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.
Critical: kernel_ref() UB eliminated
- kernel_ref() returned &'static mut, creating aliasing mutable
references across trap handler + boot code (13+ call sites)
- Replaced with kernel_ptr() -> *mut Kernel, each use site does
explicit unsafe { &mut *kernel_ptr() }
- KernelCell: removed get_mut(), added as_ptr() -> *mut T
- UB is gone: raw pointer access makes the single-core invariant
explicit at every use site
Important: process cleanup on exit/fault
- New destroy_process() method consolidates cleanup:
- Removes all threads from scheduler and endpoints
- Clears pending messages and results
- Destroys process and frees ProcessMemory
- handle_exit and handle_fault both use destroy_process()
- handle_exit_thread uses destroy_process when last thread exits
IPC hardening:
- Added invariant comment on pending_messages[sender].take()
(sender in wait queue must have a pending message)
handle_release_pages:
- Now uses translate_va to convert VA→PA (was treating VA as PA)
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.
