ACPI: Add vmgenid blob storage to the build tables

This allows them to be centrally initialized and destroyed

The "AcpiBuildTables.vmgenid" array will be used to construct the
"etc/vmgenid_guid" fw_cfg blob.

Its contents will be linked into fw_cfg after being built on the
pc_machine_done() -> acpi_setup() -> acpi_build() call path, and dropped
without use on the subsequent, guest triggered, acpi_build_update() ->
acpi_build() call path.
Signed-off-by: NBen Warren <ben@skyportsystems.com>
Reviewed-by: NLaszlo Ersek <lersek@redhat.com>
Reviewed-by: NIgor Mammedov <imammedo@redhat.com>
Tested-by: NLaszlo Ersek <lersek@redhat.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

hw/acpi/aml-build.c

@@ -1559,6 +1559,7 @@ void acpi_build_tables_init(AcpiBuildTables *tables)
     tables->rsdp = g_array_new(false, true /* clear */, 1);
     tables->table_data = g_array_new(false, true /* clear */, 1);
     tables->tcpalog = g_array_new(false, true /* clear */, 1);
+    tables->vmgenid = g_array_new(false, true /* clear */, 1);
     tables->linker = bios_linker_loader_init();
 }
 
@@ -1568,6 +1569,7 @@ void acpi_build_tables_cleanup(AcpiBuildTables *tables, bool mfre)
     g_array_free(tables->rsdp, true);
     g_array_free(tables->table_data, true);
     g_array_free(tables->tcpalog, mfre);
+    g_array_free(tables->vmgenid, mfre);
 }
 
 /* Build rsdt table */

include/hw/acpi/aml-build.h

@@ -210,6 +210,7 @@ struct AcpiBuildTables {
     GArray *table_data;
     GArray *rsdp;
     GArray *tcpalog;
+    GArray *vmgenid;
     BIOSLinker *linker;
 } AcpiBuildTables;