[Xen-devel] Re: [PATCH RFC] x86/acpi: don't ignore I/O APICs just because there's no local APIC

[ebiederm@xxxxxxxxxxxx (Eric W. Biederman)]

Jeremy Fitzhardinge <jeremy@xxxxxxxx> writes:

> On 06/18/09 09:08, Len Brown wrote:
>>> In principle, the local APIC and the I/O APIC are distinct (but related)
>>> components, which can be independently present.
>>>     
>>
>> bzzzzt, but thanks for playing:-)
>>   
>
> Perhaps I should have expressed that a bit more clearly:  you could, if
> mad, build a machine with I/O APICs and some other mechanism for
> delivering the interrupts to CPUs.  In practice, I doubt anyone ever
> has, or ever would.
>
> The only actual exception I know of is Xen's replacement of the physical
> local APIC with a paravirtualized interrupt interface.

No one ever has.  Xen doesn't have I/O APICs either.  Not in any real
sense.  Xen just has devices that looking like I/O apics if you don't
look close.

Eric


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel