Re: Could we document exact steps for loongson3-virt in the manual?

["Alex Bennée" <alex.bennee@linaro.org>]

Peter Maydell <peter.maydell@linaro.org> writes:

> On Tue, 6 Apr 2021 at 14:23, Alex Bennée <alex.bennee@linaro.org> wrote:
>>
>> Hi,
>>
>> I was trying to bootstrap a Loongson3 Debian image but ran into some
>> roadblocks. Philippe pointed me at:
>>
>>   https://www.mail-archive.com/qemu-devel@nongnu.org/msg768848.html
>>
>> which gives a bit of detail but elides over details such as how to
>> handle block devices. AFAICT it should support virtio-blk although maybe
>> Debian bullseye doesn't support the target, it's hard to say:
>>
>>   ./qemu-system-mips64el -M loongson3-virt -m 4096 -nographic
>> -blockdev
>> driver=raw,node-name=hd0,discard=unmap,file.driver=host_device,file.filename=/dev/zvol/hackpool-0/debian-bullseye-mips64le
>> -device virtio-blk,drive=hd0 -kernel ./vmlinuz-5.9.0-4-loongson-3
>> -initrd initrd.gz -append "root=/dev/sda1 console=tty0 nokaslr"
>>
>> Gets as far as:
>>
>> [    0.008641] printk: console [tty0] enabled
>> [    0.009507] printk: bootconsole [early0] disabled
>>
>> and then just goes silent.
>
> Oddly enough somebody on stackoverflow had the same problem for
> a different board (malta) the other day:
> https://stackoverflow.com/questions/66904366/qemu-system-mips-stuck-after-console-tty0-enabled/66910192
>
> As Jiaxun says, the problem is that your kernel command line says "send the
> console output to the virtual console on the graphics device (tty0)" but your
> QEMU command line is using a serial console and not trying to use graphics.
> So as soon as the kernel gets to the point where it can honour your request
> it disables the early-boot console and enables tty0 and then you don't
> see anything any more :-)

Doh - should have spotted that. I guess the -nographic doesn't prompt
the kernel enough to warn about switching to a non-existent graphics
device. I can get to the installer now although it fails later failing
to find kernel modules. I suspect this is a Debian problem with a
mismatch between installer and archives.

>
> thanks
> -- PMM


-- 
Alex Bennée