From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from BL0PR03CU003.outbound.protection.outlook.com (mail-eastusazon11012019.outbound.protection.outlook.com [52.101.53.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 80539348C70 for ; Mon, 31 Aug 2026 12:02:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=52.101.53.19 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788177731; cv=fail; b=OfeNQgVCXkMAZ1cmBJQFMQ30bKiCjmeCEpDkLIpeMGdYlShiajsTDuq+bep5Viyz8CKxw6aFHaMbHfJoTH6rVzcUx5Yt6Jq1J+TcA9YMg3Siy+tmQQlL3eJrvKlqRNoYfeq9VMjRof5N6f+pcTj5Sb/jCKbSIvchOr/nLaWJZ4E= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788177731; c=relaxed/simple; bh=OBhfePlHSfFSSIHHuEKFsDoc//nzapG4jnXearpn55U=; h=Date:From:To:Cc:Subject:Message-ID:References:Content-Type: Content-Disposition:In-Reply-To:MIME-Version; b=Ghc64sM++lz09sQBSGeJ9SewMHpC9kzjqHw84cdpXbGkUIXYDgwOQsHEJql/6pFIVGaLtLr0QuH6kjk1qBi4k+8VgrFV9yheizbmj1+EB24cLv053qcVFScaJVapMjKhArtB1fHTdNYhG+pvkXauXFGsDBZHMbzaTph2ZZ+iD7o= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=nvidia.com; spf=fail smtp.mailfrom=nvidia.com; dkim=pass (2048-bit key) header.d=Nvidia.com header.i=@Nvidia.com header.b=femdVmQb; arc=fail smtp.client-ip=52.101.53.19 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=nvidia.com Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=nvidia.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=Nvidia.com header.i=@Nvidia.com header.b="femdVmQb" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=gyBkk0LeJo36y1b7EVy1q2pRVUS6WexcvzNPXbR+VnKgsE9aRiIIZNOjVc5X7FQMUYIzjhr5H8UkD+Lx2TJv2InlD7E/yuCf2nkQctKQUXoptRdIDi1yEuNBTT3stbw2LYIx0xS1DZhKijhPyB5zmSCcerCFFXvCD94TMSBNMCl1TK/HTBQ2uAjASCewuN1YxYOGGRbkXQRP1ICip75ygQVnW/eUePhlvXFJoDLXfPFGyBqh1C2gvy77GuNwIhtm8Jme1gpZnvFAvBzcX01QGbRyDZ1XgVgBszQHHKp5SHVHw524vT3UGqNAjKmasdDyBkUkDT66S1fKRUP58loQig== 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=32tEMqalnYinDgJiFrPy2hUA4L0wfu+x8SPLDRspAu8=; b=n2KlNZQO4BnQiWhuTxEU5rqYZcUbAt288Js6Dp7dNQ6CXYShQvHNy6hANw3rrEBD3kVmRZZtwV8tXLQ5Ez3T5V1sUQwA238B82D/PEZVd36ZEzfr7jbHhwvjuRo7gCvw2tcFd/kiqob+VRpFND+yso8r+ZB8mOKoKxJUF6ABW2lRT6uweOiHo8/+bl7pfdx8FwaMZPO6zgt/ltoPbg/BC/ElefscpZ46q8/WNLFJHCK4Qj9EmsCh/bKqCmF5w0h+9odPt0t0zgDHCExTxjTQXk3Uz9JM53Jxnl5FPOBbcDLigDH17CaFZzQpxpY7kg2C2vGv85ScLXsYojxBvkB8Kw== 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=32tEMqalnYinDgJiFrPy2hUA4L0wfu+x8SPLDRspAu8=; b=femdVmQbs7VPXjBo7tfh1rBp+eLGBtrE+ZFlpMHa+5s9vN6lAUd9JhMewpQUgAKZzOLVqLqX529aEYCxsfejsF1ENFq1xPI/EkU7NXfroYaZPR9GbTA1iRb6qxL4KX422KiPPclbw7gjWVuB2PNGejMAVLbKchIA8QDQGtkszoxiKm2u3MFsP0GEr5ewZUIniEPsAhy5yNL1Liy3X2nFBm1bxYFyx6/YrKOIqEvf0qFxSI9jAa0UZnwDmUu6ei1mGfa7Crl3Yxu6qVQXlVbDD/1z8w8OESucwSIpm0lhp8w40w6V5lPTwSL7i5+0Ifp+Mnw2k+wpXaErju2gQRSTsg== 