hw/acpi/ged: Prepare the device to react to PCI hotplug events

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 occurrence 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>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Message-Id: <20250714080639.2525563-29-eric.auger@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

2 files changed, 48 insertions, 1 deletions

diff --git a/hw/acpi/generic_event_device.c b/hw/acpi/generic_event_device.c
index 92b9317..7535d07 100644
--- a/hw/acpi/generic_event_device.c
+++ b/hw/acpi/generic_event_device.c
@@ -12,6 +12,7 @@
 #include "qemu/osdep.h"
 #include "qapi/error.h"
 #include "hw/acpi/acpi.h"
+#include "hw/acpi/pcihp.h"
 #include "hw/acpi/generic_event_device.h"
 #include "hw/pci/pci.h"
 #include "hw/irq.h"
@@ -28,6 +29,7 @@ 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,
 };
 
 /*
@@ -123,6 +125,12 @@ 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[]
@@ -316,6 +324,8 @@ 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);
@@ -427,9 +437,13 @@ static void acpi_ged_realize(DeviceState *dev, Error **errp)
 {
     SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
     AcpiGedState *s = ACPI_GED(dev);
+    AcpiPciHpState *pcihp_state = &s->pcihp_state;
     uint32_t ged_events;
     int i;
 
+    if (pcihp_state->use_acpi_hotplug_bridge) {
+        s->ged_event_bitmap |= ACPI_GED_PCI_HOTPLUG_EVT;
+    }
     ged_events = ctpop32(s->ged_event_bitmap);
 
     for (i = 0; i < ARRAY_SIZE(ged_supported_events) && ged_events; i++) {
@@ -449,6 +463,13 @@ 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),
+                               ACPI_PCIHP_REGION_NAME, ACPI_PCIHP_SIZE);
+            sysbus_init_mmio(sbd, &s->container_pcihp);
+            acpi_pcihp_init(OBJECT(s), &s->pcihp_state,
+                            &s->container_pcihp, 0);
+            qbus_set_hotplug_handler(BUS(s->pcihp_state.root), OBJECT(dev));
         }
         ged_events--;
     }
@@ -490,11 +511,22 @@ static void acpi_ged_initfn(Object *obj)
     sysbus_init_mmio(sbd, &ged_st->regs);
 }
 
+static void ged_reset_hold(Object *obj, ResetType type)
+{
+    AcpiGedState *s = ACPI_GED(obj);
+
+    if (s->pcihp_state.use_acpi_hotplug_bridge) {
+        acpi_pcihp_reset(&s->pcihp_state);
+    }
+}
+
 static void acpi_ged_class_init(ObjectClass *class, const void *data)
 {
     DeviceClass *dc = DEVICE_CLASS(class);
     HotplugHandlerClass *hc = HOTPLUG_HANDLER_CLASS(class);
     AcpiDeviceIfClass *adevc = ACPI_DEVICE_IF_CLASS(class);
+    ResettableClass *rc = RESETTABLE_CLASS(class);
+    AcpiGedClass *gedc = ACPI_GED_CLASS(class);
 
     dc->desc = "ACPI Generic Event Device";
     device_class_set_props(dc, acpi_ged_properties);
@@ -505,6 +537,8 @@ static void acpi_ged_class_init(ObjectClass *class, const void *data)
     hc->plug = acpi_ged_device_plug_cb;
     hc->unplug_request = acpi_ged_unplug_request_cb;
     hc->unplug = acpi_ged_unplug_cb;
+    resettable_class_set_parent_phases(rc, NULL, ged_reset_hold, NULL,
+                                       &gedc->parent_phases);
 
     adevc->ospm_status = acpi_ged_ospm_status;
     adevc->send_event = acpi_ged_send_event;
@@ -516,6 +550,7 @@ static const TypeInfo acpi_ged_info = {
     .instance_size = sizeof(AcpiGedState),
     .instance_init  = acpi_ged_initfn,
     .class_init    = acpi_ged_class_init,
+    .class_size    = sizeof(AcpiGedClass),
     .interfaces = (const InterfaceInfo[]) {
         { TYPE_HOTPLUG_HANDLER },
         { TYPE_ACPI_DEVICE_IF },
diff --git a/include/hw/acpi/generic_event_device.h b/include/hw/acpi/generic_event_device.h
index f5ffa67..d56adaa 100644
--- a/include/hw/acpi/generic_event_device.h
+++ b/include/hw/acpi/generic_event_device.h
@@ -69,7 +69,7 @@
 #define ACPI_POWER_BUTTON_DEVICE "PWRB"
 
 #define TYPE_ACPI_GED "acpi-ged"
-OBJECT_DECLARE_SIMPLE_TYPE(AcpiGedState, ACPI_GED)
+OBJECT_DECLARE_TYPE(AcpiGedState, AcpiGedClass, ACPI_GED)
 
 #define ACPI_GED_EVT_SEL_OFFSET    0x0
 #define ACPI_GED_EVT_SEL_LEN       0x4
@@ -102,6 +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;
@@ -109,6 +110,8 @@ typedef struct GEDState {
     uint32_t     sel;
 } GEDState;
 
+#define ACPI_PCIHP_REGION_NAME "pcihp container"
+
 struct AcpiGedState {
     SysBusDevice parent_obj;
     MemHotplugState memhp_state;
@@ -116,12 +119,21 @@ struct AcpiGedState {
     CPUHotplugState cpuhp_state;
     MemoryRegion container_cpuhp;
     AcpiPciHpState pcihp_state;
+    MemoryRegion container_pcihp;
     GEDState ged_state;
     uint32_t ged_event_bitmap;
     qemu_irq irq;
     AcpiGhesState ghes_state;
 };
 
+typedef struct AcpiGedClass {
+    /* <private> */
+    SysBusDeviceClass parent_class;
+
+    /*< public >*/
+    ResettablePhases parent_phases;
+} AcpiGedClass;
+
 void build_ged_aml(Aml *table, const char* name, HotplugHandler *hotplug_dev,
                    uint32_t ged_irq, AmlRegionSpace rs, hwaddr ged_base);
 void acpi_dsdt_add_power_button(Aml *scope);