Re: [PATCH v3 17/29] hw/arm/virt-acpi-build: Modify the DSDT ACPI table to enable ACPI PCI hotplug

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

On 6/20/25 2:38 PM, Igor Mammedov wrote:
> On Fri, 20 Jun 2025 10:35:38 +0100
> Jonathan Cameron <Jonathan.Cameron@huawei.com> wrote:
>
>> On Mon, 16 Jun 2025 11:46:46 +0200
>> Eric Auger <eric.auger@redhat.com> wrote:
>>
>>> Modify the DSDT ACPI table to enable ACPI PCI hotplug.
>>>
>>> Signed-off-by: Eric Auger <eric.auger@redhat.com>
>>>
>>> ---
>>> v2 -> v3:
>>> - use ACPI_PCIHP_SIZE instead of 0x1000 (Igor)
>>> - use cihp_state->use_acpi_hotplug_bridge  
>> pcihp_state
>>
>> Takes a bit of searching to find the various bits of the
>> same support on x86 but this seems to match up.
>> Exactly when things are built does vary but not I think
>> in a way that matters.  e.g. I think on x86 the
>> EDSM stuff is built whether or not we have pcihp enabled
>> whereas here you've made it conditional on using acpi
>> hp.  Perhaps a tiny bit more description on that would be
>> useful if you do a v4?
> edsm should be built regardless of pcihp
> (well intention was there, whether I messed it up or not I don't know)
>
> idea is that non hotplug ports can have a static acpi-index,
> so it doesn't depend on pcihp.

OK I can make it unconditional. The drawback is that it will oblige to
rebuild reference blobs again with native pci hotplug.

Eric
>
>> Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
>>
>>
>>> ---
>>>  include/hw/acpi/pcihp.h  |  2 ++
>>>  include/hw/arm/virt.h    |  1 +
>>>  hw/arm/virt-acpi-build.c | 22 ++++++++++++++++++++++
>>>  hw/arm/virt.c            |  2 ++
>>>  hw/arm/Kconfig           |  2 ++
>>>  5 files changed, 29 insertions(+)
>>>
>>> diff --git a/include/hw/acpi/pcihp.h b/include/hw/acpi/pcihp.h
>>> index 5506a58862..9ff548650b 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_PCIHP_SIZE 0x0018
>>> +
>>>  typedef struct AcpiPciHpPciStatus {
>>>      uint32_t up;
>>>      uint32_t down;
>>> diff --git a/include/hw/arm/virt.h b/include/hw/arm/virt.h
>>> index 9a1b0f53d2..0ed2e6b732 100644
>>> --- a/include/hw/arm/virt.h
>>> +++ b/include/hw/arm/virt.h
>>> @@ -79,6 +79,7 @@ enum {
>>>      VIRT_ACPI_GED,
>>>      VIRT_NVDIMM_ACPI,
>>>      VIRT_PVTIME,
>>> +    VIRT_ACPI_PCIHP,
>>>      VIRT_LOWMEMMAP_LAST,
>>>  };
>>>  
>>> diff --git a/hw/arm/virt-acpi-build.c b/hw/arm/virt-acpi-build.c
>>> index d7547c8d3b..a2e58288f8 100644
>>> --- a/hw/arm/virt-acpi-build.c
>>> +++ b/hw/arm/virt-acpi-build.c
>>> @@ -34,6 +34,7 @@
>>>  #include "hw/core/cpu.h"
>>>  #include "hw/acpi/acpi-defs.h"
>>>  #include "hw/acpi/acpi.h"
>>> +#include "hw/acpi/pcihp.h"
>>>  #include "hw/nvram/fw_cfg_acpi.h"
>>>  #include "hw/acpi/bios-linker-loader.h"
>>>  #include "hw/acpi/aml-build.h"
>>> @@ -809,6 +810,8 @@ static void
>>>  build_dsdt(GArray *table_data, BIOSLinker *linker, VirtMachineState *vms)
>>>  {
>>>      VirtMachineClass *vmc = VIRT_MACHINE_GET_CLASS(vms);
>>> +    AcpiGedState *acpi_ged_state = ACPI_GED(vms->acpi_dev);
>>> +    AcpiPciHpState *pcihp_state = &acpi_ged_state->pcihp_state;
>>>      Aml *scope, *dsdt;
>>>      MachineState *ms = MACHINE(vms);
>>>      const MemMapEntry *memmap = vms->memmap;
>>> @@ -868,6 +871,25 @@ build_dsdt(GArray *table_data, BIOSLinker *linker, VirtMachineState *vms)
>>>  
>>>      aml_append(dsdt, scope);
>>>  
>>> +    if (pcihp_state->use_acpi_hotplug_bridge) {
>>> +        Aml *pci0_scope = aml_scope("\\_SB.PCI0");
>>> +
>>> +        aml_append(pci0_scope, aml_pci_edsm());
>>> +        build_acpi_pci_hotplug(dsdt, AML_SYSTEM_MEMORY,
>>> +                               memmap[VIRT_ACPI_PCIHP].base);
>>> +        build_append_pcihp_resources(pci0_scope,
>>> +                                     memmap[VIRT_ACPI_PCIHP].base,
>>> +                                     memmap[VIRT_ACPI_PCIHP].size);
>>> +
>>> +        /* Scan all PCI buses. Generate tables to support hotplug. */
>>> +        build_append_pci_bus_devices(pci0_scope, vms->bus);
>>> +        if (object_property_find(OBJECT(vms->bus), ACPI_PCIHP_PROP_BSEL)) {
>>> +            build_append_pcihp_slots(pci0_scope, vms->bus);
>>> +        }
>>> +        build_append_notification_callback(pci0_scope, vms->bus);
>>> +        aml_append(dsdt, pci0_scope);
>>> +    }
>>> +
>>>      /* copy AML table into ACPI tables blob */
>>>      g_array_append_vals(table_data, dsdt->buf->data, dsdt->buf->len);
>>>