[RFC 18/24] hw/acpi/ged: Prepare the device to react to PCI hotplug events

[Eric Auger <eric.auger@redhat.com>]

QEMU will notify the OS about PCI hotplug/hotunplug events through
GED interrupts. Let the GED device handle a new PCI hotplug event.
On its occurence it calls the \\_SB.PCI0.PCNT method with the BLCK
mutex held.

The GED device uses a dedicated MMIO region that will be mapped
by the machine code.

At this point the GED still does not support PCI device hotplug in
its TYPE_HOTPLUG_HANDLER implementation. This will come in a
subsequent patch

Signed-off-by: Eric Auger <eric.auger@redhat.com>
---
 include/hw/acpi/generic_event_device.h |  5 +++++
 include/hw/acpi/pcihp.h                |  2 ++
 hw/acpi/generic_event_device.c         | 14 ++++++++++++++
 3 files changed, 21 insertions(+)

diff --git a/include/hw/acpi/generic_event_device.h b/include/hw/acpi/generic_event_device.h
index d2dac87b4a..28be6c0582 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 "hw/acpi/cpu.h"
+#include "hw/acpi/pcihp.h"
 #include "qom/object.h"
 
 #define ACPI_POWER_BUTTON_DEVICE "PWRB"
@@ -101,6 +102,7 @@ OBJECT_DECLARE_SIMPLE_TYPE(AcpiGedState, ACPI_GED)
 #define ACPI_GED_PWR_DOWN_EVT      0x2
 #define ACPI_GED_NVDIMM_HOTPLUG_EVT 0x4
 #define ACPI_GED_CPU_HOTPLUG_EVT    0x8
+#define ACPI_GED_PCI_HOTPLUG_EVT    0x10
 
 typedef struct GEDState {
     MemoryRegion evt;
@@ -114,6 +116,9 @@ struct AcpiGedState {
     MemoryRegion container_memhp;
     CPUHotplugState cpuhp_state;
     MemoryRegion container_cpuhp;
+    AcpiPciHpState pcihp_state;
+    MemoryRegion container_pcihp;
+
     GEDState ged_state;
     uint32_t ged_event_bitmap;
     qemu_irq irq;
diff --git a/include/hw/acpi/pcihp.h b/include/hw/acpi/pcihp.h
index 451ef74284..abb6e14549 100644
--- a/include/hw/acpi/pcihp.h
+++ b/include/hw/acpi/pcihp.h
@@ -38,6 +38,8 @@
 #define ACPI_PCIHP_SEJ_BASE 0x8
 #define ACPI_PCIHP_BNMR_BASE 0x10
 
+#define ACPI_PCI_HOTPLUG_REG_LEN 0x14
+
 typedef struct AcpiPciHpPciStatus {
     uint32_t up;
     uint32_t down;
diff --git a/hw/acpi/generic_event_device.c b/hw/acpi/generic_event_device.c
index 7b2d582fff..0fd8baba97 100644
--- a/hw/acpi/generic_event_device.c
+++ b/hw/acpi/generic_event_device.c
@@ -26,6 +26,7 @@ static const uint32_t ged_supported_events[] = {
     ACPI_GED_PWR_DOWN_EVT,
     ACPI_GED_NVDIMM_HOTPLUG_EVT,
     ACPI_GED_CPU_HOTPLUG_EVT,
+    ACPI_GED_PCI_HOTPLUG_EVT,
 };
 
 /*
@@ -121,6 +122,12 @@ 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_PCI_HOTPLUG_EVT:
+                aml_append(if_ctx,
+                           aml_acquire(aml_name("\\_SB.PCI0.BLCK"), 0xFFFF));
+                aml_append(if_ctx, aml_call0("\\_SB.PCI0.PCNT"));
+                aml_append(if_ctx, aml_release(aml_name("\\_SB.PCI0.BLCK")));
+                break;
             default:
                 /*
                  * Please make sure all the events in ged_supported_events[]
@@ -299,6 +306,8 @@ static void acpi_ged_send_event(AcpiDeviceIf *adev, AcpiEventStatusBits ev)
         sel = ACPI_GED_NVDIMM_HOTPLUG_EVT;
     } else if (ev & ACPI_CPU_HOTPLUG_STATUS) {
         sel = ACPI_GED_CPU_HOTPLUG_EVT;
+    } else if (ev & ACPI_PCI_HOTPLUG_STATUS) {
+        sel = ACPI_GED_PCI_HOTPLUG_EVT;
     } else {
         /* Unknown event. Return without generating interrupt. */
         warn_report("GED: Unsupported event %d. No irq injected", ev);
@@ -428,6 +437,11 @@ static void acpi_ged_realize(DeviceState *dev, Error **errp)
             cpu_hotplug_hw_init(&s->container_cpuhp, OBJECT(dev),
                                 &s->cpuhp_state, 0);
             break;
+        case ACPI_GED_PCI_HOTPLUG_EVT:
+            memory_region_init(&s->container_pcihp, OBJECT(dev),
+                                "pcihp container",
+                                ACPI_PCI_HOTPLUG_REG_LEN);
+            sysbus_init_mmio(sbd, &s->container_pcihp);
         }
         ged_events--;
     }
-- 
2.49.0