Re: [PATCH v3 2/4] s390x: Add missing vcpu reset functions

[Cornelia Huck <cohuck@redhat.com>]

On Wed, 4 Dec 2019 16:08:48 +0100
David Hildenbrand <david@redhat.com> wrote:

> On 04.12.19 16:07, David Hildenbrand wrote:
> > On 04.12.19 15:59, Cornelia Huck wrote:  
> >> On Tue,  3 Dec 2019 08:28:11 -0500
> >> Janosch Frank <frankja@linux.ibm.com> wrote:
> >>  
> >>> Up to now we only had an ioctl to reset vcpu data QEMU couldn't reach
> >>> for the initial reset, and that was also called for the clear
> >>> reset. To be architecture compliant, we also need to clear local
> >>> interrupts on a normal reset.  
> >>
> >> Do we also need to do something like that for tcg? David?
> >>  
> > 
> > So, we have
> > 
> > /* Fields up to this point are not cleared by initial CPU reset */
> > struct {} start_initial_reset_fields;
> > [...]
> > int pending_int
> > uint16_t external_call_addr;
> > DECLARE_BITMAP(emergency_signals, S390_MAX_CPUS);
> > [...]
> > /* Fields up to this point are cleared by a CPU reset */
> > struct {} end_reset_fields;
> > 
> > This means, local interrupts will be cleared by everything that zeroes
> > "start_initial_reset_fields->end_reset_fields"
> > 
> > So, they will get cleared by S390_CPU_RESET_INITIAL only if I am not
> > wrong. In order to clear them on S390_CPU_RESET_NORMAL, we have to
> > manually set them to zero.  
> 
> Sorry, by S390_CPU_RESET_INITIAL and S390_CPU_RESET_CLEAR.

Ok. Will you cook up a patch, or should I do it?

> 
> > 
> > (we really should wrap TCG-only fields by ifdefs)

They probably do not get into the way, but making it obvious that they
a tcg-only is something we really should do.

> >   
> 
>