I’m not sure how to solve the first error.
However, the “no kernel image” error is usually raised, if you’ve build your extension for a specific compute architecture (e.g. 7.0 for Volta), while you are now trying to run it on another one.
You could use TORCH_CUDA_ARCH_LIST="6.0 7.0" python setu.py build_ext to use the specified compute capabilities.