[PATCH V16 3/7] hw/acpi: Update ACPI GED framework to support vCPU Hotplug

Salil Mehta via posted 7 patches 3 months ago
Maintainers: Paolo Bonzini <pbonzini@redhat.com>, "Michael S. Tsirkin" <mst@redhat.com>, Igor Mammedov <imammedo@redhat.com>, Ani Sinha <anisinha@redhat.com>, "Alex Bennée" <alex.bennee@linaro.org>, "Philippe Mathieu-Daudé" <philmd@linaro.org>, Eduardo Habkost <eduardo@habkost.net>, Marcel Apfelbaum <marcel.apfelbaum@gmail.com>, Yanan Wang <wangyanan55@huawei.com>, Richard Henderson <richard.henderson@linaro.org>, Peter Xu <peterx@redhat.com>, David Hildenbrand <david@redhat.com>
[PATCH V16 3/7] hw/acpi: Update ACPI GED framework to support vCPU Hotplug
Posted by Salil Mehta via 3 months ago
ACPI GED (as described in the ACPI 6.4 spec) uses an interrupt listed in the
_CRS object of GED to intimate OSPM about an event. Later then demultiplexes the
notified event by evaluating ACPI _EVT method to know the type of event. Use
ACPI GED to also notify the guest kernel about any CPU hot(un)plug events.

Note, GED interface is used by many hotplug events like memory hotplug, NVDIMM
hotplug and non-hotplug events like system power down event. Each of these can
be selected using a bit in the 32 bit GED IO interface. A bit has been reserved
for the CPU hotplug event.

ACPI CPU hotplug related initialization should only happen if ACPI_CPU_HOTPLUG
support has been enabled for particular architecture. Add cpu_hotplug_hw_init()
stub to avoid compilation break.

Co-developed-by: Keqian Zhu <zhukeqian1@huawei.com>
Signed-off-by: Keqian Zhu <zhukeqian1@huawei.com>
Signed-off-by: Salil Mehta <salil.mehta@huawei.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Shaoqin Huang <shahuang@redhat.com>
Tested-by: Vishnu Pajjuri <vishnu@os.amperecomputing.com>
Tested-by: Xianglai Li <lixianglai@loongson.cn>
Tested-by: Miguel Luis <miguel.luis@oracle.com>
Reviewed-by: Vishnu Pajjuri <vishnu@os.amperecomputing.com>
Tested-by: Zhao Liu <zhao1.liu@intel.com>
Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
---
 docs/specs/acpi_hw_reduced_hotplug.rst |  3 +-
 hw/acpi/acpi-cpu-hotplug-stub.c        |  6 ++++
 hw/acpi/generic_event_device.c         | 47 ++++++++++++++++++++++++++
 include/hw/acpi/generic_event_device.h |  4 +++
 4 files changed, 59 insertions(+), 1 deletion(-)

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/acpi-cpu-hotplug-stub.c b/hw/acpi/acpi-cpu-hotplug-stub.c
index 3fc4b14c26..c6c61bb9cd 100644
--- a/hw/acpi/acpi-cpu-hotplug-stub.c
+++ b/hw/acpi/acpi-cpu-hotplug-stub.c
@@ -19,6 +19,12 @@ void legacy_acpi_cpu_hotplug_init(MemoryRegion *parent, Object *owner,
     return;
 }
 
+void cpu_hotplug_hw_init(MemoryRegion *as, Object *owner,
+                         CPUHotplugState *state, hwaddr base_addr)
+{
+    return;
+}
+
 void acpi_cpu_ospm_status(CPUHotplugState *cpu_st, ACPIOSTInfoList ***list)
 {
     return;
diff --git a/hw/acpi/generic_event_device.c b/hw/acpi/generic_event_device.c
index 2d6e91b124..4641933a0f 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,
 };
 
