vasilito
b681a2fb66
Two parallel review agents cross-checked the virtio-inputd driver against
the Linux 7.1 reference (drivers/virtio/virtio_input.c, virtio_input.h)
and the proven redox-drm virtio transport. 12 issues were found across
BLOCKER, MAJOR, MINOR, and NIT severity, all fixed in this commit before
runtime testing.
BLOCKERs (would have prevented the driver from working in QEMU):
1. fill_avail() never wrote avail_idx after pushing the 64 ring
entries. The device reads avail_ring[avail_idx % size] to discover
new buffers, so without publishing avail_idx = size, the device
saw avail_idx = 0 and ignored all initial buffers. Fix: explicit
'fence(Release); write_avail_idx(self.size)' with a spec citation.
2. drain() recycled IDs derived from 'last_used_idx - drained_count',
which is wrong when the used ring wraps and a single drain cycle
spans more than one full ring revolution. Fix: collect the actual
drained 'id' values in a stack '[u16; 64]' array during the drain
loop, then push those exact ids back to the avail ring. The
doc-comment explains why the derivation is unsafe.
3. config_read_string() and config_read_bitmap() used
'self.device_cfg.size()' (the MMIO region size = 40) instead of
the device-reported config size from offset 2. Fix: use
'config_read_size()' to read the actual size field.
4. config/redbear-full.toml: device_id_range was a TOML string
('0x1042..=0x107F') but serde's Range<u16> deserializes from a
sequence, not a string. pcid-spawner would have silently failed
to load the fragment. Fix: use serde array form
'device_id_range = [0x1042, 0x107F]'.
MAJORs (silent failure modes or runtime bugs):
5. activate_queue() had no fence between address writes and
'queue_enable = 1'. A CPU write buffer may reorder writes to
distinct MMIO addresses. Fix: explicit 'fence(SeqCst)' with
a comment citing virtio spec 2.8 and Linux's virtio_wmb.
6. No 'reset_device()' on error path after partial init. The device
would be left in ACKNOWLEDGE|DRIVER with no driver active,
requiring a guest reboot to recover. Fix: wrap init in a closure;
any error calls 'transport.reset_device()' before propagating.
7. Drain loop never checked DEVICE_NEEDS_RESET or DEVICE_STATUS_FAILED.
If the device entered an unrecoverable state, the driver would
poll forever with stale state. Fix: 'device_in_error_state()' on
the transport; loop checks it each iteration and exits cleanly.
8. The abs_count probe used 'config_read_size() == 24', which was
always false (virtio_input_absinfo is 20 bytes, not 24). The
count was always logged as 0. Fix: '>= 20' per spec.
MINORs / NITs (hardening, no functional impact):
9. config_read_absinfo() returned AbsInfo without validating
device-reported size. Now returns Option<AbsInfo> and validates
size >= 20.
10. map_cap_region() missing bounds check: capability range may
extend past BAR end (QEMU is permissive; bare-metal is not).
Added 'cap_end > bar_size' check with spec reference.
11. Legacy device 0x1052 entry in pcid fragment caused spurious
spawn + log noise. Removed.
12. notify_queue() error silently dropped with .ok(). Now logs warn
and continues.
Plan update:
The CONSOLE-TO-KDE-DESKTOP-PLAN.md v5.1 changelog now has a new
'9.1.1 Phase 5.1 review-driven fixes' section documenting all 12
findings with file:line, severity, and fix. Future maintainers can
trace the BLOCKERs back to specific commits to understand the
critical-path safety net this review provided.
Verification: cargo check zero errors, 64 warnings (all unused
keycode constants reserved for Phase 5.2 expansion). The driver
is now ready for runtime testing in QEMU.
Red Bear OS
A microkernel operating system written in Rust, derived from Redox OS
What is Red Bear OS?
Red Bear OS is a general-purpose, Unix-like operating system with a microkernel architecture, written in Rust. It is a full fork of Redox OS, frozen at release 0.1.0, with added hardware support, filesystem drivers, and a KDE Plasma desktop path.
