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https://github.com/sysprog21/semu
A minimalist RISC-V system emulator capable of running Linux kernel
https://github.com/sysprog21/semu
emulator linux-kernel risc-v riscv riscv-emulator rv32ima
Last synced: 1 day ago
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A minimalist RISC-V system emulator capable of running Linux kernel
- Host: GitHub
- URL: https://github.com/sysprog21/semu
- Owner: sysprog21
- License: mit
- Created: 2022-07-09T05:51:44.000Z (over 2 years ago)
- Default Branch: master
- Last Pushed: 2024-12-16T03:23:28.000Z (about 1 month ago)
- Last Synced: 2025-01-12T23:04:22.494Z (9 days ago)
- Topics: emulator, linux-kernel, risc-v, riscv, riscv-emulator, rv32ima
- Language: C
- Homepage:
- Size: 3.71 MB
- Stars: 256
- Watchers: 8
- Forks: 50
- Open Issues: 14
-
Metadata Files:
- Readme: README.md
- Contributing: CONTRIBUTING.md
- License: LICENSE
Awesome Lists containing this project
README
# semu
A minimalist RISC-V system emulator capable of running Linux the kernel and corresponding userland.
`semu` implements the following:
- RISC-V instruction set architecture: RV32IMA
- Privilege levels: S and U modes
- Control and status registers (CSR)
- Virtual memory system: RV32 MMU
- UART: 8250/16550
- PLIC (platform-level interrupt controller): 32 interrupts, no priority
- Standard SBI, with the timer extension
- VirtIO: virtio-blk acquires disk image from the host, and virtio-net is mapped as TAP interface
## Prerequisites
[Device Tree](https://www.kernel.org/doc/html/latest/devicetree/) compiler (dtc) is required.
To install it on Debian/Ubuntu Linux, enter the following command:
```shell
$ sudo apt install device-tree-compiler
```
For macOS, use the following command:
```shell
$ brew install dtc
```
For demonstration purposes, ext4 is used for file system mounting.
`ext4` is a native Linux filesystem, offering stability, high capacity, reliability,
and performance while requiring minimal maintenance. The `mkfs.ext4` command can
create an ext4 file system from disk partitions. This command is a symbolic link of
the [mke2fs](https://man7.org/linux/man-pages/man8/mke2fs.8.html) command, and its
usage is the same as the mke2fs command.
For most GNU/Linux distributions, `mkfs.ext4` command should be installed in advance.
For macOS, use the following command:
```shell
$ brew install e2fsprogs
```
## Build and Run
Build the emulator:
```shell
$ make
```
Download prebuilt Linux kernel image:
```shell
$ make check
```
Please be patient while `semu` is running.
Reference output:
```
Starting syslogd: OK
Starting klogd: OK
Running sysctl: OK
Starting network: OK
Welcome to Buildroot
buildroot login:
```
Enter `root` to access shell.
You can exit the emulator using: \. (press Ctrl+A, leave it, afterwards press X)
## Usage
```shell
./semu -k linux-image [-b dtb-file] [-i initrd-image] [-d disk-image]
```
* `linux-image` is the path to the Linux kernel `Image`.
* `dtb-file` is optional, as it specifies the user-specified device tree blob.
* `initrd-image` is optional, as it specifies the user-specified initial RAM disk image.
* `disk-image` is optional, as it specifies the path of a disk image in ext4 file system for the virtio-blk device.
## Build Linux kernel image and root file system
An automated build script is provided to compile the RISC-V cross-compiler, Busybox, and Linux kernel from source.
Please note that it only supports the Linux host environment.
```shell
$ make build-image
```
## License
`semu` is released under the MIT License.
Use of this source code is governed by a MIT-style license that can be found in the LICENSE file.