Module io 

IO subsystem - GPU↔runtime DMA request queue for the persistent megakernel.

Module ownership:

• mod.rs: doc + constants + IoRequest/IoCompletion + word/op/status modules
• queue.rs: ResidentIoQueue + view
• poll.rs: host poll/claim/peek surface + the GPU completion-poll IR builder
• complete.rs: completion-write surface
• encode.rs: bytes <-> validated queue helpers
• queue_words.rs: bounds-checked slot-word addressing + queue validation
• tests.rs: full test suite

Protocol

Each IO slot is 8 × u32 words:

[op_type, src_handle, dst_handle, offset_lo, offset_hi, byte_count, status, tag]

The GPU CAS-claims slots like the work ring, but uses the io_queue buffer. The host polls status for REQUEST and services the DMA.

Modules

io_op

IO operation types.

io_status

IO completion status codes written by the host pump.

io_word

Word offsets within an IO slot.

Structs

IoCompletion

Host-side completion record published into io_queue for a mapped ingest slot the GPU can consume.

IoRequest

Host-side IO request decoded from the io_queue buffer.

ResidentIoQueue

Host-side handle to the megakernel IO queue. Wraps a Vec<u32> slot ring and exposes typed poll/publish/complete entry points.

Constants

IO_DESTINATION_CAPABILITY_TABLE

Resource table name used for resolving IO destination handles.

IO_QUEUE_DMA_TAG

Async stream tag used by megakernel IO DMA requests.

IO_SLOT_COUNT

Default number of IO queue slots.

IO_SLOT_WORDS

Number of u32 words per IO queue slot.

IO_SOURCE_CAPABILITY_TABLE

Resource table name used for resolving IO source handles.

Functions

claim_io_requests_into

Poll and claim pending requests into caller-owned storage.

complete_io_request

Write a completion status for a serviced IO request.

complete_io_requests_batch

Complete several serviced IO requests.

encode_empty_io_queue

Encode an empty IO queue buffer.

io_completion_poll_body

Build the GPU-side IO poll body as Vec<Node> for composition into the megakernel persistent loop.

try_claim_io_requests_into

Strictly poll and claim pending requests into caller-owned storage.

try_complete_io_request

Strictly write a completion status for a serviced IO request.

try_complete_io_requests_batch

Strictly complete several claimed IO requests after one validation pass.

try_encode_empty_io_queue

Strictly encode an empty IO queue buffer.

try_encode_empty_io_queue_into

Strictly encode an empty IO queue buffer into caller-owned storage.

try_poll_io_requests

contains a partial IO slot, or exceeds the compiled poll window.

try_poll_io_requests_into

Strictly poll pending requests into caller-owned storage without claiming.

validate_io_queue_bytes

contains a partial IO slot, or exceeds the compiled poll window.