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

[Eric Auger]

Hi Gustavo,

On 5/14/25 6:20 PM, Gustavo Romero wrote:
> Hi Eric,
>
> On 4/28/25 07:25, Eric Auger wrote:
>> 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
>
> nit: occurrence -^
>
>
>> 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
>
> nit: period missing ^
>
>
>> 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
>
> This is wrong, no? It should be 0x18, i.e. 24 bytes or 6 registers of
> 4 bytes.
yes this is wrong. you are totally right. I am about to send a new
version where this is fixed, sorry. I noticed that when testing the acpi
index modality which did not work with the RFC series.

Now I am using ACPI_PCIHP_SIZE.

Cheers

Eric
>
> I think it's better to move the defines in pcihp.c into pcihp.h and
> use them to define ACPI_PCI_HOTPLUG_REG_LEN so the values are
> consistent, like:
>
> diff --git a/hw/acpi/pcihp.c b/hw/acpi/pcihp.c
> index 82b8ea2811..3ab8b9de94 100644
> --- a/hw/acpi/pcihp.c
> +++ b/hw/acpi/pcihp.c
> @@ -44,14 +44,6 @@
>  #include "qobject/qnum.h"
>  #include "trace.h"
>  
> -#define ACPI_PCIHP_SIZE 0x0018
> -#define PCI_UP_BASE 0x0000
> -#define PCI_DOWN_BASE 0x0004
> -#define PCI_EJ_BASE 0x0008
> -#define PCI_RMV_BASE 0x000c
> -#define PCI_SEL_BASE 0x0010
> -#define PCI_AIDX_BASE 0x0014
> -
>  typedef struct AcpiPciHpFind {
>      int bsel;
>      PCIBus *bus;
> diff --git a/include/hw/acpi/pcihp.h b/include/hw/acpi/pcihp.h
> index abb6e14549..6b79adcaef 100644
> --- a/include/hw/acpi/pcihp.h
> +++ b/include/hw/acpi/pcihp.h
> @@ -38,7 +38,15 @@
>  #define ACPI_PCIHP_SEJ_BASE 0x8
>  #define ACPI_PCIHP_BNMR_BASE 0x10
>  
> -#define ACPI_PCI_HOTPLUG_REG_LEN 0x14
> +#define ACPI_PCIHP_SIZE 0x0018
> +#define PCI_UP_BASE 0x0000
> +#define PCI_DOWN_BASE 0x0004
> +#define PCI_EJ_BASE 0x0008
> +#define PCI_RMV_BASE 0x000c
> +#define PCI_SEL_BASE 0x0010
> +#define PCI_AIDX_BASE 0x0014
> +
> +#define ACPI_PCI_HOTPLUG_REG_LEN ACPI_PCIHP_SIZE
>  
>  typedef struct AcpiPciHpPciStatus {
>      uint32_t up;
>
>
> or even use only one of them (ACPI_PCI_HOTPLUG_REG_LEN,
> ACPI_PCIHP_SIZE, or
> another new name that would fit better in both contexts).
>
>
> Cheers,
> Gustavo
>
>> +
>>   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--;
>>       }
>