- Add VirtIO input device driver (device ID 18) reading from eventq
- Translate Linux keycodes (WASD, arrows) to InputEvent
- Kernel probes for VirtIO input device, falls back to UART
- Add -device virtio-keyboard-device to run-gui Makefile target
- input-qemu tries VirtIO first, falls back to UART
- Fix swapped command IDs: attach_backing was 0x0104 (FLUSH),
resource_flush was 0x0106 (ATTACH_BACKING). Now correct.
- Increase process stack from 4 pages (16 KB) to 16 pages (64 KB)
to prevent stack overflow in display process.
- Restructure display-qemu to avoid MockFramebuffer's 32 KB array
inflating the VirtIO path's stack frame.
- Wire snake app to render through display server via IPC instead
of UART escape codes. Uses existing renderer.rs pixel renderer.
- Init now delegates display endpoint to snake process.
VirtIO GPU:
- Removed QEMU 11.x command type swap hack (0x0104↔0x0106).
The hack was wrong — swapping types without swapping data formats
meant handlers read wrong struct layouts. Commands returned OK
but did nothing.
- Restored correct VirtIO spec command types.
- Removed broken test pattern (fill + flush that never displayed).
- GPU setup now reports success/failure without crashing.
Display server resilience:
- VirtioFramebuffer::new() → try_new() -> Option<Self>.
Returns None if phys-info page is unmapped or has zero dimensions.
- bins/display-qemu: tries VirtioFramebuffer, falls back to
MockFramebuffer. Display server runs headless instead of crashing.
- No more page faults when GPU is absent.
The GPU driver code is architecturally correct (proper VirtIO
commands, proper data formats) but doesn't produce visible output
on QEMU 11.x due to a suspected QEMU legacy MMIO bug where
transfer_to_host_2d succeeds but doesn't transfer data. The driver
is ready for when this is fixed or a different QEMU version is used.
Snake renders using ANSI escape codes via debug_putchar syscall,
bypassing the VirtIO GPU (which has a QEMU 11.x legacy MMIO bug
where transfer_to_host_2d succeeds but doesn't transfer data).
Full microkernel stack running end-to-end:
adapter → init → storage-server IPC → load snake from disk →
input-server IPC (UART keyboard) → snake game logic →
debug_putchar syscall → UART → terminal display
Controls: WASD to steer, runs at 0.2s tick rate.
Green O=head, o=body, red @=food, #=border.
Every syscall stub now uses proper types from types/ — CapSlot,
EntryPoint, StackPointer, VirtualAddress, PageCount, ProcessId,
PermissionSet, Ticks. The compiler prevents swapping entry/stack,
passing a ProcessId where a CapSlot is expected, or using an
address as a page count.
New display types in types/display.rs:
- Color(u32) with rgb() constructor
- ScreenCoord(u16) for x/y positions
- Dimension(u16) for width/height
Updated throughout:
- userspace/syscall.rs: all params typed, returns Option instead
of sentinel usize::MAX
- server-framework: endpoint param is CapSlot
- port-framebuffer: trait uses Color, ScreenCoord, Dimension
- hw-virtio: DmaAddrs uses PhysicalAddress/VirtualAddress,
GPU commands use Dimension
- All servers, drivers, bins, apps updated for new signatures
- permission-manager: process field uses ProcessId
- PermissionSet: added bits() accessor
89 tests pass, full QEMU boot verified.
Separate abstractions from implementations following DIP:
servers/ drivers/
│ │
▼ ▼
ports/ (trait-only crates, zero deps)
New crates:
ports/ (abstractions):
- port-framebuffer: Framebuffer trait
- port-block-device: BlockDevice trait + SectorId
- port-input-device: InputDevice trait + InputEvent types
drivers/ (implementations depend on ports/):
- driver-framebuffer-virtio: VirtIO GPU framebuffer
- driver-framebuffer-mock: test double
- driver-block-virtio: VirtIO block device
bins/ (composition roots wire server + driver):
- display-qemu: DisplayServer<VirtioFramebuffer>
- storage-qemu: storage server with VirtIO block
Servers no longer own their hardware traits or driver code.
Neither server nor driver depends on the other — both point
inward to the port abstraction.
