Re: No print info when starrting qemu-system-aarch64

[Peter Maydell]

On Fri, 16 Jun 2023 at 08:23, 吕贤 <xian.lv@enjoymove.com> wrote:
>
> Dear qemu guys,
>
>     I've met with a strange problem when using qemu as simulator for arm64.
> I tried to start qemu with the command below:
> ------
> sudo qemu-system-aarch64 -machine virt -cpu cortex-a72 -smp 2 -m 2048 -kernel 
> Image -append "console=ttyAMA0 root=/dev/vda" -nographic -drive 
> file=ramdisk.img -drive file=disk.img -nic 
> tap,model=e1000,script=/etc/qemu-ifup
> ------
> The file:Image is the kernel bin of linux kernel  which compiled with default 
> config.
> While I tried with linux kernel-5.15, then the simulator can be started 
> properly.
> For the kernel 6.3.8; kernel-5.10.130, the result is OK as well
> But there's no output info after the command executed if the kernel before 
> 4.19 is used.
> Is there any problem when early linux kernel (before 4.19) is used for qemu 
> tools ?

The further back in kernel history you go, the more likely it
is that you will run into some kernel bug or other that
was fixed in later versions. 4.19 was first released nearly
5 years ago, which makes it pretty ancient in the aarch64 world.
There was also some point at which the defconfig had the
extra devices added into it to make it boot on QEMU, so if you're
building a kernel before that point you need to manually
add them. I forget when that was.

If you care about trying to track this down you probably need
to start debugging the cause of the boot failure, and perhaps
bisecting the upstream kernels to see when it started booting
OK. But the simplest approach is "don't use such old kernel
versions" :-)

thanks
-- PMM