Re: [PATCH v6 11/13] xen/arm: Add support for system suspend triggered by hardware domain

[Jan Beulich <jbeulich@xxxxxxxx>]

On 09.09.2025 11:55, Mykola Kvach wrote:
> On Tue, Sep 9, 2025 at 12:14 PM Jan Beulich <jbeulich@xxxxxxxx> wrote:
>> On 09.09.2025 10:14, Mykola Kvach wrote:
>>> On Tue, Sep 9, 2025 at 9:57 AM Jan Beulich <jbeulich@xxxxxxxx> wrote:
>>>> Furthermore with continuing to (ab)use domain_shutdown() also for the
>>>> suspend case (Dom0 isn't really shut down when suspending, aiui), you
>>>> retain the widening of the issue with the bogus setting of
>>>> d->is_shutting_down (and hence the need for later clearing the flag
>>>> again) that I mentioned elsewhere. (Yes, I remain of the opinion that
>>>> you don't need to sort that as a prereq to your work, yet at the same
>>>> time I think the goal should be to at least not make a bad situation
>>>> worse.)
>>>
>>> From the perspective of ARM logic inside Xen, we perform the exact same
>>> shutdown steps as for other domains, except that in the end we need to
>>> call Xen suspend.
>>
>> Which, as said, feels wrong. Domains to be revived after resume aren't
>> really shut down, so imo they should never have ->is_shutting_down set.
> 
> I believe this is out of scope for this series;

Yes, but see at the bottom.

> actually, the same applies to shutdown_code.

Not quite sure there.

>>> The is_shutting_down flag is easily reset on Xen resume via a
>>> domain_resume call, so I don’t see any problems with that.
>>
>> You did read my earlier mail though, regarding concerns towards the clearing
>> of that flag once it was set? (You must have, since iirc you even asked [1]
>> whether you're expected to address those issues up front.)
> 
> As far as I understand, this issue is relevant to x86, and I believe
> it is out of scope for this series.

Yes and ...

> See my previous message here:
> https://lists.xen.org/archives/html/xen-devel/2025-08/msg02127.html
> 
> I will prepare a separate patch series to address it.

... thanks. My request to not extend the badness remains though, as to the
series here.

Jan