Re: [PATCH v6 16/21] vfio/ccw: Allow the selection of a given iommu backend

[Eric Farman]

On Tue, 2023-11-14 at 18:09 +0800, Zhenzhong Duan wrote:
> Now we support two types of iommu backends, let's add the capability
> to select one of them. This depends on whether an iommufd object has
> been linked with the vfio-ccw device:
> 
> If the user wants to use the legacy backend, it shall not
> link the vfio-ccw device with any iommufd object:
> 
>  -device vfio-ccw,sysfsdev=/sys/bus/mdev/devices/XXX
> 
> This is called the legacy mode/backend.
> 
> If the user wants to use the iommufd backend (/dev/iommu) it
> shall pass an iommufd object id in the vfio-ccw device options:
> 
>  -object iommufd,id=iommufd0
>  -device vfio-ccw,sysfsdev=/sys/bus/mdev/devices/XXX,iommufd=iommufd0
> 
> Suggested-by: Alex Williamson <alex.williamson@redhat.com>
> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
> Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>
> ---
>  hw/vfio/ccw.c | 6 ++++++
>  1 file changed, 6 insertions(+)

Reviewed-by: Eric Farman <farman@linux.ibm.com>