Goals:
- AMD & Intel parity — first-class support for both platforms on bare metal
- KDE Plasma desktop — Wayland-based desktop environment via the KWin compositor
- Hardware GPU acceleration — AMD GPU (amdgpu) and Intel GPU drivers via
redox-drm - Modern subsystems — USB, Wi‑Fi, Bluetooth, ext4, GRUB, D-Bus
- Offline-first builds — reproducible from archived, BLAKE3-verified sources
Quick Start
Prerequisites
Linux x86_64 host with Rust nightly, QEMU, nasm, and standard build tools.
See the Redox Build Guide for full setup.
Build & Run
# Clone
git clone https://gitea.redbearos.org/vasilito/RedBear-OS.git
cd RedBear-OS
# Build and run the desktop target in QEMU
./scripts/run.sh --build
# Build a live ISO for bare metal
./scripts/build-iso.sh redbear-full
# Build the text-only recovery target
./scripts/run.sh --build --config redbear-mini
Repository Hosting
The canonical Red Bear OS Git server is Gitea at
https://gitea.redbearos.org/vasilito/RedBear-OS.git. GitHub is not a Red Bear OS source of
truth and must not be used for pushes, issues, releases, or project coordination.
Public Scripts
| Script | Purpose |
|---|---|
scripts/run.sh |
Build and run in QEMU (-b to build, -c <config> for target) |
scripts/build-iso.sh |
Build a live ISO for bare-metal boot |
scripts/build-all-isos.sh |
Build all live ISO targets |
scripts/network-boot.sh |
PXE network boot helper |
scripts/dual-boot.sh |
Dual-boot installation helper |
Config Targets
| Target | Type | Description |
|---|---|---|
redbear-full |
Desktop | Wayland + KDE + GPU drivers + D-Bus services |
redbear-mini |
Console | Text-only recovery / install target |
redbear-grub |
Console | Text-only with GRUB boot manager |
Current Status
Red Bear OS boots to a login prompt in QEMU with working wired networking, D-Bus system bus, hardware detection daemons, and filesystem support (RedoxFS, ext4, FAT).
| Area | Status |
|---|---|
| Boot (ACPI/x2APIC/SMP) | ✅ Bare-metal proven |
| Userspace drivers (PCI, storage, net) | ✅ Working in QEMU |
| D-Bus system bus + services | ✅ Working (login1, PolicyKit, UDisks, UPower) |
| ext4 / FAT filesystems | ✅ Compiles, installer-wired |
| POSIX gaps (relibc) | 🚧 Bounded Wayland-facing support |
| DRM/KMS display drivers | 🚧 AMD + Intel compile; HW validation pending |
| Wayland compositor | 🚧 Bounded proof; Qt6/KF6 clients crash at init |
| KDE Plasma desktop | 🔄 In progress (Qt6/KF6 compile; KWin/QML blocked) |
| Wi‑Fi / Bluetooth | 📋 Planned (architected, implementation pending) |
How It Works
Red Bear OS uses a userspace driver model — all drivers run as unprivileged daemons:
Kernel (microkernel)
└── schemes: memory, irq, event, pipe, debug
└── Driver daemons (userspace)
├── pcid → PCI enumeration
├── e1000d → Intel ethernet
├── xhcid → USB controller
└── vesad → Display framebuffer
The kernel provides minimal services (memory, interrupts, IPC). Everything else — filesystems, networking, graphics, input — runs in userspace.
Documentation
- Implementation Plan — roadmap and execution model
- Desktop Path Plan — kernel → DRM → Mesa → Wayland → KDE
- D-Bus Integration — session bus architecture
- USB Plan — USB stack design
- Wi‑Fi Plan — wireless architecture
- Bluetooth Plan — BT stack design
- Documentation Index — full doc map
Contributing
Red Bear OS uses a full fork model. Upstream Redox sources are frozen and archived. All custom work lives in local/:
local/
├── sources/ # Red Bear source forks (git repos, directly editable)
├── recipes/ # Custom packages (drivers, GPU, system)
├── docs/ # Integration and planning docs
└── scripts/ # Build, test, and release tooling
We welcome contributions made with or without AI assistance — we care about quality, not how the code was produced.
License
MIT — same as upstream Redox OS.