From 603cbcc5efdd35f518a5bd0a5067d40c2c4eb8d6 Mon Sep 17 00:00:00 2001
From: Keqian Zhu <zhukeqian1@huawei.com>
Date: Fri, 3 Apr 2020 15:41:01 +0800
Subject: [PATCH] acpi/ged: Extend ACPI GED to support CPU hotplug

This adds a new GED event called ACPI_GED_CPU_HOTPLUG_EVT.
The basic workflow is that: GED sends this event to guest,
then ACPI driver in guest will call _EVT method of GED aml,
then _EVT will call CSCN method in cpus aml to get status of
all cpus.

The status of cpus is maintained by CPUHotplugState in GED and
is made accessable to guest through memory region.

This also adds migration support to CPUHotplugState.

Signed-off-by: Keqian Zhu <zhukeqian1@huawei.com>
Signed-off-by: Salil Mehta <salil.mehta@huawei.com>
---
 docs/specs/acpi_hw_reduced_hotplug.rst |  3 ++-
 hw/acpi/cpu.c                          |  1 -
 hw/acpi/generic_event_device.c         | 35 ++++++++++++++++++++++++++
 hw/arm/Kconfig                         |  1 +
 include/hw/acpi/cpu.h                  |  2 ++
 include/hw/acpi/generic_event_device.h |  4 +++
 6 files changed, 44 insertions(+), 2 deletions(-)

diff --git a/docs/specs/acpi_hw_reduced_hotplug.rst b/docs/specs/acpi_hw_reduced_hotplug.rst
index 0bd3f9399f..3acd6fcd8b 100644
--- a/docs/specs/acpi_hw_reduced_hotplug.rst
+++ b/docs/specs/acpi_hw_reduced_hotplug.rst
@@ -64,7 +64,8 @@ GED IO interface (4 byte access)
        0: Memory hotplug event
        1: System power down event
        2: NVDIMM hotplug event
-    3-31: Reserved
+       3: CPU hotplug event
+    4-31: Reserved
 
 **write_access:**
 
diff --git a/hw/acpi/cpu.c b/hw/acpi/cpu.c
index a9c2ee952a..f9ce0a7f41 100644
--- a/hw/acpi/cpu.c
+++ b/hw/acpi/cpu.c
@@ -6,7 +6,6 @@
 #include "trace.h"
 #include "sysemu/numa.h"
 
-#define ACPI_CPU_HOTPLUG_REG_LEN 12
 #define ACPI_CPU_SELECTOR_OFFSET_WR 0
 #define ACPI_CPU_FLAGS_OFFSET_RW 4
 #define ACPI_CPU_CMD_OFFSET_WR 5
diff --git a/hw/acpi/generic_event_device.c b/hw/acpi/generic_event_device.c
index e28457a7d1..042a8ef8a5 100644
--- a/hw/acpi/generic_event_device.c
+++ b/hw/acpi/generic_event_device.c
@@ -25,6 +25,7 @@ static const uint32_t ged_supported_events[] = {
     ACPI_GED_MEM_HOTPLUG_EVT,
     ACPI_GED_PWR_DOWN_EVT,
     ACPI_GED_NVDIMM_HOTPLUG_EVT,
+    ACPI_GED_CPU_HOTPLUG_EVT,
 };
 
 /*
@@ -117,6 +118,9 @@ void build_ged_aml(Aml *table, const char *name, HotplugHandler *hotplug_dev,
                            aml_notify(aml_name("\\_SB.NVDR"),
                                       aml_int(0x80)));
                 break;
+            case ACPI_GED_CPU_HOTPLUG_EVT:
+                aml_append(if_ctx, aml_call0("\\_SB.CPUS.CSCN"));
+                break;
             default:
                 /*
                  * Please make sure all the events in ged_supported_events[]
@@ -234,6 +238,8 @@ static void acpi_ged_device_plug_cb(HotplugHandler *hotplug_dev,
         } else {
             acpi_memory_plug_cb(hotplug_dev, &s->memhp_state, dev, errp);
         }
+    } else if (object_dynamic_cast(OBJECT(dev), TYPE_CPU)) {
+        acpi_cpu_plug_cb(hotplug_dev, &s->cpuhp_state, dev, errp);
     } else {
         error_setg(errp, "virt: device plug request for unsupported device"
                    " type: %s", object_get_typename(OBJECT(dev)));
@@ -279,6 +285,8 @@ static void acpi_ged_send_event(AcpiDeviceIf *adev, AcpiEventStatusBits ev)
         sel = ACPI_GED_PWR_DOWN_EVT;
     } else if (ev & ACPI_NVDIMM_HOTPLUG_STATUS) {
         sel = ACPI_GED_NVDIMM_HOTPLUG_EVT;
+    } else if (ev & ACPI_CPU_HOTPLUG_STATUS) {
+        sel = ACPI_GED_CPU_HOTPLUG_EVT;
     } else {
         /* Unknown event. Return without generating interrupt. */
         warn_report("GED: Unsupported event %d. No irq injected", ev);
@@ -311,6 +319,16 @@ static const VMStateDescription vmstate_memhp_state = {
     }
 };
 
