VFIO_DEVICE_PCI_HOT_RESET requires user to pass an array of group fds to prove that it owns all devices affected by resetting the calling device. This series introduces several extensions to allow the ownership check better aligned with iommufd and coming vfio device cdev support. First, resetting an unopened device is always safe given nobody is using it. So relax the check to allow such devices not covered by group fd array. [1] When iommufd is used we can simply verify that all affected devices are bound to a same iommufd then no need for the user to provide extra fd information. This is enabled by the user passing a zero-length fd array and moving forward this should be the preferred way for hot reset. [2] However the iommufd method has difficulty working with noiommu devices since those devices don't have a valid iommufd, unless the noiommu device is in a singleton dev_set hence no ownership check is required. [3] For noiommu backward compatibility a 3rd method is introduced by allowing the user to pass an array of device fds to prove ownership. [4] As suggested by Jason [5], we have this series to introduce the above stuffs to the vfio PCI hot reset. Per the dicussion in [6] [7], in the end of this series, the VFIO_DEVICE_GET_PCI_HOT_RESET_INFO is extended to report devid for the devices opened as cdev. This is goging to support the device fd passing usage. The new hot reset method and updated _INFO ioctl are tested with two test commits in below qemu: https://github.com/yiliu1765/qemu/commits/iommufd_rfcv3 (requires to test with cdev kernel) [1] https://lore.kernel.org/kvm/Y%2FdobS6gdSkxnPH7@xxxxxxxxxx/ [2] https://lore.kernel.org/kvm/Y%2FZOOClu8nXy2toX@xxxxxxxxxx/#t [3] https://lore.kernel.org/kvm/ZACX+Np%2FIY7ygqL5@xxxxxxxxxx/ [4] https://lore.kernel.org/kvm/DS0PR11MB7529BE88460582BD599DC1F7C3B19@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/#t [5] https://lore.kernel.org/kvm/ZAcvzvhkt9QhCmdi@xxxxxxxxxx/ [6] https://lore.kernel.org/kvm/ZBoYgNq60eDpV9Un@xxxxxxxxxx/ [7] https://lore.kernel.org/kvm/20230327132619.5ab15440.alex.williamson@xxxxxxxxxx/ Change log: v3: - Remove the new _INFO ioctl of v2, extend the existing _INFO ioctl to report devid (Alex) - Add r-b from Jason - Add t-b from Terrence Xu and Yanting Jiang (mainly regression test) v2: https://lore.kernel.org/kvm/20230327093458.44939-1-yi.l.liu@xxxxxxxxx/ - Split the patch 03 of v1 to be 03, 04 and 05 of v2 (Jaon) - Add r-b from Kevin and Jason - Add patch 10 to introduce a new _INFO ioctl for the usage of device fd passing usage in cdev path (Jason, Alex) v1: https://lore.kernel.org/kvm/20230316124156.12064-1-yi.l.liu@xxxxxxxxx/ Regards, Yi Liu Yi Liu (12): vfio/pci: Update comment around group_fd get in vfio_pci_ioctl_pci_hot_reset() vfio/pci: Only check ownership of opened devices in hot reset vfio/pci: Move the existing hot reset logic to be a helper vfio-iommufd: Add helper to retrieve iommufd_ctx and devid for vfio_device vfio/pci: Allow passing zero-length fd array in VFIO_DEVICE_PCI_HOT_RESET vfio: Refine vfio file kAPIs for vfio PCI hot reset vfio: Accpet device file from vfio PCI hot reset path vfio/pci: Renaming for accepting device fd in hot reset path vfio/pci: Accept device fd in VFIO_DEVICE_PCI_HOT_RESET ioctl vfio: Mark cdev usage in vfio_device iommufd: Define IOMMUFD_INVALID_ID in uapi vfio/pci: Report dev_id in VFIO_DEVICE_GET_PCI_HOT_RESET_INFO drivers/iommu/iommufd/device.c | 12 ++ drivers/vfio/group.c | 32 +++-- drivers/vfio/iommufd.c | 14 +++ drivers/vfio/pci/vfio_pci_core.c | 204 ++++++++++++++++++++++--------- drivers/vfio/vfio.h | 2 + drivers/vfio/vfio_main.c | 44 +++++++ include/linux/iommufd.h | 3 + include/linux/vfio.h | 21 ++++ include/uapi/linux/iommufd.h | 3 + include/uapi/linux/vfio.h | 42 ++++++- 10 files changed, 301 insertions(+), 76 deletions(-) -- 2.34.1