 /*
@@ -234,6 +235,8 @@ 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)));
@@ -248,6 +251,8 @@ static void acpi_ged_unplug_request_cb(HotplugHandler *hotplug_dev,
     if ((object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM) &&
                        !(object_dynamic_cast(OBJECT(dev), TYPE_NVDIMM)))) {
         acpi_memory_unplug_request_cb(hotplug_dev, &s->memhp_state, dev, errp);
+    } else if (object_dynamic_cast(OBJECT(dev), TYPE_CPU)) {
+        acpi_cpu_unplug_request_cb(hotplug_dev, &s->cpuhp_state, dev, errp);
     } else {
         error_setg(errp, "acpi: device unplug request for unsupported device"
                    " type: %s", object_get_typename(OBJECT(dev)));
@@ -261,6 +266,8 @@ static void acpi_ged_unplug_cb(HotplugHandler *hotplug_dev,
 
     if (object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM)) {
         acpi_memory_unplug_cb(&s->memhp_state, dev, errp);
+    } else if (object_dynamic_cast(OBJECT(dev), TYPE_CPU)) {
+        acpi_cpu_unplug_cb(&s->cpuhp_state, dev, errp);
     } else {
         error_setg(errp, "acpi: device unplug for unsupported device"
                    " type: %s", object_get_typename(OBJECT(dev)));
@@ -272,6 +279,7 @@ static void acpi_ged_ospm_status(AcpiDeviceIf *adev, ACPIOSTInfoList ***list)
     AcpiGedState *s = ACPI_GED(adev);
 
     acpi_memory_ospm_status(&s->memhp_state, list);
+    acpi_cpu_ospm_status(&s->cpuhp_state, list);
 }
 
 static void acpi_ged_send_event(AcpiDeviceIf *adev, AcpiEventStatusBits ev)
@@ -286,6 +294,8 @@ 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);
@@ -371,6 +381,42 @@ static const VMStateDescription vmstate_acpi_ged = {
     }
 };
 
+static void acpi_ged_realize(DeviceState *dev, Error **errp)
+{
+    SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
+    AcpiGedState *s = ACPI_GED(dev);
+    uint32_t ged_events;
+    int i;
+
+    ged_events = ctpop32(s->ged_event_bitmap);
+
+    for (i = 0; i < ARRAY_SIZE(ged_supported_events) && ged_events; i++) {
+        uint32_t event = s->ged_event_bitmap & ged_supported_events[i];
+
+        if (!event) {
+            continue;
+        }
+
+        switch (event) {
+        case ACPI_GED_CPU_HOTPLUG_EVT:
+            /* initialize CPU Hotplug related regions */
+            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);
+            break;
+        }
+        ged_events--;
+    }
+
+    if (ged_events) {
+        error_report("Unsupported events specified");
+        abort();
+    }
+}
+
 static void acpi_ged_initfn(Object *obj)
 {
     DeviceState *dev = DEVICE(obj);
@@ -411,6 +457,7 @@ static void acpi_ged_class_init(ObjectClass *class, void *data)
     dc->desc = "ACPI Generic Event Device";
     device_class_set_props(dc, acpi_ged_properties);
     dc->vmsd = &vmstate_acpi_ged;
+    dc->realize = acpi_ged_realize;
 
     hc->plug = acpi_ged_device_plug_cb;
     hc->unplug_request = acpi_ged_unplug_request_cb;
diff --git a/include/hw/acpi/generic_event_device.h b/include/hw/acpi/generic_event_device.h
index ba84ce0214..e091ac2108 100644
--- a/include/hw/acpi/generic_event_device.h
+++ b/include/hw/acpi/generic_event_device.h
@@ -62,6 +62,7 @@
 #include "hw/sysbus.h"
 #include "hw/acpi/memory_hotplug.h"
 #include "hw/acpi/ghes.h"
+#include "hw/acpi/cpu.h"
 #include "qom/object.h"
 
 #define ACPI_POWER_BUTTON_DEVICE "PWRB"
@@ -95,6 +96,7 @@ 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;
@@ -106,6 +108,8 @@ 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;
-- 
2.34.1
Re: [PATCH V16 3/7] hw/acpi: Update ACPI GED framework to support vCPU Hotplug
Posted by Igor Mammedov 3 months ago
On Tue, 16 Jul 2024 12:14:58 +0100
Salil Mehta <salil.mehta@huawei.com> wrote:

