I accidentally browsed using Firefox in the default dvm template. Since it’s not safe, please tell me how to create a clean default dvm template.
If you ever need to reconfigure according to defaults, you can find salt scripts at /srv/formula/base/virtual-machines-formula/qvm/, and execute sudo qubesctl state.sls qvm.<your-vm-here>. For example: sudo qubesctl state.sls qvm.sys-whonix. Note that must correlate to a file in the aforementioned directory ending in .top, and the VM in question must not be present.
It might be more convenient to clear the ‘private’ volume of the disposable template (e.g. default-dvm), resetting it to a pristine state containing no data. This function is not exposed in the tooling but it’s straightforward to invoke:
$ qvm-shutdown --wait default-dvm
$ qubesd-query --empty --fail dom0 admin.vm.volume.Clear default-dvm private
Or even simpler, revert the volume to its previous state - if you’re sure that you just dirtied it up the last time the disposable template was running, and that you haven’t started it since:
$ qvm-shutdown --wait default-dvm
$ qvm-volume revert default-dvm:private
You can restore the previous state of your dvm template after a mistake using qvm-volume revert, unless you rebooted it more times than you have backups.
qubesd-query --empty --fail dom0 admin.vm.volume.Clear default-dvm private
this command is very easy!! how did you know this?
Sorry to say I don’t have a good answer for that. There’s a qubesd-query manpage covering just the tool itself, but to figure out the actual admin API calls you have to read their code.
Really though, this low-level stuff should be exposed in one of the qvm-something commands. E.g. admin.vm.volume.Clear is yearning to be hooked up as qvm-volume clear VM:VOLUME