Re: [RFC PATCH 3/3] iommufd/tsm: Add tsm_bind/unbind iommufd ioctls

[Jason Gunthorpe <jgg@nvidia.com>]

On Thu, May 29, 2025 at 07:07:56PM +0530, Aneesh Kumar K.V (Arm) wrote:

> +static struct mutex *vdev_lock(struct iommufd_vdevice *vdev)
> +{
> +
> +	if (device_lock_interruptible(vdev->dev) != 0)
> +		return NULL;
> +	return &vdev->dev->mutex;
> +}
> +DEFINE_FREE(vdev_unlock, struct mutex *, if (_T) mutex_unlock(_T))

I know I suggested this, but maybe it would be happier to use a mutex
in the viommu?

What is the locking model you need for TSM calls here anyhow? Can you
concurrently call tsms for vommu creation with bind/unbind or so on?
> +/**
> + * struct iommu_vdevice_id - ioctl(IOMMU_VDEVICE_TSM_BIND/UNBIND)
> + * @size: sizeof(struct iommu_vdevice_id)
> + * @vdevice_id: Object handle for the vDevice. Returned from IOMMU_VDEVICE_ALLOC
> + */
> +struct iommu_vdevice_id {
> +	__u32 size;
> +	__u32 vdevice_id;
> +} __packed;

???
Why is it called vdevice_id?
Why is it packed?

The struct should be per-ioctl. Does anyone need a TSM specific argument
blob for bind?

Jason