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 F291BCCD1BB for ; Wed, 22 Oct 2025 11:39:08 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 5B9718E001B; Wed, 22 Oct 2025 07:39:08 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 56A3C8E0017; Wed, 22 Oct 2025 07:39:08 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 431CA8E001B; Wed, 22 Oct 2025 07:39:08 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 2A1A88E0017 for ; Wed, 22 Oct 2025 07:39:08 -0400 (EDT) Received: from smtpin22.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id E32C41407AA for ; Wed, 22 Oct 2025 11:39:07 +0000 (UTC) X-FDA: 84025553934.22.0892417 Received: from PH0PR06CU001.outbound.protection.outlook.com (mail-westus3azon11011052.outbound.protection.outlook.com [40.107.208.52]) by imf01.hostedemail.com (Postfix) with ESMTP id E30CD40008 for ; Wed, 22 Oct 2025 11:39:04 +0000 (UTC) Authentication-Results: imf01.hostedemail.com; dkim=pass header.d=Nvidia.com header.s=selector2 header.b=OCWFBLFF; dmarc=pass (policy=reject) header.from=nvidia.com; spf=pass (imf01.hostedemail.com: domain of jgg@nvidia.com designates 40.107.208.52 as permitted sender) smtp.mailfrom=jgg@nvidia.com; arc=pass ("microsoft.com:s=arcselector10001:i=1") ARC-Seal: i=2; s=arc-20220608; d=hostedemail.com; t=1761133145; a=rsa-sha256; cv=pass; b=YW7dqBT7/PUOXflYdobVN4rEpqgN0UzPON0S7xAQrrX8VX2Kj5OSvZ24gOn4lWi//S18YO Oa6JtEElE5UCRsrZtQGkuIWYn0ehaXSkQgzXGMRyuPyFCIQoezsQ+mTsuE41FM9zAOOAAo XKi77LOw1hKhAEzw/xdMmz/nKjJ4cDo= ARC-Authentication-Results: i=2; imf01.hostedemail.com; dkim=pass header.d=Nvidia.com header.s=selector2 header.b=OCWFBLFF; dmarc=pass (policy=reject) header.from=nvidia.com; spf=pass (imf01.hostedemail.com: domain of jgg@nvidia.com designates 40.107.208.52 as permitted sender) smtp.mailfrom=jgg@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=1761133145; 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=cTtVOw2VIMWaeIE4dqsLwPxGHKwqdsL8xGT9i4GE9zE=; b=YR5KOIMjAAigKIa1jKqiIr3jBSsopHZYBcg3pT9fl394zS92iXzRvHko/0pu0JeHzDziZ1 DODoCHrpAe550SF2WwZzTkJYw6VqCyr/uJ2AVD6OCPUVIMATMhBncN1j5/+SLbln3TL7tm sAkfAysNROi016KLAaHln7G1SlqxuzE= ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=aLKXpbgDB+BpZjjvsMpwKh2k7u+wjda9dcfPV+AeVCIDTk1MF8qmxxmTPpAZWAqu6fZwQ3ZX2Hba7e0PRYLmmUmNUmPHgKnQn9ixORhqhEZc5icHlaDQ6KE4fyrO6KFMBsaohjCqqk1AC2V6ubdp+Fgb2MUH5KDPBVqoeCqt9JQyFdAqiwYDDtvmANWyl+yHLdAt6wW4wUsWXZWYnFjTCxPmiNQQhD3N3jkdax36B7n6qn/kO2ipIwpY9m2oZ1Jb+ebKp2Fe/TzJoMyFmRehWeaAvQcqsMyBkcacem42BDUaXFKUe+vMbNdeIsIDcQlrs08hXqlGh0iLHnuUW18dGA== 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=cTtVOw2VIMWaeIE4dqsLwPxGHKwqdsL8xGT9i4GE9zE=; b=a2ZvGoBa+xRrjTc/v1F8IX3zxPSLogpT4fQW/bleWRzrH6S+pHzcjnLbgUstYAcSt489PlKEMJMrcTxO2fzCuWCOKi5f9Pt72/20Lq3w6qL3Rms3MEdJr1HE0i3fxteo1GBacilOFNlBdgg0w/047Sr1p1iCgao6bjCCLY+iGUPf99W9FqBfNkE1nNv2NNgmbvo2mvk7J7TLLDeE9Oo/1S6kCsZ0cB9uSjcdac0c4QrcmunA42rB5iNSmZUSGy8pM9HV5IrG7uSQZ5LfFMN108chEzaUqeC+/PjuCOHaKxZOeUkK67OU1ET18oJa3PIbXphXZc20VvX1fsTrACk7vw== 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=cTtVOw2VIMWaeIE4dqsLwPxGHKwqdsL8xGT9i4GE9zE=; b=OCWFBLFFIjQ4wkj9rtX9dBLGVFPQEU6eHPc4TVgl3V8I3gWQpeoqBbNg+OILssVzTCRQ4shOKl9er/oGJA8tN19Ww1jBDoIDByPwJ6t1qN+MvfaiKBmb2nl2DgziU4P/J4WgwLgogC87IaMZFBE/cbHhE5l01FwKt79wX3QgwFiJm8+aEvXIX9Yqude7/4AE1r8Yhf9iucuJOcglSCLYEIBLuRCu6h/ETkWSbuh1MTPRRAcSCQjBVXWXP+nPJ8e4Mpi7Znb2tr6GOAlZsbNB1wb29LYsGYnuLal0BLwlO+XjATfzRsIRuu8MSlfym1fu7/0uq6XU9XYGDBQbq5nB8A== Received: from MN2PR12MB3613.namprd12.prod.outlook.com (2603:10b6:208:c1::17) by MN6PR12MB8491.namprd12.prod.outlook.com (2603:10b6:208:46f::22) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9228.10; Wed, 22 Oct 2025 11:39:00 +0000 Received: from MN2PR12MB3613.namprd12.prod.outlook.com ([fe80::1b3b:64f5:9211:608b]) by MN2PR12MB3613.namprd12.prod.outlook.com ([fe80::1b3b:64f5:9211:608b%4]) with mapi id 15.20.9253.011; Wed, 22 Oct 2025 11:39:00 +0000 Date: Wed, 22 Oct 2025 08:38:59 -0300 From: Jason Gunthorpe To: Christoph Hellwig Cc: Leon Romanovsky , Alex Williamson , 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 v5 8/9] vfio/pci: Enable peer-to-peer DMA transactions by default Message-ID: <20251022113859.GC21107@nvidia.com> References: <20251017115524.GG3901471@nvidia.com> <20251020130855.GM316284@nvidia.com> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-ClientProxiedBy: BL0PR02CA0071.namprd02.prod.outlook.com (2603:10b6:207:3d::48) To MN2PR12MB3613.namprd12.prod.outlook.com (2603:10b6:208:c1::17) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: MN2PR12MB3613:EE_|MN6PR12MB8491:EE_ X-MS-Office365-Filtering-Correlation-Id: 31b0f1f5-ddd0-4ed7-193d-08de115f97a9 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|376014|7416014|1800799024|366016; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?WMFVrojgk1zDebrVlDS8NJyKw1YfCDj574XDv5e9S00BAUwEas1ta8n83in6?