diff --git a/tools/testing/selftests/kvm/s390x/memop.c b/tools/testing/selftests/kvm/s390x/memop.c
index 69869c7e2ab1..286185a59238 100644
--- a/tools/testing/selftests/kvm/s390x/memop.c
+++ b/tools/testing/selftests/kvm/s390x/memop.c
@@ -48,6 +48,8 @@ struct mop_desc {
 	uint8_t key;
 };
 
+const uint8_t NO_KEY = 0xff;
+
 static struct kvm_s390_mem_op ksmo_from_desc(const struct mop_desc *desc)
 {
 	struct kvm_s390_mem_op ksmo = {
@@ -85,7 +87,7 @@ static struct kvm_s390_mem_op ksmo_from_desc(const struct mop_desc *desc)
 		ksmo.flags |= KVM_S390_MEMOP_F_INJECT_EXCEPTION;
 	if (desc->_set_flags)
 		ksmo.flags = desc->set_flags;
-	if (desc->f_key) {
+	if (desc->f_key && desc->key != NO_KEY) {
 		ksmo.flags |= KVM_S390_MEMOP_F_SKEY_PROTECTION;
 		ksmo.key = desc->key;
 	}
@@ -268,34 +270,28 @@ static void prepare_mem12(void)
 #define ASSERT_MEM_EQ(p1, p2, size) \
 	TEST_ASSERT(!memcmp(p1, p2, size), "Memory contents do not match!")
 
-#define DEFAULT_WRITE_READ(copy_cpu, mop_cpu, mop_target_p, size, ...)		\
-({										\
-	struct test_info __copy_cpu = (copy_cpu), __mop_cpu = (mop_cpu);	\
-	enum mop_target __target = (mop_target_p);				\
-	uint32_t __size = (size);						\
-										\
-	prepare_mem12();							\
-	CHECK_N_DO(MOP, __mop_cpu, __target, WRITE, mem1, __size,		\
-			GADDR_V(mem1), ##__VA_ARGS__);				\
-	HOST_SYNC(__copy_cpu, STAGE_COPIED);					\
-	CHECK_N_DO(MOP, __mop_cpu, __target, READ, mem2, __size,		\
-			GADDR_V(mem2), ##__VA_ARGS__);				\
-	ASSERT_MEM_EQ(mem1, mem2, __size);					\
-})
+static void default_write_read(struct test_info copy_cpu, struct test_info mop_cpu,
+			       enum mop_target mop_target, uint32_t size, uint8_t key)
+{
+	prepare_mem12();
+	CHECK_N_DO(MOP, mop_cpu, mop_target, WRITE, mem1, size,
+		   GADDR_V(mem1), KEY(key));
+	HOST_SYNC(copy_cpu, STAGE_COPIED);
+	CHECK_N_DO(MOP, mop_cpu, mop_target, READ, mem2, size,
+		   GADDR_V(mem2), KEY(key));
+	ASSERT_MEM_EQ(mem1, mem2, size);
+}
 
-#define DEFAULT_READ(copy_cpu, mop_cpu, mop_target_p, size, ...)		\
-({										\
-	struct test_info __copy_cpu = (copy_cpu), __mop_cpu = (mop_cpu);	\
-	enum mop_target __target = (mop_target_p);				\
-	uint32_t __size = (size);						\
-										\
-	prepare_mem12();							\
-	CHECK_N_DO(MOP, __mop_cpu, __target, WRITE, mem1, __size,		\
-			GADDR_V(mem1));						\
-	HOST_SYNC(__copy_cpu, STAGE_COPIED);					\
-	CHECK_N_DO(MOP, __mop_cpu, __target, READ, mem2, __size, ##__VA_ARGS__);\
-	ASSERT_MEM_EQ(mem1, mem2, __size);					\
-})
+static void default_read(struct test_info copy_cpu, struct test_info mop_cpu,
+			 enum mop_target mop_target, uint32_t size, uint8_t key)
+{
+	prepare_mem12();
+	CHECK_N_DO(MOP, mop_cpu, mop_target, WRITE, mem1, size, GADDR_V(mem1));
+	HOST_SYNC(copy_cpu, STAGE_COPIED);
+	CHECK_N_DO(MOP, mop_cpu, mop_target, READ, mem2, size,
+		   GADDR_V(mem2), KEY(key));
+	ASSERT_MEM_EQ(mem1, mem2, size);
+}
 
 static void guest_copy(void)
 {
@@ -310,7 +306,7 @@ static void test_copy(void)
 
