vm: setup device permission to allow non-root vchan servers

This will allow to start pulseaudio as normal user and get rid of preloaded
library.

vm-init.d/qubes_core

@@ -17,6 +17,8 @@ start()
 
 	# Set permissions to /proc/xen/xenbus, so normal user can use xenstore-read
 	chmod 666 /proc/xen/xenbus
+	# Set permissions to files needed to listen at vchan
+	chmod 666 /proc/u2mfn /dev/xen/evtchn
 
 	mkdir -p /var/run/xen-hotplug
 

vm-systemd/qubes-sysinit.sh

@@ -25,6 +25,8 @@ mkdir -p /var/run/xen-hotplug
 
 # Set permissions to /proc/xen/xenbus, so normal user can use xenstore-read
 chmod 666 /proc/xen/xenbus
+# Set permissions to files needed to listen at vchan
+chmod 666 /proc/u2mfn /dev/xen/evtchn
 
 # Set default services depending on VM type
 TYPE=`$XS_READ qubes_vm_type 2> /dev/null`