Re: [Intel-gfx] [PATCH v3 03/15] vfio: Accept vfio device file in the driver facing kAPI

[Alex Williamson <alex.williamson@redhat.com>]

On Mon, 13 Feb 2023 07:13:36 -0800
Yi Liu <yi.l.liu@intel.com> wrote:

> This makes the vfio file kAPIs to accepte vfio device files, also a
> preparation for vfio device cdev support.
> 
> For the kvm set with vfio device file, kvm pointer is stored in struct
> vfio_device_file, and use kvm_ref_lock to protect kvm set and kvm
> pointer usage within VFIO. This kvm pointer will be set to vfio_device
> after device file is bound to iommufd in the cdev path.
> 
> Signed-off-by: Yi Liu <yi.l.liu@intel.com>
> Reviewed-by: Kevin Tian <kevin.tian@intel.com>
> ---
>  drivers/vfio/vfio.h      |  2 ++
>  drivers/vfio/vfio_main.c | 51 ++++++++++++++++++++++++++++++++++++----
>  2 files changed, 49 insertions(+), 4 deletions(-)

This subtly changes the behavior of the vfio-pci hot reset functions
without updating the uAPI description or implementation to use less
group-centric variables.  The new behavior appears to be that cdev fds
can also be passed to prove ownership of the affected set of devices
for a hot reset, but this probably needs to be examined for gaps.
Thanks,

Alex