= =?us-ascii?Q?mzgx/51yxz3FtlistESu4M5u/zBwzLpYo6E9A8xXTuMzHGNm429Eg5BC/9wK?= =?us-ascii?Q?igTta7zj6flTAHlEHGls3sycZ84Ff9ugAjQB6ekPt5f+fwqTp8PecbqUkFoK?= =?us-ascii?Q?zf8nczicMTF8yqexx7Dnrg2Xt/TdPtsUPz6d1LVyloCBONZtCLUiJIxNpgKl?= =?us-ascii?Q?Vla+4Cw2AWDqOcFIqxQF3HbY3DYBOg0oqKuV4Bj3J/n8H+pmPGQeeJAAk0Fi?= =?us-ascii?Q?/mp/CyqpvbhJNLJZE9FzWFiE5ryjBGnvNBluUklkjKqfB+VJbbt7Z5Xg4bl/?= =?us-ascii?Q?3WRH/3Oqe2I1IxCIPQQQYZYqgykDjcxuJsBAY8QAVzpoQfaC66q83aDtfcIh?= =?us-ascii?Q?HZJ4y1pp692Q86q/WrsxUEIVztUk0pJFlKE6bCjOE3Dfum2FmrxTOwQwYqcO?= =?us-ascii?Q?fCZJRNCedycl6ZewV4amCHs0dtY5FosB8WukI61QZs4BMl9O9K2sG7uydk2/?= =?us-ascii?Q?uIinxSi4FhAqt3PHVuZNs/A1yABeFxNszTg2UrhwACseB184/Q6rTTi8WAFq?= =?us-ascii?Q?t0x63mk53TdHgtD+ebjXbiTpALYKTi5+rTEJUsDEFjh82K1yADzS4ZDIZcop?= =?us-ascii?Q?MOoYoegc3h/S5g7O4tR8yMjZH157yL9fR9eIsR1Zw34cTuchELN29urNqcD2?= =?us-ascii?Q?DBOG8jqHZBK/8dNLLYnZo1tGW/w/dzy9ukg9j0el3ADog88FnK43fV5lNddf?= =?us-ascii?Q?c2M171KxOZ/AsKGDyg5mwjWM/5/sa8X1yExkUu7lwvmaWBISdi6J7NqSI7mN?= =?us-ascii?Q?v/YF8R3xfqlNfxhRso7NtrNVlICI47nSvmWM+7l7ZIGcivf0Nhze1uYQns+v?= =?us-ascii?Q?ve+CRRm+hu1TNYnGsXipuGa4SozBZW6ZiypaHONpuuZ/iyOCv4P/9mIkTKAr?= =?us-ascii?Q?k4Mu5pKWly9imK3M4I+hZV7Hu1RMjAmpzMvXXqHFemGZXFuXxlz3kKb3z8yE?= =?us-ascii?Q?Vy41Q4PJhUrMPmAIY8WYlQHBlS0ZvAHQg6J92D/DEEzUXssNswmi8YIfF5mT?= =?us-ascii?Q?RLYXX3lGYchr29xbGPfJffOVbLnMkbWSXPvZmaEzW8tPlQkxpdNbH+ZTjMyv?= =?us-ascii?Q?ODbjJfQpsHqdbc+VR6gjKcvweQvwsqVFgNu0Z5D03s76ULFdXGRmGFbg0Qsr?= =?us-ascii?Q?S4SjfRu7cmUeQBy5Iag4E13lpbU6kDKWoqTj8KgzJJU+cM4bXDhse0aT917a?= =?us-ascii?Q?0EbaO3jSh/d4ovL+PQo4nbeW8gz2msIqhzlQK6FpM8h2ETAaDpoMDWL1rLkK?= =?us-ascii?Q?TdliszJZ2gQp2sJJ1tl2lYFjTwmgeC710DHEQd6lPUdjchwNgbZYXAHNb5jW?= =?us-ascii?Q?0ZnRgdLZf4SBOFPlK5iZM6y+EXMZPpGLgPkkiFHFssFaMI2jh1r1BrujNVU/?= =?us-ascii?Q?jxkTyCT8grAKwg7vCI05zlrs6z57hgix?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:MN2PR12MB3613.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(376014)(7416014)(1800799024)(366016);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?JAp/cLBxMF3eGCTANBuxo3pwIRjMinlOdttteNo+BHFFFPqFijjyghIWEQX3?