Re: [Qemu-devel] [PATCH v2 0/7] APIC/IOAPIC cleanup

[Anthony Liguori]

On 08/22/2010 02:44 PM, Avi Kivity wrote:
> > No more MI diamond and all devices have DeviceStates.  
> > Coincidentally, it matches more closely how hardware works..
>
>
> Well, I agree, but I honestly lost the context.  How does this relate 
> to the APIC and cpu hotplug?

My original assertion was that the local APIC is not a DeviceState, but 
rather it's a CPU feature.

If you look at some of the magic that apic.c has to do in the IO 
callbacks, it should be clear that it's special.  In the not too distant 
future, I'd like to move apic.c to target-i386.  There should be no need 
to explicitly instantiate it when you instantiate a CPU.

BTW, this gets a bit funky with KVM.  If we declare that the lapic is 
part of the CPU, then in an ideal world we would have interfaces for the 
I/O APIC as part of the KVM interface so we could implement the I/O APIC 
in userspace with the lapic implemented in the kernel.

Regards,

Anthony Liguori