Re: [PATCH v8 09/12] piix4: don't reserve hw resources when hotplug is off globally

[Igor Mammedov <imammedo@redhat.com>]

On Fri, 18 Sep 2020 12:06:26 +0530
Ani Sinha <ani@anisinha.ca> wrote:

> On Fri, Sep 18, 2020 at 11:54 AM Igor Mammedov <imammedo@redhat.com> wrote:
> >
> > On Thu, 17 Sep 2020 20:30:41 +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. Follwoing 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.  
> >
> > adding this to commit description doesn't help,
> > 'make check' still fails if we apply patches till this point.
> > which leads to broken bisection.
> >
> > I'm curious, what is not clear in process description at
> > the start of tests/qtest/bios-tables-test.c.
> > You did that for new tests, but so some reason you are avoiding
> > to  follow the same rules with this patch.  
> 
> Yes because I assumed the instructions were for tests only not for
> patches which modify tables. It starts with the lines:
> " How to add or update the tests:"

any change to ACPI tables, that breaks test[s], leads to
updating relevant blobs and you point out in commit message
that it does break q35 tests.

"
 * How to add or update the tests:                                               
 * Contributor:
 * 1. add empty files for new tables, if any, under tests/data/acpi
 * 2. list any changed files in tests/qtest/bios-tables-test-allowed-diff.h      
 * 3. commit the above *before* making changes that affect the tables 
"

Above is pretty clear to me, but if you can improve it
feel free to post a patch clarifying process.

> >
> >  
> > > Signed-off-by: Ani Sinha <ani@anisinha.ca>
> > > ---
> > >  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,  
> >  
>