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 B3AC7C4450A for ; Sat, 18 Jul 2026 23:09:35 +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=UKZHedMqldFVoEfBZUSAvISzFyM19J1uAbzoZaztQ9Y=; b=lzwPpMgXi3q0p6BJOZ152iXPS8 SsF/QVK6ZvXBcOP6BGxYzk7+xSKSlzDbmig1LSHfto2E+sRZG3+ZpgX0uXhmXo8DzkyEQ4fJ9RNcP iBCPPJ3rGfRk0JGANHDqQ0iyxKdjHLNjnTWKXIVQy9mplFiv/vuzWBWpCsDDR+4mdubfbbT7VvsNK hzIobHRvgbbpJf9QVVofjk+gUg6QtAAojGpl4GXAW2v1CkgecmJPfQ0rwvKbmtA+cBNbDQxZdMZUs GYuYVM0O4Ms+WgdrfoKJ+CbHoBB2WQn69u0nBQ1X1Laoq0N/etowQ6P681Pi1xZ45//mTnb4u3gBJ gItDHkDA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wlE9w-00000004aD2-0u8k; Sat, 18 Jul 2026 23:09:28 +0000 Received: from mail-westcentralusazlp170130007.outbound.protection.outlook.com ([2a01:111:f403:c112::7] helo=CY3PR05CU001.outbound.protection.outlook.com) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1wlE9t-00000004aCg-1qDZ for linux-arm-kernel@lists.infradead.org; Sat, 18 Jul 2026 23:09:26 +0000 ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=AlnY2aqPAVy0WpH1pRSRg8A/xty/v5/whkUO3uEMfnnlCiaOjha7sxpZKzBt3wTEa+vGd/10AItm52hMCircFOiqq1aYigKI3GEkK74WUfNtO/8A21D2FrmZTn6leF4ALqLzptFAB3XtCNuPfKWyR6aFImqOVaTVj2CH5Osg0QY3s/jjgTKTKIptO+d2TgkcZDFHa/DccVhMGF26flLctmUlRBF9HfAbKxsjuNXP03CS2YfX5Lto3ZjYXWA8LXkzkkVWA/PBZ90JbnS4gh1KA0uyDKqeRG6d5xlpq7mp5D7yNKrsWQjxbUQk3/ZxxxXfy/tjrpiq5FzPS1Z+Ld92RA== 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=UKZHedMqldFVoEfBZUSAvISzFyM19J1uAbzoZaztQ9Y=; b=V6y6qUo43As+bRbZZrLD+lGq8jZLOXCOB5A3lLiNbQOst6v1cZnJUJQwM5JroZEivqVk31iePq+SxZLkotBKL0+3/9jjQvEBdYB6wVYk7AcDq84B0gAi4KJzqhYLFbjjAhB6NasvpBSHx6q/xgHSzBzHem/aRLd6lU2jzyksAdju59y5Ir0di1RN+kBzPCWSbBchrG7PNO+v/Km+DfXyPSYqlRx1vSiiL852Yw2x5HTdlG2IrOUA+QJFAVwCPzjlju+7wIvwcyrFHAHNravRwRBVB9Zcf2Kaf6HtgZMqCeDN0NaWjMcX8U0ijd4hZUgUhrGWjduloh24mCzbp0n75A== 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=UKZHedMqldFVoEfBZUSAvISzFyM19J1uAbzoZaztQ9Y=; b=NlSOHup6hjV63hY/AApbyu/q7ixIXMjM+SEVBF1DhIfxj5/p4WUbO5kBzfTaHFAg8MWcDnnMwC2z2B+QXWhch9bOQ7IbrWWXWZGjLIKNWVRVyoEOO7uNMMCJFLVBfe74jPvq+8Q9EHQa84V+le9F2QjS7EE1i16/bii6pFpl8XtrYLqX/pYXHrzSadMXDaJCz3YLn4JG199bK7hsC9x48uvNxB6UpxtbuuoOYwVuDtpINAfU21KoykVs9xHFpF5RmeN4J29Fx1vUftNdRE36f0dvJ4oGgXB4qAyUE2B/X4/DMYvWo+r6ZzJY1oxK3vu+xvoQX0Cwh+kaLBMJMEHTUQ== Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=nvidia.com; Received: from LV8PR12MB9620.namprd12.prod.outlook.com (2603:10b6:408:2a1::19) by CH3PR12MB7713.namprd12.prod.outlook.com (2603:10b6:610:14d::19) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.21.223.13; Sat, 18 Jul 2026 23:09:18 +0000 Received: from LV8PR12MB9620.namprd12.prod.outlook.com ([fe80::299d:f5e0:3550:1528]) by LV8PR12MB9620.namprd12.prod.outlook.com ([fe80::299d:f5e0:3550:1528%4]) with mapi id 15.21.0202.014; Sat, 18 Jul 2026 23:09:18 +0000 Date: Sat, 18 Jul 2026 20:09:17 -0300 From: Jason Gunthorpe To: Mostafa Saleh Cc: Will Deacon , Vijayanand Jitta , "Joerg Roedel (AMD)" , Robin Murphy , linux-arm-msm@vger.kernel.org, iommu@lists.linux.dev, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Prakash Gupta Subject: Re: [PATCH] iommu/io-pgtable-arm: