Am 06.03.2013 um 10:58 schrieb Gleb Natapov <g...@redhat.com>:

> On Wed, Mar 06, 2013 at 10:40:18AM +0100, Paolo Bonzini wrote:
>> Il 05/03/2013 16:25, Gleb Natapov ha scritto:
>>>> 1) We need to set the generic interrupt type of the system before we 
>>>> create vcpus.
>>>> 
>>>> This is a new ioctl that sets the overall system interrupt controller type 
>>>> to a specific model. This used so that when we create vcpus, we can create 
>>>> the appended "local interrupt controller" state without the actual 
>>>> interrupt controller device available yet. It is also used later to switch 
>>>> between interrupt controller implementations.
>>>> 
>>>> This interrupt type is write once and frozen after the first vcpu got 
>>>> created.
>>> 
>>> Why explicit ioctl is needed? Why not require specific irqchip to be
>>> created before first vcpu. The device created determines system interrupt
>>> controller type.
>> 
>> QEMU creates CPUs before devices, and CPUs need to know what kind of
>> local interrupt controller to create.  Similar to how in-kernel LAPIC
>> state is created long before the userspace device that proxies the LAPIC.
> So what is the difference between calling this special ioctl before
> creating vcpus and calling create device ioctl instead and create QEMU
> proxy device at whatever point in time QEMU wants to create it?

I don't understand the question really. What proxy device?


Alex

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