Dear Andreas Messer,

On 05.11.2025 19:05, Andreas Messer wrote:
> Hello Mr. Oberhage,
>
> thanks for the bug report.

first, many thanks for your kind replay. It is really
appreciated.

Now let's dive into the matter.

> Am Wed, Nov 05, 2025 at 02:07:03PM +0100 schrieb H.-R. Oberhage:
>> When starting a Xen PV VM, virt-manager shows the message:
>> "This VM has no graphic display device".
>> This concerns the "Display VNC" driver.
>>
>> This behavior started for all such VMs after the transition from
>> Devuan Daedalus to Devuan Excalibur. Before that, they worked fine.
>
> I just checked that VMs here migrated successfully and work as
> expected.
>
> Can you please check, that the device config of your VM has proper
> video device and a display device. I'm using video device "virtio"
> and display device "spice" here.

The problem here most probably are the PV (paravirtualized) VMs.
There is no "spice" option available for it, to my dismay, so
I'm stuck with VNC as display device and the "video" is "xen".

> I found some rumors via google, that after update of libvirt,
> others observed such issues too. (quite a while ago, however)
> It could be also a problem with apparmor preventing
> the virt-viewer to access the stream.
>
> After starting the vm, you could try to run:
>
> $sudo apparmor_status

Yes, I have also read about that, but the (missing) entry
mentioned is now part of the configuration file. Also, the
VM itself does run properly, I just have to switch the view
in virt-manager to the text console - in the running VM -, and
it's there, up and accepting input and showing output.

> This might show were apparmor prevented access. (I have absolutely no
> experience using apparmor)

Me neither, but I don't think it's apparmor's fault. Nevertheless I
shall append it output below.

The link, that I think comes next to my problem or even is it, is:
No display in Xen PV guests: "This VM has no graphic display device."
[https://mail.gnu.org/archive/html/qemu-devel/2024-12/msg02294.html]
and the link within it.
I just never learned what the outcome was/is, and I think that you
have better connections to the "upstream community", than I do.

May be, someone can help.

> Best regards,
> Andreas

Thanks again and all the best,
Ruediger

PS: The lengthy apparmor_status output
apparmor module is loaded.
133 profiles are loaded.
32 profiles are in enforce mode.
    /usr/bin/lxc-copy
    /usr/bin/lxc-start
    /usr/bin/man
    /usr/lib/NetworkManager/nm-dhcp-client.action
    /usr/lib/connman/scripts/dhclient-script
    /usr/lib/cups/backend/cups-pdf
    /usr/sbin/cups-browsed
    /usr/sbin/cupsd
    /usr/sbin/cupsd//third_party
    /usr/{lib/NetworkManager,libexec}/nm-dhcp-helper
    /{,usr/}sbin/dhclient
    guestfs-tools
    guestfs-tools//passt
    libreoffice-senddoc
    libreoffice-soffice//gpg
    libreoffice-xpdfimport
    libvirtd
    libvirtd//qemu_bridge_helper
    lsb_release
    lxc-container-default
    lxc-container-default-cgns
    lxc-container-default-with-mounting
    lxc-container-default-with-nesting
    man_filter
    man_groff
    msmtp
    msmtp//helpers
    nvidia_modprobe
    nvidia_modprobe//kmod
    passt
    pasta
    virt-aa-helper
25 profiles are in complain mode.
    Xorg
    libreoffice-oosplash
    libreoffice-soffice
    plasmashell
    plasmashell//QtWebEngineProcess
    sbuild
    sbuild-abort
    sbuild-adduser
    sbuild-apt
    sbuild-checkpackages
    sbuild-clean
    sbuild-createchroot
    sbuild-destroychroot
    sbuild-distupgrade
    sbuild-hold
    sbuild-shell
    sbuild-unhold
    sbuild-update
    sbuild-upgrade
    transmission-cli
    transmission-daemon
    transmission-gtk
    transmission-qt
    unix-chkpwd
    unprivileged_userns
0 profiles are in prompt mode.
0 profiles are in kill mode.
76 profiles are in unconfined mode.
    1password
    Discord
    MongoDB Compass
    QtWebEngineProcess
    balena-etcher
    brave
    buildah
    busybox
    cam
    ch-checkns
    ch-run
    chrome
    chromium
    crun
    devhelp
    element-desktop
    epiphany
    evolution
    firefox
    flatpak
    foliate
    geary
    github-desktop
    goldendict
    ipa_verify
    kchmviewer
    keybase
    lc-compliance
    libcamerify
    linux-sandbox
    loupe
    lxc-attach
    lxc-create
    lxc-destroy
    lxc-execute
    lxc-stop
    lxc-unshare
    lxc-usernsexec
    mmdebstrap
    msedge
    nautilus
    notepadqq
    obsidian
    opam
    opera
    pageedit
    polypane
    privacybrowser
    qcam
    qmapshack
    qutebrowser
    rootlesskit
    rpm
    rssguard
    runc
    scide
    signal-desktop
    slack
    slirp4netns
    steam
    stress-ng
    surfshark
    systemd-coredump
    toybox
    trinity
    tup
    tuxedo-control-center
    userbindmount
    uwsgi-core
    vdens
    virtiofsd
    vivaldi-bin
    vpnns
    vscode
    wike
    wpcom
6 processes have profiles defined.
5 processes are in enforce mode.
    /usr/sbin/cups-browsed (2233)
    /usr/sbin/cupsd (2258)
    /usr/sbin/dhclient (1688) /{,usr/}sbin/dhclient
    /usr/sbin/dhclient (1772) /{,usr/}sbin/dhclient
    /usr/sbin/libvirtd (2671) libvirtd
1 processes are in complain mode.
    /usr/lib/xorg/Xorg (2283) Xorg
0 processes are in prompt mode.
0 processes are in kill mode.
0 processes are unconfined but have a profile defined.
0 processes are in mixed mode.
-- 
Dr. H.-R. Oberhage
Mail: Univ. Duisburg-Essen    E-Mail: oberhage@???
       Fakultaet fuer Physik