Re: [XEN][PATCH v5 10/17] xen/iommu: Introduce iommu_remove_dt_device()

[Michal Orzel <michal.orzel@xxxxxxx>]

Hi Vikram,

On 11/04/2023 21:16, Vikram Garhwal wrote:
> 
> 
> Remove master device from the IOMMU. This will be helpful when removing the
> overlay nodes using dynamic programming during run time.
> 
> Signed-off-by: Vikram Garhwal <vikram.garhwal@xxxxxxx>
> ---
>  xen/drivers/passthrough/device_tree.c | 38 +++++++++++++++++++++++++++
>  xen/include/xen/iommu.h               |  2 ++
>  2 files changed, 40 insertions(+)
> 
> diff --git a/xen/drivers/passthrough/device_tree.c 
> b/xen/drivers/passthrough/device_tree.c
> index 457df333a0..a77a217f3d 100644
> --- a/xen/drivers/passthrough/device_tree.c
> +++ b/xen/drivers/passthrough/device_tree.c
> @@ -126,6 +126,44 @@ int iommu_release_dt_devices(struct domain *d)
>      return 0;
>  }
> 
> +int iommu_remove_dt_device(struct dt_device_node *np)
> +{
> +    const struct iommu_ops *ops = iommu_get_ops();
> +    struct device *dev = dt_to_dev(np);
> +    int rc;
> +
> +    if ( !ops )
> +        return -EOPNOTSUPP;
> +
> +    spin_lock(&dtdevs_lock);
> +
> +    if ( iommu_dt_device_is_assigned_locked(np) )
> +    {
> +        rc = -EBUSY;
> +        goto fail;
> +    }
> +
> +    /*
> +     * The driver which supports generic IOMMU DT bindings must have
> +     * these callback implemented.
s/these/this since you are checking for a single callback.

> +     */
> +    if ( !ops->remove_device )
> +    {
> +        rc = -EOPNOTSUPP;
> +        goto fail;
> +    }
> +
> +    /* Remove master device from the IOMMU if latter is present and 
> available. */
80 chars length exceeded -> please fix.
Apart from that, similarly to comment inside iommu_add_dt_device(), I would 
also write
something that the driver is responsible for unsetting is_protected flag.

Apart from that:
Reviewed-by: Michal Orzel <michal.orzel@xxxxxxx>

~Michal