Re: Guest Ubuntu 18.04 fails to boot with -serial mon:stdio, cannot find ttyS0.

[David Fernandez]

On 11/11/2021 16:40, Peter Maydell wrote:
> On Mon, 8 Nov 2021 at 18:05, David Fernandez <david.fernandez@sen.com> wrote:
>> I couldn't get the stock qemu-system-x86_04 to boot correctly, as it was
>> an old version 2.11.1, I decided to recompile from sources to see if
>> that would fix the problem, but the problem still persists, using both
>> top of master and stable-2.12 (currently on that).[ TIME ] Timed out
>> waiting for device dev-ttyS0.device.
> FWIW, I tried to repro this on an aarch64 server I have access to,
> and I don't see that error -- the system boots (eventually) to
> the installer UI.
>
> QEMU version built: upstream git, commit 70f872ca916ac45.
>
> Configure options:
> --target-list=x86_64-softmmu --disable-tools --disable-docs
>
> vmlinuz and initrd extracted from the iso with
> isoinfo  -i ubuntu-18.04.6-live-server-amd64.iso -x '/CASPER/INITRD.;1' > 
> initrd
> isoinfo  -i ubuntu-18.04.6-live-server-amd64.iso -x
> '/CASPER/VMLINUZ.;1' > vmlinuz
>
> QEMU command:
> ./build/tgt-x86/qemu-system-x86_64 -boot order=dc,menu=on -cdrom
> ubuntu-18.04.6-live-server-amd64.iso -nographic -serial mon:stdio -m
> 16384 -kernel /tmp/vmlinuz -initrd /tmp/initrd -append 'boot=casper
> console=ttyS0 ---'
>
> (I didn't bother creating any of the devices for this test, so as
> you note there's a bunch of harmless complaints from the kernel
> floppy driver.)
>
> Total time to reach first screen of the text installer: 5m26s
>
> It's maybe also worth mentioning that "emulate x86-64" is, although
> a supported use case, not one that as far as I'm aware anybody is
> paid to work on, so enhancements and bugfixes to it are largely
> done on a volunteer basis. (This is as distinct from, for example,
> "using KVM on either x86-64 or aarch64" and "emulation of aarch64
> on x86-64", which have more people working on them.)
>
> -- PMM

For whatever is worth, I compiled v6.1.0 on my Fedora Intel laptop and 
the issue is not there either, so this seems closely related to aarch64 
and most likely to Ubuntu 18.04.5 as a host... and I am more and more 
afraid that it might have to do with the kernel configuration for the 
Jetson... I can recompile it if needed, so if there is some test that 
needs to be done to find out, I am happy to do.