Re: Problems with APIC on versions 4.9 and later (4.8 works)

[Jan Beulich <jbeulich@xxxxxxxx>]

On 01.02.2021 16:26, Claudemir Todo Bom wrote:
> Em seg., 1 de fev. de 2021 às 12:09, Jan Beulich <jbeulich@xxxxxxxx> escreveu:
>>
>> On 01.02.2021 15:46, Claudemir Todo Bom wrote:
>>> Tested first without the debug patch and with following parameters:
>>
>> And this test was all three of the non-debugging patches?
> 
> Yes, all three patches.
> 
>>> xen: dom0_mem=1024M,max:2048M dom0_max_vcpus=4 dom0_vcpus_pin=true smt=true
>>> kernel: loglevel=3
>>>
>>> same behaviour as before... black screen right after the xen messages.
>>>
>>> adding earlyprintk=xen to the kernel command line is sufficient to
>>> make it boot, I can imagine this can be happening because Xen is not
>>> releasing console to the kernel at that moment.
>>
>> If the answer to the above question is "yes", then I start
>> suspecting this to be a different problem. I'm not sure I
>> see a way to debug this without having access to any output
>> (i.e. neither video nor serial). Without "earlyprintk=xen"
>> and instead with "vga=keep watchdog" on the Xen command
>> line, is there anything helpful (without or if need be with
>> the debugging patch in place)?
> 
> with "vga=text-80x25,keep watchdog" and without the earlyprintk,
> system booted.

Well, you clearly don't want to keep "vga=keep". There has to
be something that's still going wrong, but this may now be a
kernel side issue. In the logs you provided I couldn't spot
anything odd, but these were from working cases after all. So
as said, for now I'm lost, and you may need to live with some
form of workaround (which you've said you're okay with).

Jan