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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?T+ACDNp/tXLSJzpCSX0v5QzDJrH2hv8rCX5/xLNZeRobJG1IAs2dG7ic4dSC?= =?us-ascii?Q?paq1r2B2rKn8pbIeI12HGdo9AE00QF4HeznSnTxMHvgoSZZQeDCQ+sosME1R?= =?us-ascii?Q?yEQ8J1e90byLWfDmNb3NwkZKAjeXlvoMnT9regg2NMRltrXB1OOWmAWCMZ8h?= =?us-ascii?Q?M0vQFmuQXGX+tfqvhta4T91+ysh0oQiq/+fbGSZJcHvQ+AKvsZQfHEJlSVCX?= =?us-ascii?Q?1uByUNxM9yO2f+tec7KSyXtA6G2xt2kKsCSKgrwQszueslK8oPcS9K1Zr3Ib?= =?us-ascii?Q?FkBPtoomzQGDih50gPQC7Xc5bwx7mCg/Nuq/RkI755pWL9lz2M6RMTAXGYM5?= =?us-ascii?Q?w6yG3+Wnp6ftgvtw+ioVTq5frXI3z4ysm+r+y/d9r+n4hCC6x2RH2zXA6pRw?= =?us-ascii?Q?/lSp122rVSVYmCErsSb5H028xlXkWsCTWWvO1MvMDQ20ebciNd0+MG/UjQF0?= =?us-ascii?Q?xrQWGEppo2iM5Xe8sUbq8VmvsZMjmVQzxGihIqRvt4w36OZxU0VKgq9Q2xPN?= =?us-ascii?Q?6sg4HAd+1XKViV9H7qoktBNYqvpDRHpniDXtL35ZqC63FnFhK+rfmaDI0kLh?= =?us-ascii?Q?/paiLgja7SG87qmdIxoYASqUZxz0u7g7uexFMxbuK/C4G+BFw1v2/8Y4I2zj?= =?us-ascii?Q?Y+PVqFcKunHXcLo+HWo9gpT7DYuLg2vC6Re3NZZHo5AO/cRJoVZtBQJANePo?= =?us-ascii?Q?JPT1UwAljCenEEg9TDAO1ROGK9Pf6EPNDfmVXWwho4Fad9yZ+JjKce236/uo?= =?us-ascii?Q?Mjq95qaAiRJ7UDHa7nvuGom8nJ5xmerF065nI64veSGQbNEgiWE+UXyXm7OO?= =?us-ascii?Q?/JjAAvmz9A7J7Rhzp/GjJJuDeIQ1dD9pNDdWdJQko9i0G+062FVMyBzp+oxi?= =?us-ascii?Q?BhdApZLPQmjTaiq+lA13tCtM1Lq6JrtMTdsxam1iSTt9FJyebPGyawz9IOEE?= =?us-ascii?Q?mDnBTrM7VyfidQ4BTqvkCvSFAXJCNFX6sVNmsRC+I0nzLn71tc9AlejIxT9U?= =?us-ascii?Q?lP5V8D5x4oP2p1jviNcmXVkOHy5B/oErapkK8/aQcE6qXTCw+EI9hn6S/w3G?= =?us-ascii?Q?Osoi4833idUHtHF5NKI+7lBA8Jfcq4nB3/JdTSw5GRKW5S562JvJHkfB03sT?= =?us-ascii?Q?oKUk0zSMvFtwE0VFwR5W1lDcvCoXaPMSABcTY7Tvg2fa7tLQTVO5R4lqbdoO?= =?us-ascii?Q?kl7a6dLVl5Z61AM5jqlyKGyoMaEm86c+NFBboCjVTSnRR/Pvp768wFSTKVrX?= =?us-ascii?Q?R5wATA3XXWUEpE7q0bdB9n4y2G8m/83KU3Km/TOXmRBXgzGI4nA47aNdnfun?= =?us-ascii?Q?8C1/lTkpwyPu2uPOWiKpSNmL3V4FmeO2C3G7sQHIEwSVz28u/rUGdP3qyrXr?= =?us-ascii?Q?1/XTWPl7Nnuj0F0x0tUZQ7wBI5n559ysU5Y6l5vtHSQtmYzCfONM5cDqM61B?= =?us-ascii?Q?hz/sBt1J1g0/mD0In891D1sr4ewrWxpd9pXPEVGuM+qxQkEkqQOObfRwvBdG?= =?us-ascii?Q?WKkdzjXl070B/+2d6tW4J4Wh+3H0sPsRBQRUoSBaRfOQCcHfDJ5hZpSZY52U?= =?us-ascii?Q?4z7PUV8xDmJCOybnlxs=3D?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: a96bc76b-1808-468c-9b84-08dd3bb27c53 X-MS-Exchange-CrossTenant-AuthSource: CH3PR12MB8659.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 23 Jan 2025 13:33:13.4932 (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: WRbOTWgjF6Foq75vYkjWBRktg/rburOrsETnIZAgLOgGuPLr0hLJv5ZU1DL1ydO/ X-MS-Exchange-Transport-CrossTenantHeadersStamped: MW4PR12MB7142 On Wed, Jan 22, 2025 at 12:14:02PM -0600, Nishanth Aravamudan wrote: > On Mon, Jan 13, 2025 at 04:42:00PM -0400, Jason Gunthorpe wrote: > > On Mon, Jan 06, 2025 at 03:52:31PM -0600, Nishanth Aravamudan wrote: > > > vfio_pci_ioctl_get_pci_hot_reset_info checks if either the vdev's slot > > > or bus is not resettable by calling pci_probe_reset_{slot,bus}. Those > > > functions in turn call pci_{slot,bus}_resettable() to see if the PCI > > > device supports reset. > > > > This change makes sense to me, but.. > > > > > However, commit d88f521da3ef ("PCI: Allow userspace to query and set > > > device reset mechanism") added support for userspace to disable reset of > > > specific PCI devices (by echo'ing "" into reset_method) and > > > pci_{slot,bus}_resettable methods do not check pci_reset_supported() to > > > see if userspace has disabled reset. Therefore, if an administrator > > > disables PCI reset of a specific device, but then uses vfio-pci with > > > that device (e.g. with qemu), vfio-pci will happily end up issuing a > > > reset to that device. > > > > How does vfio-pci endup issuing a reset? It looked like all the paths > > are blocked in the pci core with pci_reset_supported()? Is there also > > a path that vfio is calling that is missing a pci_reset_supported() > > check? If yes that should probably be fixed in another patch. > > This is the path I observed: You didn't answer the question, I didn't ask about pci_probe_*() I asked why doesn't pci_reset_supported() directly block the actual reset? Should we be adding: @@ -5919,6 +5919,9 @@ int __pci_reset_bus(struct pci_bus *bus) */ int pci_reset_bus(struct pci_dev *pdev) { + if (!pci_reset_supported(pdev)) + return -EOPNOTSUPP; + return (!pci_probe_reset_slot(pdev->slot)) ? __pci_reset_slot(pdev->slot) : __pci_reset_bus(pdev->bus); And maybe more? Jason