diff --git a/hw/acpi/aml-build.c b/hw/acpi/aml-build.c
index 363e83b851..501a98847e 100644
--- a/hw/acpi/aml-build.c
+++ b/hw/acpi/aml-build.c
@@ -1240,6 +1240,14 @@ Aml *aml_unicode(const char *str)
     return var;
 }
 
+/* ACPI 1.0b: 16.2.5.4 Type 2 Opcodes Encoding: DefDerefOf */
+Aml *aml_derefof(Aml *arg)
+{
+    Aml *var = aml_opcode(0x83 /* DerefOfOp */);
+    aml_append(var, arg);
+    return var;
+}
+
 void
 build_header(GArray *linker, GArray *table_data,
              AcpiTableHeader *h, const char *sig, int len, uint8_t rev,
diff --git a/include/hw/acpi/aml-build.h b/include/hw/acpi/aml-build.h
index 9fa61a3f6e..89fb15e8e4 100644
--- a/include/hw/acpi/aml-build.h
+++ b/include/hw/acpi/aml-build.h
@@ -307,6 +307,7 @@ Aml *aml_create_dword_field(Aml *srcbuf, Aml *index, const char *name);
 Aml *aml_varpackage(uint32_t num_elements);
 Aml *aml_touuid(const char *uuid);
 Aml *aml_unicode(const char *str);
+Aml *aml_derefof(Aml *arg);
 
 void
 build_header(GArray *linker, GArray *table_data,