Re: [PATCH v2 2/4] hw/acpi: arm: bump MADT to revision 5

[Eric DeVolder <eric.devolder@oracle.com>]

On 4/19/23 00:30, Michael S. Tsirkin wrote:
> On Tue, Apr 18, 2023 at 12:52:17PM -0400, Eric DeVolder wrote:
>> Currently ARM QEMU generates, and reports, MADT revision 4. ACPI 6.3
>> introduces MADT revision 5.
>>
>> For MADT revision 5, the GICC structure adds an SPE Overflow Interrupt
>> field. This new 2-byte field is created from the existing 3-byte
>> Reserved field. The spec indicates if the SPE overflow interrupt is
>> not supported, to zero the field.
>>
>> Signed-off-by: Eric DeVolder <eric.devolder@oracle.com>
> 
> So why do we bother changing this? I'd rather defer until
> we actually intend to fill this field.

Perfectly reasonable to me. I'll drop the ARM change going forward.
eric

> 
>> ---
>>   hw/arm/virt-acpi-build.c | 6 ++++--
>>   1 file changed, 4 insertions(+), 2 deletions(-)
>>
>> diff --git a/hw/arm/virt-acpi-build.c b/hw/arm/virt-acpi-build.c
>> index 4156111d49..23268dd981 100644
>> --- a/hw/arm/virt-acpi-build.c
>> +++ b/hw/arm/virt-acpi-build.c
>> @@ -705,7 +705,7 @@ build_madt(GArray *table_data, BIOSLinker *linker, VirtMachineState *vms)
>>       int i;
>>       VirtMachineClass *vmc = VIRT_MACHINE_GET_CLASS(vms);
>>       const MemMapEntry *memmap = vms->memmap;
>> -    AcpiTable table = { .sig = "APIC", .rev = 4, .oem_id = vms->oem_id,
>> +    AcpiTable table = { .sig = "APIC", .rev = 5, .oem_id = vms->oem_id,
>>                           .oem_table_id = vms->oem_table_id };
>>   
>>       acpi_table_begin(&table, table_data);
>> @@ -763,7 +763,9 @@ build_madt(GArray *table_data, BIOSLinker *linker, VirtMachineState *vms)
>>           /* Processor Power Efficiency Class */
>>           build_append_int_noprefix(table_data, 0, 1);
>>           /* Reserved */
>> -        build_append_int_noprefix(table_data, 0, 3);
>> +        build_append_int_noprefix(table_data, 0, 1);
>> +        /* SPE overflow Interrupt */
>> +        build_append_int_noprefix(table_data, 0, 2);
>>       }
>>   
>>       if (vms->gic_version != VIRT_GIC_VERSION_2) {
>> -- 
>> 2.31.1
>