Re: [kvm-unit-tests PATCH v5 3/6] s390x: sie: switch to home space mode before entering SIE

Thomas Huth
2023-07-13T08:32:18Z

On 13/07/2023 10.17, Claudio Imbrenda wrote:
> On Thu, 13 Jul 2023 09:28:19 +0200
> Thomas Huth <thuth@redhat.com> wrote:
>
> [...]
>
>>> + irq_set_dat_mode(IRQ_DAT_ON, AS_PRIM);
>>> + psw_mask_clear_bits(PSW_MASK_HOME);
>>> +
>>> + /* restore the old CR 13 */
>>> + lctlg(13, old_cr13);
>>
>> Wouldn't it be better to always switch to HOME address mode directly in our
>> startup code already (where we enable DAT)? Switching back and forth every
>> time we enter SIE looks confusing to me ... or is there a reason why we
>> should continue to run in primary address mode by default and only switch to
>> home mode here?
>
> the existing tests are written with the assumption that they are
> running in primary mode.
>
> switching back and forth might be confusing, but avoids having to
> fix all the tests

Which tests are breaking? And why? And how much effort would it be to fix them?

Thomas