io_uring_restriction->opcode values
REGISTER_OP = 0,
Allow an io_uring_register(2) opcode
SQE_OP = 1,
Allow an sqe opcode
SQE_FLAGS_ALLOWED = 2,
Allow sqe flags
SQE_FLAGS_REQUIRED = 3,
Require sqe flags (these flags must be set on each submission)