NFU Specification

Simple overview:

• NFU server -- "adjacent" to IBP depot.
• NFU Op -- lightweight program, written in C, or Java, depending on server.
• NFU client -- launches nfuOps and exchanges data with it.
• NFU API:
  • Two types of data exchange:
  • 1. variable exchange
    • IBP_VAL_[IN, OUT, INOUT]
    • variable/values exchanged directly between nfu client and nfu Op
  • 2. IBP Cap handling
    • IBP_REF_[RD, WR, RDWR]
    • E.G. _RD: client sends readCap to server, NFU server provides nfuOp a pointer to mmap of the allocation
    • nfuOp does not receive readCap string
• security issues
  • Java NFU server has VM isolation of nfuOp
  • UTK NFU server has option to run Cap as process to isolate nfuOp from server