> ACPI GED (as described in the ACPI 6.4 spec) uses an interrupt listed in the
> _CRS object of GED to intimate OSPM about an event. Later then demultiplexes the
> notified event by evaluating ACPI _EVT method to know the type of event. Use
> ACPI GED to also notify the guest kernel about any CPU hot(un)plug events.
> 
> Note, GED interface is used by many hotplug events like memory hotplug, NVDIMM
> hotplug and non-hotplug events like system power down event. Each of these can
> be selected using a bit in the 32 bit GED IO interface. A bit has been reserved
> for the CPU hotplug event.
> 
> ACPI CPU hotplug related initialization should only happen if ACPI_CPU_HOTPLUG
> support has been enabled for particular architecture. Add cpu_hotplug_hw_init()
> stub to avoid compilation break.
> 
> Co-developed-by: Keqian Zhu <zhukeqian1@huawei.com>
> Signed-off-by: Keqian Zhu <zhukeqian1@huawei.com>
> Signed-off-by: Salil Mehta <salil.mehta@huawei.com>
> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> Reviewed-by: Gavin Shan <gshan@redhat.com>
> Reviewed-by: David Hildenbrand <david@redhat.com>
> Reviewed-by: Shaoqin Huang <shahuang@redhat.com>
> Tested-by: Vishnu Pajjuri <vishnu@os.amperecomputing.com>
> Tested-by: Xianglai Li <lixianglai@loongson.cn>
> Tested-by: Miguel Luis <miguel.luis@oracle.com>
> Reviewed-by: Vishnu Pajjuri <vishnu@os.amperecomputing.com>
> Tested-by: Zhao Liu <zhao1.liu@intel.com>
> Reviewed-by: Zhao Liu <zhao1.liu@intel.com>

I haven't tested it but looks fine to me,
it missing migration bits, but as long as there is no actual users
in this release it could be a patch on top later on.

