[V2,6/6] hw/acpi: Update GED with vCPU Hotplug VMSD for migration

Commit Message

Salil Mehta Oct. 31, 2024, 8:05 p.m. UTC

The ACPI CPU hotplug state `is_enabled` must be migrated along with
other vCPU hotplug states to the destination VM. Update the GED's VM
State Description (VMSD) table subsection to include the CPU Hotplug
VM State Description (VMSD).

Question: How to stop `is_enabled` state being migrated in case of x86?

Excerpt of GED VMSD State Dump at Source:

    "acpi-ged (16)": {
        "ged_state": {
            "sel": "0x00000000"
        },
        [...]
        "acpi-ged/cpuhp": {
            "cpuhp_state": {
                "selector": "0x00000005",
                "command": "0x00",
                "devs": [
                    {
                        "is_inserting": false,
                        "is_removing": false,
                        "is_enabled": true,
                        "ost_event": "0x00000000",
                        "ost_status": "0x00000000"
                    },
		    [...]
                    {
                        "is_inserting": false,
                        "is_removing": false,
                        "is_enabled": false,
                        "ost_event": "0x00000000",
                        "ost_status": "0x00000000"
                    }
                ]
            }
        }
    },

Signed-off-by: Salil Mehta <[e-mail]>
---
 hw/acpi/cpu.c                  |  1 +
 hw/acpi/generic_event_device.c | 19 +++++++++++++++++++
 2 files changed, 20 insertions(+)

Patch

diff --git a/hw/acpi/cpu.c b/hw/acpi/cpu.c
index 017b847815..514d671bfb 100644
--- a/hw/acpi/cpu.c
+++ b/hw/acpi/cpu.c
@@ -308,6 +308,7 @@  static const VMStateDescription vmstate_cpuhp_sts = {
     .fields = (const VMStateField[]) {
         VMSTATE_BOOL(is_inserting, AcpiCpuStatus),
         VMSTATE_BOOL(is_removing, AcpiCpuStatus),
+        VMSTATE_BOOL(is_enabled, AcpiCpuStatus),
         VMSTATE_UINT32(ost_event, AcpiCpuStatus),
         VMSTATE_UINT32(ost_status, AcpiCpuStatus),
         VMSTATE_END_OF_LIST()
diff --git a/hw/acpi/generic_event_device.c b/hw/acpi/generic_event_device.c
index d00f5a6c1c..663d9cb093 100644
--- a/hw/acpi/generic_event_device.c
+++ b/hw/acpi/generic_event_device.c
@@ -331,6 +331,24 @@  static const VMStateDescription vmstate_memhp_state = {
     }
 };
 
+static bool cpuhp_needed(void *opaque)
+{
+    MachineClass *mc = MACHINE_GET_CLASS(qdev_get_machine());
+
+    return mc->has_hotpluggable_cpus;
+}
+
+static const VMStateDescription vmstate_cpuhp_state = {
+    .name = "acpi-ged/cpuhp",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .needed = cpuhp_needed,
+    .fields      = (VMStateField[]) {
+        VMSTATE_CPU_HOTPLUG(cpuhp_state, AcpiGedState),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
 static const VMStateDescription vmstate_ged_state = {
     .name = "acpi-ged-state",
     .version_id = 1,
@@ -379,6 +397,7 @@  static const VMStateDescription vmstate_acpi_ged = {
     },
     .subsections = (const VMStateDescription * const []) {
         &vmstate_memhp_state,
+        &vmstate_cpuhp_state,
         &vmstate_ghes_state,
         NULL
     }