Re: hanging process with commit 69562648f9 ("vl: revert behaviour for -display none")

[Sebastian Ott <sebott@redhat.com>]

On Mon, 27 Nov 2023, Peter Maydell wrote:
> On Mon, 27 Nov 2023 at 12:29, Sebastian Ott <sebott@redhat.com> wrote:
>> qemu fails to start a guest using the following command (the process just
>> hangs): qemu-system-aarch64 -machine virt -cpu host -smp 4 -m 8192
>> -kernel /boot/vmlinuz-6.7.0-rc1 -initrd ~/basic.img -append "root=/dev/ram
>> console=ttyAMA0" -enable-kvm -device virtio-gpu,hostmem=2G -display none
>>
>> ..which I've used to debug a potential virtio-gpu issue. Bisect points to
>> 69562648f9 ("vl: revert behaviour for -display none")
>
> Is it actually hanging, or is the guest starting up fine but
> outputting to a serial port which you haven't directed anywhere?

Ough, that's indeed the case. I only had a quick glance at the bt in gdb
and obviously misinterpreted what I got there.

> The commandline is a bit odd because it doesn't set up any of:
> * a serial terminal
> * a graphical window/display
> * network forwarding that would allow ssh into the guest
>
> If you add '-serial stdio' do you see the guest output?

I do. I was using the serial terminal which got setup implicitly I guess.
I'll make sure to always add this.

Sry and thanks,
Sebastian