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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id B7F88CCA470 for ; Tue, 30 Sep 2025 18:04:44 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 8E36B8E0005; Tue, 30 Sep 2025 14:04:43 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 893868E0002; Tue, 30 Sep 2025 14:04:43 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 733758E0005; Tue, 30 Sep 2025 14:04:43 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 5B2CE8E0002 for ; Tue, 30 Sep 2025 14:04:43 -0400 (EDT) Received: from smtpin30.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 006935B6FA for ; Tue, 30 Sep 2025 18:04:42 +0000 (UTC) X-FDA: 83946692046.30.8632E19 Received: from CY3PR05CU001.outbound.protection.outlook.com (mail-westcentralusazon11013071.outbound.protection.outlook.com [40.93.201.71]) by imf04.hostedemail.com (Postfix) with ESMTP id 3871F40007 for ; Tue, 30 Sep 2025 18:04:40 +0000 (UTC) Authentication-Results: imf04.hostedemail.com; dkim=pass header.d=Nvidia.com header.s=selector2 header.b=OyX3g3G+; spf=pass (imf04.hostedemail.com: domain of jgg@nvidia.com designates 40.93.201.71 as permitted sender) smtp.mailfrom=jgg@nvidia.com; dmarc=pass (policy=reject) header.from=nvidia.com; arc=pass ("microsoft.com:s=arcselector10001:i=1") ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1759255480; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=DRborw5V+5sPkrv12VBxiU/Je0fts6K9uJXD57mjqw0=; b=03hjkbUFYaQ8sVAGwBCbnGd5Hnbh4kij7qoUPITFQSr8KH/u0dcNRmLBmH8nJh05pMVhLU WXRMA3nI1Gj7pRU2TwYNph7Plgw7ucv2QP2v9fKJk2JEWiX5Vy1IdCSypWwxuf3W49XPju QA0oPMzS8+xUKsNtJSZBO3wlS0xVMgw= ARC-Authentication-Results: i=2; imf04.hostedemail.com; dkim=pass header.d=Nvidia.com header.s=selector2 header.b=OyX3g3G+; spf=pass (imf04.hostedemail.com: domain of jgg@nvidia.com designates 40.93.201.71 as permitted sender) smtp.mailfrom=jgg@nvidia.com; dmarc=pass (policy=reject) header.from=nvidia.com; arc=pass ("microsoft.com:s=arcselector10001:i=1") ARC-Seal: i=2; s=arc-20220608; d=hostedemail.com; t=1759255480; a=rsa-sha256; cv=pass; b=G0Lr6FqZ8ef8BFD7aDlwZr//AYXnBKMFlo2G1pLX9eKZCSyqgIA9tvkQ8j5nghvUq+f5aO 3ljLiHqlW0bV6ccS5z968BY7/LkEl2pnpOtAPiB6l9VOWhq+362YGfqUanr/PT2jdGIym0 MjWuYAMFxH/h5ntnKcSXVzWYppmfDx8= ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=Jug1ArO0CQ6HutZthr38LjNIFNhQ54f/5DpjEVvKYWWcKr/fiLG6wbHCsBPJf5wgK4yg2BrOJvvO4vBOQzYNsEvJYGjB3saVXYjetYOrHoNWSBl+SBCdDu1No00FOZClSia1emymFWa7P/bU10fn2CgU80e86v//qmdDQ8d+hJP5nHsb5DeKq+ALg3UUrlGopgKT+9PuYrauiDgkS74lpBYOaKYwCV3lHuGy0rc9VuWnhscBH9AvIASGjkW76qcl1wLeC3bmjNkbX9PcA/1W1EYQCXmhNV5f7gsbtZw7ImsOhNdU3YpETAgSSuO2CKBECCRqMkg+n/myQYJWPn4Nbw== 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=DRborw5V+5sPkrv12VBxiU/Je0fts6K9uJXD57mjqw0=; b=DPTPfdQkPbRqIZJTkw6YYn752tEhF4b1+1nuhNuHazjdTAVV2lXka/drMMBdQfSBn5Om0eYfwBv8shp9c4MGP80/0pJDrllKewjHHuD8jablCwt0/i9Aj0S4GCmk3b6m0gX6mjdZetmO1iK1DQ0XWi2XDKoMbk4RjSXg6PtUG+hLCNciAu0OBb6FVKwGasvTZeSckE/NDi8p8Z1Frs/yRR+SM7nVNnDnnv9W0/DU6TzDvxIGtTIq5+q5sTGLiGMbSEhV3JVaVRJvuyed4v4qmiCk04+sp0OVhFHSWUjAJI85wg5xaz3ROig7/g7YqbRuGlFQsmaN7qK9uIgALM7khg== 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=DRborw5V+5sPkrv12VBxiU/Je0fts6K9uJXD57mjqw0=; b=OyX3g3G+aY8E2fIN+ftroggmAp/zuhf4uPB6EFdsdTa9bLZl4HvulJhCXIqR5leb7ci3jEbG1mhRi/tmCsOQbLRsrkPRnHd7awR8YJ90Qkmpp3tAgCAx5V810Hhr1oFKBT0byuVwTgT+xCB2r5pftTC/n/n2k1rLW4pIq6V6D5t43yO/GVID8cGb/pKCaiG0WZSDpuqsbmUCb4k6xp5HvJXZxBXm5DWcfNIdHs6XGvNjqiFoDmtQRFtgFOEjqM33H+KjQRH/BMRiP1o7dGaIa1Z+9uvy6HYSxAKuAevx57HzXlTZ3783NcVcS/DAEyZbp/LehmgRX7DxsjbPYTZXNA== Received: from PH7PR12MB5757.namprd12.prod.outlook.com (2603:10b6:510:1d0::13) by BL1PR12MB5924.namprd12.prod.outlook.com (2603:10b6:208:39b::15) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9160.17; Tue, 30 Sep 2025 18:04:36 +0000 Received: from PH7PR12MB5757.namprd12.prod.outlook.com ([fe80::f012:300c:6bf4:7632]) by PH7PR12MB5757.namprd12.prod.outlook.com ([fe80::f012:300c:6bf4:7632%2]) with mapi id 15.20.9160.014; Tue, 30 Sep 2025 18:04:35 +0000 Date: Tue, 30 Sep 2025 15:04:34 -0300 From: Jason Gunthorpe To: Alex Williamson Cc: Shameer Kolothum , Leon Romanovsky , Andrew Morton , Bjorn Helgaas , Christian =?utf-8?B?S8O2bmln?= , "dri-devel@lists.freedesktop.org" , "iommu@lists.linux.dev" , Jens Axboe , Joerg Roedel , "kvm@vger.kernel.org" , "linaro-mm-sig@lists.linaro.org" , "linux-block@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-media@vger.kernel.org" , "linux-mm@kvack.org" , "linux-pci@vger.kernel.org" , Logan Gunthorpe , Marek Szyprowski , Robin Murphy , Sumit Semwal , Vivek Kasireddy , Will Deacon Subject: Re: [PATCH v4 10/10] vfio/pci: Add dma-buf export support for MMIO regions Message-ID: <20250930180434.GK2942991@nvidia.com> References: <53f3ea1947919a5e657b4f83e74ca53aa45814d4.1759070796.git.leon@kernel.org> <20250929151749.2007b192.alex.williamson@redhat.com> <20250930090048.GG324804@unreal> <20250930143408.GI2942991@nvidia.com> <20250930105247.1935b553.alex.williamson@redhat.com> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250930105247.1935b553.alex.williamson@redhat.com> X-ClientProxiedBy: SJ0PR03CA0045.namprd03.prod.outlook.com (2603:10b6:a03:33e::20) To PH7PR12MB5757.namprd12.prod.outlook.com (2603:10b6:510:1d0::13) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: PH7PR12MB5757:EE_|BL1PR12MB5924:EE_ X-MS-Office365-Filtering-Correlation-Id: d52a0017-4e68-4215-af83-08de004bd0aa X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|366016|1800799024|376014|7416014; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?E3SK2j+3tbuJU/AkKlswzOcFqjySaVCIkhNRkbHIiu/k+iZvrMi39stQaa06?= =?us-ascii?Q?dSp/iGI6Ft3khh+PP9atLbqALZUUikd4rYbXTCSaodoidAX7vhl6CCQoQwtR?= =?us-ascii?Q?v7+pR59XSbKWR/Cs0FcuZvz+Ll8FJdvFXGmdXOLeWLRXl6raMZHgDaT8c/Ok?= =?us-ascii?Q?7OpM1hthoHg/aVG9q4qichsWZ9W0TNEQuy0ve6NtlJGVq8SU8XxniC2tdRmF?= =?us-ascii?Q?MQhdCvlL0+yCPkTlZNhnv1mO7KzJEwsy15t5LQv32WulqA0yEcjNIiBhvl1p?= =?us-ascii?Q?IFw2B5Z6bb4U98zCH3zEGrmAAdK9EUg1bxJEgtZJKqRjOcXzTTJaxLwH5rx2?= =?us-ascii?Q?0R1R/uEyrjyrTWhT8nyeF7YXeDuMz7tpCyUZivnI28u0wtdwWyhyi9gAlqmg?= =?us-ascii?Q?aMn31LNbKyw0DqOd1NTHd8K5bbbyp/pR7Ovi6yzQyj3wiHd75DBhvjVD/U+U?= =?us-ascii?Q?FDP2NLTNBL6TZFXYTQU7pr2b7w2BUI91tyyRMM8RsjPHTZo5WCxlGyM7uQiL?= =?us-ascii?Q?QFXt97yzs2oUg4wqqmXv0fmTxd9pKd6uRpuVB9+IN8t/NFryEdxdUoWtBRwd?= =?us-ascii?Q?wCS6eKVd2qQUyN5THKbZ4h5BHceFH2ZWDm+b0Fbw7bn9ywcc36EJ27loPiul?= =?us-ascii?Q?5dVA3TLPlLRwkTINIzHbkmsbtixUqLpdKsELEEMGZtQyJ/f7u9tGI0QRUyHy?= =?us-ascii?Q?MPAwU4GpBUr0zJbhAqeZHwEXHloYllsXTSU33yGVL6Nhwt1vVCDNgjIITiDl?= =?us-ascii?Q?2oDdAtfm8uxLP3oDpwImSQsHpEKEJ1unhSIVktVx3DRuPZHI66AOhn+/6A4v?= =?us-ascii?Q?/t5Z0wGsSNmV1t/N9QjlJHsLK5OX0tUffCIvNTV7VU4PBFh1H7XeBSnyIchB?= =?us-ascii?Q?CrT98s56ej8n+lLWa1e792L6e8DV7kZbaFIrY7HJuZ5OrWMqLJ+6BMS38t4I?= =?us-ascii?Q?sna5gkA22MC6ezsnuB3sllo6EPwKVSl599d+eRM8K1A615QuFNRfOmQvuU6k?= =?us-ascii?Q?B3V2vM2BkcXariqq4pQoMCWVIhdKsp6Lf2F4tUkU4Sq9/FSIsysYhsA3ocWX?= =?us-ascii?Q?I4tIaNr7UwkzbDupWSFdBPJFPgk1J9xv/mmG3Ey59uqFCFWC/VimkpV7r9jX?= =?us-ascii?Q?83xtjrNO2GdLuSeOmf4x1gAT5+Z+1P61jSu6CbpeMrf1GMBmxltk452BMJr7?= =?us-ascii?Q?Nbz0B7MegpMeNW52Da0yJ6neg//9NEZMRY2CP2BDKv4n7x0T7ZZP4f7C15EK?