Re: [PATCH v5 1/3] vfio: Fix container device registration life cycle

[Jason Gunthorpe <jgg@ziepe.ca>]

On Sat, Nov 05, 2022 at 03:44:56PM -0700, Anthony DeRossi wrote:
> In vfio_device_open(), vfio_container_device_register() is always called
> when open_count == 1. On error, vfio_device_container_unregister() is
> only called when open_count == 1 and close_device is set. This leaks a
> registration for devices without a close_device implementation.
> 
> In vfio_device_fops_release(), vfio_device_container_unregister() is
> called unconditionally. This can cause a device to be unregistered
> multiple times.
> 
> Treating container device registration/unregistration uniformly (always
> when open_count == 1) fixes both issues.
> 
> Fixes: ce4b4657ff18 ("vfio: Replace the DMA unmapping notifier with a callback")
> Signed-off-by: Anthony DeRossi <ajderossi@gmail.com>
> ---
>  drivers/vfio/vfio_main.c | 13 ++++++++-----
>  1 file changed, 8 insertions(+), 5 deletions(-)

This seems to only effect the mbochs sample, but it looks OK

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

This will generate conflicts with the iommufd treee, so please lets
think about how to avoid them..

Jason