Virt-Manager Scale Display not Working

Support Virtualization
1

Hi,

I have a Manjaro Host. I have always used Virtual Box. Today decided to give KVM a try. Followed: Virt-manager - Manjaro.

Now I have a Manjaro guest as well, and I am very impressed with the performance of KVM.

There are 2 small issues I don’t seem to be able to resolve:
1 - View/Scale Display - sub-menu is completely missing
2 - Although I can share files, I don’t seem to be able to c/p between host & guest

I figure I am missing a package or something. I checked guest and I do have spice-vdagent

In desperation I even installed spice-vdagent on the host (I don’t think that was necessary).

Not sure what info I can share with you so you can help me :slight_smile: Please let me know and I’ll update the post.

Thanks in advance!
for what it’s worth - I also created windows guest and the same issue there (even after installing the client tools on windows)

2

I use gnome-boxes, which also uses libvirt.

On XFCE live session, it actually detects the resolution, but it doesn’t update automatically when you resize the vm window. Wouldn’t be hard to run another service, which will watch and update the resolution. If you run xrandr, then the first resolution change when you change the window size.

There are efforts to create a webdav-server for folder-sharing: Spice User Manual

gnome-boxes has it integrated in the settings and is easy to use. You need to install phodav and spice-webdavd.service must be running in the VM. There is also a msi setup for windows.

However, webdav has limitations. Especially the performance for big files is not great, but it does the job well when transferring files or open small files.

Hope that helps :wink:

3

For Linux distos:

spice-vdagent should be installed on Linux guest, not host.

It support:

  • Auto resize of display on KVM guest.
  • Share clipboard using copy/paste any text (It should work on X11 guest, not wayland)

You need to enable spice-vdagent for autostart on Linux guest.
Video model should be set “Virtio” in the virtual hardware setting.

For Windows:

You need to install virtio-win-guest-tool.exe on Windows guest. It supports auto resize display and share clipboard too.

virtio-win ISO driver helps improve performance on virt image. (It is optional, but it requires new installation of Windows)

Multiple Linux distros and Windows 11 setup in virt-manager works fine for me using libvirt 9.1.0.

You don’t need to update libvirt 9.2.0 as it disabled the nice ability to create offline internal snapshot when guests use UEFI.

4

Thank you megavolt & Zesko.

So for some reason spice-vdagent is not running at start up, even though on the host I can see it in /etc/xdg/autostart/spice-vdagent.desktop

When I ran it manually I was able to c/p from the clipboard between host & guest.

However resizing the window does not change display resolution. I would expect the resolution to readjust to the size of the window (maybe my expectations are wrong).

  • Resize to VM works
  • There are still no submenus for Scale Display
6

Yes, however, /etc/xdg/autostart/spice-vdagent.desktop has the bug with KDE.

If you use KDE guest, just remove the line X-GNOME-Autostart-Phase=WindowManager in it. Then reboot.

But pacman will overwrite it back when update or reinstall spice-vdagent.

There are possible two solutions:

  • You can create a separate same file in ~/.config/autostart/spice-vdagent.desktop
    OR
  • Edit /etc/pacman.conf to add
NoUpgrade = etc/xdg/autostart/spice-vdagent.desktop
7

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