The "default NetVM" is usually the first created ProxyVM which is
set by qubes-core during its creation. [1] If there is no ProxyVM,
there is no "default NetVM". Therefore, creating an AppVM and
launching its settings dialog raised AttributeError, because
get_default_netvm method returned None.
This can be reproduced by installing QubesOS without creating VMs
by installer.
[1] https://github.com/QubesOS/qubes-core-admin/blob/master/core/qubes.py#L355Fixesqubesos/qubes-issues#1008
Those changes will take effect after VM restart (at least for VM windows
borders), so to not confuse the user with partly updated colors, simply
block the change while the VM is running. The same applies to VM name.
Check init_mem and max_mem_size in a single function (merging the
previous two) taking into account the minimum init memory that allows
the requested maximum memory.
Explanation:
Linux kernel needs space for memory-related structures created at boot.
If init_mem is just 400MB, then max_mem can't balloon above 4.3GB (at
which poing it yields "add_memory() failed: -17" messages and apps
crash), regardless of the max_mem_size value.
Base of Marek's findings and my tests on a 16GB PC, using several
processes like:
stress -m 1 --vm-bytes 1g --vm-hang 100
result in the following points:
init_mem ==> actual max memory
400 4300
700 7554
800 8635
1024 11051
1200 12954
1300 14038
1500 14045 <== probably capped on my 16GB system
The actual ratio of max_mem_size/init_mem is surprisingly constant at
10.79
If less init memory is set than that ratio allows, then the set
max_mem_size is unreachable and the VM becomes unstable (app crashes)
Based on qubes-devel discussion titled "Qubes Dom0 init memory against
Xen best practices?" at:
https://groups.google.com/d/msg/qubes-devel/VRqkFj1IOtA/UgMgnwfxVSIJ
Use directly rule provided by qubes core, not intermediate class
QubesFirewallRuleItem. This also will improve compatibility - if no
firewall changes made (but still "OK" clicked instead of "Cancel")
really the same settings are saved, even if rules contains some not
supported by Qubes Manager attributes.
Settings are applied in separate thread, so when any exception occured there,
the user had no way to know it (besides hanging "applying settings" window).
