I have installed Arch Linux with Plasma 5.3 in a Virtual Box VM today at work, simply to be able to enjoy the breeze at work and to become a little bit more productive by taking advantage of enhanced desktop features that Windows 8 simply cannot offer. Working with Windows is really cumbersome, to say the least.

Anyway, on my Windows 8 host I've created a new VM and installed Arch Linux with Plasma 5 on it. I also installed the Virtual Box guest extensions on it, providing the vboxvideo kernel module as video driver. The desktop and everything works just fine when the drivers are not loaded, although everything is very sluggish. But when I boot with the drivers loaded, I can log in with sddm fine, but then I only see the wallpaper for a minute or two until the main panel appears. I can open apps through the "start menu" as well as through KRunner, but the apps take forever to load, then the main panel disappears again only to reappear half a minute later with the app I started, but without window title and all that. Cannot drag it nor resize. I tried "kwin_x11 --replace" but that just made disappear everything for a minute just to come back broken. I checked journalctl and there were a lot of KWin messages with some errors, but unfortunately I'm home now and I didn't have had the time to better analyze the journal, dmesg and X.org log files and all that.

Now my question is if someone knows if KWin works in Virtual Box with the vboxdriver module enabled? If this isn't supported at all then that's unfortunate but fine, because I can understand that using a virtualized 3D GPU isn't that trivial, and

Almost forgot to mention the PC at work I try to do this: it's an Core i5-4xxx (not sure about exact model number), with the integrated Intel GPU which I unfortunately have to use.

Thanks in advance for any insights!

a) suspend the compositor (SHIFT+Alt+F12)
b) use the xrender compositing backend (kcmshell5 kwincompositing) - the GL emulation will be done with accelerated QML in plasmashell etc.

I think kwin uses xrender by default on virtualbox anyway (because already in KDE4 llvmpipe accelerated compositing is anything but great), if it's not, please dump the output of "qdbus org.kde.KWin /KWin supportInformation" in that virtual machine and file a bug.

Thanks a lot! Suspending the compositor does indeed help. That's a shortcut I'll probably never forget

Rendering backend is set to XRender, I can choose Open GL GLX/EGL but it does always revert back to XRender. Also plasmashell inside the VM is consuming constantly around 70% CPU in fullscreen, and 60% in windowed mode accross all the 4 vCores I gave it. I assume this is because its now doing most of the heavy lifting in software mode on the CPU, right?

Anyway, I did some more research and will now look into vmware player and workstation trial, from what I've gathered it's supposed to give pretty good 3D performance in OpenGL and Direct3D. Virtualbox unfortunately doesn't seem to be there yet.

Reversion to xrender is expected (we thus won't need the supportInformation) and yes, the heavy CPU load is -likely- due to the emulated GL acceleration in all those QML scenes (at least that was the reason why KWin compositing was restricted to xrender on virtualbox, OpenGL compositing was terribly slow)

You may try to
export LIBGL_ALWAYS_SOFTWARE=1
in eg. /etc/profile of the *guest* to force guest-side llvmpipe SW rendering rather than the virtualbox pseudo-HW renderer. No idea whether that's gonna improve things, though.

I tried the export you suggested, but it didn't seem to change much, CPU load was also still high.

I have now installed the trial version of VMware Workstation 11 on my Arch Linux on my home PC now, and even though I can't get the 3D acceleration to work (have an ATI HD5850, using the Xorg radeon drivers), performance of Plasma 5 in XRender mode is quite good in VMware! Also, CPU load is very low when idle, somewhere between 1-5%, which makes me believe there could be a bug in plasmashell that causes the high CPU load in vbox in XRender mode, or maybe it's vbox's fault, can't really tell.

I'm very surprised with VMwares performance, it makes the plasma desktop almost usable. Now I just need to get OpenGL working

Edit: yesterday evening I also installed vbox on my linux home PC and also installed Arch + Plasma 5 inside, and the performance and issues are the same like on my windows host at work. 3D acceleration also doesn't work with my HD5850 in vbox.

Code: Select all

export KWIN_COMPOSE=O2
kwin_x11 --replace &


O2 like OpenGL2, *not* "Zero-Two"