Re: [qemu-s390x] [Qemu-devel] [PATCH v3 5/7] s390x/vfio: ap: Introduce VFIO AP device

[Halil Pasic]

On 03/16/2018 04:29 PM, Tony Krowiak wrote:
>>> However it is a general switch for the VM.
>>> It looks strange to have this inside the realize callback
>>>
>> I kind of semi agree.
>>
>> The previous solution (having this transparent for QEMU) had
>> benefits. Why did we move away from that again?
> This was done to address the multitude of objections and opinions related to
> how/when/where ECA_APIE is set. Pierre summed it up best with his comment "we
> need to separate the CPU feature defining 'if AP instructions are available'
> from the QEMU property defining 'How we provide the instructions'. I agree and
> this is how I chose to implement that.

It's even more separated if the one is controlled via a
userspace facing interface (cpu models) and the other
is controlled via an in-kernel interface (e.g. like
done previously in vfio open AFAIR).

I can not accept this answer. I don't recall the multitude
and I think I've showed that the 'need to separate' argument
does not work.

Regards,
Halil