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

[Eric DeVolder]

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