Make qubes.NotifyTools reuse logic of qubes.FeaturesRequest, then move
actual request processing to 'features-request' event handler. At the
same time implement handling 'qrexec' and 'gui' features request -
allowing to set template features when wasn't already there.
Behavior change: template is no longer allowed to change feature value
(regardless of being True or False). This means the user will always be
able to override what template have set.
This way it will work independently from where qrexec-policy tool will
be called (in most cases - from a system service, as root).
This is also very similar architecture to what we'll need when moving to
GUI domain - there GUI part will also be separated from policy
evaluation logic.
QubesOS/qubes-issues#910
Implement required event handlers according to documentation in
qubes.devices.
A modification of qubes.devices.DeviceInfo is needed to allow dynamic,
read-only properties.
QubesOS/qubes-issues#2257
Allow device plugin to list attached and available devices. Enforce
at API level every device being exposed by some domain.
This commit only changes devices API, but not update existing users
(pci) yet.
QubesOS/qubes-issues#2257
This allows the user to start VM based on "old" system (from R3.x) in
R4.0. For example after restoring from backup, or migration. This also
makes upgrade instruction much easier - no need complex recovery
instruction if one upgrade dom0 before upgrading all the templates.
QubesOS/qubes-issues#1812
