In which mode of the BlueField DPU does the ARM system on the DPU control...

InDPU Mode, theARM cores on BlueFieldown theNIC data path, while still allowing thehost system to access the DPU OS (via OOB or virtio).

From NVIDIA BlueField Documentation:

"In DPU Mode, the data path is offloaded to the BlueField Arm cores, enabling advanced security and networking functions, while still allowing host access to the BlueField OS."

This is different from:

NIC Mode: Data path controlled by host, ARM cores inactive.

Separated Host Mode: Complete isolation; host cannot access DPU OS.

Restricted Mode: Limited host access to DPU OS, but without full offload capabilities.