On 09/02/2021 05:13, Jason Gunthorpe wrote:
On Fri, Feb 05, 2021 at 11:42:11AM +1100, Alexey Kardashevskiy wrote:
A real nvswitch function?
What do you mean by this exactly? The cpu side of nvlink is "emulated pci
devices", the gpu side is not in pci space at all, the nvidia driver manages
it via the gpu's mmio or/and cfg space.
Some versions of the nvswitch chip have a PCI-E link too, that is what
I though this was all about when I first saw it.
So, it is really a special set of functions for NVIDIA GPU device
assignment only applicable to P9 systems, much like IGD is for Intel
on x86.
These GPUs are not P9 specific and they all have both PCIe and NVLink2
links. The special part is that some nvlinks are between P9 and GPU and
the rest are between GPUs, everywhere else (x86, may be ARM) the nvlinks
are used between GPUs but even there I do not think the nvlink logic is
presented to the host in the PCI space.
--
Alexey