Acked-by: Igor Mammedov <imammedo@redhat.com>

> ---
>  docs/specs/acpi_hw_reduced_hotplug.rst |  3 +-
>  hw/acpi/acpi-cpu-hotplug-stub.c        |  6 ++++
>  hw/acpi/generic_event_device.c         | 47 ++++++++++++++++++++++++++
>  include/hw/acpi/generic_event_device.h |  4 +++
>  4 files changed, 59 insertions(+), 1 deletion(-)
> 
> 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/acpi-cpu-hotplug-stub.c b/hw/acpi/acpi-cpu-hotplug-stub.c
> index 3fc4b14c26..c6c61bb9cd 100644
> --- a/hw/acpi/acpi-cpu-hotplug-stub.c
> +++ b/hw/acpi/acpi-cpu-hotplug-stub.c
> @@ -19,6 +19,12 @@ void legacy_acpi_cpu_hotplug_init(MemoryRegion *parent, Object *owner,
>      return;
>  }
>  
> +void cpu_hotplug_hw_init(MemoryRegion *as, Object *owner,
> +                         CPUHotplugState *state, hwaddr base_addr)
> +{
> +    return;
> +}
> +
>  void acpi_cpu_ospm_status(CPUHotplugState *cpu_st, ACPIOSTInfoList ***list)
>  {
>      return;
> diff --git a/hw/acpi/generic_event_device.c b/hw/acpi/generic_event_device.c
> index 2d6e91b124..4641933a0f 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,
>  };
>  
>  /*
> @@ -234,6 +235,8 @@ 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)));
> @@ -248,6 +251,8 @@ static void acpi_ged_unplug_request_cb(HotplugHandler *hotplug_dev,
>      if ((object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM) &&
>                         !(object_dynamic_cast(OBJECT(dev), TYPE_NVDIMM)))) {
>          acpi_memory_unplug_request_cb(hotplug_dev, &s->memhp_state, dev, errp);
> +    } else if (object_dynamic_cast(OBJECT(dev), TYPE_CPU)) {
> +        acpi_cpu_unplug_request_cb(hotplug_dev, &s->cpuhp_state, dev, errp);
>      } else {
>          error_setg(errp, "acpi: device unplug request for unsupported device"
>                     " type: %s", object_get_typename(OBJECT(dev)));
> @@ -261,6 +266,8 @@ static void acpi_ged_unplug_cb(HotplugHandler *hotplug_dev,
>  
>      if (object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM)) {
>          acpi_memory_unplug_cb(&s->memhp_state, dev, errp);
> +    } else if (object_dynamic_cast(OBJECT(dev), TYPE_CPU)) {
> +        acpi_cpu_unplug_cb(&s->cpuhp_state, dev, errp);
>      } else {
>          error_setg(errp, "acpi: device unplug for unsupported device"
>                     " type: %s", object_get_typename(OBJECT(dev)));
> @@ -272,6 +279,7 @@ static void acpi_ged_ospm_status(AcpiDeviceIf *adev, ACPIOSTInfoList ***list)
>      AcpiGedState *s = ACPI_GED(adev);
>  
>      acpi_memory_ospm_status(&s->memhp_state, list);
> +    acpi_cpu_ospm_status(&s->cpuhp_state, list);
>  }
>  
>  static void acpi_ged_send_event(AcpiDeviceIf *adev, AcpiEventStatusBits ev)
> @@ -286,6 +294,8 @@ 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);
> @@ -371,6 +381,42 @@ static const VMStateDescription vmstate_acpi_ged = {
>      }
>  };
>  
> +static void acpi_ged_realize(DeviceState *dev, Error **errp)
> +{
> +    SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
> +    AcpiGedState *s = ACPI_GED(dev);
> +    uint32_t ged_events;
> +    int i;
> +
> +    ged_events = ctpop32(s->ged_event_bitmap);
> +
> +    for (i = 0; i < ARRAY_SIZE(ged_supported_events) && ged_events; i++) {
> +        uint32_t event = s->ged_event_bitmap & ged_supported_events[i];
> +
> +        if (!event) {
> +            continue;
> +        }
> +
> +        switch (event) {
> +        case ACPI_GED_CPU_HOTPLUG_EVT:
> +            /* initialize CPU Hotplug related regions */
