2) when "ctrl+c" is pressed, unlike before, vmtap does not terminate the whole program but instead the "vmtap.run()" function returns. thus, python programmer can write some finish-up code after instrumentation.
3) a bug that vmprobes could not handle probe unregistration properly has been solved out - leaving domains in debugging or singlestep mode was the reason why guests remained paused.
4) another bug in xenaccess that it could not read or write guest's memory has been solved out - not setting os type as linux was the cause of the problem.