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 E8307F36B96 for ; Fri, 10 Apr 2026 00:05:29 +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=nkY9qsV+fcaQNIraPAgrgREF0/R4OYf17eX/BbrEZvY=; b=EaPLwQd+Wpn/y+HNdz3RySv4va meT+M7C6KqI2+kR5YJBXJFixobGraJb7czqsskygGgWSQaemFUX4T815e2QQQOCDVcyssAMXCu5Df E867MI5t/iaZ2/IGJTud0qHPWET8hSPC88fur/R+5TCpvVyL6BO9NbRqoNoTpwtbP7RUyrKynVe8P EuDKxXR+6WZbrZy64yNtmv3aRQHX7/w/sOuXAXKWrcV8nGd+KUmhb0g+AuXcOcZcUcyHrATkqt3TK +BNI5FY/aGxwB5kpuEFD+WbSGOupwOXz9HEdw+6bkJQvIhemNZDFdesSjYMVcveJQLJKhirNsBSey RXTJFPkg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1wAzND-0000000BLrw-3v1H; Fri, 10 Apr 2026 00:05:23 +0000 Received: from mail-westusazlp170120002.outbound.protection.outlook.com ([2a01:111:f403:c001::2] helo=SJ2PR03CU001.outbound.protection.outlook.com) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1wAzNB-0000000BLrP-3DlM for linux-arm-kernel@lists.infradead.org; Fri, 10 Apr 2026 00:05:22 +0000 ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=oHvknIJRJQdQqDDIyqwWYTOLKbDY5pK0zvTObH5Illf3yN9rQm1E4z/AUgrggOWavKY48kUkPPoex70EchOD4n1Ua7FUlTa0N0fOywSlbww+We1qc8cSqjiLUw1OdjexK8k/rBnQ3jDtzm6+LNfVu3Rrr2mzMrEHcon1ZimOPIGJqPNp/JnWZGeyPUKRPb+hr6UCzyknLmuhe5tgnB5kl/hwg0AfG0UvrrxWlI2yTrPx+N796USfdaIt8SC9y5ugKUQk8EuulyXImxoT3OJ7Y45tG4SM/OCcBo5dEEjk+hdWjPC3Lcxd4Xgh48N8umLWchsCP7XhdqQfQWujNZbsbg== 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=nkY9qsV+fcaQNIraPAgrgREF0/R4OYf17eX/BbrEZvY=; b=pk9OaecWBxC6/oXLL2iKwRUA7+JGZkJr1SGMcIoe70rkddGWTcZ1Vp47g7a27w0vQWh8y40c+EzBInJmv0Hge4wKLyIWbAz6h963LkYOjslCsBoFUtAvT+nEeOVHsO3L3iJfM1kcCiF+eNt2Clop51EYugUcszSAHwCLXu234fvV7Tj37Z0YnZApIzCSS/fcNfjHX2Og2uUnNLEFFe2w1xuuWq22Gp+L5DZSOnXpgROkbUd1CKl4+iCKTrMJHgvra+k7mvaVvmN8+5nzC2BCSUF4pvcsYATQOd3sbAB/b/4MyaIzsJ8E1cH/p2b1dnYBOj3XKIdfuiLB9U/W/VOdBA== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass (sender ip is 216.228.117.161) 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=nkY9qsV+fcaQNIraPAgrgREF0/R4OYf17eX/BbrEZvY=; b=qjGWa/ftUw7BYRa+kJT8AOCP7zXenjHwKrFhXse9ej/52giy55R3RU+nkboctTEtxfGKLhyp/9K2rnW5dkq2DqLpYT5mNuoECJZfJnmbB3aXI34rN9IrWxlAyLMmxFauNxIo+gs3ioQ8Em9GbwoMvqFbJge+cAvRsUwcdNHShTi9UJ70qIn102r7krL30rgY/+XwsSEnItivnHSzCIF1peOyBwnQTM8WIIhezP3jYwNTgTbiUg41xuzit8NehFBQUxeghZ7ouCnSD7Hp6EheCfLw6HKp6szI0nY5oMxxVpXDuZFm5EAeJtRFvAFDhl8bTD6IN8UjHJ2fvi+IosO0rw== Received: from BN9PR03CA0072.namprd03.prod.outlook.com (2603:10b6:408:fc::17) by CY1PR12MB9560.namprd12.prod.outlook.com (2603:10b6:930:fd::16) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9769.41; Fri, 10 Apr 2026 00:05:08 +0000 Received: from BN2PEPF000044A8.namprd04.prod.outlook.com (2603:10b6:408:fc:cafe::b7) by BN9PR03CA0072.outlook.office365.com (2603:10b6:408:fc::17) with Microsoft SMTP Server (version=TLS1_3, cipher=TLS_AES_256_GCM_SHA384) id 15.20.9769.42 via Frontend Transport; Fri, 10 Apr 2026 00:05:06 +0000 X-MS-Exchange-Authentication-Results: spf=pass (sender IP is 216.228.117.161) 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 216.228.117.161 as permitted sender) receiver=protection.outlook.com; client-ip=216.228.117.161; helo=mail.nvidia.com; pr=C Received: from mail.nvidia.com (216.228.117.161) by BN2PEPF000044A8.mail.protection.outlook.com (10.167.243.102) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9769.17 via Frontend Transport; Fri, 10 Apr 2026 00:05:06 +0000 Received: from rnnvmail202.nvidia.com (10.129.68.7) by mail.nvidia.com (10.129.200.67) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.20; Thu, 