Zero-Copy and cudaMemcpy()

Hi,

I want to copy data from linear CUDA memory to pinned memory with zero-copy access. Therefore I get a device pointer by calling cudaHostGetDevicePointer() followed by a cudaMemcpy() operation which reports the device pointer to be invalid.

Is such a copy operation forbidden? Am I supposed to call a kernel for the copy-operation?

Thx,
Marcel Beister

.