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

[Tony Krowiak]

On 03/16/2018 11:36 AM, Halil Pasic wrote:
> 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).
There were objections to that.
> 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.
I suppose it depends upon how you define multitude. I counted at
at least 11 - actually more - review comments related to the
CPU model feature and setting ECA_APIE. I suggest you go back
and look at the thread.

Where did you show that the 'need to separate' argument does
not work?
> Regards,
> Halil