Re: [PATCH 9/9] piix4: don't reserve hw resources when hotplug is off globally

[Igor Mammedov]

On Fri, 11 Sep 2020 23:37:55 +0530
Ani Sinha <ani@anisinha.ca> wrote:

> When acpi hotplug is turned off for both root pci bus as well as for pci
> bridges, we should not generate the related amls for DSDT table or initialize
> related hw ports or reserve hw resources. This change makes sure all those
> operations are turned off in the case acpi pci hotplug is off globally.

it still leaves around pure PCI hotplug ACPI code:
 
            Method (PCNT, 0, NotSerialized)                                     
 
            {                                                                   
 
            } 
> 
> Signed-off-by: Ani Sinha <ani@anisinha.ca>
> ---
>  hw/acpi/piix4.c      |  6 ++++--
>  hw/i386/acpi-build.c | 10 ++++++++--
>  2 files changed, 12 insertions(+), 4 deletions(-)
> 
> diff --git a/hw/acpi/piix4.c b/hw/acpi/piix4.c
> index e6163bb6ce..b70b1f98af 100644
> --- a/hw/acpi/piix4.c
> +++ b/hw/acpi/piix4.c
> @@ -596,8 +596,10 @@ static void piix4_acpi_system_hot_add_init(MemoryRegion 
> *parent,
>                            "acpi-gpe0", GPE_LEN);
>      memory_region_add_subregion(parent, GPE_BASE, &s->io_gpe);
>  
> -    acpi_pcihp_init(OBJECT(s), &s->acpi_pci_hotplug, bus, parent,
> -                    s->use_acpi_hotplug_bridge);
> +    if (s->use_acpi_hotplug_bridge || s->use_acpi_root_pci_hotplug) {
> +        acpi_pcihp_init(OBJECT(s), &s->acpi_pci_hotplug, bus, parent,
> +                        s->use_acpi_hotplug_bridge);
> +    }
>  
>      s->cpu_hotplug_legacy = true;
>      object_property_add_bool(OBJECT(s), "cpu-hotplug-legacy",
> diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
> index e079b686f5..7e3cf3b57b 100644
> --- a/hw/i386/acpi-build.c
> +++ b/hw/i386/acpi-build.c
> @@ -95,6 +95,7 @@ typedef struct AcpiPmInfo {
>      bool s3_disabled;
>      bool s4_disabled;
>      bool pcihp_bridge_en;
> +    bool pcihp_root_en;
>      uint8_t s4_val;
>      AcpiFadtData fadt;
>      uint16_t cpu_hp_io_base;
> @@ -245,6 +246,9 @@ static void acpi_get_pm_info(MachineState *machine, 
> AcpiPmInfo *pm)
>      pm->pcihp_bridge_en =
>          object_property_get_bool(obj, "acpi-pci-hotplug-with-bridge-support",
>                                   NULL);
> +    pm->pcihp_root_en =
> +        object_property_get_bool(obj, "acpi-root-pci-hotplug",
> +                                 NULL);
>  }
>  
>  static void acpi_get_misc_info(AcpiMiscInfo *info)
> @@ -1504,7 +1508,9 @@ build_dsdt(GArray *table_data, BIOSLinker *linker,
>          build_hpet_aml(dsdt);
>          build_piix4_isa_bridge(dsdt);
>          build_isa_devices_aml(dsdt);
> -        build_piix4_pci_hotplug(dsdt);
> +        if (pm->pcihp_bridge_en || pm->pcihp_root_en) {
> +            build_piix4_pci_hotplug(dsdt);
> +        }
>          build_piix4_pci0_int(dsdt);
>      } else {
>          sb_scope = aml_scope("_SB");
> @@ -1698,7 +1704,7 @@ build_dsdt(GArray *table_data, BIOSLinker *linker,
>      crs_range_set_free(&crs_range_set);
>  
>      /* reserve PCIHP resources */
> -    if (pm->pcihp_io_len) {
> +    if (pm->pcihp_io_len && (pm->pcihp_bridge_en || pm->pcihp_root_en)) {
>          dev = aml_device("PHPR");
>          aml_append(dev, aml_name_decl("_HID", aml_string("PNP0A06")));
>          aml_append(dev,