Graphics and Mouse Integration

In Linux and Oracle Solaris guests, Oracle VM VirtualBox graphics and mouse integration goes through the X Window System. Oracle VM VirtualBox can use the X.Org variant of the system, or XFree86 version 4.3 which is identical to the first X.Org release. During the installation process, the X.Org display server will be set up to use the graphics and mouse drivers which come with the Guest Additions.

After installing the Guest Additions into a fresh installation of a supported Linux distribution or Oracle Solaris system, many unsupported systems will work correctly too, the guest's graphics mode will change to fit the size of the Oracle VM VirtualBox window on the host when it is resized. You can also ask the guest system to switch to a particular resolution by sending a video mode hint using the VBoxManage tool.

Multiple guest monitors are supported in guests using the X.Org server version 1.3, which is part of release 7.3 of the X Window System version 11, or a later version. The layout of the guest screens can be adjusted as needed using the tools which come with the guest operating system.

If you want to understand more about the details of how the X.Org drivers are set up, in particular if you wish to use them in a setting which our installer does not handle correctly, see Guest Graphics and Mouse Driver Setup in Depth.

Starting from Oracle VM VirtualBox 7, Linux guest screen resize functionality for guests running VMSVGA graphics configuration has been changed. Since then, this functionality consists of a standalone daemon called VBoxDRMClient and its Desktop Environment helper counterpart.

VBoxDRMClient runs as a root process and is a bridge between the host and the guest's vmwgfx driver. This means that VBoxDRMClient listens to screen resize hints from the host and forwards them to the vmwgfx driver. This enables guest screen resize functionality to be available before the user has performed a graphical login.

In order to perform Desktop Environment specific actions, such as setting the primary screen in a multimonitor setup, a Desktop Environment helper is used. Once the user has performed a graphical login operation, the helper daemon starts with user session scope and attempts to connect to VBoxDRMClient using an IPC connection. When VBoxDRMClient has received a corresponding command from the host, it is forwarded to the helper daemon over IPC and the action is then performed.

By default, VBoxDRMClient allows any process to connect to its IPC socket. This can be restricted by using the following steps:

  1. The Guest Additions Linux installer creates a vboxdrmipc user group. A corresponding user needs to be added to this group.

  2. You must set the DRMIpcRestricted guest property, as follows: 

    VBoxManage guestproperty set "VM name" /VirtualBox/GuestAdd/DRMIpcRestricted 1 \
--flags RDONLYGUEST

    It is important to set only the RDONLYGUEST flag for the property, so that it cannot be changed from inside the guest.

Both steps are required. If one of them is missing, all processes will have access to the IPC socket.

Restricted mode can be disabled by unsetting the guest property, as follows: 

VBoxManage guestproperty unset "VM name" /VirtualBox/GuestAdd/DRMIpcRestricted