Guest Additions kernel modules not bitness clean (32bit userspace on 64bit kernel) -> won't fix for now

[Fernando]

When booting a 64bit kernel inside a 32ul, the mouse integration fails with

from Xorg.0.log

[    81.214] (EE) VBoxVideo(0): Unable to determine whether the virtual machine supports mouse
pointer integration - request initialization failed with return code -2

from dmesg

ioctl32(X:17150): Unknown cmd fd(9) cmd(c0245603){t:'V';sz:36} arg(ffc487ec) on 
                           /dev/vboxguest

[Fernando]

vbox.log

[Fernando]

dmesg|grep vbox; output

[Fernando]

glxinfo

[Fernando]

Xorg.0.log

[Fernando]

Just to add this is somewhat related to Tickets: #3345

[Michael Thayer]

This is not something that we will be able to resolve in the near future, as the Guest Additions kernel code is not 32bit/64bit clean, and unfortunately the issue isn't important enough to justify the review of the code that would be needed to fix that just now.

[Cédric Cabessa]

add-compat_ioctl-for-32bit-userland

[Cédric Cabessa]

FYI with the patch add-compat_ioctl-for-32bit-userland.patch I've succeed to run a 32bit userspace on a 64bit kernel. I use a simple tool based on vbox api to mount a shared folder and use vboxproperty. Using the 64bit data structure (-DRT_ARCH_AMD64,-DVBOX_WITH_64_BITS_GUESTS) this works well.

[Frank Mehnert]

This patch works probably for a number of interfaces but as written above, a revision of all guest interfaces is necessary. You tested only a subset of the interfaces.

[ptomato]

Nonetheless, this patch works surprisingly well for me on VirtualBox 5.0.14 (with the appropriate name change for the functions.) I've been using it for a few weeks and all the guest additions except for the shared clipboard seem to function now.