Re: [PATCH] target/s390x: Move trans_exc_code update to do_program_interrupt

[Richard Henderson]

On 7/31/23 01:26, Ilya Leoshkevich wrote:
> > > +    case PGM_PROTECTION:
> > > +    case PGM_TRANS_SPEC:
> > > +        assert(env->int_pgm_code == env->tlb_fill_exc);
> > > +        set_trans_exc_code = true;
> > > +        advance = true;
> > > +        break;
> >
> > These exceptions came from seeing an early kernel fault, grepping for
> > the set of
> > exceptions raised in mmu_helper.c, and eliminating PGM_ADDRESSING per
> > the first hunk.
>
> Does POp specify that the CPU stores Translation-Exception
> Identification on Translation-Specification Exceptions
> (PGM_TRANS_SPEC)? I re-read the 0xA8 documentation a few times, but
> could not find it.

Neither could I.

> It's also interesting what the kernel was attempting when it got
> PGM_TRANS_SPEC and recovered from it. Maybe something else is wrong?

I think the kernel was testing PGM_PROTECTION, to see if LowCore protection 
worked.

But since that one wasn't listed for 0xA8 either, I preserved previous behaviour in 
setting trans_exc_code for all mmu exceptions except for PGM_ADDRESSING.


r~