On 04.11.2021 15:59, Ian Jackson wrote:
> Jan Beulich writes ("[PATCH][4.16] x86/x2APIC: defer probe until after IOMMU
> ACPI table parsing"):
>> While commit XXXXXXXXXXXX ("x86/IOMMU: mark IOMMU / intremap not in use
>> when ACPI tables are missing") deals with apic_x2apic_probe() as called
>> from x2apic_bsp_setup(), the check_x2apic_preenabled() path is similarly
>> affected: The call needs to occur after acpi_boot_init() (which is what
>> calls acpi_iommu_init()), such that iommu_intremap getting disabled
>> there can be properly taken into account by apic_x2apic_probe().
>>
>> Signed-off-by: Jan Beulich <jbeul...@suse.com>
>> ---
>> Based on code inspection only - I have no affected system and hence no
>> way to actually test the case.
>
> Do we have any tests for this ?
If you mean in osstest, then I'm unaware of any, but I also don't have
a clear view on how much x2APIC-capable hardware we have, and whether
among those there are any where the firmware pre-enables x2APIC.
> I see it's tagged for 4.16 (and I'm
> favourably inclined) but I'm not sure I follow the implications.
The main aspect here is: This is the other side of the medal as to the
referenced earlier change (which I did commit an hour or so ago).
Jan