> +            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);
> +            break;
> +        }
> +        ged_events--;
> +    }
> +
> +    if (ged_events) {
> +        error_report("Unsupported events specified");
> +        abort();
> +    }
> +}
> +
>  static void acpi_ged_initfn(Object *obj)
>  {
>      DeviceState *dev = DEVICE(obj);
> @@ -411,6 +457,7 @@ static void acpi_ged_class_init(ObjectClass *class, void *data)
>      dc->desc = "ACPI Generic Event Device";
>      device_class_set_props(dc, acpi_ged_properties);
>      dc->vmsd = &vmstate_acpi_ged;
> +    dc->realize = acpi_ged_realize;
>  
>      hc->plug = acpi_ged_device_plug_cb;
>      hc->unplug_request = acpi_ged_unplug_request_cb;
> diff --git a/include/hw/acpi/generic_event_device.h b/include/hw/acpi/generic_event_device.h
> index ba84ce0214..e091ac2108 100644
> --- a/include/hw/acpi/generic_event_device.h
> +++ b/include/hw/acpi/generic_event_device.h
> @@ -62,6 +62,7 @@
>  #include "hw/sysbus.h"
>  #include "hw/acpi/memory_hotplug.h"
>  #include "hw/acpi/ghes.h"
> +#include "hw/acpi/cpu.h"
>  #include "qom/object.h"
>  
>  #define ACPI_POWER_BUTTON_DEVICE "PWRB"
> @@ -95,6 +96,7 @@ 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;
> @@ -106,6 +108,8 @@ 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;
RE: [PATCH V16 3/7] hw/acpi: Update ACPI GED framework to support vCPU Hotplug
Posted by Salil Mehta via 3 months ago
>  From: Igor Mammedov <imammedo@redhat.com>
>  Sent: Tuesday, July 16, 2024 3:53 PM
>  To: Salil Mehta <salil.mehta@huawei.com>
>  
>  On Tue, 16 Jul 2024 12:14:58 +0100
>  Salil Mehta <salil.mehta@huawei.com> wrote:
>  
>  > ACPI GED (as described in the ACPI 6.4 spec) uses an interrupt listed
>  > in the _CRS object of GED to intimate OSPM about an event. Later then
>  > demultiplexes the notified event by evaluating ACPI _EVT method to
>  > know the type of event. Use ACPI GED to also notify the guest kernel
>  about any CPU hot(un)plug events.
>  >
>  > Note, GED interface is used by many hotplug events like memory
>  > hotplug, NVDIMM hotplug and non-hotplug events like system power
>  down
>  > event. Each of these can be selected using a bit in the 32 bit GED IO
>  > interface. A bit has been reserved for the CPU hotplug event.
>  >
>  > ACPI CPU hotplug related initialization should only happen if
>  > ACPI_CPU_HOTPLUG support has been enabled for particular
>  architecture.
>  > Add cpu_hotplug_hw_init() stub to avoid compilation break.
>  >
>  > Co-developed-by: Keqian Zhu <zhukeqian1@huawei.com>
>  > Signed-off-by: Keqian Zhu <zhukeqian1@huawei.com>
>  > Signed-off-by: Salil Mehta <salil.mehta@huawei.com>
>  > Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
>  > Reviewed-by: Gavin Shan <gshan@redhat.com>
>  > Reviewed-by: David Hildenbrand <david@redhat.com>
>  > Reviewed-by: Shaoqin Huang <shahuang@redhat.com>
>  > Tested-by: Vishnu Pajjuri <vishnu@os.amperecomputing.com>
>  > Tested-by: Xianglai Li <lixianglai@loongson.cn>
>  > Tested-by: Miguel Luis <miguel.luis@oracle.com>
>  > Reviewed-by: Vishnu Pajjuri <vishnu@os.amperecomputing.com>
>  > Tested-by: Zhao Liu <zhao1.liu@intel.com>
>  > Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
>  
>  I haven't tested it but looks fine to me, it missing migration bits, but as long
>  as there is no actual users in this release it could be a patch on top later on.
>  
>  Acked-by: Igor Mammedov <imammedo@redhat.com>

