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 5AD3FD15D9F for ; Mon, 21 Oct 2024 14:36:27 +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:MIME-Version:In-Reply-To: Content-Type: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=uUTJOaWuqLadThOdaaqUC9VoqbUCeSQcrwkT5PJRmeQ=; b=WYJZP+ADgAieIuv2Aaax6+tgRS t+ycb5aBfWnddLrr1Ol3vfCKiwFCvjAgIuNJgUUeZgkuS9nJzsvRsxnP+0isKtCK4IcieKFK3wlBK PGN3je8xjQImmUOS1gFd8oNkU+aq8x+smdcbdb4uzlhf8KqH5Ab7593lDZIl1hO4lt6xeZC2xHYZq vUvrPOxzfLMm5SFwasZ/G7p6Cohxi4FciOp+pmk5sl99QwESUZPn0nsE1cQWpX2WbWJt6ayJ2yOqT oqGsnKs2ZH7z0aQXp4wRs+OI+kuoVJxeNfKSYIyoEwOzsV3gwDaCdKI+1FkPp8aPfr96rjjd7nG7r tdlKHx1A==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1t2tW2-00000007dVz-2S4b; Mon, 21 Oct 2024 14:36:14 +0000 Received: from mail-bn8nam04on20601.outbound.protection.outlook.com ([2a01:111:f403:2408::601] helo=NAM04-BN8-obe.outbound.protection.outlook.com) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1t2tGV-00000007b6B-3Jg4 for linux-arm-kernel@lists.infradead.org; Mon, 21 Oct 2024 14:20:13 +0000 ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=LUFFjiI3Q8Xa2oB+Ts+PxGMDGsIGVU/tmkVMq/x8S5I0vVKlKhyg+7eKHDyfC4fcmnZWokn9rInXBiNPcMcrkPRnLYSs/NjV1DC6jsUtXsNt874oYZBbnH4rJosjYIxfszYfWMb0vVj22X/ZpWPpTZqRsEjL9eGmemOGoz/GhCoEPv+FcSExZIFTuAyPWWwxXffgvXAT1faat4QXF9VAv7Aq/ZmT3v0H1TzV4D/8eSSA5vsE5k7df2L/QJQbTa32wTFVc+fXP+dhKiBUx8Mfvjwlb9SlNE/odcAmsoCno55hGEv5O8Cr7EfzUq9Rttc7RfCkwYiLI4LWqNzsWaRWSw== 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=uUTJOaWuqLadThOdaaqUC9VoqbUCeSQcrwkT5PJRmeQ=; b=g9zBpU5SPg8Auyr8DNiGmLn6tAuvE+DEaxq+/mGN4RcMQI9XTGExJHZO/U1TGHTQWJ5SR4xs8tevghRsMdnSgyt7HY8xokGUkUiYA4YxZqaBHkye4Zjar/ZK75bJoOYbKpo1m+SeQaMhkvJmOeFfeaaQgYE14rYcIbdCDM6/OrSbAKKNNptUON5gYmLHnuG7WUSLqZndxQzMQgLi0MRqddPK8MX6CntWZsgurwTcEBUfMMuqPwHE50bryBdV+U0h6/F0fgqdXT7RzYyCeiYb8O/P1AOkcI19C+XWe1FAvWFvxjzYBUrRxV3nZsr/SCeOe6cGNwtDlSnSfH+R+42W9Q== 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=uUTJOaWuqLadThOdaaqUC9VoqbUCeSQcrwkT5PJRmeQ=; b=JXelXbgm9/E+7cHXenCjeaSyt1NcWjy1ivSiCrq7G8offJREXjGIKB1cxNv8iP9LIU/iWKuZwIp5Wqj0A6iFyFuViLVEDAu8dUW+AmUe5+xUsjYUwvGd+YBwKyAoLLMm8k33zLsAEcrnMAOPdsE3y2cZPZx0u0GuPazZCo91+8nFSRZzu6BdEDEiJ2U82m315Vj2oMqFN6DHDNTy0By14ZyGWrrT5u4Hq1BODYHuJyhUXVVNnP5Q6jyP31k5IcsRFkfBXYgz2BM45gJHZhi2A2jDyAXh3d7L2lR8TpzH24q+dnCIbkXmAdFSfZ/ChlnDwNGgu4t/26yK0yzEKVwX8g== 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 PH7PR12MB8108.namprd12.prod.outlook.com (2603:10b6:510:2bc::14) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.8069.28; Mon, 21 Oct 2024 14:20:05 +0000 Received: from CH3PR12MB8659.namprd12.prod.outlook.com ([fe80::6eb6:7d37:7b4b:1732]) by CH3PR12MB8659.namprd12.prod.outlook.com ([fe80::6eb6:7d37:7b4b:1732%4]) with mapi id 15.20.8069.027; Mon, 21 Oct 2024 14:20:04 +0000 Date: Mon, 21 Oct 2024 11:20:03 -0300 From: Jason Gunthorpe To: Robin Murphy Cc: Steven Price , Boris Brezillon , iommu@lists.linux.dev, Joerg Roedel , linux-arm-kernel@lists.infradead.org, Will Deacon , dri-devel@lists.freedesktop.org, Liviu Dudau , patches@lists.linux.dev Subject: Re: [PATCH] iommu/io-pgtable-arm: Remove split on unmap behavior Message-ID: <20241021142003.GS3559746@nvidia.com> References: <0-v1-8c5f369ec2e5+75-arm_no_split_jgg@nvidia.com> <20241021111758.561c81ca@collabora.com> <850c70ff-a7f0-4a0b-83a4-0b03a039831d@arm.com> <20241021121724.GN3559746@nvidia.com> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-ClientProxiedBy: BN9PR03CA0952.namprd03.prod.outlook.com (2603:10b6:408:108::27) To CH3PR12MB8659.namprd12.prod.outlook.com (2603:10b6:610:17c::13) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: CH3PR12MB8659:EE_|PH7PR12MB8108:EE_ X-MS-Office365-Filtering-Correlation-Id: 0c7f3915-f693-4033-e618-08dcf1db7530 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|366016|376014|7416014; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?GL0aa2RGVrpyopp9X2yRM7AY68cqPLJbSJI2mnLkSKTP+9QZSnUtkeAwz7nn?= =?us-ascii?Q?dzZGEs/nUdridjC0njjtfdOIOSJgDS/mmuqifv0FZ53Vg9SAlV7zrYOyflby?= =?us-ascii?Q?9lUkW5ICbH/tHxQiqCRx7q58MzeNdRXjwbg53QGKloeI1ZVbhVbUaWqF7ZLV?= =?us-ascii?Q?b9an75JbhExruc21P8mlPFBx0PNta//oXUTiKS3GaKM2fNdUmPeg8vPgrvEa?= =?us-ascii?Q?SP9oNXZgD/OdNSflinOEEhgy4A36rhZHIXVzwcXF1FSViBAy+cbAaXTaSVZX?= =?us-ascii?Q?RUfbCQiAMwQRRuVdA5Mbh/+IgiQxyOr3MlEsUU8rEnlixPERgNpN4MCVxbFi?= =?us-ascii?Q?8vXpMSRiJ5AodWxJYLYV0btVVlIWMiqX+rhyHyjhUNwLbUEDKC8Ab/0XxZ5A?= =?us-ascii?Q?a5Jbg5zbuoGgByrtxWM1KK8FB/veuBE00chbZTvcfYoLDbUoADpAzxQ2NKmT?= =?us-ascii?Q?hq4Zplfu7PGe830wU1v4Ydlc/7xQdFliCCsr/qrccQ2NEIMR5IJInxP36x2n?= =?us-ascii?Q?GrtAMNouvQd2MuO07ekmt6/CvH5ShYGYL83Em7Ln/ORHf8jTInd+Rq4vmOcA?= =?us-ascii?Q?l3qBqrnAdyUxbPq3W2611Rv3sFJn/wOtvYnx9TqlZXFYA6DYBl08m+i4RCWi?= =?us-ascii?Q?U1KphrdSpdOIZvTGriNLs0q5VcD7FrSEsRLWdMtkVR0gUFEjmNwIEbrEI9X1?= =?us-ascii?Q?/ni82ClFA1ypjWJnixp9Vr5X89/XFBjVNmqHEVp1T8k0ntCAVt7nJl+guSLS?= =?us-ascii?Q?w4Uiey9GErAmRDW1Bug83DtlGKZuGgK544H/6inGbJLKNKKtQVKYXT2C8emy?= =?us-ascii?Q?e722nQwixqimJXOtxJ9rigsxUS84Wgi/M8kdXlwp89Z7MYMP/QkO37EPubky?