[PATCH v2 07/11] vfio-iommufd: Support iommufd for physical VFIO devices

[Nicolin Chen]

On Mon, Nov 07, 2022 at 08:52:51PM -0400, Jason Gunthorpe wrote:

> @@ -795,6 +800,10 @@ static int vfio_device_first_open(struct vfio_device *device)
>  		ret = vfio_group_use_container(device->group);
>  		if (ret)
>  			goto err_module_put;
> +	} else if (device->group->iommufd) {
> +		ret = vfio_iommufd_bind(device, device->group->iommufd);

Here we check device->group->iommufd...

> +		if (ret)
> +			goto err_module_put;
>  	}
>  
>  	device->kvm = device->group->kvm;
> @@ -812,6 +821,7 @@ static int vfio_device_first_open(struct vfio_device *device)
>  	device->kvm = NULL;
>  	if (device->group->container)
>  		vfio_group_unuse_container(device->group);
> +	vfio_iommufd_unbind(device);

...yet, missing here, which could result in kernel oops.

Should probably add something similar:
+	if (device->group->iommufd)
+		vfio_iommufd_unbind(device);

Or should check !vdev->iommufd_device inside the ->unbind.

>  err_module_put:
>  	mutex_unlock(&device->group->group_lock);
>  	module_put(device->dev->driver->owner);
> @@ -830,6 +840,7 @@ static void vfio_device_last_close(struct vfio_device *device)
>  	device->kvm = NULL;
>  	if (device->group->container)
>  		vfio_group_unuse_container(device->group);
> +	vfio_iommufd_unbind(device);

Ditto