Re: KVM handling external interrupts

[Jan Kiszka <jan.kiszka@web.de>]

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On 2012-06-07 13:51, Abel Gordon wrote:
> 
> 
> Jan Kiszka <jan.kiszka@web.de> wrote on 07/06/2012 14:13:45:
> 
>>> Well, the shadow IDT only needs to be synced with interrupts coming
> from
>>> assigned devices. The rest of the entries doesn't matter, they just
>>> generate an exception. Once they generate an exception, they are
> delivered
>>> through the host IDT. So, all you need to know are the vectors assigned
>>> to the guest to build the shadow IDT.
>>
>> Not totally true. If the host decides to allocate some new vector that
>> collides with some guest usage, you need to rearrange the shadow IDT and
>> the physical IRQ routing. So you need to track what the host does.
> 
> Well, depends if you re-allocate the vector used by the guest or the vector
> used by the host. Anyway, I think we understand each other :)

KVM is just a subsystem of the Linux kernel, usually not involved in
LAPIC vector allocations. Your suggestion would turn this around a bit.
Not impossible, but expect some discussions. ;)

Jan


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