Fast RISC-V emulator written in Rust. Boots Linux.
- RV64IMAFDC with M/S/U privilege levels and Sv39 virtual memory
- JIT compilation for ARM64 and x86_64 hosts (adaptive selection)
- Full Linux boot with BusyBox userland and interactive shell
- Snapshot/restore for saving and resuming full machine state
- Daemon mode with HTTP API and live UART command injection
- Differential checker to validate JIT against interpreter
- Peripherals: UART 16550, CLINT, PLIC, SBI 1.0, FDT generation
- Single dependency (
zstd), pure Rust
This is a direct comparison with commonly used RISC-V emulators/simulators: QEMU, Spike, and Renode.
Legend: ✅ = built in / directly documented, — = not built in (or not documented in the referenced source).
| Feature | emuko | QEMU (RISC-V virt) |
Spike (riscv-isa-sim) |
Renode |
|---|---|---|---|---|
| JIT / dynamic translation backend | ✅ | ✅ | — | — |
| Snapshot save + restore | ✅ | ✅ | — | ✅ |
| Autosnapshot (periodic) | ✅ | — | — | ✅ |
| HTTP API for machine control | ✅ | — | — | — |
| WebSocket UART console endpoint | ✅ | — | — | — |
| Scriptable UART host bridge primitives | ✅ | — | — | ✅ |
| One-command Debian kernel/initrd download with SHA256 verification | ✅ | — | — | — |
| Built-in JIT-vs-interpreter differential checker | ✅ | — | — | — |
| GDB debugging workflow | — | ✅ | ✅ | ✅ |
Large RISC-V board/device ecosystem (PCIe/virtio on virt) |
— | ✅ | — | — |
| Multi-node simulation focus | — | — | — | ✅ |
| Broad ISA extension coverage (incl. RVV, crypto, etc.) | — | — | ✅ | — |
Sources:
The main binary is target/release/emuko.
alias emuko=target/release/emuko
emuko dow
Downloads the Debian RISC-V netboot kernel and initrd to ~/.emuko/ with SHA256 verification.
This starts the emulator daemon and attaches an interactive console. You'll see the kernel boot and get a shell prompt. Keyboard shortcuts:
| Key | Action |
|---|---|
| Ctrl+] | Detach from console (daemon keeps running) |
| Ctrl+C | Sent to guest (interrupt running command) |
| Ctrl+D | Sent to guest (EOF) |
emuko start # reattach console to running daemon
emuko dump # print CPU state
emuko stop # pause execution
emuko con # continue execution
emuko step 1000 # step N instructions
emuko snap # take a snapshot
emuko kill # shut down daemon
The daemon exposes an HTTP API at http://127.0.0.1:7788/v1/api/ and a WebSocket console at ws://127.0.0.1:7788/v1/ws/uart.
emuko snap # take a snapshot now
emuko snap 5000000 # auto-snapshot every 5M steps
emuko snap stop # disable auto-snapshots
emuko ls # list snapshots
emuko restore <snapshot> # restore a snapshot
Pass options after emuko start, or set via environment variables or emuko.yml:
| Option | Env Var | Default | Description |
|---|---|---|---|
--ram-size |
RAM_SIZE |
1 GB | RAM in bytes |
--backend |
EMUKO_BACKEND |
adaptive |
adaptive, arm64_jit, amd64_jit, arm64, x86_64 |
--bootargs |
BOOTARGS |
serial console | Kernel command line |
Use emuko dow (see Quick Start above) or grab pre-built images from DQIB (Debian Quick Image Baker). To download a specific set:
Apache 2.0. See LICENSE.