diff --git a/include/kvm/kvm.h b/include/kvm/kvm.h
index 4eeed87..7d90d35 100644
--- a/include/kvm/kvm.h
+++ b/include/kvm/kvm.h
@@ -43,7 +43,7 @@ struct kvm {
 	int                     nr_disks;
 };
 
-struct kvm *kvm__init(const char *kvm_dev, unsigned long ram_size);
+struct kvm *kvm__init(const char *kvm_dev, u64 ram_size);
 int kvm__max_cpus(struct kvm *kvm);
 void kvm__init_ram(struct kvm *kvm);
 void kvm__delete(struct kvm *kvm);
diff --git a/kvm-run.c b/kvm-run.c
index f121a2b..6ad55aa 100644
--- a/kvm-run.c
+++ b/kvm-run.c
@@ -324,8 +324,8 @@ static u64 host_ram_size(void)
 
 static u64 get_ram_size(int nr_cpus)
 {
-	long available;
-	long ram_size;
+	u64 available;
+	u64 ram_size;
 
 	ram_size	= 64 * (nr_cpus + 3);
 
diff --git a/kvm.c b/kvm.c
index 2c56a79..8874cf9 100644
--- a/kvm.c
+++ b/kvm.c
@@ -236,7 +236,7 @@ int kvm__max_cpus(struct kvm *kvm)
 	return ret;
 }
 
-struct kvm *kvm__init(const char *kvm_dev, unsigned long ram_size)
+struct kvm *kvm__init(const char *kvm_dev, u64 ram_size)
 {
 	struct kvm_pit_config pit_config = { .flags = 0, };
 	struct kvm *kvm;