How can I attach the rootfs image to the emulator?

[DreamChaser-luzeyu]

How can I attach the rootfs image to the emulator?

[cyyself]

How to provide the rootfs to CEMU? AFAIK, we need an additional block device to do so.

The simplest way is using initramfs and compiling with the kernel by passing CONFIG_INITRAMFS_SOURCE in kernel .config.

If you want an emulated block device, you can just use memory in cemu, and write a driver in the kernel. You can refer to my blog https://blog.cyyself.name/linux-block-device-drvier-ramdisk/.

Is it necessary to provide the dtc when compiling Linux kernel?

Not necessary if you have set FW_FDT_PATH when compiling opensbi. As you can get the output from opensbi, there is no problem.

In your case, I guess you forgot to set CONFIG_SERIAL_UARTLITE and CONFIG_SERIAL_UARTLITE_CONSOLE in the linux kernel, so linux does not know how to print characters. This does not affect qemu as qemu uses UART16550 by default, which is included in kernel defconfig. You can also select CONFIG_HVC_RISCV_SBI and pass earlycon=sbi to get serial output from SBI; it will not need additional serial drivers.

[DreamChaser-luzeyu]

Thanks. I'll try your solution.

[DreamChaser-luzeyu]

It works. Thanks for your time.