Hi Tomasz,

On Tue, 26 May 2020 09:09:20 +0200
Tomasz Bursztyka <tomasz.bursztyka@...> wrote:

Hi,

So as the title says I am bit stuck on how to debug a UOS
efficiently.

I could not find a way to get a gdb server available for the
UOS, besides for linux which requires to be built with kgdb support
if
I understood well(?).

But I am running zephyr as UOS.
And using only printk() is a no go, not because it's the poor man's
solution but because when the vm crashes, I will not be able to
stop
it with acrn-dm (even with -f). The only way to recover is to
reboot
the entire setup (acrn runs on up squared). It takes then a lot of
time, too much time in fact.

What would be a better method?

My understanding is that you want to debug UOS (which is zephyr)
itself.
There are two thing need check:
1. Whether zephyr could support kgdb like debug methodology?
2. If it could, because the limitation that ACRN doesn't support
hardware debugging register, only software breakpoint could be
used.

Talking about UOS can't be stopped, if you doesn't care real time
performance (I suppose this is likely true), you can start zephyr as
standard guest. Then you could try to kill acrn-dm to restart UOS.
If you want to shutdown it. a minor change to acrn-dm could achieve
that.


Regards
Yin, Fengwei

Br,

Tomasz