Re: [PATCH v9 10/13] piix4: don't reserve hw resources when hotplug is off globally

[Igor Mammedov <imammedo@redhat.com>]

On Fri, 18 Sep 2020 12:53:22 +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 ACPI code 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.
> 
> In this change, we also make sure ACPI code for the PCNT method are only
> added when bsel is enabled for the corresponding pci bus or bridge hotplug
> is turned on.
> 
> As q35 machines do not use bsel for it's pci buses at this point in time, this
> change affects DSDT acpi table for q35 machines as well. Therefore, we will
> also need to commit the updated golden master DSDT table acpi binary blobs as
> well. Following is the list of blobs which needs updating:
> 
>  tests/data/acpi/q35/DSDT
>  tests/data/acpi/q35/DSDT.acpihmat
>  tests/data/acpi/q35/DSDT.bridge
>  tests/data/acpi/q35/DSDT.cphp
>  tests/data/acpi/q35/DSDT.dimmpxm
>  tests/data/acpi/q35/DSDT.ipmibt
>  tests/data/acpi/q35/DSDT.memhp
>  tests/data/acpi/q35/DSDT.mmio64
>  tests/data/acpi/q35/DSDT.numamem
>  tests/data/acpi/q35/DSDT.tis
> 
> These tables are updated in the following commit. Without the updated table
> blobs, the unit tests would fail with this patch.
> 
> Signed-off-by: Ani Sinha <ani@anisinha.ca>

Reviewed-by: Igor Mammedov <imammedo@redhat.com>

> ---
>  hw/acpi/piix4.c      |  6 ++++--
>  hw/i386/acpi-build.c | 25 ++++++++++++++++++-------
>  2 files changed, 22 insertions(+), 9 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..e41bb0992b 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)
> @@ -450,10 +454,12 @@ static void build_append_pci_bus_devices(Aml *parent_scope, PCIBus *bus,
>      }
>  
>      /* Append PCNT method to notify about events on local and child buses.
> -     * Add unconditionally for root since DSDT expects it.
> +     * Add this method for root bus only when hotplug is enabled since DSDT
> +     * expects it.
>       */
> -    method = aml_method("PCNT", 0, AML_NOTSERIALIZED);
> -
> +    if (bsel || pcihp_bridge_en) {
> +        method = aml_method("PCNT", 0, AML_NOTSERIALIZED);
> +    }
>      /* If bus supports hotplug select it and notify about local events */
>      if (bsel) {
>          uint64_t bsel_val = qnum_get_uint(qobject_to(QNum, bsel));
> @@ -479,7 +485,10 @@ static void build_append_pci_bus_devices(Aml *parent_scope, PCIBus *bus,
>              aml_append(method, aml_name("^S%.02X.PCNT", devfn));
>          }
>      }
> -    aml_append(parent_scope, method);
> +
> +    if (bsel || pcihp_bridge_en) {
> +        aml_append(parent_scope, method);
> +    }
>      qobject_unref(bsel);
>  }
>  
> @@ -1504,7 +1513,9 @@ 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");
> @@ -1546,7 +1557,7 @@ build_dsdt(GArray *table_data, BIOSLinker *linker,
>      {
>          aml_append(scope, aml_name_decl("_HID", aml_string("ACPI0006")));
>  
> -        if (misc->is_piix4) {
> +        if (misc->is_piix4 && (pm->pcihp_bridge_en || pm->pcihp_root_en)) {
>              method = aml_method("_E01", 0, AML_NOTSERIALIZED);
>              aml_append(method,
>                  aml_acquire(aml_name("\\_SB.PCI0.BLCK"), 0xFFFF));
> @@ -1698,7 +1709,7 @@ 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,