Re: [PATCH 1/1] s390: vfio-ccw: push down unsupported IDA check
From: Cornelia Huck
Date: Mon May 14 2018 - 11:01:46 EST
On Mon, 14 May 2018 16:44:29 +0200
Halil Pasic <pasic@xxxxxxxxxxxxx> wrote:
> On 05/14/2018 04:00 PM, Cornelia Huck wrote:
> > On Mon, 14 May 2018 15:37:17 +0200
> > Halil Pasic <pasic@xxxxxxxxxxxxx> wrote:
> >> On 05/14/2018 01:55 PM, Cornelia Huck wrote:
> >>> On Wed, 9 May 2018 19:36:47 +0200
> >>> Halil Pasic <pasic@xxxxxxxxxxxxx> wrote:
> >>>> + /*
> >>>> + * 2k byte block IDAWs (fmt1 or fmt2) are not yet supported.
> >>>> + * There are however CPs that don't use IDA at all, and can
> >>>> + * benefit from not failing until failure is eminent.
> >>> What about:
> >>> "As we don't want to fail direct addressing even if the orb specified
> >>> one of the unsupported formats, we defer checking for IDAWs in
> >>> unsupported formats to here."
> >> Was the second sentence only confusing because of CP? I'm not perfectly
> >> satisfied with your version either:
> >> * 'fail direct addressing even if the orb specified one of the unsupported formats'
> >> I wanted to say: 'hey it does not matter what format for IDA the orb implies
> >> if the channel program does not use any IDA at all'. That could be paraphrased
> >> as channel programs using direct addressing exclusively. But failing the direct
> >> addressing does not fit for me.
> > But that's effectively what happens now, no? We reject the orb out of
> > hand due to unsupported flags that do not have any relevance for the
> > channel program in that case.
> Yes, that's what happens now, except that we make the whole channel program fail,
> and not the direct addressing. But the comment should describe what happens
> with the patch applied.
Even more, it should describe _why_ it is done that way (the reason
being "we don't want to fail..."). That's where I've been coming from.
> >>> The patch looks sane, I have only issues with the description/comments.
> >> Thanks for having a look. Please give me short feedback about the one
> >> open point and I will respin with the requested changes.
> > Does anybody else have feedback?
> Will wait a day or so. Dong Jia and Jason have already seen the patch, and
> they only complained about the text. Since that spin was mainly for the
> tested-by tags, and I stated that any substantial discussion should happen
> upstream, I ignored those complaints.
> So yes I will wait a bit so everybody can chime in.