x86: pci: acpi: consolidate PCI slots creation

No functional changes nor AML bytecode changes.
Consolidate code that generates empty and populated slot
descriptors. Besides eliminating duplication,
it helps consolidate conditions for generating
parts of Device{} desriptor in one place, which makes
code more compact and easier to read.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Message-Id: <20220701133515.137890-18-imammedo@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

hw/i386/acpi-build.c

@@ -427,60 +427,53 @@ static void build_append_pci_bus_devices(Aml *parent_scope, PCIBus *bus,
         int func = PCI_FUNC(devfn);
         /* ACPI spec: 1.0b: Table 6-2 _ADR Object Bus Types, PCI type */
         int adr = slot << 16 | func;
-        bool hotplug_enabled_dev;
-        bool bridge_in_acpi;
-        bool cold_plugged_bridge;
+        bool hotpluggbale_slot = false;
+        bool bridge_in_acpi = false;
+        bool cold_plugged_bridge = false;
+        bool is_vga = false;
+
+        if (pdev) {
+            pc = PCI_DEVICE_GET_CLASS(pdev);
+            dc = DEVICE_GET_CLASS(pdev);
+
+            if (pc->class_id == PCI_CLASS_BRIDGE_ISA) {
+                continue;
+            }
+
+            is_vga = pc->class_id == PCI_CLASS_DISPLAY_VGA;
 
-        if (!pdev) {
             /*
-             * add hotplug slots for non present devices.
+             * Cold plugged bridges aren't themselves hot-pluggable.
+             * Hotplugged bridges *are* hot-pluggable.
+             */
+            cold_plugged_bridge = pc->is_bridge && !DEVICE(pdev)->hotplugged;
+            bridge_in_acpi =  cold_plugged_bridge && pcihp_bridge_en;
+
+            hotpluggbale_slot = bsel && dc->hotpluggable &&
+                                !cold_plugged_bridge;
+
+            /*
+             * allow describing coldplugged bridges in ACPI even if they are not
+             * on function 0, as they are not unpluggable, for all other devices
+             * generate description only for function 0 per slot
+             */
+            if (func && !bridge_in_acpi) {
+                continue;
+            }
+        } else {
+            /*
              * hotplug is supported only for non-multifunction device
              * so generate device description only for function 0
              */
             if (bsel && !func) {
                 if (pci_bus_is_express(bus) && slot > 0) {
                     break;
                 }
-                dev = aml_device("S%.02X", devfn);
-                aml_append(dev, aml_name_decl("_ADR", aml_int(adr)));
-                aml_append(dev, aml_name_decl("ASUN", aml_int(slot)));
-                aml_append(dev, aml_pci_device_dsm());
-                aml_append(dev, aml_name_decl("_SUN", aml_int(slot)));
-                method = aml_method("_EJ0", 1, AML_NOTSERIALIZED);
-                aml_append(method,
-                    aml_call2("PCEJ", aml_name("BSEL"), aml_name("_SUN"))
-                );
-                aml_append(dev, method);
-                aml_append(parent_scope, dev);
-
-                build_append_pcihp_notify_entry(notify_method, slot);
+                /* mark it as empty hotpluggable slot */
+                hotpluggbale_slot = true;
+            } else {
+                continue;
             }
-            continue;
-        }
-
-        pc = PCI_DEVICE_GET_CLASS(pdev);
-        dc = DEVICE_GET_CLASS(pdev);
-
-        /*
-         * Cold plugged bridges aren't themselves hot-pluggable.
-         * Hotplugged bridges *are* hot-pluggable.
-         */
-        cold_plugged_bridge = pc->is_bridge && !DEVICE(pdev)->hotplugged;
-        bridge_in_acpi =  cold_plugged_bridge && pcihp_bridge_en;
-
-        hotplug_enabled_dev = bsel && dc->hotpluggable && !cold_plugged_bridge;
-
-        if (pc->class_id == PCI_CLASS_BRIDGE_ISA) {
-            continue;
-        }
-
-        /*
-         * allow describing coldplugged bridges in ACPI even if they are not
-         * on function 0, as they are not unpluggable, for all other devices
-         * generate description only for function 0 per slot
-         */
-        if (func && !bridge_in_acpi) {
-            continue;
         }
 
         /* start to compose PCI device descriptor */
@@ -496,7 +489,7 @@ static void build_append_pci_bus_devices(Aml *parent_scope, PCIBus *bus,
             aml_append(dev, aml_pci_device_dsm());
         }
 
-        if (pc->class_id == PCI_CLASS_DISPLAY_VGA) {
+        if (is_vga) {
             /* add VGA specific AML methods */
             int s3d;
 
@@ -517,19 +510,10 @@ static void build_append_pci_bus_devices(Aml *parent_scope, PCIBus *bus,
             method = aml_method("_S3D", 0, AML_NOTSERIALIZED);
             aml_append(method, aml_return(aml_int(s3d)));
             aml_append(dev, method);
-        } else if (hotplug_enabled_dev) {
-            aml_append(dev, aml_name_decl("_SUN", aml_int(slot)));
-            /* add _EJ0 to make slot hotpluggable  */
-            method = aml_method("_EJ0", 1, AML_NOTSERIALIZED);
-            aml_append(method,
-                aml_call2("PCEJ", aml_name("BSEL"), aml_name("_SUN"))
-            );
-            aml_append(dev, method);
+        }
 
-            if (bsel) {
-                build_append_pcihp_notify_entry(notify_method, slot);
-            }
-        } else if (bridge_in_acpi) {
+        bridge_in_acpi =  cold_plugged_bridge && pcihp_bridge_en;
+        if (bridge_in_acpi) {
             /*
              * device is coldplugged bridge,
              * add child device descriptions into its scope
@@ -538,6 +522,19 @@ static void build_append_pci_bus_devices(Aml *parent_scope, PCIBus *bus,
 
             build_append_pci_bus_devices(dev, sec_bus, pcihp_bridge_en);
         }
+
+        if (hotpluggbale_slot) {
+            aml_append(dev, aml_name_decl("_SUN", aml_int(slot)));
+            /* add _EJ0 to make slot hotpluggable  */
+            method = aml_method("_EJ0", 1, AML_NOTSERIALIZED);
+            aml_append(method,
+                aml_call2("PCEJ", aml_name("BSEL"), aml_name("_SUN"))
+            );
+            aml_append(dev, method);
+
+            build_append_pcihp_notify_entry(notify_method, slot);
+        }
+
         /* device descriptor has been composed, add it into parent context */
         aml_append(parent_scope, dev);
     }