> -----Original Message----- > From: Liu, Yi L <yi.l.liu@xxxxxxxxx> > Sent: Monday, March 27, 2023 5:35 PM > > 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], this series also adds a new > _INFO ioctl to get hot reset scope for given device. > > [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 > @DS0PR11MB7529.namprd11.prod.outlook.com/#t > [5] https://lore.kernel.org/kvm/ZAcvzvhkt9QhCmdi@xxxxxxxxxx/ > [6] https://lore.kernel.org/kvm/ZBoYgNq60eDpV9Un@xxxxxxxxxx/ > > Change log: > > v2: > - 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 (10): > 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/pci: Add VFIO_DEVICE_GET_PCI_HOT_RESET_GROUP_INFO > > drivers/iommu/iommufd/device.c | 12 ++ > drivers/vfio/group.c | 32 ++-- > drivers/vfio/iommufd.c | 16 ++ > drivers/vfio/pci/vfio_pci_core.c | 244 ++++++++++++++++++++++++------- > drivers/vfio/vfio.h | 2 + > drivers/vfio/vfio_main.c | 44 ++++++ > include/linux/iommufd.h | 3 + > include/linux/vfio.h | 14 ++ > include/uapi/linux/vfio.h | 65 +++++++- > 9 files changed, 364 insertions(+), 68 deletions(-) > > -- > 2.34.1 Verified this series by "Intel GVT-g GPU device mediated passthrough". Passed VFIO legacy mode / compat mode / cdev mode basic functionality and GPU force reset test. Tested-by: Terrence Xu <terrence.xu@xxxxxxxxx>
