[vbox-dev] BLUF: Consider enabling 3D acceleration by default (as least for KDE-based Linux guest OSs)

[Aaron Rainbolt]

On 3/8/24 11:24, Aaron Rainbolt wrote:
> On 3/8/24 11:10, Nate Graham via vbox-dev wrote:
>> Hello! I'm Nate Graham from KDE. We're tracking an issue that causes 
>> Linux guest OSs with KDE Plasma 6 to fail when 3D acceleration is 
>> disabled: https://bugs.kde.org/show_bug.cgi?id=481937. The changes 
>> made in Plasma 6 that resulted in this issue are unfortunately not 
>> easily revertable, and 3D acceleration improves the UX in general for 
>> our systems, so our developers aren't feeling a strong incentive for 
>> to try.
>>
>> I'd like to discuss the possibility of enabling 3D acceleration by 
>> default--at least for as least for KDE-based Linux guest OSs.
>
> I am not a VBox dev, but this change has potentially severe security 
> implications that would make me highly uncomfortable enabling this if 
> I were a VBox dev. Quoting from the VirtualBox 7.0 user manual 
> (https://docs.oracle.com/en/virtualization/virtualbox/7.0/user/guestadditions.html#guestadd-video):
>
> Note:
>
> Untrusted guest systems should not be allowed to use the 3D 
> acceleration features ofOracle VM VirtualBox, just as untrusted host 
> software should not be allowed to use 3D acceleration. Drivers for 3D 
> hardware are generally too complex to be made properly secure and any 
> software which is allowed to access them may be able to compromise the 
> operating system running them. In addition, enabling 3D acceleration 
> gives the guest direct access to a large body of additional program 
> code in theOracle VM VirtualBoxhost process which it might conceivably 
> be able to use to crash the virtual machine.
>
> If KDE-based Linux VMs have 3d acceleration become mandatory, 
> KDE-based Linux VMs will also no longer be suitable for any 
> security-sensitive use of VirtualBox (malware analysis, sandboxing of 
> suspicious applications, etc.). The ability for VirtualBox to sandbox 
> insecure software is important enough that the guide specifically 
> mentions it as a primary use case for VirtualBox 
> (https://docs.oracle.com/en/virtualization/virtualbox/7.0/user/Introduction.html#virtintro):
>
> In addition to that, with the use of anotherOracle VM 
> VirtualBoxfeature calledsnapshots, one can save a particular state of 
> a virtual machine and revert back to that state, if necessary. This 
> way, one can freely experiment with a computing environment. If 
> something goes wrong, such as problems after installing software or 
> infecting the guest with a virus, you can easily switch back to a 
> previous snapshot and avoid the need of frequent backups and restores.
>
> It would help to know what exactly these changes are that "cannot be 
> easily reverted" (probably not on the VBox ML though). Perhaps someone 
> who is willing to put in the necessary time and effort can discover a 
> way to make KWin compatible with more secure graphics options under 
> VirtualBox? I personally would be willing to try and help with that.
>
So actually, as it turns out, this appears to be an issue with the 
VMSVGA graphics controller in VirtualBox in particular. If I switch to 
the VBoxSVGA controller instead, I can boot the latest KDE neon User 
Edition ISO with Plasma 6 without 3d acceleration. It appears to work 
just fine.

Changing to VBoxSVGA graphics in an Ubuntu VM results in a warning in 
VirtualBox stating "The virtual machine is configured to use a graphics 
controller other than the recommended one (VMSVGA). Please consider 
switching unless you have a reason to keep the currently selected 
graphics controller." Is there a particular reason this is still shown? 
Is VMSVGA even still a good default for Linux virtual machines? I 
believe Windows virtual machines use VBoxSVGA by default, and Linux 
appears to work with it, so perhaps it would help to simply change the 
default graphics adapter for (at least some) Linux OSes.

-- 
Aaron Rainbolt
Lubuntu Developer
Matrix: @arraybolt3:matrix.org
IRC: arraybolt3 on irc.libera.chat
GitHub:https://github.com/ArrayBolt3

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