= =?us-ascii?Q?4fgDk8vPQmNN9XrYG9wRASjity9SVbIfMGn+xu1o4vMGrgbEnL2nqkkdI40f?= =?us-ascii?Q?qtKCSdczO1vnA0ezbyclR6HNcNhsGn6kAFHfaCbWrGfsUBN3fT03ziTqEn+a?= =?us-ascii?Q?3j1ImKZoGLcnrfQlTPvknOjmJJ1qzvt4AqsxFVO9fqMJPcbn068GAfg0UBhN?= =?us-ascii?Q?bQrFSHi0YKgCVegdjX1OGdHXtkjrfgaRmnJJUduBpYLdWv3r7fzrSp3J7SWi?= =?us-ascii?Q?nv7oamRtHbxjEQf73iV+iOZLm/yh+lj6a/Bys+yO86h1hsg4Fs01ObrP/Fv8?= =?us-ascii?Q?dTMo3L68Mgxr4kSNgkJGD2MORy8E+t7uLJMAj57nLrjD15P3B1FTcrxGNZP/?= =?us-ascii?Q?/b4QiHyNMZpjtLE/OJvH7aYvnwSA1Su7Err33+qU5m3dPkyN+jUeCFDqwT2o?= =?us-ascii?Q?3HfSZhkHGwOkVg17TaNBEREm?= 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)(1800799024)(366016)(376014)(7416014);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?iBGpauD4WHTjoDCJSy40diO5KxP0QOqmQy2/NJTGn76E82c7bUm5HL9spMcO?= =?us-ascii?Q?yroVfnjjKfLuJr96mFXn8D+BsXdLSLK0xfa8SGe/AQBYMuHch4xqL6Ox9pcy?= =?us-ascii?Q?meIG3n93RRQykn4LPI/kOOMECkgmuVcoXvg7+OBY88/kheclZYgJY84aS+Fo?= =?us-ascii?Q?BFZE/PZw60qItSB8tydacZxfjaNo2S0wDCnWneeB7E5cBAoBf6/YDH2VbF71?= =?us-ascii?Q?8l55PHm158SYS8SR2oV7c/lT5mio9RZguzOTRUbesx+QBantEZe6fFJ/NSO8?= =?us-ascii?Q?IaVGshcKMg2NeDGLGKXnqVTX6Fzi8r9JAqX+3CT3F8hHMzPFe7J6AKB/Cz5H?= =?us-ascii?Q?qznQRw/s3bXOydsiXcpU1ydNDB+0VpstL7n9DAmQrKQYz5yyEcAPKZla8uRA?= =?us-ascii?Q?L6oroS4yOEqpMpSMANEr+38xdRAzurybxSz5U1XClXNc1Yn11g4sDLOeTpWu?= =?us-ascii?Q?jTMA7WboWjJ5+Jc+z/6BnyXUL5AyN/7NTA4TiDwsp878CbLNn+k6LmQT+x5k?= =?us-ascii?Q?MuKHCf+R5xb0yPAMi8vcF59RYE8MZFhBk/VkzKREJaqFdtauESlyE7zJgwFI?= =?us-ascii?Q?r/SEC2NoGy0Xbgve0IJVCwL+Ts+guC9+iHwYf85VJSo92CVmy9jZuGg9/rty?= =?us-ascii?Q?1aJXOxwCRAfUr//8zxO8vxT6ynD7d6XoPQjeG17BxhRuxwzioqAVi0xKoHAg?= =?us-ascii?Q?0FRd5GouW5yDf3ue1RZYa3ZyC6Dx1qAVcexW86b66vVmzh2tIOyz1FWm+t63?= =?us-ascii?Q?PuIZu67nfz9q3Q1XahaNt/OB9P3JKhajz33OfDkxrHsOws+Dvgywn1VMlG1U?= =?us-ascii?Q?ywXcjU8xs4YQ0Zv8OmwrxHUMh3WgyUvYD/zmkDZSmK6K40zk5dtd+cnHh1sn?= =?us-ascii?Q?hBbvoNEGY+LwleErRV11ugy0Typf/dmaoPx8e0OabtsCurizZjFKFypslJ4T?= =?us-ascii?Q?k1oeakpSc3VWf/op5ReC0jhBXgHtGBUwGvbxHE/nLmPU6+u8CFdpWhxLdNGA?= =?us-ascii?Q?mO2VB/BxXJxWolVQXNxAoQTzRv4jVF5HtFj/SXpE+YyMBHQClw54reaHnRDK?= =?us-ascii?Q?7mcUqkhKjrAfg18cyQZQ6Wtn2mISn3Vz4T3vgfj6fGwBJaa5zYqjqBbJrM1m?= =?us-ascii?Q?M2EX5SI+js00ISzZCLQb/GR0M+v7/q5m4qXybfTWnWrh4CD8A0jojFxT549z?= =?us-ascii?Q?pPy/4LIG1L6R6vs1LvN3YSztq0fmjfUPE0ak32SP7nlUw4dfC6kJ9RPgX1N7?= =?us-ascii?Q?fCGNFwjtItzQYTKJi0swoXHPmfejhyCTcOYaEURsKd3jalqVo1TbhXzeaZGl?= =?us-ascii?Q?zuC99cSsa/ykjPeWS/U2tlO6LOYTR8ICfhRKgO6JnFGAnSnJlYBfq3dvcXYx?