Add support for contiguous hint bit Message-ID: <20260718230917.GG699082@nvidia.com> References: <20260618-iommu_contig_hint-v1-1-4502a59e6388@oss.qualcomm.com> <20260703161228.GA1948451@nvidia.com> <20260715113913.GA3775915@nvidia.com> <20260715122830.GB3775915@nvidia.com> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-ClientProxiedBy: YT4PR01CA0147.CANPRD01.PROD.OUTLOOK.COM (2603:10b6:b01:ac::22) To LV8PR12MB9620.namprd12.prod.outlook.com (2603:10b6:408:2a1::19) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: LV8PR12MB9620:EE_|CH3PR12MB7713:EE_ X-MS-Office365-Filtering-Correlation-Id: 525c140f-6d7e-4289-f0ae-08dee5219835 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|7416014|376014|23010399003|366016|22082099003|18002099003|10067099003|5023799004|56012099006|4143699003|11063799006; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:LV8PR12MB9620.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(1800799024)(7416014)(376014)(23010399003)(366016)(22082099003)(18002099003)(10067099003)(5023799004)(56012099006)(4143699003)(11063799006);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?z0Kztu/WN62se3++zyEJ+HMepWA4oiBduypVeW2ffDFy6Mmno0H5ItwT3dn4?= =?us-ascii?Q?PMQzBzFjJacK/soI/k9R6DVHoaXctXMhydmjTbesQUZBqHOu12Gh/4p2Du6J?= =?us-ascii?Q?nA0muuaQ8VSRB03mkYboaCxCKIH7JxM9V3cYMcUSyk2DiBQ+j1CFwcAdTU7c?= =?us-ascii?Q?bBZ98ocHm3585b6zjXNhcvWy8/UFfP/amwwv1wjZKkFY6UjM5RT3W+6PXajf?= =?us-ascii?Q?fj3kuVnJgM8pKtXM5o6Dw8iDvCFwM+jhDigdx0crRXgiQrq2Qyhd+Aoq3oL0?= =?us-ascii?Q?I514YEa1bayxGl9N+nK6++L6TPu/8sZwmdHmy8Zjg2iQU7jQPuys9aiHpKgx?= =?us-ascii?Q?928Z3X3u7JA4Ua8/9Xy9W4OWPd9UYh+Pzdp6TjK6tzZK9u5rxE3aKhdYKI88?= =?us-ascii?Q?Q9z/8ix/HVOjPIXNG/xA4Gl3YY0IxuTj7fKkYO7IU8CexVg+YZlMbTGfJzHR?= =?us-ascii?Q?sHpo+k9/mbOcILIBnEprzC6jhK2rLvXChjvYROjgwiWZjz73fJ/uiYTOhAHW?= =?us-ascii?Q?Dgpr4dNBLjKZL2xu2QNhaOrnS/nfPmwBr7ls1hTnUylW54p7mDvw6BlZfQtP?= =?us-ascii?Q?SqmjwGfC+kWaDSt2sqyO5TWi2CaUjMiz3lmPTBgjQVIkcHDILmlfwgz8tPA4?= =?us-ascii?Q?5d0W3poms/Y92JIwSpI59KPHSlZCQWpuj+knyeAp3SY8qwyj94cJJ8A7p/Qe?= =?us-ascii?Q?HLjeVbgb+2SXOOXfUsrdguu6QfvU5QeulKDlysDZCsuX02dGO88FIkPSmyXU?= =?us-ascii?Q?CEfNAJrnD7XZLzUkLOm50Mrtecd5XCC2gCsQPENfREJENu26SLbpp0TG2B4+?= =?us-ascii?Q?BmdRLDoanBlkTqsxSWk42sNbwWMVKDKTIf+Oj0leL+TxlK6RUg9DhWw3gXZB?= =?us-ascii?Q?nNU4is7GBvbcWEGRfdgj7Lm+IrW2XHssYGyZIDTjF6LRNS5eoG1zJrYVlAuJ?= =?us-ascii?Q?t/Mv2fJiiSt08JV473R2RigtHuGCF3GRFH4GudHD/txUsQXbgZfBoLMZg4KM?= =?us-ascii?Q?8hA2W2OKxHV/xcaf7n9ZU547EfOsFnyH+c3HUeT7Gg/V/w3tfy81nQJsn2xP?= =?us-ascii?Q?2aA2WxTNSRPwNli/l0eQqtR8TkFb0bs/mtiJq7hhMox+Dx+qS+44lhfCHEaj?= =?us-ascii?Q?p8gKNw39h23L2nN9lHalHrq1MQpRI5n/hyab/TPY7fUsxHkgzVxF8alCqmHa?= =?us-ascii?Q?Y7yWzZ8gWjD/t30UqOOskyNoYZ3IFDWUZvpSETQ/x3ZZvX1DMznbmDVOJq6a?= =?us-ascii?Q?UFa22T0kig3ODtjeN1D6m2CK6BeYCOauhmHNeabisCxPbMAdadBvwIVCghF3?= =?us-ascii?Q?xZEUHiVkZTQ8NmxaOEa5RP/ICWFXNzYO5rmHxsJkLDzi7FT2IyU+z6lh3a2u?= =?us-ascii?Q?TemgMjpcBTN8QECv5dCIYk691sTHw4qkQGZf9oxYsb7mZkO5tJR72l/Exhd4?= =?us-ascii?Q?fHazTNeuNHMLViXMjDW6HM5LCFowCT0fnT65bO9jLe1U5hkgBZXQ7dT3xacB?= =?us-ascii?Q?+xSunu0puu0fGPywIybffL1gaFg+J5Y7DzBFMegvFvUP0j0yx4NMQAH7OoFp?