This was neccessary in order to make the memory available via GDRcopy
when multiple small allocations were made. cudaMalloc() would return
multiple memory chunks located in the same GPU page, which GDRcopy
pretty much dislikes (`gdrdrv:offset != 0 is not supported`).
As a side effect, this will keep the number of BAR-mappings done
via GDRcopy low, because they seem to be quite limited.

Virtual inheritance is required because (for example) the Rtds2Gpu
IP inherits from Hls and IpNode who both inherit from IpCore.

 - better tested IP (testbenches)
 - detect invalid frame sizes
 - more status reporting

This is still very simple. Only really free memory, when all allocation
have been deallocated so we only need to keep track of the current
number of allocations.

Using CUDA, memory can be allocated on the GPU and shared to peers on
the PCIe bus such as the FPGA. Furthermore, the DMA on the GPU can also
be used to read and write to/from other memory on the PCIe bus, such as
BRAM on the FPGA.

It is probably too costly to do (and verify) it on every read
or write. Furthermore, the user knows better how to make a certain
memory available to the DMA.

In this case, VFIO cannot create DMA mappings.

This is used for translations that don't use VFIO which used to bridge
the PCIe address space by creating direct mappings from process VA to
the FPGA. When we want to communicate directly via PCIe without the
involvment of the CPU/VFIO, we need the proper translations that are
configured in the FPGA hardware.