= =?us-ascii?Q?CjZpTusVBcpX5hTOnG3VAvEahdmq1CuxmQI1GYvzkDqKqG0bddX14O2h4cKa?= =?us-ascii?Q?gH3245zviJd0YO/ixrZkYZBLHUo+B5ArSZxjIys4hptY8dJfvLl5Gso746Iv?= =?us-ascii?Q?Iva3aK80lfD6eQvef9eQ7Zdpihj3KUoq6n3DAtFH8DpWJpvEsJncaZ/nONO4?= =?us-ascii?Q?gyhZG9N8kBQMKGp7LgU=3D?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 0c7f3915-f693-4033-e618-08dcf1db7530 X-MS-Exchange-CrossTenant-AuthSource: CH3PR12MB8659.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 21 Oct 2024 14:20:04.8064 (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: jXigYFxBlo46MLSjHlSl93KupdQZ9IAX3Bz8SOpYG8SmH+LrnhQiWd4lyFnRNxBf X-MS-Exchange-Transport-CrossTenantHeadersStamped: PH7PR12MB8108 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20241021_072011_867570_89F4F49E X-CRM114-Status: GOOD ( 17.77 ) 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 Mon, Oct 21, 2024 at 02:50:34PM +0100, Robin Murphy wrote: > Beware that whatever the Mali drivers might have the option to do for > themselves, there's still no notion of "atomic update" for SMMU and > io-pgtable-arm in general, other than perhaps for permission changes - even > BBML is quite explicitly non-atomic, as it's defined in terms of two > otherwise-identical mappings existing at the same time, just guaranteeing > that while they do, you'll still get behaviour consistent with one *or* the > other, and not anything in-between. one or the other is mostly what atomic means in this context. CC just doesn't want any sort of fault. > As far as this patch goes, though, I would not be at all unhappy to see the > back of split_blk_unmap... However if we are going to do this then I'd like > even more to formally define it as the behaviour of iommu_unmap() and fix up > all the other drivers which behave still differently (the statement in the > commit message is incorrect - io-pgtable-arm-v7s still splits; at least > exynos fails the unmap entirely.) Hmm, my kunit does cover io-pgtable-arm-v7 but I see there is a mistake. I can remove it and test it there too. Exynos looks like it triggers WARN_ONs so nobody uses it there at least: if (lv1ent_section(ent)) { if (WARN_ON(size < SECT_SIZE)) { err_pgsize = SECT_SIZE; goto err; } We just need to delete that WARN block? I'm not sure what to document here, I don't think we should tell people to rely on this given we can't test every single implementation. I'm mostly interested to ensure that nobody has quietly started relying on split behavior. Jason