= =?us-ascii?Q?or0uCirikmIIDDqH9mggXZhnuBJbvq2Kl8qMvgL2vdmiG1048NOhasSbFJHf?= =?us-ascii?Q?0YGtM5M+PfCUUtTKLyTajDhg96sOsZyX5op6KqZQbZ3XDCWc/CGYiCApzdoG?= =?us-ascii?Q?JCuNu8x0jeMxuaLRjcRTTTSUGw2fC8oVt9m5F1eM6SE2h6St?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 525c140f-6d7e-4289-f0ae-08dee5219835 X-MS-Exchange-CrossTenant-AuthSource: LV8PR12MB9620.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 18 Jul 2026 23:09:18.6205 (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: kpuGd5dMzJPeh5fl3WsMRTZvud/NI0ORieExSXrsOm+QTVjfOR2/LsykHduR/k7q X-MS-Exchange-Transport-CrossTenantHeadersStamped: CH3PR12MB7713 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260718_160925_511959_99E29B65 X-CRM114-Status: GOOD ( 34.16 ) 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 Sat, Jul 18, 2026 at 08:11:35PM +0000, Mostafa Saleh wrote: > On Wed, Jul 15, 2026 at 09:28:30AM -0300, Jason Gunthorpe wrote: > > On Wed, Jul 15, 2026 at 01:03:22PM +0100, Will Deacon wrote: > > > > > From what I can tell, the fiddly parts for iommupt will be: > > > > > > 1. Hardware bugs / quirks. Some of the simpler ones could probably be > > > handled but for the more invasive stuff like the Mali format > > > format, io-pgtable will probably need to hang around. Perhaps > > > it becomes io-pgtable-mali.c? > > > > I briefly looked at Mali a while back and it didn't seem so bad, but > > that was for a GPU driver not the iommu so a bit different > > issue. Exactly what the GPU drivers should be doing is less clear to > > me, they don't really fit well with the iommu focused interface (eg > > the memory preload issues/etc). > > > > > 2. The pKVM work from Mostafa. We'll probably end up with something > > > separate at EL2 for this (ideally, just reusing the CPU page-table > > > code when it learns about BBML3). > > > > Yeah, I'm not sure here, it isn't great that is adding another user > > and open coding some of the logic (eg smmu_pgsize_idmap). It would be > > much better if it could just use all the existing flow more directly > > somehow. > > I was under the impression that io-pgtable-arm will remain the same, > but if it is going to be removed (or at least the LPAE format) I need > to figure out an alternative for pKVM: I wasn't going to suggest you change anything with your series at this point, just opining it is "not great", but I wouldn't object to merging it as you've constructed it right now. > - Compile iommupt for the hypervisor (similar to what we do with > io-pgtable-arm in the SMMUv3 pKVM series which compiles in both) > I am not sure how easy is that for iommupt, I have the SMMUv3 > iommupt series on my review list, I will check that. It is probably similarish, I thought your new version was pretty clean when I glanced at it. > - Write a small IO page table implementation just for the hypervisor, > that's not ideal as it would benefit also from features as CONTPTE. You can do this pretty easially with the generic_pt and you can write the thing exactly as you need. I wouldn't do this unless there was a big mismatch with what iommu_domain provides. Jason