In this step, you use the set_property command to set two required properties: sdx_kernel and sdx_kernel_type. Then, issue ipx::update_source_project_archive and ipx::save_core commands to package the Vivado project into Vivado IP. Finally, use package_xo command to generate the Vitis XO file.
set_property sdx_kernel true [ipx::current_core]
set_property sdx_kernel_type rtl [ipx::current_core]
ipx::update_source_project_archive -component [ipx::current_core]
ipx::save_core [ipx::current_core]
package_xo -force -xo_path ../krnl_cbc.xo -kernel_name krnl_cbc -ctrl_protocol ap_ctrl_chain -ip_directory ./krnl_cbc_ip -output_kernel_xml ../krnl_cbc.xml
Note that in the above package_xo command usage, you let the tool to generate the kernel description XML file automatically, and therefore you do not need to manually create it.