Re: Any way to trigger system_powerdown from a signal?

[Brett Neumeier]

On Wed, 24 Jul 2024 12:35:16 -0500
Brett Neumeier <random@freesa.org> wrote:
> I'm trying to set up supervision for a QEMU virtual machine on a machine that 
> uses s6 and s6-rc for service management.
> 
> I currently have my QEMU configured so that it shuts down gracefully when the 
> "system_powerdown" monitor command is executed. With s6, though, the only 
> idiomatic way that I can get the supervision frameowork to shut down a 
> long-running process is to send it a signal. I've verified that I can get 
> QEMU to terminate by sending it a SIGINT, SIGTERM, or SIGPWR; but all of 
> those just cause it to terminate, they don't send an ACPI shutdown request to 
> the guest operating system.
> 
> Is there any way to trigger the same "system_powerdown" mechanism by sending 
> QEMU a signal? If not, can anyone suggest a way to add a signal handler that 
> does that?

Following up on this in case anyone does a search of the mailing list in future:

I asked the same question on the supervision mailing list hosted at 
skarnet.org, and Jan Braun pointed me to other times this has been discussed 
already:

https://patchwork.kernel.org/project/qemu-devel/patch/23d89ab3bd16ebf7a864ab75c300de7b@whitewinterwolf.com/
and
https://gitlab.com/qemu-project/qemu/-/issues/148

Jan also provided a patch that applies cleanly to QEMU 9.0 that uses SIGPWR for 
this purpose, see:

https://skarnet.org/lists/supervision/3164.html

Cheers!

Brett

-- 
Brett Neumeier <random@freesa.org>