Re: [kvm-devel] [PATCH] add acpi powerbutton support

[Avi K. <av...@qu...>]

Avi Kivity wrote:
> Guido Guenther wrote:
>> On Tue, Jan 08, 2008 at 10:50:00AM +0200, Avi Kivity wrote:
>>  
>>> Yes, you can press the VM's power button (system_powerdown in the 
>>> monitor) and it will invoke the OS shutdown sequence.
>>>
>>> Only worked on Linux in my testing though.
>>>     
>> It works for me _when_ I pass --no-kvm-irqchip. So it seems Windows
>> ignores the MADT entries or something.
>>   
>
> -no-kvm-irqchip implies ignoring the polarity, since qemu doesn't 
> implement ioapic polarity.
>
> I think we need to go back to active low pci irqs, and to have 
> no-ioapic working we need to insert an inverter between the pci irq 
> links and the pic.  I base this on the following:
>
> - piix doesn't contain an ioapic, so the actual lines must be active low
> - the piix pic elcr is documented as active-high for level-triggered irqs
>

Okay, this is likely right as I was able to shutdown both Windows and 
Linux with the following:

- backout the madt interrupt source override changes
- declare all interrupts as active low
- negate pci irq interrupts in qemu just before forwarding to kvm (so 
they become active low)
- negate pci irq interrupts in the kernel just before forwarding to the 
pic (so that they become active high, but leaving the ioapic interrupts 
active low)

There's quite a bit of work before that can be committed, though.  I 
want to generalize interrupt routing in the kernel, and we need tons of 
backward compatibility in the dsdt so that older hosts can still function.

-- 
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