Bug#889990: gnome-boxes: Unable to start VMs because CPU mode 'custom' for x86_64 kvm domain on x86_64 host is not supported

[Julien Viard de Galbert]

Package: gnome-boxes
Version: 3.26.2-3
Followup-For: Bug #889990

Dear Maintainer,

I was having the same issue on a derivative distribution (pureos).
After discussing on their bug system they found that the user should be
in the kvm group.
You can see the discussion there: https://tracker.pureos.net/T320

so you can try:
   sudo adduser <youruser> kvm
   newgrp kvm
   gnome-boxes

And see if it works for you !

Hope this helps,

Julien VdG

-- System Information:
Distributor ID:	PureOS
Description:	PureOS GNU/Linux 8
Release:	8
Codename:	green
Architecture: x86_64

Kernel: Linux 4.14.0-3-amd64 (SMP w/4 CPU cores)
Locale: LANG=fr_FR.UTF-8, LC_CTYPE=fr_FR.UTF-8 (charmap=UTF-8), LANGUAGE=fr_FR.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages gnome-boxes depends on:
ii  dconf-gsettings-backend [gsettings-backend]  0.26.1-3
ii  libarchive13                                 3.2.2-3.1
ii  libc6                                        2.26-6
ii  libcairo-gobject2                            1.15.10-1
ii  libcairo2                                    1.15.10-1
ii  libgdk-pixbuf2.0-0                           2.36.11-1
ii  libglib2.0-0                                 2.54.3-2
ii  libgovirt2                                   0.3.4-2
ii  libgtk-3-0                                   3.22.26-2
ii  libgtk-vnc-2.0-0                             0.7.1-1
ii  libgudev-1.0-0                               232-2
ii  libosinfo-1.0-0                              1.1.0-1
ii  libosinfo-bin                                1.1.0-1
ii  libpango-1.0-0                               1.40.14-1
ii  libpangocairo-1.0-0                          1.40.14-1
ii  librest-0.7-0                                0.8.0-2
ii  libsecret-1-0                                0.18.5-6
ii  libsoup2.4-1                                 2.60.3-1
ii  libspice-client-glib-2.0-8                   0.34-1.1
ii  libspice-client-gtk-3.0-5                    0.34-1.1
ii  libtracker-sparql-2.0-0                      2.0.3-1
ii  libusb-1.0-0                                 2:1.0.21-2
ii  libvirt-daemon                               4.0.0-2
ii  libvirt-glib-1.0-0                           1.0.0-1
ii  libxml2                                      2.9.4+dfsg1-6.1
ii  mtools                                       4.0.18-2+b1
ii  tracker                                      2.0.3-1

Versions of packages gnome-boxes recommends:
ii  qemu-system-x86  1:2.11+dfsg-1

gnome-boxes suggests no packages.

-- no debconf information