diff --git a/user/kvmctl.c b/user/kvmctl.c
index 82d1926..e01410c 100644
--- a/user/kvmctl.c
+++ b/user/kvmctl.c
@@ -204,23 +204,26 @@ void kvm_finalize(kvm_context_t kvm)
 
 int kvm_create(kvm_context_t kvm, unsigned long memory, void **vm_mem)
 {
-	unsigned long dosmem = 0xa0000;
-	unsigned long exmem = 0xc0000;
+#define DOSMEM	0xa0000
+#define EXMEM	0xc0000
 	long mmap_size;
 	int fd = kvm->fd;
 	int zfd;
 	int r;
 	struct kvm_memory_region low_memory = {
 		.slot = 3,
-		.memory_size = memory  < dosmem ? memory : dosmem,
+		.memory_size = memory  < DOSMEM ? memory : DOSMEM,
 		.guest_phys_addr = 0,
 	};
 	struct kvm_memory_region extended_memory = {
 		.slot = 0,
-		.memory_size = memory < exmem ? 0 : memory - exmem,
-		.guest_phys_addr = exmem,
+		.memory_size = memory < EXMEM ? 0 : memory - EXMEM,
+		.guest_phys_addr = EXMEM,
 	};
 
+#undef DOSMEM
+#undef EXMEM
+
 	kvm->vcpu_fd[0] = -1;
 
 	fd = ioctl(fd, KVM_CREATE_VM, 0);