I am having trouble today with creating a new VM with a serial console under KVM running Rocky 9.3 (5.14.0-362.8.1.el9_3 to be exact). The VM creates fine and I can complete the install with a minimal setup. I access the ssyetm and make my normal mods to /etc/default/grub:
GRUB_CMDLINE_LINUX="crashkernel=1G-4G:192M,4G-64G:256M,64G-:512M resume=/dev/mapper/V1uv046-swap rd.lvm.lv=V0uv046/root rd.lvm.lv=V1uv046/swap audit=1 audit_backlog_limit=8192 console=ttyS0,115200"
GRUB_SERIAL_COMMAND="serial --unit=0 --speed=115200 --word=8 --parity=no --stop=1"
# grub2-mkconfig -o /boot/grub2/grub.cfg
But after doing this, the virtual serial console does not get used much by the instance. The grub menu appears there, but none of the boot output goes there and I do not get a login prompt.
From an OS perspective, the ttyS0 is there - an echo to the device goes through and I can see that output when connected to it.
This is very weird because this setup works on my other Rocky 9.3 systems
Any ideas about what I am missing?