arceos-msgqueue

A standalone message-queue application running on ArceOS unikernel, with all dependencies sourced from crates.io. Demonstrates cooperative multi-task scheduling with a producer-consumer message queue and PFlash MMIO access across multiple architectures.

What It Does

This application demonstrates cooperative scheduling and inter-task communication:

1. Message queue: A VecDeque protected by SpinNoIrq (interrupt-safe spinlock) serves as the shared message queue between tasks.
2. Producer task (worker1): Pushes numbered messages (0..64) into the queue, calling thread::yield_now() after each push to cooperatively hand over the CPU.
3. Consumer task (worker2): Pops messages from the queue, printing each one. When the queue is empty, it yields the CPU back to the producer.
4. Cooperative scheduling: Tasks voluntarily yield via thread::yield_now(), demonstrating the basic cooperative scheduling algorithm — without yielding, a task runs until completion.
5. PFlash MMIO: Before starting the message queue, the main task verifies PFlash access via page-table-mapped MMIO.

PFlash Address Map

Supported Architectures

Prerequisites

• Rust nightly toolchain (edition 2024)

  rustup install nightly
  rustup default nightly
  

• Bare-metal targets (install the ones you need)

  rustup target add riscv64gc-unknown-none-elf
  rustup target add aarch64-unknown-none-softfloat
  rustup target add x86_64-unknown-none
  rustup target add loongarch64-unknown-none
  

• QEMU (install the emulators for your target architectures)

  # Ubuntu/Debian
  sudo apt install qemu-system-riscv64 qemu-system-aarch64 \
                   qemu-system-x86 qemu-system-loongarch64  # OR qemu-system-misc
  
  # macOS (Homebrew)
  brew install qemu
  

• SeaBIOS (required for x86_64 only)

  # Ubuntu/Debian
  sudo apt install seabios
  

• rust-objcopy (from cargo-binutils, required for non-x86_64 targets)

  cargo install cargo-binutils
  rustup component add llvm-tools
  

Quick Start

# install cargo-clone sub-command
cargo install cargo-clone
# get source code of arceos-msgqueue crate from crates.io
cargo clone arceos-msgqueue
# into crate dir
cd arceos-msgqueue
# Build and run on RISC-V 64 QEMU (default)
cargo xtask run

# Build and run on other architectures
cargo xtask run --arch aarch64
cargo xtask run --arch x86_64
cargo xtask run --arch loongarch64

# Build only (no QEMU)
cargo xtask build --arch riscv64
cargo xtask build --arch aarch64

Expected output (abbreviated):

Multi-task message queue is starting ...
PFlash check: [0xFFFFFFC022000000] -> PFLA
Wait for workers to exit ...
worker1 (producer) ...
worker1 [0]
worker2 (consumer) ...
worker2 [0]
worker1 [1]
worker2 [1]
...
worker1 [64]
worker1 ok!
worker2 [64]
worker2 ok!
Multi-task message queue OK!

QEMU will automatically exit after printing the message.

Project Structure

app-msgqueue/
├── .cargo/
│   └── config.toml       # cargo xtask alias & AX_CONFIG_PATH
├── xtask/
│   └── src/
│       └── main.rs       # build/run tool (pflash image creation + QEMU launch)
├── configs/
│   ├── riscv64.toml      # Platform config with PFlash MMIO range
│   ├── aarch64.toml
│   ├── x86_64.toml
│   └── loongarch64.toml
├── src/
│   └── main.rs           # Producer-consumer message queue with cooperative scheduling
├── build.rs              # Linker script path setup (auto-detects arch)
├── Cargo.toml            # Dependencies (axstd with paging + multitask features)
└── README.md

How It Works

The cargo xtask pattern uses a host-native helper crate (xtask/) to orchestrate cross-compilation and QEMU execution:

1. cargo xtask build --arch <ARCH>

   • Copies configs/<ARCH>.toml to .axconfig.toml
   • Runs cargo build --release --target <TARGET> --features axstd

2. cargo xtask run --arch <ARCH>

   • Performs the build step above
   • Creates a PFlash image with magic string "PFLA" at offset 0
   • For x86_64: embeds SeaBIOS at the end of the pflash image
   • Converts ELF to raw binary via rust-objcopy (except x86_64)
   • Launches QEMU with the PFlash image attached

Key Components

License

GPL-3.0-or-later OR Apache-2.0 OR MulanPSL-2.0