Re: [kvm-unit-tests PATCH v10 9/9] s390x: css: ssch/tsch with sense and interrupt

[Cornelia Huck <cohuck@redhat.com>]

On Tue, 7 Jul 2020 12:57:03 +0200
Pierre Morel <pmorel@linux.ibm.com> wrote:

> On 2020-07-06 16:24, Cornelia Huck wrote:
> > On Mon, 6 Jul 2020 15:01:50 +0200
> > Pierre Morel <pmorel@linux.ibm.com> wrote:
> >   
> >> On 2020-07-06 11:46, Cornelia Huck wrote:  
> >>> On Thu,  2 Jul 2020 18:31:20 +0200
> >>> Pierre Morel <pmorel@linux.ibm.com> wrote:
> >>>      
> >>>> After a channel is enabled we start a SENSE_ID command using
> >>>> the SSCH instruction to recognize the control unit and device.
> >>>>
> >>>> This tests the success of SSCH, the I/O interruption and the TSCH
> >>>> instructions.
> >>>>
> >>>> The SENSE_ID command response is tested to report 0xff inside
> >>>> its reserved field and to report the same control unit type
> >>>> as the cu_type kernel argument.
> >>>>
> >>>> Without the cu_type kernel argument, the test expects a device
> >>>> with a default control unit type of 0x3832, a.k.a virtio-net-ccw.
> >>>>
> >>>> Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
> >>>> ---
> >>>>    lib/s390x/asm/arch_def.h |   1 +
> >>>>    lib/s390x/css.h          |  32 ++++++++-
> >>>>    lib/s390x/css_lib.c      | 148 ++++++++++++++++++++++++++++++++++++++-
> >>>>    s390x/css.c              |  94 ++++++++++++++++++++++++-
> >>>>    4 files changed, 272 insertions(+), 3 deletions(-)  
> > 
> > (...)
> >   
> >>>> @@ -114,6 +128,7 @@ retry:
> >>>>    		return cc;
> >>>>    	}
> >>>>    
> >>>> +	report_info("stsch: flags: %04x", pmcw->flags);  
> >>>
> >>> It feels like all of this already should have been included in the
> >>> previous patch?  
> >>
> >> Yes, I did not want to modify it since it was reviewed-by.  
> > 
> > It's not such a major change (the isc change and this here), though...
> > what do the others think?  
> changed my mind:
> What about keeping css_enable() to only do enable, in case we only want 
> to do this, and add a function to modify the ISC.

Hm, the isc is only really relevant while the subchannel is enabled, so
this would be fine if we only ever modified the isc while the
subchannel is disabled. On the other hand, we introduce an extra round
of msch. No strong opinion on my side.