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

[Michael S. Tsirkin]

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.

> ---
>  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