Re: [PATCH v2 17/25] hw/arm/virt-acpi-build: Modify the DSDT ACPI table to enable ACPI PCI hotplug

[Igor Mammedov <imammedo@redhat.com>]

On Tue, 27 May 2025 09:40:19 +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>
> ---
>  include/hw/arm/virt.h    |  1 +
>  hw/arm/virt-acpi-build.c | 21 +++++++++++++++++++++
>  hw/arm/virt.c            |  1 +
>  hw/arm/Kconfig           |  2 ++
>  4 files changed, 25 insertions(+)
> 
> diff --git a/include/hw/arm/virt.h b/include/hw/arm/virt.h
> index 10ea581f06..1b2e2e1284 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 be5e00a56e..9d88ffc318 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"
> @@ -836,6 +837,7 @@ build_dsdt(GArray *table_data, BIOSLinker *linker, VirtMachineState *vms)
>                           (irqmap[VIRT_MMIO] + ARM_SPI_BASE),
>                           0, NUM_VIRTIO_TRANSPORTS);
>      acpi_dsdt_add_pci(scope, memmap, irqmap[VIRT_PCIE] + ARM_SPI_BASE, vms);
> +
>      if (vms->acpi_dev) {
>          build_ged_aml(scope, "\\_SB."GED_DEVICE,
>                        HOTPLUG_HANDLER(vms->acpi_dev),
> @@ -864,6 +866,25 @@ build_dsdt(GArray *table_data, BIOSLinker *linker, VirtMachineState *vms)
>  
>      aml_append(dsdt, scope);
>  
> +    if (vms->acpi_pcihp) {
> +        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);
>  
> diff --git a/hw/arm/virt.c b/hw/arm/virt.c
> index a0deeaf2b3..4aa40c8e8b 100644
> --- a/hw/arm/virt.c
> +++ b/hw/arm/virt.c
> @@ -183,6 +183,7 @@ static const MemMapEntry base_memmap[] = {
>      [VIRT_NVDIMM_ACPI] =        { 0x09090000, NVDIMM_ACPI_IO_LEN},
>      [VIRT_PVTIME] =             { 0x090a0000, 0x00010000 },
>      [VIRT_SECURE_GPIO] =        { 0x090b0000, 0x00001000 },
> +    [VIRT_ACPI_PCIHP] =         { 0x090c0000, 0x00001000 },
                                                  ^^^^^
why not use actual len define here?
                                             
>      [VIRT_MMIO] =               { 0x0a000000, 0x00000200 },
>      /* ...repeating for a total of NUM_VIRTIO_TRANSPORTS, each of that size */
>      [VIRT_PLATFORM_BUS] =       { 0x0c000000, 0x02000000 },
> diff --git a/hw/arm/Kconfig b/hw/arm/Kconfig
> index a55b44d7bd..572b4dabd5 100644
> --- a/hw/arm/Kconfig
> +++ b/hw/arm/Kconfig
> @@ -34,6 +34,8 @@ config ARM_VIRT
>      select ACPI_HW_REDUCED
>      select ACPI_APEI
>      select ACPI_VIOT
> +    select ACPI_PCIHP
> +    select ACPI_PCI_BRIDGE
>      select VIRTIO_MEM_SUPPORTED
>      select ACPI_CXL
>      select ACPI_HMAT