piix4: don't reserve hw resources when hotplug is off globally

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>
Message-Id: <20200918084111.15339-11-ani@anisinha.ca>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

2 files changed, 22 insertions, 9 deletions

diff --git a/hw/acpi/piix4.c b/hw/acpi/piix4.c
index 832f8fba82..894d357f8c 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 2b17843837..8d14e4667a 100644
--- a/hw/i386/acpi-build.c
+++ b/hw/i386/acpi-build.c
@@ -96,6 +96,7 @@ typedef struct AcpiPmInfo {
     bool s4_disabled;
     bool pcihp_bridge_en;
     bool smi_on_cpuhp;
+    bool pcihp_root_en;
     uint8_t s4_val;
     AcpiFadtData fadt;
     uint16_t cpu_hp_io_base;
@@ -251,6 +252,9 @@ 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)
@@ -456,10 +460,12 @@ 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));
@@ -485,7 +491,10 @@ 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);
 }
 
@@ -1510,7 +1519,9 @@ 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");
@@ -1579,7 +1590,7 @@ 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));
@@ -1731,7 +1742,7 @@ 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,