diff --git a/builtin-run.c b/builtin-run.c
index 4a6ff1a..117a9de 100644
--- a/builtin-run.c
+++ b/builtin-run.c
@@ -57,7 +57,6 @@ struct kvm *kvm;
 struct kvm_cpu **kvm_cpus;
 __thread struct kvm_cpu *current_kvm_cpu;
 
-extern bool mmio_debug;
 static int  kvm_run_wrapper;
 extern int  active_console;
 extern int  debug_iodelay;
@@ -472,7 +471,7 @@ static int shmem_parser(const struct option *opt, const char *arg, int unset)
 			"Enable single stepping"),			\
 	OPT_BOOLEAN('\0', "debug-ioport", &(cfg)->ioport_debug,		\
 			"Enable ioport debugging"),			\
-	OPT_BOOLEAN('\0', "debug-mmio", &mmio_debug,			\
+	OPT_BOOLEAN('\0', "debug-mmio", &(cfg)->mmio_debug,		\
 			"Enable MMIO debugging"),			\
 	OPT_INTEGER('\0', "debug-iodelay", &debug_iodelay,		\
 			"Delay IO by millisecond"),			\
diff --git a/include/kvm/kvm-config.h b/include/kvm/kvm-config.h
index f45edb0..e3edf29 100644
--- a/include/kvm/kvm-config.h
+++ b/include/kvm/kvm-config.h
@@ -49,6 +49,7 @@ struct kvm_config {
 	bool no_net;
 	bool no_dhcp;
 	bool ioport_debug;
+	bool mmio_debug;
 };
 
 #endif
diff --git a/mmio.c b/mmio.c
index dd28ef3..38ce117 100644
--- a/mmio.c
+++ b/mmio.c
@@ -21,7 +21,6 @@ struct mmio_mapping {
 };
 
 static struct rb_root mmio_tree = RB_ROOT;
-bool mmio_debug = false;
 
 static struct mmio_mapping *mmio_search(struct rb_root *root, u64 addr, u64 len)
 {
@@ -130,7 +129,7 @@ bool kvm__emulate_mmio(struct kvm *kvm, u64 phys_addr, u8 *data, u32 len, u8 is_
 	if (mmio)
 		mmio->mmio_fn(phys_addr, data, len, is_write, mmio->ptr);
 	else {
-		if (mmio_debug)
+		if (kvm->cfg.mmio_debug)
 			fprintf(stderr, "Warning: Ignoring MMIO %s at %016llx (length %u)\n",
 				to_direction(is_write), phys_addr, len);
 	}