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

[Avi Kivity <avi@redhat.com>]

  On 08/23/2010 12:06 AM, Anthony Liguori wrote:
> On 08/22/2010 03:33 PM, Avi Kivity wrote:
>>  On 08/22/2010 11:03 PM, Anthony Liguori wrote:
>>> 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. 
>>
>> It's special in that it is connected to a cpu core.  So's the RTL8139 
>> device, on one hand connected to a PCI bus, on the other hand 
>> connected to a PHY (netdev in qemu).
>>
>>> 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.
>>
>> But then there's a need explicitly not to instantiate it when using 
>> -isapc.
>
> No.  isapc has nothing to do with whether a CPU has a local APIC.
>
> You don't instantiate the local APIC if you create a 486 CPU.  If you 
> create an isapc with a pentium processor, it's going to have a local 
> APIC although it's irrelevant as it's fully compatible with the 486.
>

Okay, okay.  "But then there's a need explicitly not to instantiate it 
when modelling a 486 or lower".


-- 
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signature is too narrow to contain.