Re: [PATCH v2 3/5] xen/events: only register debug interrupt for 2-level events

[Jan Beulich <jbeulich@xxxxxxxx>]

On 22.10.2020 15:09, Jürgen Groß wrote:
> On 22.10.20 12:35, Jan Beulich wrote:
>> On 22.10.2020 11:49, Juergen Gross wrote:
>>> @@ -2080,10 +2080,12 @@ void __init xen_init_IRQ(void)
>>>     int ret = -EINVAL;
>>>     evtchn_port_t evtchn;
>>>   
>>> -   if (fifo_events)
>>> +   if (xen_fifo_events)
>>>             ret = xen_evtchn_fifo_init();
>>> -   if (ret < 0)
>>> +   if (ret < 0) {
>>>             xen_evtchn_2l_init();
>>> +           xen_fifo_events = false;
>>> +   }
>>
>> Another note: While it may not matter right here, maybe better
>> first set the variable and the call the function?
> 
> I don't think this is really important, TBH.
> 
> This code is executed before other cpus are up and we'd have major
> other problems in case the sequence would really matter here.

Fair enough; I was thinking in particular that it ought to be
legitimate for xen_evtchn_2l_init() to BUG_ON(xen_fifo_events).

Jan