Re: [Qemu-devel] [PATCH v1 for-2.12 2/5] s390x/tcg: fix and cleanup mcck injection

[Cornelia Huck <cohuck@redhat.com>]

On Mon, 4 Dec 2017 18:27:06 +0100
David Hildenbrand <david@redhat.com> wrote:

> On 04.12.2017 18:20, Cornelia Huck wrote:
> > On Mon,  4 Dec 2017 13:55:02 +0100
> > David Hildenbrand <david@redhat.com> wrote:
> >   
> >> The architecture mode indication wasn't stored. The split of certain
> >> 64bit fields was unnecessary. Also, the complete clock comparator, not
> >> just bit 0-55 (starting at byte 1) was stored.
> >>
> >> We now generate a proper MCIC via the same helper we use for KVM.
> >>
> >> While at it, also get rid of two local variables. There is be more to
> >> clean up, but we will change the other parts later on either way.
> >>
> >> Signed-off-by: David Hildenbrand <david@redhat.com>
> >> ---
> >>  target/s390x/excp_helper.c | 18 ++++++++----------
> >>  target/s390x/internal.h    |  6 +++---
> >>  2 files changed, 11 insertions(+), 13 deletions(-)
> >>
> >> diff --git a/target/s390x/excp_helper.c b/target/s390x/excp_helper.c
> >> index d831537544..840cf7641a 100644
> >> --- a/target/s390x/excp_helper.c
> >> +++ b/target/s390x/excp_helper.c
> >> @@ -369,7 +369,6 @@ static void do_io_interrupt(CPUS390XState *env)
> >>  static void do_mchk_interrupt(CPUS390XState *env)
> >>  {
> >>      S390CPU *cpu = s390_env_get_cpu(env);
> >> -    uint64_t mask, addr;
> >>      LowCore *lowcore;
> >>      MchkQueue *q;
> >>      int i;  
> > 
> > [BTW, there's also a CR 14 check in here that probably could use the
> > new #define.]  
> 
> Yes, will be gone with my floating IRQ rework, that's why I am not
> touching it here. (We will no longer track machine checks in a list but
> per cr14 sublcass - initially only crw).

Sounds good. So let's just do the minimum to get this going and wait
for the rework.

> 
> >   
> >> @@ -395,6 +394,9 @@ static void do_mchk_interrupt(CPUS390XState *env)
> >>  
> >>      lowcore = cpu_map_lowcore(env);
> >>  
> >> +    /* we are always in z/Architecture mode */
> >> +    lowcore->ar_access_id = 1;
> >> +
> >>      for (i = 0; i < 16; i++) {
> >>          lowcore->floating_pt_save_area[i] = cpu_to_be64(get_freg(env, i)->ll);
> >>          lowcore->gpregs_save_area[i] = cpu_to_be64(env->regs[i]);
> >> @@ -404,17 +406,12 @@ static void do_mchk_interrupt(CPUS390XState *env)
> >>      lowcore->prefixreg_save_area = cpu_to_be32(env->psa);
> >>      lowcore->fpt_creg_save_area = cpu_to_be32(env->fpc);
> >>      lowcore->tod_progreg_save_area = cpu_to_be32(env->todpr);
> >> -    lowcore->cpu_timer_save_area[0] = cpu_to_be32(env->cputm >> 32);
> >> -    lowcore->cpu_timer_save_area[1] = cpu_to_be32((uint32_t)env->cputm);
> >> -    lowcore->clock_comp_save_area[0] = cpu_to_be32(env->ckc >> 32);
> >> -    lowcore->clock_comp_save_area[1] = cpu_to_be32((uint32_t)env->ckc);
> >> +    lowcore->cpu_timer_save_area = cpu_to_be64(env->cputm);
> >> +    lowcore->clock_comp_save_area = cpu_to_be64(env->ckc >> 8);
> >>  
> >> -    lowcore->mcck_interruption_code[0] = cpu_to_be32(0x00400f1d);
> >> -    lowcore->mcck_interruption_code[1] = cpu_to_be32(0x40330000);
> >> +    lowcore->mcic = cpu_to_be64(s390_build_validity_mcic() | MCIC_SC_CP);  
> > 
> > Hm... I'm not sure that is a good idea (the nature of the helper, not
> > that you remove the magic values).
> > 
> > This function is called do_mchk_interrupt(), which sounds like a more
> > generic thing. Maybe we need to enhance the machine check code to save
> > the mcic etc. somewhere (after it has been generated) and just inject
> > it here? Similar to what the kernel does.
> > 
> > If you want to avoid rework, just add a TODO here?  
> 
> Will also be gone with my floating IRQ rework ;) I can add a TODO if
> that helps, but 99.99996% it will be gone within 2-4 weeks.

Whatever floats your interrupt.

> 
> >   
> >>      lowcore->mcck_old_psw.mask = cpu_to_be64(get_psw_mask(env));
> >>      lowcore->mcck_old_psw.addr = cpu_to_be64(env->psw.addr);
> >> -    mask = be64_to_cpu(lowcore->mcck_new_psw.mask);
> >> -    addr = be64_to_cpu(lowcore->mcck_new_psw.addr);
> >>  
> >>      cpu_unmap_lowcore(lowcore);
> >>    
> 
>