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 MW4PR12MB6875.namprd12.prod.outlook.com (2603:10b6:303:209::5) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.21.360.13; Mon, 31 Aug 2026 12:02:06 +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 15.21.0360.008; Mon, 31 Aug 2026 12:02:06 +0000 Date: Mon, 31 Aug 2026 09:02:05 -0300 From: Jason Gunthorpe To: Leon Romanovsky Cc: Bjorn Helgaas , Logan Gunthorpe , Chaitanya Kulkarni , Greg Kroah-Hartman , Jens Axboe , Alex Williamson , Ankit Agrawal , Jonathan Corbet , Shuah Khan , "Joerg Roedel (AMD)" , Will Deacon , Robin Murphy , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, iommu@lists.linux.dev, Tushar Dave Subject: Re: [PATCH v4 10/18] PCI: Account for ACS egress control in isolation checks Message-ID: <20260831120205.GF4157646@nvidia.com> References: <20260821-fix-p2p-acs-v4-0-v4-0-94426b96de73@nvidia.com> <20260821-fix-p2p-acs-v4-0-v4-10-94426b96de73@nvidia.com> <178761377056.3197084.2573998749847027711.b4-review@b4> <20260830092033.GE24140@unreal> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260830092033.GE24140@unreal> X-ClientProxiedBy: YT4PR01CA0050.CANPRD01.PROD.OUTLOOK.COM (2603:10b6:b01:111::10) To LV8PR12MB9620.namprd12.prod.outlook.com (2603:10b6:408:2a1::19) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: LV8PR12MB9620:EE_|MW4PR12MB6875:EE_ X-MS-Office365-Filtering-Correlation-Id: 16d673ea-03ae-4554-0874-08df0757ad6e X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|376014|23010399003|366016|3023799007|10067099003|4143699003|56012099006|11063799006|22082099003|18002099003; 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)(376014)(23010399003)(366016)(3023799007)(10067099003)(4143699003)(56012099006)(11063799006)(22082099003)(18002099003);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?9YMXwDEa+uW+4bGCAh1xRIKE8py7tLL3W6VRT7fPtPIkgyewfSIS0yOBfBUQ?= =?us-ascii?Q?jFiBDT8uNog8+E3LBoVkPkV692LjRyu1aJlGs31kMsudmkm5LZiBH8POcIrB?= =?us-ascii?Q?PWtm+xOkjBePEvQduMoairvKYpjutV2WatsxHeNzHg3SXHFvT5uU793d5R/+?= =?us-ascii?Q?UHkXwP0V8c3GAWIN5D0++Kt831+Y/y4ZV3Sn/Nb33h28Km8wwgJ2nwHKnSZq?= =?us-ascii?Q?SBY107OWHqUNs0gyP64sY5ydD34GoL1QZBP8ZWVZHybxsiqQQAVr1+aLdtwk?= =?us-ascii?Q?dfobbt4oaMC4sq3w7UIhBOC52VcPNtoaatZDP/WJcdBoExfFZoWCbz3W93QD?= =?us-ascii?Q?bEUKqnPuyn3G59VWiGqyYi3pl09ArN1r1dpv61tpOjRGDUBvpRVOnqe8eDI0?= =?us-ascii?Q?bk9qWUNTQo96Nc2oBjWKuHYMvUKID4Ic6BBj1QDI/gxFQcYabqagn1ctjEgl?= =?us-ascii?Q?PCqGs3SB0mALiJUF+ZPaYmNs7IslOvJQo2JPuLKRviHkJBSyoBR64nVl4t1I?= =?us-ascii?Q?G+YexO4uwdk2SO7ZgWtmgP1eYgYz/iZdqP27gQjvdRlmqRO2gXqPC5EbWIjz?= =?us-ascii?Q?F4Pwr9GC4JTP9Jfc68yySm+7a8AD1jaGrEV22w7FoV9Gm6pfSzzhTQvEsWbS?