Re: [PATCH for-4.22 v2.5] xen/arm: gic: defer host LPI allocation until after ITS init

[Oleksii Kurochko <oleksii.kurochko@gmail.com>]

On 6/19/26 1:52 PM, Julien Grall wrote:
> 
> 
> On 19/06/2026 12:34, Orzel, Michal wrote:
>>
>>
>> On 19-Jun-26 13:23, Julien Grall wrote:
>>> Hi Michal,
>>>
>>> On 19/06/2026 10:48, Orzel, Michal wrote:
>>>> @Oleksii, can we ask for a release ack here?
>>>
>>> Can you explain the pros/cons of introducing this patch quite late?
>> The advantage is that it fixes the broken LPIs on affected hardware.
> 
>  > The disadvantage is the reordering risk but I don't think there is 
> any issue.
> 
> See more below.
>>>
>>> One of the risk here is that we are now initializing the LPIs *after*
>>> the ITSes. I understand this is because we want to know the workaround.
>>> However, I vaguely recall that there was a dependency in the
>>> configuration. So are we confident the new ordering will not bring other
>>> issues? Ideally this should have been explained in the commit message.
>> gic-v3-its.c never references host LPI state, so ITS init has no 
>> dependency on LPIs.
> 
> My concern is at the HW level. The ITS is using LPIs. But we will 
> configure the ITS first and then the LPIs.
> 
> What probaly saves us is the fact gicv3_lpi_init_host_lpis() only seem 
> to allocate memory. This is a bit fragile though.

Julien, do you think that a fix should be done differently and this one 
isn't really acceptable?

~ Oleksii