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https://github.com/humphd/browser-vm
A small Linux x86 VM meant for use in the browser
https://github.com/humphd/browser-vm
browser buildroot docker vm x86
Last synced: 14 days ago
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A small Linux x86 VM meant for use in the browser
- Host: GitHub
- URL: https://github.com/humphd/browser-vm
- Owner: humphd
- License: mit
- Created: 2019-02-06T22:50:15.000Z (almost 6 years ago)
- Default Branch: master
- Last Pushed: 2023-05-27T08:55:34.000Z (over 1 year ago)
- Last Synced: 2024-08-02T02:13:07.763Z (3 months ago)
- Topics: browser, buildroot, docker, vm, x86
- Language: Dockerfile
- Size: 92.8 KB
- Stars: 171
- Watchers: 7
- Forks: 41
- Open Issues: 9
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
- awesome-list - browser-vm
README
# Browser VM
A custom [Buildroot](https://buildroot.org/) config for a Linux x86 VM, meant to
be run in the browser as part of [browser-shell](https://github.com/humphd/browser-shell).
The resulting Linux ISO is meant to be run under
emulation in the browser via [v86](https://github.com/copy/v86), and includes:
* a custom Linux 4.15 kernel, which strips out many unnecessary drivers, modules, etc. and adds [Plan 9 filesystem](https://www.kernel.org/doc/Documentation/filesystems/9p.txt) sharing
* a root filesystem and Unix commands via [BusyBox](https://busybox.net/)
* an ISO-based bootloader (i.e., we create a "DVD" that is booted by v86)
Following the [Buildroot customization docs](https://buildroot.org/downloads/manual/manual.html#customize)
we create a folder `buildroot-v86/` with all the necessary config files,
filesystem overlay, and scripts necessary to build our distribution.
## Running via Docker
To build the Docker image use the `build.sh` script, or:
```bash
$ docker build -t buildroot .
```
And then to run the build:
```bash
$ docker run \
--rm \
--name build-v86 \
-v $PWD/dist:/build \
-v $PWD/buildroot-v86/:/buildroot-v86 \
buildroot
```
NOTE: we define two [volumes](https://docs.docker.com/engine/reference/builder/#volume) to
allow the container to access the v86 config, and also to write the ISO once complete. In the
above I've used `$PWD`, but you can use any absolute path.
When the build completes, an ISO file will be places in `./dist/v86-linux.iso`
in your source tree (i.e., outside the container).
If you need to re-configure things, instead of just running the build, do the following:
```bash
$ docker run \
--rm \
--name build-v86 \
-v $PWD/dist:/build \
-v $PWD/buildroot-v86/:/buildroot-v86 \
-ti \
--entrypoint "bash" \
buildroot
```
Now in the resulting bash terminal, you can run `make menuconfig` and [other make commands](https://buildroot.org/downloads/manual/manual.html#make-tips).
## `buildroot-v86/` Layout
We define a `v86` buildroot "board" via the following files and directories:
```
+-- board/
+-- v86
+-- linux.config # our custom Linux kernel config (make linux-menuconfig)
+-- post_build.sh # script to copy ISO file out of docker container
+-- rootfs_overlay/ # overrides for files in the root filesystem
+-- etc/
+-- inittab # we setup a ttyS0 console terminal to auto-login
+-- fstab # we auto-mount the Plan 9 Filer filesystem to /mnt
+-- configs/
+-- v86_defconfig # our custom buildroot config (make menuconfig)
+-- Config.in # empty, but required https://buildroot.org/downloads/manual/manual.html#outside-br-custom
+-- external.mk # empty, but required https://buildroot.org/downloads/manual/manual.html#outside-br-custom
+-- external.desc # our v86 board config for make
+-- build-v86.sh # entrypoint for Docker to run our build
```
If you need or want to update these config files, do the following:
```bash
$ make BR2_EXTERNAL=/buildroot-v86 v86_defconfig
$ make menuconfig
...
$ make savedefconfig
$ make linux-menuconfig
...
$ make linux-savedefconfig
```
## Configuration Notes
These are the options I set when configuring buildroot for v86. I'm only
specifying the things I set.
```bash
$ cd buildroot-2018.02
$ make menuconfig
```
Then follow these config steps in the buildroot config menu (NOTE: these docs
may have drifted from the actual config in the source, so consult that first):
### Target options
* Target Architecture: i386
* Target Architecture Variant: pentium mobile (Pentium with MMX, SSE)
### Build options
* Enable compiler cache (not strictly necessary, but helps with rebuilds)
### Toolchain
* C library: uLibc-ng (I'd like to experiment with musl too)
### System configuration
* remount root filesystem read-write during boot (I think this is unnecessary)
* Root filesystem overlay directories: /build/overlay-fs (for etc/inittab)
### Kernel
* Linux Kernel: true
* Defconfig name: i386
* Kernel binary format: bzImage (vmlinux seemed to break on boot)
### Target packages
Need to figure this out. I tried adding imagemagik, git, uemacs, but they
are all adding too much size to the image.
### Filesystem images
* cpio the root filesystem (for use as an initial RAM filesystem)
* initial RAM filesystem linked into the linux kernel (not sure I need this, trying without...)
* iso image
* Use initrd
* tar the root filesystem Compression method (no compression)
### Bootloaders
* syslinux
* install isolinux
## Linux configuration
Now configure the Linux Kernel:
```
$ make linux-menuconfig
```
And set the following options to accomplish this:
```
CONFIG_NET_9P=y
CONFIG_NET_9P_VIRTIO=y
CONFIG_9P_FS=y
CONFIG_9P_FS_POSIX_ACL=y
CONFIG_PCI=y
CONFIG_VIRTIO_PCI=y
CONFIG_PCI=y
CONFIG_VIRTIO_PCI=y
```
# Processor type and features
* Processor family (Pentium-Pro) also tried Pentium M before.
# Bus options (PCI, etc.)
* PCI Debugging: true (I want to see what's happening with PCI errors, normally not needed)
# Networking support
* Plan 9 Resource Sharing Support (9P2000) (built into kernel * vs. M)
* 9P Virtio Transport (* - make this is on, it won't exist if virtio is off)
* Debug information (* - optional)
# Device Drivers
* Virtio drivers
* PCI driver for virtio devices (built into kernel * vs. M)
* Support for legacy virtio draft 0.9.X and older devices (New)
* Platform bus driver for memory mapped virtio devices (* vs. M) - not sure I need this...
* Memory mapped virtio devices parameter parsing - or this...
# Filesystems
* Caches
* General filesystem local caching manager (*)
* Filesystem caching on files (*)
* Network File Systems
* Plan 9 Resource Sharing Support (9P2000) (*)
* Enable 9P client caching support
* 9P Posic Access Control Lists
Now run `make`
When it finishes, the built image is in `./output/images`.