hw/i386: expose a "smbios-entry-point-type" PC machine property

The i440fx and Q35 machine types are both hardcoded to use the
legacy SMBIOS 2.1 (32-bit) entry point. This is a sensible
conservative choice because SeaBIOS only supports SMBIOS 2.1

EDK2, however, can also support SMBIOS 3.0 (64-bit) entry points,
and QEMU already uses this on the ARM virt machine type.

This adds a property to allow the choice of SMBIOS entry point
versions For example to opt in to 64-bit SMBIOS entry point:

   $QEMU -machine q35,smbios-entry-point-type=64

Based on a patch submitted by Daniel Berrangé.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Message-Id: <20211026151100.1691925-4-ehabkost@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>

hw/i386/pc.c

@@ -77,6 +77,7 @@
 #include "hw/mem/nvdimm.h"
 #include "qapi/error.h"
 #include "qapi/qapi-visit-common.h"
+#include "qapi/qapi-visit-machine.h"
 #include "qapi/visitor.h"
 #include "hw/core/cpu.h"
 #include "hw/usb.h"
@@ -1524,6 +1525,23 @@ static void pc_machine_set_default_bus_bypass_iommu(Object *obj, bool value,
     pcms->default_bus_bypass_iommu = value;
 }
 
+static void pc_machine_get_smbios_ep(Object *obj, Visitor *v, const char *name,
+                                     void *opaque, Error **errp)
+{
+    PCMachineState *pcms = PC_MACHINE(obj);
+    SmbiosEntryPointType smbios_entry_point_type = pcms->smbios_entry_point_type;
+
+    visit_type_SmbiosEntryPointType(v, name, &smbios_entry_point_type, errp);
+}
+
+static void pc_machine_set_smbios_ep(Object *obj, Visitor *v, const char *name,
+                                     void *opaque, Error **errp)
+{
+    PCMachineState *pcms = PC_MACHINE(obj);
+
+    visit_type_SmbiosEntryPointType(v, name, &pcms->smbios_entry_point_type, errp);
+}
+
 static void pc_machine_get_max_ram_below_4g(Object *obj, Visitor *v,
                                             const char *name, void *opaque,
                                             Error **errp)
@@ -1614,6 +1632,8 @@ static void pc_machine_initfn(Object *obj)
     pcms->vmport = ON_OFF_AUTO_OFF;
 #endif /* CONFIG_VMPORT */
     pcms->max_ram_below_4g = 0; /* use default */
+    pcms->smbios_entry_point_type = SMBIOS_ENTRY_POINT_TYPE_32;
+
     /* acpi build is enabled by default if machine supports it */
     pcms->acpi_build_enabled = PC_MACHINE_GET_CLASS(pcms)->has_acpi_build;
     pcms->smbus_enabled = true;
@@ -1756,6 +1776,12 @@ static void pc_machine_class_init(ObjectClass *oc, void *data)
         NULL, NULL);
     object_class_property_set_description(oc, PC_MACHINE_MAX_FW_SIZE,
         "Maximum combined firmware size");
+
+    object_class_property_add(oc, PC_MACHINE_SMBIOS_EP, "str",
+        pc_machine_get_smbios_ep, pc_machine_set_smbios_ep,
+        NULL, NULL);
+    object_class_property_set_description(oc, PC_MACHINE_SMBIOS_EP,
+        "SMBIOS Entry Point type [32, 64]");
 }
 
 static const TypeInfo pc_machine_info = {

hw/i386/pc_piix.c

@@ -177,7 +177,7 @@ static void pc_init1(MachineState *machine,
         smbios_set_defaults("QEMU", "Standard PC (i440FX + PIIX, 1996)",
                             mc->name, pcmc->smbios_legacy_mode,
                             pcmc->smbios_uuid_encoded,
-                            SMBIOS_ENTRY_POINT_TYPE_32);
+                            pcms->smbios_entry_point_type);
     }
 
     /* allocate ram and load rom/bios */

hw/i386/pc_q35.c

@@ -200,7 +200,7 @@ static void pc_q35_init(MachineState *machine)
         smbios_set_defaults("QEMU", "Standard PC (Q35 + ICH9, 2009)",
                             mc->name, pcmc->smbios_legacy_mode,
                             pcmc->smbios_uuid_encoded,
-                            SMBIOS_ENTRY_POINT_TYPE_32);
+                            pcms->smbios_entry_point_type);
     }
 
     /* allocate ram and load rom/bios */

include/hw/i386/pc.h

@@ -13,6 +13,7 @@
 #include "hw/hotplug.h"
 #include "qom/object.h"
 #include "hw/i386/sgx-epc.h"
+#include "hw/firmware/smbios.h"
 
 #define HPET_INTCAP "hpet-intcap"
 
@@ -40,6 +41,7 @@ typedef struct PCMachineState {
     /* Configuration options: */
     uint64_t max_ram_below_4g;
     OnOffAuto vmport;
+    SmbiosEntryPointType smbios_entry_point_type;
 
     bool acpi_build_enabled;
     bool smbus_enabled;
@@ -63,6 +65,8 @@ typedef struct PCMachineState {
 #define PC_MACHINE_SATA             "sata"
 #define PC_MACHINE_PIT              "pit"
 #define PC_MACHINE_MAX_FW_SIZE      "max-fw-size"
+#define PC_MACHINE_SMBIOS_EP        "smbios-entry-point-type"
+
 /**
  * PCMachineClass:
  *