us-ascii?Q?b63LtQJYPrlBzZU5uFlAzpd/JsCnNV1qHeDfxJzjKBvURgBucesmw7SPiEun?= =?us-ascii?Q?qrutaFcKjXUlxfGlFeX+KcTRYYD1+znH5MNOjmZFF9ABdOmR56wRQ5mCXCSG?= =?us-ascii?Q?Q4WlPtDdxd0jwX+DtWyFkZn748YYtXwc0vGOc7mE3KB46Pxe1MziXbr0PBpJ?= =?us-ascii?Q?/0tZ4rSPOnCXELBP4aqTGt5PvqXCODxNqOE0JlV1Z3HzpPKS/vb8HkDlEoAq?= =?us-ascii?Q?6CGa2F4uwcO9g3A3xe412853d7akpQ6faPjlfvCRDNRrtlE0/4NLsHkEOzxe?= =?us-ascii?Q?8IZ2o6m5Gik06Ib0hXuW2EoEQlPP7oVsinDMITxzp6uQ1CZFFvysk56zRzXK?= =?us-ascii?Q?O8vwu/uVsBnVxtXlViq7eXyhXoGhZMWG7xV/kPXRVwh63m7KMAiR9oZo82Kx?= =?us-ascii?Q?4sRIzlDxvp14WJoywWDufZGRRmF8W0/kV4ziQZXJTGTc9skM5KYRWkCx6EeK?= =?us-ascii?Q?AapBja9lLKYK3q2c3A//n50QWWOzLOM7gsm02a5rWn1Qxb4rJBmRRap/bfrZ?= =?us-ascii?Q?8juBGvPitfwxvTGWamlOZs3AfGICPmUIverujdFAKhNLkahQ2PV+ya1mQZ34?= =?us-ascii?Q?P3p65tXO7beEOiWexb00KbxhmyBk916st502ORejkpoDDBpSDFLsA+Jkvz6P?= =?us-ascii?Q?79OMOMXCmU0LTeX2hck/IGcEqjhEc7tB4USDiQWEiIAEsYnLF9ItXhC1lOik?= =?us-ascii?Q?9Ctax9ivQrT3nBSIt6z9b2URS0pxa2DEJ1mePHu+gKLobc+xrOq2LltdT4eo?= =?us-ascii?Q?7QDVIjyAEaOVPjkosubFjE60FZjYarX0UUzgAg/ERXKyg9XjdssurSow+zV5?= =?us-ascii?Q?DDZ2SxaAJYk/NWpKvQ0yCq7An3bd6b3iHJVL1og1xE7mKrQtAq8bnqpd3Dxi?= =?us-ascii?Q?1rtPNywd9CrIk3wPtURJs/0bcM5Nh6hKsUIECMEIoLqQYY83m3QdxgzKvIuV?= =?us-ascii?Q?YLSGyOpvQM3cWN8rdZw+pIFnMGnQUGpPL9bRqdBACN4p/oEA0r2026uk6pfI?= =?us-ascii?Q?eAZLrrCZcyJc5zheH6i/cBk5gcm6TFYb/Zu2GWUFGmhuHIUYPHpsAlkv1wB7?= =?us-ascii?Q?ikf/ks5IBzkC9/gJvuDylOfeDMhg160d5T4uNMnXm8ktRvl9CxgDg9rHTibG?= =?us-ascii?Q?FQxCZz1Bx4cq5A7dsR2d+9spywXeJZkz4KNdasPTh3BCw6bI3a42BZaDeIgx?= =?us-ascii?Q?DG/jHwZNI+cl96Rd6eyDqkZ1wdtXS45508+yiMvI5FMaqoksVOSeZsV3g7FC?= =?us-ascii?Q?b+nVCvwCw5F+TMI9J4z4fZQry0kKWR44gVmTz4T3gsIYsF8ltVNli6KQWPhW?= =?us-ascii?Q?CV+mHbh5LIWCumucQlmVFwiBHaGxQXGptWPN2z4mOsX/08DZd012c+8pGBCo?= =?us-ascii?Q?ihEekMz/cNu1W57d2jyoiNXW01ASYwQqgFavlqqY6nwEm3JSkPW5kGtkBc0o?= =?us-ascii?Q?lASYmzj2V3en/N1OYCtT/GGcQ2S3B2UUdkEb?= X-Forefront-Antispam-Report: CIP:216.228.117.160;CTRY:US;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:mail.nvidia.com;PTR:dc6edge1.nvidia.com;CAT:NONE;SFS:(13230040)(82310400026)(376014)(7416014)(36860700013)(1800799024);DIR:OUT;SFP:1101; X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 06 May 2025 19:55:26.9970 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: fb43138a-a590-47e3-49c8-08dd8cd7f27f X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=43083d15-7273-40c1-b7db-39efd9ccc17a;Ip=[216.228.117.160];Helo=[mail.nvidia.com] X-MS-Exchange-CrossTenant-AuthSource: SJ5PEPF000001F5.namprd05.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: SA1PR12MB7248 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250506_125536_413928_7FD9BBC6 X-CRM114-Status: GOOD ( 18.73 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, May 06, 2025 at 09:58:47AM -0300, Jason Gunthorpe wrote: > On Mon, May 05, 2025 at 07:53:44PM -0700, Nicolin Chen wrote: > > On Mon, May 05, 2025 at 02:08:07PM -0300, Jason Gunthorpe wrote: > > > On Wed, Apr 30, 2025 at 12:58:47AM -0700, Nicolin Chen wrote: > > > The bus numbers can be reassigned at any time on the fly by the guest > > > by reprogramming the PCI hierarchy. > > > > Yes. If we take some aggressive use case into account, where its > > BDF number could change multiple times, I think it's natural for > > VMM to simply destroy the previous vDEVICE and allocate a new one > > with a new BDF number, right? > > We should not destroy the vdevice for something like that. In a CC > case that would unplug it from the VM which is not right. CC needs BDF to allocate a VDEV in the CC world. So, it cannot allocate a VDEV with BDF=0 firstly, which is what Alex reported. And even for a normal case that the device is migrating between PCI buses, CC might not be able to update the BDF (which can be a part of CC_VDEV_ALLOC instruction), even if iommufd supports an update ioctl. So, the underlying handler for an update ioctl is still to first destroy the VDEV and re-allocate a new one? Thanks Nicolin