Ah rats, Debian stable's kernel is new enough that the VirtualBox 6.0 guest additions don't build for it any more.
VirtualBox 6.0 was the last branch to support 3D accelleration passthrough for Windows XP, because they reimplemented it all and didn't bother with the guest addition 3D support for pre-WDDM.
Since it runs a service, I suspect you can only have one version of VirtualBox installed at once.
I don't think we're quite Future enough to be doing nested VM/emulation stacking here yet.
(I was kind of wishfully hoping someone would dive into making the new VboxSVGA stuff work with XP, but I can't exactly blame the VBox devs for not doing a feature nobody is actually *paying* for, nor can I exactly blame that there's no hobbyists out there deeply gung-ho about diving into grody legacy Windows driver internals.
The Foones et. al. of the world are still playing with 3.1, after all; 95 at most.)
(Kinda hoping if I *do* go to VBox 6.1 it'll at least fix a stupid host-0,0-mouse-warping issue I have with mouse integration *off* that makes it useless and I can't find anyone else experiencing, at least.
Yes, ironically this is a problem in combination with games...which is what the 3D WinXP VM is for. It's been broken a while. Software updates are a sadness.)
