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Add input module: broadcast keyboard events over IPC

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Programs can now subscribe to keyboard events (key_down/key_up/key_press)
and drivers can broadcast them, through a new user-space input service.

The delivery model is forced by danos IPC: a synchronous rendezvous holds
one pending reply, so a server cannot park N subscribers blocked in a
"wait for next event" call — delivery must be push. But a synchronous push
has no timeout and the kernel never wakes a sender parked on a dead peer's
endpoint, so one dying subscriber would hang all input. So this lands the
roadmap's planned asynchronous buffered send and builds the service on it:

- ipc_send (syscall 26): non-blocking post to an endpoint's bounded payload
  ring, delivered through reply_wait as a buffered message (notify_message_bit).
  A full ring drops the oldest. It can never hang on a dead/slow peer.
- input-protocol + runtime.input helpers (subscribe/next, connectSource/
  publish) — the first real consumer of M13 capability passing: a subscriber
  hands the service its own endpoint as a capability.
- input service (fan-out via ipc_send, dead-subscriber pruning), a synthetic
  input-source, and input-test; the ps2-bus keyboard driver publishes to it.
  Real IRQ1 scancode decoding (which must live in the bus, the PNP0303 owner)
  is a documented follow-up; the source is synthetic for now.
- build/init wiring, an `input` QEMU case, and docs/input.md.

Full QEMU suite 48/48, including the new input case and every IPC/endpoint
regression (ipc, ipc-call, ipc-cap, vfs, hpet, bus, irqfree).
This commit is contained in:
Daniel Samson
2026-07-11 15:03:24 +01:00
parent 2a583d55a8
commit 65244e3103
19 changed files with 765 additions and 5 deletions
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docs/ipc.md
+6 -1
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@@ -95,6 +95,11 @@ This is what makes a user-space driver possible at all, and it's the subject of
every capability is either well-known (the registry) or inherited — there's no way
to delegate one.
- **Asynchronous / buffered send** for the cases where a rendezvous is the wrong
shape (logging, notifications between servers).
shape (logging, notifications between servers). *Landed as `ipc_send`* — a
non-blocking post to an endpoint's bounded payload queue, delivered through
`reply_wait` as a buffered message (badge bit `notify_message_bit`). Built for, and
first used by, the [input service](input.md)'s keyboard-event broadcast, where a
synchronous push would let one dead subscriber hang the fan-out. A full queue drops
the oldest (discrete messages, not a coalescing level like the notification ring).
- **A bounded reply.** `MSG_MAX` is 256 bytes and the copy runs under the big kernel
lock; a bulk transfer wants shared pages, not a copy.