On Thu, 31 Aug 2023, Vikram Garhwal wrote:
> Update sysctl XEN_SYSCTL_dt_overlay to enable support for dtbo nodes addition
> using device tree overlay.
>
> xl dt-overlay add file.dtbo:
> Each time overlay nodes are added using .dtbo, a new fdt(memcpy of
> device_tree_flattened) is created and updated with overlay nodes. This
> updated fdt is further unflattened to a dt_host_new. Next, it checks if
> any
> of the overlay nodes already exists in the dt_host. If overlay nodes
> doesn't
> exist then find the overlay nodes in dt_host_new, find the overlay node's
> parent in dt_host and add the nodes as child under their parent in the
> dt_host. The node is attached as the last node under target parent.
>
> Finally, add IRQs, add device to IOMMUs, set permissions and map MMIO for
> the
> overlay node.
>
> When a node is added using overlay, a new entry is allocated in the
> overlay_track to keep the track of memory allocation due to addition of
> overlay
> node. This is helpful for freeing the memory allocated when a device tree node
> is removed.
>
> The main purpose of this to address first part of dynamic programming i.e.
> making xen aware of new device tree node which means updating the dt_host with
> overlay node information. Here we are adding/removing node from dt_host, and
> checking/setting IOMMU and IRQ permission but never mapping them to any
> domain.
> Right now, mapping/Un-mapping will happen only when a new domU is
> created/destroyed using "xl create".
>
> Signed-off-by: Vikram Garhwal <vikram.garh...@amd.com>
> @@ -359,6 +546,312 @@ static long handle_remove_overlay_nodes(const void
> *overlay_fdt,
> return rc;
> }
>
> +static void free_nodes_full_path(unsigned int num_nodes, char
> **nodes_full_path)
> +{
> + unsigned int i;
> +
> + if ( nodes_full_path != NULL )
> + return;
Shouldn't this be:
if ( nodes_full_path == NULL )
return;
> + for ( i = 0; i < num_nodes && nodes_full_path[i] != NULL; i++ )
> + {
> + xfree(nodes_full_path[i]);
> + }
> +
> + xfree(nodes_full_path);
> +}