= =?us-ascii?Q?CQ2E6JSwNqBbPqKusYt23jTuTn5vXb0tmRbQkWWlNXDWtQExU9ANSSvdTKWb?= =?us-ascii?Q?5aKxR2TAvScRbWdhxT7eA0PGyuIyv+9Kpd0pMb0wTv9KpawLxh6MpVirciKc?= =?us-ascii?Q?zUNowJEm6budHUtqu2S1iAbHnkxzB93FBVGIn1WmJCbe6vKFnah/wh+lS1Rx?= =?us-ascii?Q?fo/KRGvM2HjiyV6voyMEveV4Lp7axj5IGTWxdhttgAu+r/bq/5+NpceW4Tl8?= =?us-ascii?Q?YvDIj110CAjylQLdhw0k6RfRzEBiJQ690kGlSW7AkFgsvXjP65ur5AH5Fapi?= =?us-ascii?Q?YEzZDXMSNAjQl4ELdI67GqQhF4PuilfCW90UwzpLgt8vy9e3q3bNbhdIkH7Y?= =?us-ascii?Q?85c/85Fcg+J7EGs/7nv/HhjHohGaqI46SjU4lbrFBAxf8UZdrtRtxQv4FdPW?= =?us-ascii?Q?Q9ezXds4A6h34SEZv/Ll2fd9usrM6y3YU/5fzv6w4i9E3URWRvSMR/mQ0Zcf?= =?us-ascii?Q?QBO8OpQ/lYWK9E2f4uFL6d5WFwiN5wMmXXFOdUBXR3pMj1c2prbvMas3QaUE?= =?us-ascii?Q?1RDmNYF46EzPGSrfCx3mK+8aYLfS7Zlx2ycpDkX3kbpVgQLPs2BsWAe9KqpI?= =?us-ascii?Q?jYEE/FLHAaaQ3te/0w5ZQ8Nd45q7u/x71TGw3KxNSATIhq5k2br9ylq/0xs0?= =?us-ascii?Q?b1R1BPYS32JmHvFkNlTa/TGX1Zeup/F7yU8aSeWbZaodHHvuCJhMTvb/zUFV?= =?us-ascii?Q?dozWjpUNk//umhM1v/7WmybVTQ+jLR7TH+CX/YZxZkhwfVSEaLsjl7dAdcE6?= =?us-ascii?Q?IAZDGEXRF4huqQazObi/taXuApUlQKs3uAmOtXWludrVgDkSmiHYyaHCBP6J?= =?us-ascii?Q?nMkK2r+GK8+q7FHIj1le8I2YdGV9EdcDCgRODCmSL3MOFUs1Bxt7JJNmVwx1?= =?us-ascii?Q?JV1SuqqKFPXl33vFn1chJUwNsFSv7rnaMQixzrV8dtKk8XM+py8JlBZfdxid?= =?us-ascii?Q?1nYmwWuMM8PCguFM73rhPnvUslt7RLDW9V8S8xa31eFbep41OPXXrBFYS6lk?= =?us-ascii?Q?/OnM2HZFCfTcxQCHiJCfX3DH2Zc/NHGuNIx2oZqKNN+WRm7N?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 16d673ea-03ae-4554-0874-08df0757ad6e X-MS-Exchange-CrossTenant-AuthSource: LV8PR12MB9620.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 31 Aug 2026 12:02:06.5189 (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: fFGBGg6oy/ws2Si1xOrAbQOKh8T4vcRqA2rmKi9N4CT+fFdaB/a/N30LwiFFq6Ya X-MS-Exchange-Transport-CrossTenantHeadersStamped: MW4PR12MB6875 On Sun, Aug 30, 2026 at 12:20:33PM +0300, Leon Romanovsky wrote: > On Mon, Aug 24, 2026 at 08:22:50PM -0300, Jason Gunthorpe wrote: > > > pci_acs_enabled() treats P2P Request Redirect as effective whenever its > > > control bit is set. PCIe r7.0, sec 6.12.3, table 6-11 lets an enabled > > > Egress Control Vector override it: a clear vector bit routes the request > > > directly. > > > > This may well all be correct, but I'd prefer not to touch grouping in > > this series working on p2pdma.. The grouping logic is already not > > doing a good job with the spec and we can't change it because it > > creates regression. > > The longer we wait, the harder it will be to address this deviation > from the PCI specification. I think it is too late already. People already made HW that probably doesn't match the intention of the spec because Linux works with that HW so we are good and properly trapped now. Jason