= =?us-ascii?Q?OGyufYZ07tTO74JmoLiCMZ9KcIuL4yjZDfPb0bqyBvwqX+KxAhlOcI9OJeqh?= =?us-ascii?Q?JdpaFu5fHvXJlrkp8RtlFFpDQH5b/4wbNMxZBcjhIktisq3mZh8ZjjInq7ip?= =?us-ascii?Q?uN34OPqAs1eOXh6sFiyiuJXtKgS1fWQgqt9/XdYg40q8kuVL0NVXpFQ+PTpP?= =?us-ascii?Q?HN55GIyvfFQWks54S/tZudvQT5+tpqY8pTWXQEA6of2fGZsWIsqRbLHiSycC?= =?us-ascii?Q?/CVk8L0rdi0/H9dQnPehSu51+nCKCU48GIJZOYqXx+0ch5/5Z0iQ0QbqcKBc?= =?us-ascii?Q?pfTd1tGxY3JBNWaeoSvyiVmvmWTz/d4dlWNveFl7AdqIN3QVZxMFz6TfbOdj?= =?us-ascii?Q?i1ThSWJmtMnENi0Du2Wp1qq9Y5GFnxq94mwg51L29O2jLwYQWtFW7Uc2kxDR?= =?us-ascii?Q?3VK75rvX/aNhLxhA3Ll3oWswdlLTkCeGF/a/OBiwUhGK9/XWlooUBwx6k6Pg?= =?us-ascii?Q?bLzpUVpHoIucIn+JVVJ4/a+Qb/rjWwHLnA6kSYi99W59WXe3sAcpeZqWZBhI?= =?us-ascii?Q?5Svn/NjSeA7tFw3pwwtMFcpRTrHCjQULq5cAS2NYqEY4/EC08H+Qrk6WH1Jb?= =?us-ascii?Q?HkwZHLF78lNrxbO8ZKlmggmUnA5GT+dq+SnDWLcEugRyfZjVTswQ4/EE2abN?= =?us-ascii?Q?PJANte8FmFgzibkcv3q/JQJQ3D4NV2CDu0B88dwCh/URreBXBRFbWpTEc5zB?= =?us-ascii?Q?AX3F9nRaTrkW0t4qP1+LUNAp90gZVG21vtVtHSBHnw6PkBiW5Nuy/5NGmpLp?= =?us-ascii?Q?joQTWzLYF9t7W2k0qdDZoJXk0s8U+pF4bIodSZsKl/Xk+UF0rj83oXDMZC4f?= =?us-ascii?Q?LL+7w90NR2dDRa23J64AIOOGv5RBQH4qOxhwZ307Qawub3d/TVW0xXM7fyXd?= =?us-ascii?Q?jxwolhBt0kRuWLirg2Yw7jH1qASgSesX5Zi9LikJgN31lIVPBCKB5dtJcw3K?= =?us-ascii?Q?WgK87jWb5H8mkeWeY1PS6/ZGSne3mfzFhmFN1m8+OOHwcOqa42tiTK5uJzP1?= =?us-ascii?Q?D+skafbLBsjF0ZjudgCnpQeXpxG6bMNfEwK7G8G8MR3r37rrdZz3jocxS7ee?= =?us-ascii?Q?70TDXAydA6nwtOahD0L+5dg5xNPVshN7yw3CmdWVDhJKKys7IcG1xMMLH7be?= =?us-ascii?Q?ylM9e6bJhcz+ChKIDpFPb0Wpvmw0bo3h9qVqO8uiEbnQTUbD7NUm/M4CRK/j?= =?us-ascii?Q?JIvKULXrKFVmLRrbgHFlD2plx8ylbXkfuSmnrnaq0BNr/Hh8Ca8VoEVyX5WN?= =?us-ascii?Q?LuLtXiQ0434+ayMgDySOLGRz2oBC6DQzx0tAWvEZF157E8JQzDHrvX1OpHMx?= =?us-ascii?Q?RVTvpDKk5gDQybiObaXfs1sOg+vPArOy5I90QhmQ8MPHgpjy/tsru1PnIFf2?= =?us-ascii?Q?Q5lEz2/JbP3az3ysVQma3hz6ED646KYo2rmxNEbn1fOtw+G+zHyrjRKb9k6K?= =?us-ascii?Q?FZuro+8oJbIdw0Ow9WMflXZm0+80aXLoI6XExt4/lZfTEcPI/qt9UEYcFeNM?= =?us-ascii?Q?Kq2R+IL95pthnwY/yO4=3D?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 31b0f1f5-ddd0-4ed7-193d-08de115f97a9 X-MS-Exchange-CrossTenant-AuthSource: MN2PR12MB3613.