virtualbox.org

Like in the subject. As we all knows, Oracle adopted VMSVGA VMware driver for unix guests.

Im BSD, even installing a mix of virtualbox-ose-additions (for clipboard share and mouse interaction) and vmware-guest-additions, it is impossible to resize the host OS windows automatically using mouse drag and drop with every window manager in X or wayland.

Any hint to overcome this big limitations?

I can't suggest any hints, but I can suggest it will very likely have to be a home-rolled solution.

From the manual, https://www.virtualbox.org/manual/ch03. ... tossupport :

FreeBSD:

Limited support.

Note that you must enable hardware virtualization when running FreeBSD.

Guest Additions are not available.

Without Guest Additions, there are no Virtualbox drivers for the video card available, so only basic video is available as supported by FreeBSD's drivers.

Oracle adopted the virtual VMSVGA video card, not VMware's drivers. From the manual https://www.virtualbox.org/manual/ch03. ... gs-display :

VMSVGA: Use this graphics controller to emulate a VMware SVGA graphics device

Installing 3rd-party drivers to handle Virtualbox-provided hardware that the guest OS doesn't have drivers for has worked (I did this once for a network card in an XP guest, and it works for virt-io setups.) Installing VMware drivers for the video card may or may not work. However, even if it does, the Guest Additions trigger won't be there, because the extra stuff that Guest Additions provides isn't generated for FreeBSD, so won't be calling out to the host to let the magic start.

Guest Additions for FreeBSD haven't been made because no (or not enough) Oracle customers want them.

FreeBSD has its own guide for getting VirtualBox Guest Additions working (so they say) - https://www.freebsd.org/doc/handbook/vi ... VirtualBox™.,integration.%20Host%20time%20synchronization.%20Window%20scaling.%20Seamless%20mode.

This would definitely qualify as a Guest Additions 'hack', which obviously can't be supported by Oracle Devs/this Forum and the FreeBSD Forums would need to be used if problems are experienced or further advice is required. I don't use BSD based system myself (other than MacOS), so can't give any indication of whether the Guide actually works, but there would be limited risk if fully restorable backups of the working FreeBSD VM(s) were maintained.

The solution to have windows automagically resized is to use VBoxVGA option (and not VMSVGA).

Then install virtualbox-ose-additions package from FreeBSD repository and you should be done.

From this point, the old FreeBSD instructions for running the OS (rc.config configuration, boot options, guest autostart) as a guest should be helpfull.

That's all.