RE: [PATCH v5 17/19] vfio: Add VFIO_DEVICE_AT[DE]TACH_IOMMUFD_PT

Liu, Yi L
2023-02-28T13:36:43Z

> From: Jason Gunthorpe <jgg@nvidia.com>
> Sent: Tuesday, February 28, 2023 9:26 PM
>
> On Tue, Feb 28, 2023 at 01:22:50PM +0000, Liu, Yi L wrote:
>
> > > A null iommufd pointer and a bound df flag is sufficient to see that
> > > it is compat mode.
> >
> > Hope df->is_cdev_device suits your expectation.:-) The code will look
> > like below:
>
> Yes, this is better.. However I'd suggest 'uses_container' as it is
> clearer what the special case is

Surely doable. Need to add a helper like below:

bool vfio_device_group_uses_container()
{
lockdep_assert_held(&device->group->group_lock);
return device->group->container;
}

But I'm poor at naming it. If it is true, the code would call
vfio_device_group_use_iommu(). If doing it in this way,
I think it's better to rename vfio_device_group_use_iommu()
as well.

Regards,
Yi Liu