+static const VMStateDescription vmstate_cpuhp_state = {
+    .name = "acpi-ged/cpuhp",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .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,
@@ -360,6 +378,7 @@ static const VMStateDescription vmstate_acpi_ged = {
     .subsections = (const VMStateDescription * []) {
         &vmstate_memhp_state,
         &vmstate_ghes_state,
+        &vmstate_cpuhp_state,
         NULL
     }
 };
@@ -370,6 +389,7 @@ static void acpi_ged_initfn(Object *obj)
     AcpiGedState *s = ACPI_GED(dev);
     SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
     GEDState *ged_st = &s->ged_state;
+    MachineClass *mc;
 
     memory_region_init_io(&ged_st->evt, obj, &ged_evt_ops, ged_st,
                           TYPE_ACPI_GED, ACPI_GED_EVT_SEL_LEN);
@@ -393,6 +413,21 @@ static void acpi_ged_initfn(Object *obj)
     memory_region_init_io(&ged_st->regs, obj, &ged_regs_ops, ged_st,
                           TYPE_ACPI_GED "-regs", ACPI_GED_REG_COUNT);
     sysbus_init_mmio(sbd, &ged_st->regs);
+
+    mc = MACHINE_GET_CLASS(qdev_get_machine());
+    if (!mc->possible_cpu_arch_ids) {
+        /*
+         * MachineClass should support possible_cpu_arch_ids in
+         * cpu_hotplug_hw_init below.
+         */
+        return;
+    }
+
+    memory_region_init(&s->container_cpuhp, OBJECT(dev), "cpuhp container",
+                       ACPI_CPU_HOTPLUG_REG_LEN);
+    sysbus_init_mmio(sbd, &s->container_cpuhp);
+    cpu_hotplug_hw_init(&s->container_cpuhp, OBJECT(dev),
+                        &s->cpuhp_state, 0);
 }
 
 static void acpi_ged_class_init(ObjectClass *class, void *data)
diff --git a/hw/arm/Kconfig b/hw/arm/Kconfig
index 2d37d29f02..006a4b4c4b 100644
--- a/hw/arm/Kconfig
+++ b/hw/arm/Kconfig
@@ -27,6 +27,7 @@ config ARM_VIRT
     select DIMM
     select ACPI_HW_REDUCED
     select ACPI_APEI
+    select ACPI_CPU_HOTPLUG
 
 config CHEETAH
     bool
diff --git a/include/hw/acpi/cpu.h b/include/hw/acpi/cpu.h
index a0fdc44bdd..d521025830 100644
--- a/include/hw/acpi/cpu.h
+++ b/include/hw/acpi/cpu.h
@@ -17,6 +17,8 @@
 #include "hw/acpi/aml-build.h"
 #include "hw/hotplug.h"
 
+#define ACPI_CPU_HOTPLUG_REG_LEN 12
+
 typedef struct AcpiCpuStatus {
     struct CPUState *cpu;
     uint64_t arch_id;
diff --git a/include/hw/acpi/generic_event_device.h b/include/hw/acpi/generic_event_device.h
index d49217c445..6bb2ade385 100644
--- a/include/hw/acpi/generic_event_device.h
+++ b/include/hw/acpi/generic_event_device.h
@@ -63,6 +63,7 @@
 #include "hw/acpi/memory_hotplug.h"
 #include "hw/acpi/ghes.h"
 #include "qom/object.h"
+#include "hw/acpi/cpu.h"
 
 #define ACPI_POWER_BUTTON_DEVICE "PWRB"
 
@@ -97,6 +98,7 @@ OBJECT_DECLARE_SIMPLE_TYPE(AcpiGedState, ACPI_GED)
 #define ACPI_GED_MEM_HOTPLUG_EVT   0x1
 #define ACPI_GED_PWR_DOWN_EVT      0x2
 #define ACPI_GED_NVDIMM_HOTPLUG_EVT 0x4
+#define ACPI_GED_CPU_HOTPLUG_EVT   0x8
 
 typedef struct GEDState {
     MemoryRegion evt;
@@ -108,6 +110,8 @@ struct AcpiGedState {
     SysBusDevice parent_obj;
     MemHotplugState memhp_state;
     MemoryRegion container_memhp;
+    CPUHotplugState cpuhp_state;
+    MemoryRegion container_cpuhp;
     GEDState ged_state;
     uint32_t ged_event_bitmap;
     qemu_irq irq;
-- 
2.27.0