Re: [Qemu-devel] [RFC][PATCH 14/16] kvm: x86: Add user space part for in-kernel i8259

[Jan Kiszka <jan.kiszka@siemens.com>]

On 2011-12-05 14:14, Avi Kivity wrote:
> On 12/05/2011 02:47 PM, Jan Kiszka wrote:
>>>
>>> (the memory API added unstable names, hopefully the QOM can take over
>>> the stable ones and we'll have a good way to denote the unstable ones).
>>>
>>
>> OK, maybe - or likely - we should make those device models have the same
>> names in QOM once instantiated. But I'm still convinced they should
>> remain separated models in contrast to a single model with a property.
> 
> What do you mean by separate models?  You share all the code you can,
> and don't share the code you can't.  To me, single model == single name.

But different configuration.

> 
>> The kvm ioapic, e.g., requires an additional property (gsi_base) that is
>> meaningless for user space devices. And its interrupts have to be
>> wired&configured differently at board model level. So, from the QEMU
>> POV, it is a very different device. Just the guest does not notice.
> 
> It's like qcow2 and raw/native IO are wire differently, or virtio-net
> and vhost-net.  But it's the same IDE device or virtio NIC.

That would mean introducing a backend/frontend concept for irqchips.

Jan

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