Re: [Qemu-devel] [PATCH][RESEND] Add monitor command for system_reboot

[Anthony Liguori <aliguori@us.ibm.com>]

Ryan Harper wrote:
>> That suffers from the same problem as a system_reboot command in that
>> the guest may never start the shutdown. If that's an acceptable 
>> limitation, then we might as well implement it directly in QEMU as
>> system_reboot so its easily available to everyone. Make 'system_reboot'
>> take an optional timeout arg (default to 60 seconds) after which it
>> cancels its plans. 
>>     
>
> This seems the most reasonable thing to me.  As already mentioned,
> system_powerdown already is non-deterministic since the guest could
> ignore the ACPI event.
>   

It's a different class of non-determinism though.  With 
system_powerdown, you make a request to the guest.  You don't know 
whether the guest will comply with the request.  The same level of 
non-determinism exists with ballooning.

With system_reboot, you're taking an action (system_reset) and what's 
not deterministic is whether you're taking that action based on what 
someone requested on the monitor (system_reboot) verses whether you're 
taking that action based on something the user did (shutdown).  In the 
later case, you're action is functionally incorrect.

-- 
Regards,

Anthony Liguori