printk in the driver doesn't appear in a virtual machine..

[Chan Kim]

Hello all,

When I run linux kernel on a virtual machine(a modified arm64 virt machine),
I use this command.

/home/ckim/prj/QEMU/qemu-6.2.0/build-baremetal/aarch64-softmmu/qemu-system-a
arch64 -machine virt,gic-version=max,secure=off,virtualization=true -cpu max
-kernel /home/ckim/prj/LinuxDevDrv/linux-5.15.68/arch/arm64/boot/Image -m 1G
-nographic -netdev user,id=vnet,hostfwd=:127.0.0.1:0-:22,tftp=/srv/tftp
-device virtio-net-pci,netdev=vnet -machine iommu=smmuv3 --append
"root=/dev/ram init=/init nokaslr earlycon ip=dhcp hugepages=16"

By the way, the above 'Image' has busybox file system image and that image
has a kernel driver module. After booting, when I do insmod, it prints the
all the printk message on real FPGA board but not in this virtual machine. I
think I forgot what makes this difference. 

In real FPGA board, I use u-boot to boot the linux and in the dts, in the
chosen node, I have this line 
bootargs = "earlycon root=/dev/ram init=/init nokaslr, cpuidle.off=1";
But as you know qemu has its own boot loader.
What can I try to make printk in the driver appear?

Thank you!

Chan Kim