On Fri, 1 Mar 2019 13:05:54 +0100
Christian Borntraeger <borntraeger@xxxxxxxxxx> wrote:
> On 01.03.2019 13:03, Pierre Morel wrote:
> > On 28/02/2019 15:14, Pierre Morel wrote:
> >> On 28/02/2019 14:52, Cornelia Huck wrote:
> >>> On Thu, 28 Feb 2019 14:16:09 +0100
> >>> Pierre Morel <pmorel@xxxxxxxxxxxxx> wrote:
> >>>
> >>>> On 28/02/2019 12:22, Cornelia Huck wrote:
> >>>
> >>>>> So, to summarize, the function should do:
> >>>>> - Is userspace supposed to emulate everything (!ECA_APIE)? Return
> >>>>> -EOPNOTSUPP to hand control to it.
> >>>>> - We are now interpreting the instruction in KVM. Do common checks
> >>>>> (PSTATE etc.) and inject exceptions, if needed.
> >>>>> - Now look at the fc; if there's a handler for it, call that; if not
> >>>>> (case does not attempt to call a specific handler, or no handler
> >>>>> registered), inject a specification exception. (Do we want pre-checks
> >>>>> like for facility 65 here, or in the handler?)
> >>>>>
> >>>>> That response code 0x01 thingy probably needs to go into the specific
> >>>>> handler function, if anywhere (don't know the semantics, sorry).
> >>>>
> >>>> What do you mean with specific handler function?
> >>>>
> >>>> If you mean a switch around the FC with static function's call, I agree,
> >>>> if you mean a jump into a hook I do not agree.
> >>>
> >>> Ah, ok; so each case (that we want to handle) should call into a
> >>> subhandler that does
> >>> {
> >>> (... check things like facilities ...)
> >>> if (!specific_hook)
> >>> inject_specif_excp_and_return();
> >>> ret = specific_hook();
> >>> if (ret)
> >>> set_resp_code_0x01(); // or in specific_hook()?
> >>> }
> >>>
> >>> ?
> >>
> >> Yes something in this direction.
> >
> > Sorry, after reflection, no, we do not want to change the previous behavior so we only handle the AQIC case.
>
> I think what you wanted to say is the following:
> Today (without the patch set) we will answer PQAP with an exception.
> With this patch set we want to handle FC==3, but nothing else. So for anything FC!=3 we
> will continue to return an exception?
>
> Correct?
>
That sounds reasonable; but I don't see how this conflicts with my
proposal? Just don't introduce a subfunction for fc != 3...
