I tried to install Jessie on a brand-new virtual machine (kvm), but it has a problem about serial console login.
At least, wheezy installer worked fine because it adds getty entry on /etc/inittab. Jessie uses systemd but no care about getty service for serial console. The probrem is reported as #769406.
My solution is invoke “systemctl enable serial-getty@ttyS0.service” via ssh.