Re: [PATCH v2 05/10] vfio/pci: Allow passing zero-length fd array in VFIO_DEVICE_PCI_HOT_RESET

Jason Gunthorpe
2023-03-30T23:49:23Z

On Mon, Mar 27, 2023 at 02:34:53AM -0700, Yi Liu wrote:
> as an alternative method for ownership check when iommufd is used. In
> this case all opened devices in the affected dev_set are verified to
> be bound to a same valid iommufd value to allow reset. It's simpler
> and faster as user does not need to pass a set of fds and kernel no
> need to search the device within the given fds.
>
> a device in noiommu mode doesn't have a valid iommufd, so this method
> should not be used in a dev_set which contains multiple devices and one
> of them is in noiommu. The only allowed noiommu scenario is that the
> calling device is noiommu and it's in a singleton dev_set.
>
> Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
> Signed-off-by: Yi Liu <yi.l.liu@intel.com>
> ---
> drivers/vfio/pci/vfio_pci_core.c | 42 +++++++++++++++++++++++++++-----
> include/uapi/linux/vfio.h | 9 ++++++-
> 2 files changed, 44 insertions(+), 7 deletions(-)

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>

Jason