serial output

Hi,
 sorry about my poor english.
 I have a linux vm (RHEL7) over ESX.
 I want to enter kdb mode for debugging, I set the grub.conf file with kgdboc parameterlike this:
 console=tty0 kgdboc=kbd,ttyS0
 when I cause a crash the system goes to kdb mode but I cant see it happens the console just freeze...
  I managed to watch the serial output from another vm with named pipe.
 There is a way to get the serial output through my debugged vm?

Thank you.