= =?us-ascii?Q?hzgOm3sjX6jd2Db1YPFVTNYc5+ojIjy7jT48Ow1iG36lq8eBSokA85GNexRl?= =?us-ascii?Q?vc+50eprgwQD9mEnuiZbpgrdsI1tZ3nRUaMOKRjdZ8GrA4tzHoiHmZ4v4tpY?= =?us-ascii?Q?ch7LgcGV6NoO9h4tLTehSCALwcN6ePzMHJq+smpLvipn1aqjAxVP92uEcJxz?= =?us-ascii?Q?EPDmJA0evJvj2UoL5WwX+/NOqQO0O7VH?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:PH7PR12MB5757.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(366016)(1800799024)(376014)(7416014);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?LXBO/duRDt96Rw04K2RNJO2YLZpmtHvZaP9kROxOXtN1SdC3wBQfzw9Flr0D?= =?us-ascii?Q?28l2hgcxTeFj71l8T6tsVlCol7eNWusyzhOqC2Q5/cVHosyRA2BnveYJGawZ?= =?us-ascii?Q?oUjuVxEyDCM2AK4LkX1/mKHrPzw+SfFwQtAnTkNJU1jD4sEAfHFdyCMLxj+/?= =?us-ascii?Q?lj2aAnVkhqm8cd57c7gukEOYMHJqUAW+PtUg6Mu6/oSv9jqU2TFgvgZMfnPd?= =?us-ascii?Q?7LkXBzPu4h6XUJsm3i0B64MCMRrENSM0MR5xvDUPqkt4KfOQoog/4QzlxZJn?= =?us-ascii?Q?o4Hb/sG96ZAt8qoYuuBDJNZoTA3MkSF9uQYrnAKWK+hn234iEwtGnY6FvyF9?= =?us-ascii?Q?q2jkDSnUdG2qgUWG4GQG5EHVvzkhxa73Dh/lgDu/KM+ug1y0xlYkEMHFUGpJ?= =?us-ascii?Q?to81YGQQS68RluMKKJ+MIGTv0swaZchGoe+P3N9dHzAODRLHyWjTsx6H8yZr?= =?us-ascii?Q?7FFtyTEeE/pCuqYaBnqxKe8zKlebCpV1s933dqzavRw6quVAh0edWJibC/so?= =?us-ascii?Q?E6/rhXHLtI/IErImH2+bqwWkDoMq8IwoCCFG5KSM+B5+Yc06AL3HgGuc5Wta?= =?us-ascii?Q?0OkPpbAOAn/NZig1f2oMg3pkDenrxmyRVxKbeJns/3y2736zsAoPxqlVoj44?= =?us-ascii?Q?f39LvSGvLD4a/SAZm+uDuosecBUV034SFPvhs7vYhX0OUeUszz/Y8pUdDwqX?= =?us-ascii?Q?w7+vt0cNF4pKu3Xog08R15gljmJjAJNQVut+OOgKWw6VDIdVcPpeCFY7bAPn?= =?us-ascii?Q?sgDniD5yg1y6sLE8Qh3jCNEWwgRzzf6b1eP9v5nlP/pLgE8HtxflH8I1eZ9T?= =?us-ascii?Q?DHhDXNtinAMFdpj0EX1IWXNPfod+lImTPQmNiTmE0htAmJxxHXtDu76qiU7w?= =?us-ascii?Q?+yGB5w1yImYEGKhQRznn9MYuaidSJx2bN2430I38wB0QD2V3QdLGEPlNe/xm?= =?us-ascii?Q?chaviLtIlt30fZYYDKEfVGN2pAlJ3bfAxdlI4hdvnbVdGFela2Bipg7YppGW?= =?us-ascii?Q?QP9Z6NVCDw5DePAXC7Mj+YSsGuznO1mGguJdXR4l3KRIy5NqPNBNzKjNSFiq?= =?us-ascii?Q?TnvyJj0YT5gcpyIJ7s8VXjCSNVEieyXy84ffIDowcWcEEQpwYBVOHFUwfrVk?= =?us-ascii?Q?qwKQ8Zt3vK5//kwGuoZz5NBqBzsQYD2eIEQLriPBfnOPRvEjMqjoSJL9Axsf?= =?us-ascii?Q?0RjXIz4fNWCsTn2Kv1JbyX8GHZgLz3rs9uBBE3pMUwT7l1PBIENtj6cR9vbV?= =?us-ascii?Q?1fJeRguCMKm4YWXdauigM6dE/XSqBnTdS0SzmOWUf5688EDlJ3D3ApaQc34b?= =?us-ascii?Q?uHk4LSwlTL/71JHRRnr5JU4JbB40g2x7BqpHK6TAHSVGch5hgdZPQzekSiRP?= =?us-ascii?Q?F4jS5oA3fVLcOBUKfCrl3VLYLJF1bRA59iZF1xvJR7GLRE4F/viDkQISF4re?= =?us-ascii?Q?rPL0qPYKcvvxNY28Y6q0q1NV8X7I/VfKBXIJBou9Qxuqox5/7cuWmtwdGLwR?= =?us-ascii?Q?bHweoBeYRAJdylUw8OgfjrowchtZwQBrRbVqbp01R55k98E0Jd9ajk6FRpIG?