diff --git a/src/northbridge/intel/gm45/Kconfig b/src/northbridge/intel/gm45/Kconfig
index 4637a22..256b088 100644
--- a/src/northbridge/intel/gm45/Kconfig
+++ b/src/northbridge/intel/gm45/Kconfig
@@ -29,6 +29,10 @@
 config MMCONF_BASE_ADDRESS
 	default 0xf0000000
 
+config MMCONF_BUS_NUMBER
+	int
+	default 64
+
 config SMM_RESERVED_SIZE
 	hex
 	default 0x100000