9 Apr 2026 17:04:49 -0700 Received: from rnnvmail203.nvidia.com (10.129.68.9) by rnnvmail202.nvidia.com (10.129.68.7) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.20; Thu, 9 Apr 2026 17:04:49 -0700 Received: from Asurada-Nvidia (10.127.8.11) by mail.nvidia.com (10.129.68.9) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.20 via Frontend Transport; Thu, 9 Apr 2026 17:04:47 -0700 Date: Thu, 9 Apr 2026 17:04:46 -0700 From: Nicolin Chen To: Jason Gunthorpe CC: "Tian, Kevin" , "will@kernel.org" , "robin.murphy@arm.com" , "bhelgaas@google.com" , "joro@8bytes.org" , "praan@google.com" , "baolu.lu@linux.intel.com" , "miko.lenczewski@arm.com" , "linux-arm-kernel@lists.infradead.org" , "iommu@lists.linux.dev" , "linux-kernel@vger.kernel.org" , "linux-pci@vger.kernel.org" , "Williams, Dan J" , "jonathan.cameron@huawei.com" , Vikram Sethi , "linux-cxl@vger.kernel.org" Subject: Re: [PATCH v3 1/3] PCI: Allow ATS to be always on for CXL.cache capable devices Message-ID: References: <20260409225252.GU3357077@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <20260409225252.GU3357077@nvidia.com> X-NV-OnPremToCloud: ExternallySecured X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: BN2PEPF000044A8:EE_|CY1PR12MB9560:EE_ X-MS-Office365-Filtering-Correlation-Id: 7c627250-c6f6-43bf-0732-08de9694d285 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|376014|7416014|36860700016|82310400026|1800799024|18002099003|22082099003|56012099003; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:216.228.117.161;CTRY:US;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:mail.nvidia.com;PTR:dc6edge2.nvidia.com;CAT:NONE;SFS:(13230040)(376014)(7416014)(36860700016)(82310400026)(1800799024)(18002099003)(22082099003)(56012099003);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: W4/PHzH13j0NB7Nu1Ss4Q/DOUMEaWz6o/kWpL5K8NTsGwxWRnf/KfGYagAdWExN0e0MpWGilXm9VWnXPCnDxtBT+oYeAueXW4SdyQRuz5ekfZnyGSAeQMjvsOV5leyGk5JpQhKfI+zky8h5T62TiLialG4QIZaLvShVTSVBe+dPlYMZrhCcPH1vnrE7sU89eubyViYTT5D8c4F0qy3Pr2gZn1Q+AEqTRNh/j1MGM2iQ8jn3fPm2tEFsV+RT9rDY2GrK0voZeTJ4e8f/nEVKUkJAk6ANd5ZfjtrXEJsAa/x9Zc7FLSkMQx6uzDQVdgImLRetpq0Xm2qjNT4AGYBji8sq3/XrDHz9toNhQrIqftybPPnY8H3yA7KoSgijb7g8UCEbCd963GaOjybRT4y/bu+HisXEDMlNQiuPcHetMlFdYLDCUZWUy0s9kTJmuLRS8 X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 10 Apr 2026 00:05:06.2560 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 7c627250-c6f6-43bf-0732-08de9694d285 X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=43083d15-7273-40c1-b7db-39efd9ccc17a;Ip=[216.228.117.161];Helo=[mail.nvidia.com] X-MS-Exchange-CrossTenant-AuthSource: BN2PEPF000044A8.namprd04.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: CY1PR12MB9560 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260409_170521_811479_0EB3E75F X-CRM114-Status: GOOD ( 11.64 ) 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 Thu, Apr 09, 2026 at 07:52:52PM -0300, Jason Gunthorpe wrote: > On Thu, Apr 09, 2026 at 03:45:26PM -0700, Nicolin Chen wrote: > > > One question regarding VM case: if a device is ats_always_on, while > > VM somehow doesn't set nested_domain->enable_ats. Should the kernel > > at least spit a warning, given that it would surely fail the device? > > No, just let break, the resulting failure has to be contained to the > VM or the platform is broken.. > > The HV can't turn on ATS because we it can't know what invalidations > to push so not much other choice. I see. Thanks Nicolin