Re: [PATCH] ACPI: bus: Move acpi_arm_init() to the place of after acpi_ghes_init()

[Robin Murphy <robin.murphy@arm.com>]

On 2023-10-10 09:50, Sudeep Holla wrote:
> On Tue, Oct 10, 2023 at 04:21:23PM +0800, Hanjun Guo wrote:
>> acpi_agdi_init() in acpi_arm_init() will register a SDEI event, so
>> it needs the SDEI subsystem to be initialized (which is done in
>> acpi_ghes_init()) before the AGDI driver probing.
>>
>> In commit fcea0ccf4fd7 ("ACPI: bus: Consolidate all arm specific
>> initialisation into acpi_arm_init()"), the acpi_agdi_init() was
>> called before acpi_ghes_init() and it causes following failure:
>>
>> | [    0.515864] sdei: Failed to create event 1073741825: -5
>> | [    0.515866] agdi agdi.0: Failed to register for SDEI event 1073741825
>> | [    0.515867] agdi: probe of agdi.0 failed with error -5
>> | ...
>> | [    0.516022] sdei: SDEIv1.0 (0x0) detected in firmware.
>>
>> Fix it by moving acpi_arm_init() to the place of after
>> acpi_ghes_init().
>>
>> Fixes: fcea0ccf4fd7 ("ACPI: bus: Consolidate all arm specific initialisation into acpi_arm_init()")
>> Reported-by: D Scott Phillips <scott@os.amperecomputing.com>
>> Signed-off-by: Hanjun Guo <guohanjun@huawei.com>
>> ---
>>
>> I did a test on a ARM server and I didn't see regressions, but
>> I don't have a AGDI table firmware, so Scott please give a
>> test to see if it fixes your issue.
>>
>>   drivers/acpi/bus.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c
>> index f41dda2d3493..a4aa53b7e2bb 100644
>> --- a/drivers/acpi/bus.c
>> +++ b/drivers/acpi/bus.c
>> @@ -1410,10 +1410,10 @@ static int __init acpi_init(void)
>>   	acpi_init_ffh();
>>
>>   	pci_mmcfg_late_init();
>> -	acpi_arm_init();
>>   	acpi_viot_early_init();
>>   	acpi_hest_init();
>>   	acpi_ghes_init();
>> +	acpi_arm_init();
> 
> I am fine with the change, but just wanted to check with Robin/Jean-Philippe
> if there are any dependency on IORT initialisation for VIOT ? IIUC IORT was
> always initialised before VIOT but that changes after this change.

They should be independent, and typically we'd only expect to see one or 
the other anyway (although strictly a VMM *could* provide virtio-iommu 
for some devices while also emulating an SMMU for others if it really 
really wanted to).

Cheers,
Robin.