spectrum-vm is a handy way to start a crosvm instance for testing crosvm itself, the kernel, or the rootfs. This commit adds some fledgling documentation on its functionality and usage. --- Takes into account review suggestions and tweaks a bit of wording here and there. Specifically, I clarified that rootfs means the root filesystem, added an aside that the serial console can be used to run privileged commands, dropped the full `spectrum-vm --help` text, and moved and reformatted the usage examples. developer-manual.adoc | 53 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 53 insertions(+) diff --git a/developer-manual.adoc b/developer-manual.adoc index b7eb2cb..a98330f 100644 --- a/developer-manual.adoc +++ b/developer-manual.adoc @@ -106,6 +106,59 @@ the https://spectrum-os.org/doc/crosvm/crosvm/[crosvm documentation] for the version currently used by Spectrum is hosted on the Spectrum website. +==== spectrum-vm + +`spectrum-vm` is a shell script that allows for testing various Spectrum +VM components, including crosvm, the kernel, and the root filesystem +("rootfs" for short). The simplest way to use this tool is by running +`nix-shell -I nixpkgs=/path/to/nixpkgs-spectrum -p +spectrumPackages.spectrum-vm --run spectrum-vm` in a terminal, which +will start up an instance of crosvm from Nixpkgs running Wayfire in a +new window. + +**** +Be advised that Wayfire's default keymap is set to Dvorak +https://spectrum-os.org/git/nixpkgs/tree/pkgs/os-specific/linux/spectrum/rootfs/default.nix[inside +of the rootfs] -- to change this to your preferred keymap, just set the +`xkb_layout` option (or remove it altogether for a default of QWERTY). +**** + +Once you are ready to end your crosvm session, switch back to where you +ran `spectrum-vm` and type `reboot` (not `poweroff`). This window is not +limited to just stopping the VM, however; it is a functional serial +console where you can even run commands like `env` and `cat +/etc/passwd`. + +**** +Although it is currently not possible to execute commands as root inside +the graphical environment, one can instead use the serial console to run +privileged commands. +**** + +===== Examples + +As mentioned above, `spectrum-vm` also supports options that allow you +to specify custom components or run arbitrary commands before exiting: + +---- +nix-shell -I nixpkgs=/path/to/nixpkgs-spectrum -p spectrumPackages.spectrum-vm + +# display the currently supported options for spectrum-vm +nix-shell$ spectrum-vm --help + +# run a command that will print out the VM's PATH to the serial terminal and exit +nix-shell$ spectrum-vm -c 'echo $PATH' + +# use the specified crosvm and disable sandboxing +nix-shell$ spectrum-vm -C target/debug/crosvm -- --disable-sandbox + +# use the specified kernel image +nix-shell$ spectrum-vm -k result/bzImage + +# use the specified squashfs as the root filesystem image +nix-shell$ spectrum-vm -f squashfs +---- + ==== Hacking on crosvm There are a few ways to get a crosvm development environment. You can -- 2.26.2