= =?us-ascii?Q?GtOysy6PYBHdVRxrrZLU8zpDJDDi7oy0Hm4DZLTS?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: d52a0017-4e68-4215-af83-08de004bd0aa X-MS-Exchange-CrossTenant-AuthSource: PH7PR12MB5757.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 30 Sep 2025 18:04:35.8337 (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: z+7KBoYOnRK481ERDsAxSPKzEf1NezugLxYADTgrlxGDv46WZtTEWJCTmuqlcNtu X-MS-Exchange-Transport-CrossTenantHeadersStamped: BL1PR12MB5924 X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 3871F40007 X-Stat-Signature: g5fi14qnj53roc4yupdkjbyu9z4ijr4q X-HE-Tag: 1759255480-269509 X-HE-Meta: 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 W7QhvDtY 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, Sep 30, 2025 at 10:52:47AM -0600, Alex Williamson wrote: > On Tue, 30 Sep 2025 11:34:08 -0300 > Jason Gunthorpe wrote: > > > On Tue, Sep 30, 2025 at 12:50:47PM +0000, Shameer Kolothum wrote: > > > > > This is where hisi_acc reports a different BAR size as it tries to hide > > > the migration control region from Guest access. > > > > I think for now we should disable DMABUF for any PCI driver that > > implements a VFIO_DEVICE_GET_REGION_INFO > > > > For a while I've wanted to further reduce the use of the ioctl > > multiplexer, so maybe this series: > > > > https://github.com/jgunthorpe/linux/commits/vfio_get_region_info_op/ > > > > And then the dmabuf code can check if the ops are set to the generic > > or not and disable itself automatically. > > > > Otherwise perhaps route the dmabuf through an op and deliberately omit > > it (with a comment!) from hisi, virtio, nvgrace. > > > > We need to route it through an op anyhow as those three drivers will > > probably eventually want to implement their own version. > > Can't we basically achieve the same by testing the ioctl is > vfio_pci_core_ioctl? Could work to start! That's a good idea, then we don't have dependencies. > Your proposal would have better granularity, but Yes, that was my thinking > we'd probably want an ops callback that we can use without a userspace > buffer to get the advertised region size if we ever want to support a > device that both modifies the size of the region relative to the BAR > and supports p2p. Small steps.. I added some more commits that remove the userspace buffer and all the duplicated code too. Jason