[RFC,V3,12/29] arm/virt/acpi: Build CPUs AML with CPU Hotplug support

Commit Message

Salil Mehta June 13, 2024, 11:36 p.m. UTC

Support for Virtual CPU Hotplug requires a sequence of ACPI handshakes between
QEMU and the guest kernel when a vCPU is plugged or unplugged. Most of the AML
code to support these handshakes already exists. This AML needs to be built
during VM initialization for the ARM architecture as well, if GED support
exists.

Signed-off-by: Salil Mehta <[e-mail]>
---
 hw/arm/virt-acpi-build.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

Patch

diff --git a/hw/arm/virt-acpi-build.c b/hw/arm/virt-acpi-build.c
index c3ccfef026..2d44567df5 100644
--- a/hw/arm/virt-acpi-build.c
+++ b/hw/arm/virt-acpi-build.c
@@ -799,6 +799,7 @@  static void
 build_dsdt(GArray *table_data, BIOSLinker *linker, VirtMachineState *vms)
 {
     VirtMachineClass *vmc = VIRT_MACHINE_GET_CLASS(vms);
+    MachineClass *mc = MACHINE_GET_CLASS(vms);
     Aml *scope, *dsdt;
     MachineState *ms = MACHINE(vms);
     const MemMapEntry *memmap = vms->memmap;
@@ -815,7 +816,18 @@  build_dsdt(GArray *table_data, BIOSLinker *linker, VirtMachineState *vms)
      * the RTC ACPI device at all when using UEFI.
      */
     scope = aml_scope("\\_SB");
-    acpi_dsdt_add_cpus(scope, vms);
+    /* if GED is enabled then cpus AML shall be added as part build_cpus_aml */
+    if (vms->acpi_dev && mc->has_hotpluggable_cpus) {
+        CPUHotplugFeatures opts = {
+             .acpi_1_compatible = false,
+             .has_legacy_cphp = false
+        };
+
+        build_cpus_aml(scope, ms, opts, NULL, memmap[VIRT_CPUHP_ACPI].base,
+                       "\\_SB", NULL, AML_SYSTEM_MEMORY);
+    } else {
+        acpi_dsdt_add_cpus(scope, vms);
+    }
     acpi_dsdt_add_uart(scope, &memmap[VIRT_UART],
                        (irqmap[VIRT_UART] + ARM_SPI_BASE));
     if (vmc->acpi_expose_flash) {