Re: In kernel PIC support: kernel patch

[Avi Kivity <avi-atKUWr5tajBWk0Htik3J/w@public.gmane.org>]

Gregory Haskins wrote:
> On Sat, 2007-06-23 at 10:53 +0300, Avi Kivity wrote:
>   
>> Gregory Haskins wrote:
>>     
>>> In fact, my own implementation puts the ISA-userint model as hanging off
>>> the kvm structure as well (which would be replaced with a similar PIC
>>> model for layer-2 mode in the future).
>>>
>>>   
>>>       
>> The PIC is certainly a system resource, but at least in qemu it's 
>> connected to cpu 0 only. We want to preserve that.
>>
>>     
>
> I think there might be some confusion here ;) The *outputs* of the PIC
> in both QEMU and in-kernel-APIC are certainly wired to cpu0 (per the
> model that qemu/bochs support).  But the *inputs* are system-wide.  In
> qemu, you can call the global function "pic_set_irq" (which you could
> construe as per-vm, since there is a 1:1 with qemu-process/vm).
> Likewise, the inputs in both in-kernel implementation is also per vm by
> hanging off of the kvm struct, as opposed to the vcpu struct.  I hope
> this helps to clarify.
>
>   


This is my understanding too.  I didn't suggest the PIC ioctls should be 
per-vcpu, just that current semantics should be preserved.


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