Vlapic is virtualized Lapic.
Lapic = Local Advanced Programmable Interrupt Controller
[ NOTICE ][XEVTCHN]Failed to add vlapic page for vcpu 0 to physmap: -22.
Only really an issue with ACPI, otherwise the OS will handle the request. This is why it is a [ NOTICE ].
You may experience video hangs or freezes if there is a problem with vlapic, however I’d expect the message to be an [ Error ], instead of a [ NOTICE ].
Also check that the latest XenTools is installed.