Currently, the steering tag can be used for a CPU on the motherboard; the ACPI check is in place to query and obtain the supported tph settings. Here we intend to use the tph info to improve RDMA NIC memory access on a vfio-based accelerator device via PCIe peer-to-peer. When an applicantion register a RDMA memory region with DMABUF for the RDMA NIC to access the device memory, the tph associated with the memory region can be retrieved and used to set the steering tag / process hint (ph). The tph contains additional instructions or hints to the GPU or accelerator device for advanced memory operations, such as, read cache selection.
Note this RFC is for the discussion on the direction and is not intended to be a complete implementation. Once the direction is agreed on, we will work on the implementation or a real patch set. Signed-off-by: Zhiping Zhang <[email protected]> [RFC 1/2] Vfio: add callback to get tph info for dmabuf [RFC 2/2] RMDA MLX5: get tph for p2p access when registering dmabuf
