[PATCH RFC V3 16/29] hw/acpi: Make _MAT method optional

[Salil Mehta via <qemu-devel@nongnu.org>]

From: Jean-Philippe Brucker <jean-philippe@linaro.org>

The GICC interface on arm64 vCPUs is statically defined in the MADT, and
doesn't require a _MAT entry. Although the GICC is indicated as present
by the MADT entry, it can only be used from vCPU sysregs, which aren't
accessible until hot-add.

Co-developed-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Co-developed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Signed-off-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Signed-off-by: Salil Mehta <salil.mehta@huawei.com>
---
 hw/acpi/cpu.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/hw/acpi/cpu.c b/hw/acpi/cpu.c
index 40b8899125..2240c6e108 100644
--- a/hw/acpi/cpu.c
+++ b/hw/acpi/cpu.c
@@ -717,10 +717,13 @@ void build_cpus_aml(Aml *table, MachineState *machine, CPUHotplugFeatures opts,
             aml_append(dev, method);
 
             /* build _MAT object */
-            build_madt_cpu(i, arch_ids, madt_buf, true); /* set enabled flag */
-            aml_append(dev, aml_name_decl("_MAT",
+            if (build_madt_cpu) {
+                build_madt_cpu(i, arch_ids, madt_buf,
+                                true); /* set enabled flag */
+                aml_append(dev, aml_name_decl("_MAT",
                 aml_buffer(madt_buf->len, (uint8_t *)madt_buf->data)));
-            g_array_free(madt_buf, true);
+                g_array_free(madt_buf, true);
+            }
 
             if (CPU(arch_ids->cpus[i].cpu) != first_cpu) {
                 method = aml_method("_EJ0", 1, AML_NOTSERIALIZED);
-- 
2.34.1