Re: [Qemu-devel] [PATCH v2 4/7] s390x/tcg: SET CLOCK COMPARATOR can clear CKC interrupts

[Cornelia Huck <cohuck@redhat.com>]

On Thu, 21 Jun 2018 14:09:28 +0200
Thomas Huth <thuth@redhat.com> wrote:

> On 20.06.2018 12:08, David Hildenbrand wrote:
> > Let's stop the timer and delete any pending CKC IRQ before doing
> > anything else.
> > 
> > Signed-off-by: David Hildenbrand <david@redhat.com>
> > ---
> >  target/s390x/misc_helper.c | 6 ++++++
> >  1 file changed, 6 insertions(+)
> > 
> > diff --git a/target/s390x/misc_helper.c b/target/s390x/misc_helper.c
> > index 6ccbe1fe9a..d5f9f5e1d3 100644
> > --- a/target/s390x/misc_helper.c
> > +++ b/target/s390x/misc_helper.c
> > @@ -158,6 +158,12 @@ void HELPER(sckc)(CPUS390XState *env, uint64_t time)
> >      Error *err = NULL;
> >      S390TOD tod_base;
> >  
> > +    /* stop the timer and remove pending CKC IRQs */
> > +    timer_del(env->tod_timer);
> > +    qemu_mutex_lock_iothread();
> > +    env->pending_int &= ~INTERRUPT_EXT_CLOCK_COMPARATOR;
> > +    qemu_mutex_unlock_iothread();  
> 
> Reviewed-by: Thomas Huth <thuth@redhat.com>
> 
> >      if (time == -1ULL) {  
> 
> I wonder whether that check is still adequate? Is there really a way to
> disable the clock comparator like this? At least I haven't seen it in
> the PoP.

Me neither. It seems to have been in the code since the beginning...

> 
> >          return;
> >      }
> >   
>