Many thanks!

Best regards
Salil.

>  >  docs/specs/acpi_hw_reduced_hotplug.rst |  3 +-
>  >  hw/acpi/acpi-cpu-hotplug-stub.c        |  6 ++++
>  >  hw/acpi/generic_event_device.c         | 47
>  ++++++++++++++++++++++++++
>  >  include/hw/acpi/generic_event_device.h |  4 +++
>  >  4 files changed, 59 insertions(+), 1 deletion(-)
>  >
>  > 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/acpi-cpu-hotplug-stub.c
>  > b/hw/acpi/acpi-cpu-hotplug-stub.c index 3fc4b14c26..c6c61bb9cd 100644
>  > --- a/hw/acpi/acpi-cpu-hotplug-stub.c
>  > +++ b/hw/acpi/acpi-cpu-hotplug-stub.c
>  > @@ -19,6 +19,12 @@ void legacy_acpi_cpu_hotplug_init(MemoryRegion
>  *parent, Object *owner,
>  >      return;
>  >  }
>  >
>  > +void cpu_hotplug_hw_init(MemoryRegion *as, Object *owner,
>  > +                         CPUHotplugState *state, hwaddr base_addr) {
>  > +    return;
>  > +}
>  > +
>  >  void acpi_cpu_ospm_status(CPUHotplugState *cpu_st, ACPIOSTInfoList
>  > ***list)  {
>  >      return;
>  > diff --git a/hw/acpi/generic_event_device.c
>  > b/hw/acpi/generic_event_device.c index 2d6e91b124..4641933a0f 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,
>  >  };
>  >
>  >  /*
>  > @@ -234,6 +235,8 @@ 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)));
>  > @@ -248,6 +251,8 @@ static void
>  acpi_ged_unplug_request_cb(HotplugHandler *hotplug_dev,
>  >      if ((object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM) &&
>  >                         !(object_dynamic_cast(OBJECT(dev), TYPE_NVDIMM)))) {
>  >          acpi_memory_unplug_request_cb(hotplug_dev, &s->memhp_state,
>  > dev, errp);
>  > +    } else if (object_dynamic_cast(OBJECT(dev), TYPE_CPU)) {
>  > +        acpi_cpu_unplug_request_cb(hotplug_dev, &s->cpuhp_state, dev,
>  > + errp);
>  >      } else {
>  >          error_setg(errp, "acpi: device unplug request for unsupported
>  device"
>  >                     " type: %s", object_get_typename(OBJECT(dev)));
>  > @@ -261,6 +266,8 @@ static void acpi_ged_unplug_cb(HotplugHandler
>  > *hotplug_dev,
>  >
>  >      if (object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM)) {
>  >          acpi_memory_unplug_cb(&s->memhp_state, dev, errp);
>  > +    } else if (object_dynamic_cast(OBJECT(dev), TYPE_CPU)) {
>  > +        acpi_cpu_unplug_cb(&s->cpuhp_state, dev, errp);
>  >      } else {
>  >          error_setg(errp, "acpi: device unplug for unsupported device"
>  >                     " type: %s", object_get_typename(OBJECT(dev)));
>  > @@ -272,6 +279,7 @@ static void acpi_ged_ospm_status(AcpiDeviceIf
>  *adev, ACPIOSTInfoList ***list)
>  >      AcpiGedState *s = ACPI_GED(adev);
>  >
>  >      acpi_memory_ospm_status(&s->memhp_state, list);
>  > +    acpi_cpu_ospm_status(&s->cpuhp_state, list);
>  >  }
>  >
>  >  static void acpi_ged_send_event(AcpiDeviceIf *adev,
>  > AcpiEventStatusBits ev) @@ -286,6 +294,8 @@ 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); @@ -371,6 +381,42 @@ static const VMStateDescription
>  vmstate_acpi_ged = {
>  >      }
>  >  };
>  >
>  > +static void acpi_ged_realize(DeviceState *dev, Error **errp) {
>  > +    SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
>  > +    AcpiGedState *s = ACPI_GED(dev);
>  > +    uint32_t ged_events;
>  > +    int i;
>  > +
>  > +    ged_events = ctpop32(s->ged_event_bitmap);
>  > +
>  > +    for (i = 0; i < ARRAY_SIZE(ged_supported_events) && ged_events; i++)
>  {
>  > +        uint32_t event = s->ged_event_bitmap &
>  > + ged_supported_events[i];
>  > +
>  > +        if (!event) {
>  > +            continue;
>  > +        }
>  > +
>  > +        switch (event) {
>  > +        case ACPI_GED_CPU_HOTPLUG_EVT:
>  > +            /* initialize CPU Hotplug related regions */
>  > +            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);
>  > +            break;
>  > +        }
>  > +        ged_events--;
>  > +    }
>  > +
>  > +    if (ged_events) {
>  > +        error_report("Unsupported events specified");
>  > +        abort();
>  > +    }
>  > +}
>  > +
>  >  static void acpi_ged_initfn(Object *obj)  {
>  >      DeviceState *dev = DEVICE(obj);
>  > @@ -411,6 +457,7 @@ static void acpi_ged_class_init(ObjectClass *class,
>  void *data)
>  >      dc->desc = "ACPI Generic Event Device";
>  >      device_class_set_props(dc, acpi_ged_properties);
>  >      dc->vmsd = &vmstate_acpi_ged;
>  > +    dc->realize = acpi_ged_realize;
>  >
>  >      hc->plug = acpi_ged_device_plug_cb;
>  >      hc->unplug_request = acpi_ged_unplug_request_cb; diff --git
>  > a/include/hw/acpi/generic_event_device.h
>  > b/include/hw/acpi/generic_event_device.h
>  > index ba84ce0214..e091ac2108 100644
>  > --- a/include/hw/acpi/generic_event_device.h
>  > +++ b/include/hw/acpi/generic_event_device.h
>  > @@ -62,6 +62,7 @@
>  >  #include "hw/sysbus.h"
>  >  #include "hw/acpi/memory_hotplug.h"
>  >  #include "hw/acpi/ghes.h"
>  > +#include "hw/acpi/cpu.h"
>  >  #include "qom/object.h"
>  >
>  >  #define ACPI_POWER_BUTTON_DEVICE "PWRB"
>  > @@ -95,6 +96,7 @@ 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;
>  > @@ -106,6 +108,8 @@ 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;
>