Re: [qemu-s390x] [PATCH 17/26] target/s390x: Convert to CPUClass::tlb_fill

[Richard Henderson]

On 4/3/19 4:17 AM, David Hildenbrand wrote:
>> +    /*
>> +     * Note that handle_mmu_fault sets ilen to either 2 (for code)
> This comment no longer matches.
> 
>> +     * or AUTO (for data).  We can resolve AUTO now, as if it was
>> +     * set to UNWIND -- that will have been done via assignment
>> +     * in cpu_restore_state.  Otherwise re-examine access_type.
>> +     */
>> +    if (access_type == MMU_INST_FETCH) {
>> +        CPUS390XState *env = cs->env_ptr;
>> +        env->int_pgm_ilen = 2;
>> +    }

Indeed it doesn't.  It's also confusingly written.
I've tried again as

    /*
     * The ILC value for code accesses is undefined.  The important
     * thing here is to *not* leave env->int_pgm_ilen set to ILEN_AUTO,
     * which would cause do_program_interrupt to attempt to read from
     * env->psw.addr again.  C.f. the condition in trigger_page_fault,
     * but is not universally applied.
     *
     * ??? If we remove ILEN_AUTO, by moving the computation of ILEN
     * into cpu_restore_state, then we may remove this entirely.
     */
    if (access_type == MMU_INST_FETCH) {
        env->int_pgm_ilen = 2;
    }

I'll just note in passing that the ??? part of the comment alludes to

https://lists.gnu.org/archive/html/qemu-devel/2019-04/msg00063.html

to which I ought to return at some point.


r~