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 22 Oct 2025 11:39:00.2985 (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: AwVvZjaUxHfam7TjsvxTg8wT8OApxG23hlxOU7s69X5Z6j8su1yaRymRsM12q/cJ X-MS-Exchange-Transport-CrossTenantHeadersStamped: MN6PR12MB8491 X-Stat-Signature: 5z36y98zuk5rgxbqjrph5xoro3kctibm X-Rspamd-Queue-Id: E30CD40008 X-Rspamd-Server: rspam06 X-Rspam-User: X-HE-Tag: 1761133144-852269 X-HE-Meta: U2FsdGVkX18PPF2p0mZTvlPWMNRK2jPc40hpaETXBHWHl+nNaH3KH5N32e/utwzdz0k9LQXGJIL47QmWi7YsJ9PuBt+bVwO+V/CJM8wi4NcpCfW4r/ow5z2ZKRBU6ProOewLEMGW0u7w2Umrc7JOrNZu3VJt8L82I/6iksosRld9hz6xFrZCNhPo6NgTwofO+D5EBRg8+0i7OWzEHN1e29vfyJg4+KOnfUUj1jq43I3KIL+qBjrwphUSrDvheHcFP1tBmBmFqUIlskJlfuiAUI37DnH0MkXjlGVv9/5Rgx2MJMtjbjnpWeRcQ3qACddMbi0iQY9Cicpxyb3DnhKK0JQqMYpaqtcJzaaqKfmZtxFeJxiuxEoPM95R9hTOFLNQ1Y5kQ/1Vk1w+j/upW/y+Fy8Ug2c7NgYyMmW005w+R7bTuCu1IgemfmRLbK9ZWtiw68yOJVdgyR+BgU6U2fu5tm+FYskdAXbmyEpFLN3jOd5iWYj0Ig8azRpAdI94nElfvq2s1EqKs+oR2vSBP9jwJapH+1y+GKLqYYFLBY6XQ46caqHLg2/8nQgXsqoQVGICKhjDWpuHz7IxfT0Rj3DnsNvy3TZ7ERjaAZ7uoExynFzZtjjVsLhWMCngkKZZlgSIxTILZerEve/QoBWPryxb3FAUlYYieXjjIoisZvH2Dn4HIUIyB7ZN8wvV3v4B97wR1ZWZWFtJd+ri7+d5ZS3IdT6071LUN9ctdf7LryOVEdQE1GnyWu5kWTJi0kOAbjkjTV+d06ku83GRif79XjRsWhO9KMoLMB2zPel62QhrkE09QaZ/u2sZDYd0ePRAqGwsdmaAMgIoUEvXgnkB0ns28706CV0fYzk/0Awm9z0up3cCgu7f3qAX1/ZqGIEnU4U2gDDVNEdinNoVisPQ3aMz4Ay26LJ8UblNJswViEO6/o1ICVf+gxv+jNDC5FofAOpkeDrmLFgYj8N0TEeFR9Z bbXC6FIx 6WmIU1hD+D94r8j836S4rMVr7g2bS9tK1QxKFRKnRYaAwslGltCk7CKXcP5Cdw/tT9TRWGz9eiZ8ROKymOb3r1p/GFGlXT+3s22hL/9+rEmC/SFmbooGHuYqc9tU35REumWnaX401k6SyTvJOA2K2/O9PMGLVg1uXhOy7j1synp8H/7mOSvDfDT95DFXKLnnAp5XB8bS2Llg35OrCXHXAKTg3gv7fVBK7PmmriRYpNcyVieiX+QOsGpIZhgaKNAYWJZ9rMqdWztFTDrYuZG9eO1qY7mZH7zvZFf5yWmZhnWGNpUdIBEy+Kh4tpfW4LL707gZkJr5XZQKhSSdNRgCP7Gi11Iki5QYBg3/HrrNzDszJiy8CDznDCzS9yRgaJ7SAJznB/nE4er0k4U67XJfFKMR4EA== 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 Wed, Oct 22, 2025 at 12:08:48AM -0700, Christoph Hellwig wrote: > On Mon, Oct 20, 2025 at 10:08:55AM -0300, Jason Gunthorpe wrote: > > Sure, but this should be handled by the P2P subsystem and PCI quirks, > > IMHO. It isn't VFIOs job.. If people complain about broken HW then it > > is easy to add those things. > > I think it is. You now open up behavior generally that previously > had specific drivers in charge. It has always been available in VFIO. This series is fixing it up to not have the lifetime bugs. > > IDK where Intel GPU lands on this, but VFIO has always supported P2P > > How? It uses follow_pfnmap_start()/etc to fish the MMIO PFNs out of a VMA and stick them into the iommu. Jason