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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?Rc0F8cFIxKhWm1RO+FvjTent0vGVOBeQtDSIxjM6+fbB64H9QWsSM67GUGQU?= =?us-ascii?Q?5U38JVTNDl2WTo4xjlDLMHK4KAmB6kqXMsCEXJuTI5G6BaDydD/xA7Nms49I?= =?us-ascii?Q?JZFE9BkVrEBh7NVTBe0Lmha7cIzT846a2yLVG5/8MOc0qq2xr92qkkO3x5v8?= =?us-ascii?Q?ufcmjm1XGPLWuw3MEh/83apeIGlqK/K61sUgHTIRugd6JCL9v9UcuOzKS00K?= =?us-ascii?Q?ce5PwkGVJHCUFwHzq7O76ATbXOfraiQRKRP6qU3RIhycxOeURMBxNq9jzrPh?= =?us-ascii?Q?GuqdIukt/pbKCfnSeIqozQX5JKBUQrG5tQm7kxlT3k3qz73aoZsGHKoyz09q?= =?us-ascii?Q?gg7Z1yewjM0RscVI6b23JchyLFuL4IJmsz9zc383Q4EaCfPmO1A9BuAY/dwj?= =?us-ascii?Q?Gr2SQRkAHUj+nMqWAPsWiXUigUD583J2DIEe4tpe9uqaW2EB23g42011pFNQ?= =?us-ascii?Q?5n7jIXwwwvDMsZIKLl5+IIqS5oaWhkrPLjIECqoUIhrCtb9FQcy6oYn8rTxG?= =?us-ascii?Q?RRxF1nR+Fcl93tvnk+WXo7BWzNr7Mkm4MCBwfas5gosVZetxJdLjgLXwA3qu?= =?us-ascii?Q?6kP1omTHSCHiJZNjI/4idCwMgYuTpwz769zA5KhWnTNnb+jeKoK1cAXEmk1P?= =?us-ascii?Q?Stqz9cmeKgFeS3kf44GGPthym5V7TnaE7VQWYG/3I9YTdlPoELXrbDEfaeJ3?= =?us-ascii?Q?bZDH2hFq1BQc/qiXrySp44qDfR/j/FLwxrwD76bIe6E68w4M0V5cRa9kSh5E?= =?us-ascii?Q?djzl4Csj9nDaOqIpoCuQy2ElQREeCJ3Df1+DYjLImsvlqLcduQtqJD95gxu9?= =?us-ascii?Q?nwdD99InpAdkSGZUuW+MHPZTJdhFQJBUlBk1wBN93tSqCLQnzzyNKNv92GOl?= =?us-ascii?Q?e53aQ09yCkV+FW24mad10vnzYkYYLIK6Sczd9Is5mh02fpf4x/7pq2CJqtNd?= =?us-ascii?Q?d5IpOxzgRp9IzoDuL6zo/nWiGMjymXfGHVmT/enY/AldG5gdDSC7HlTFqT7A?= =?us-ascii?Q?xkdWi8disXZMFWfIRF3as2LaDzmL0G/atL98a1CV4dujaZXcAArqBdMf/Vti?= =?us-ascii?Q?tbsk6+CKM1l/v4rneaPSRfC1hLtpdnpJA0e1ozaDYyXDQB+wn5u5YwruVecU?= =?us-ascii?Q?MEDVf6rBJMsKpxg3glXOubKVU0QDwId8wvJxVShezNP5NZmyHMcLfdi1GKVY?= =?us-ascii?Q?ocdE/hVN6mUiNkmD25F8i5Ie95V5xS0BK1bSdFMFeyuqa2TAa2Rk4NxHEe1T?= =?us-ascii?Q?an6TFM0WjzHrh7BlrH+C/88U0nIHsMGtqZl7AyDTU00lpuqCyapXTvr3hCWV?= =?us-ascii?Q?2RMUdHSnEiAtfHKuhX2ET+JfPmtLH1FwJdED/tiveO3gE8eOucbLx8BnGygE?= =?us-ascii?Q?FUEkoGrzH2jqoAKSp5Iw8ynBLv1Kh8T543hhYuX1aSaGWSWW9Qb0F0+FgSP/?= =?us-ascii?Q?MKeF0WzboyMePn/adsTWlKNYW+IJJCI91S39PH4vFD4qn7iSwLNkFa8QrBXJ?= =?us-ascii?Q?L54QeSonjSfGF+Q0a81mgG2M/x36lKhoW2w2+7LOnlStxIK/vpMfQOqbehOP?= =?us-ascii?Q?tr/pfm264qccuSnz8lo=3D?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: c2caa469-a856-4979-eed0-08d9cfb813fc X-MS-Exchange-CrossTenant-AuthSource: DM6PR12MB5520.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 04 Jan 2022 19:26:16.8864 (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: jEFVfD1sGF4gxaCZ1aNHZfoR90qYkN+kI316YtokeeE9jkGidUsbIVcVNBKf3jWx X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM4PR12MB5198 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jan 04, 2022 at 11:06:31AM -0600, Bjorn Helgaas wrote: > > The existing vfio framework allows the portdrv driver to be bound > > to the bridge while its downstream devices are assigned to user space. > > I.e., the existing VFIO framework allows a switch to be in the same > IOMMU group as the devices below it, even though the switch has a > kernel driver and the other devices may have userspace drivers? Yes, this patch exists to maintain current VFIO behavior which has this same check. I belive the basis for VFIO doing this is that the these devices cannot do DMA, so don't care about the DMA API or the group->domain, and do not expose MMIO memory so do not care about the P2P attack. A comment in the code to this effect would be good, IMHO. Jason