How to get physical address of GPU memory for DMA? (OpenCL)

Question

I am writing an OpenCL program and I wish to transfer data from a frame grabber to a GPU using DMA. How can I get the physical address of an OpenCL buffer on the GPU to do that?

Answer 1

With OpenCL, you cannot get the physical GPU address of a buffer.

However, you can map a region of a buffer directly into host memory, allowing the memory to be copied in and out using standard C/C++ code such as memcpy. See clEnqueueMapBuffer.