 	HOST_SYNC(t.vcpu, STAGE_INITED);
 
-	DEFAULT_WRITE_READ(t.vcpu, t.vcpu, LOGICAL, t.size);
+	default_write_read(t.vcpu, t.vcpu, LOGICAL, t.size, NO_KEY);
 
 	kvm_vm_free(t.kvm_vm);
 }
@@ -357,26 +353,26 @@ static void test_copy_key(void)
 	HOST_SYNC(t.vcpu, STAGE_SKEYS_SET);
 
 	/* vm, no key */
-	DEFAULT_WRITE_READ(t.vcpu, t.vm, ABSOLUTE, t.size);
+	default_write_read(t.vcpu, t.vm, ABSOLUTE, t.size, NO_KEY);
 
 	/* vm/vcpu, machting key or key 0 */
-	DEFAULT_WRITE_READ(t.vcpu, t.vcpu, LOGICAL, t.size, KEY(0));
-	DEFAULT_WRITE_READ(t.vcpu, t.vcpu, LOGICAL, t.size, KEY(9));
-	DEFAULT_WRITE_READ(t.vcpu, t.vm, ABSOLUTE, t.size, KEY(0));
-	DEFAULT_WRITE_READ(t.vcpu, t.vm, ABSOLUTE, t.size, KEY(9));
+	default_write_read(t.vcpu, t.vcpu, LOGICAL, t.size, 0);
+	default_write_read(t.vcpu, t.vcpu, LOGICAL, t.size, 9);
+	default_write_read(t.vcpu, t.vm, ABSOLUTE, t.size, 0);
+	default_write_read(t.vcpu, t.vm, ABSOLUTE, t.size, 9);
 	/*
 	 * There used to be different code paths for key handling depending on
 	 * if the region crossed a page boundary.
 	 * There currently are not, but the more tests the merrier.
 	 */
-	DEFAULT_WRITE_READ(t.vcpu, t.vcpu, LOGICAL, 1, KEY(0));
-	DEFAULT_WRITE_READ(t.vcpu, t.vcpu, LOGICAL, 1, KEY(9));
-	DEFAULT_WRITE_READ(t.vcpu, t.vm, ABSOLUTE, 1, KEY(0));
-	DEFAULT_WRITE_READ(t.vcpu, t.vm, ABSOLUTE, 1, KEY(9));
+	default_write_read(t.vcpu, t.vcpu, LOGICAL, 1, 0);
+	default_write_read(t.vcpu, t.vcpu, LOGICAL, 1, 9);
+	default_write_read(t.vcpu, t.vm, ABSOLUTE, 1, 0);
+	default_write_read(t.vcpu, t.vm, ABSOLUTE, 1, 9);
 
 	/* vm/vcpu, mismatching keys on read, but no fetch protection */
-	DEFAULT_READ(t.vcpu, t.vcpu, LOGICAL, t.size, GADDR_V(mem2), KEY(2));
-	DEFAULT_READ(t.vcpu, t.vm, ABSOLUTE, t.size, GADDR_V(mem1), KEY(2));
+	default_read(t.vcpu, t.vcpu, LOGICAL, t.size, 2);
+	default_read(t.vcpu, t.vm, ABSOLUTE, t.size, 2);
 
 	kvm_vm_free(t.kvm_vm);
 }
@@ -409,7 +405,7 @@ static void test_copy_key_storage_prot_override(void)
 	HOST_SYNC(t.vcpu, STAGE_SKEYS_SET);
 
 	/* vcpu, mismatching keys, storage protection override in effect */
-	DEFAULT_WRITE_READ(t.vcpu, t.vcpu, LOGICAL, t.size, KEY(2));
+	default_write_read(t.vcpu, t.vcpu, LOGICAL, t.size, 2);
 
 	kvm_vm_free(t.kvm_vm);
 }
@@ -422,8 +418,8 @@ static void test_copy_key_fetch_prot(void)
 	HOST_SYNC(t.vcpu, STAGE_SKEYS_SET);
 
 	/* vm/vcpu, matching key, fetch protection in effect */
-	DEFAULT_READ(t.vcpu, t.vcpu, LOGICAL, t.size, GADDR_V(mem2), KEY(9));
-	DEFAULT_READ(t.vcpu, t.vm, ABSOLUTE, t.size, GADDR_V(mem2), KEY(9));
+	default_read(t.vcpu, t.vcpu, LOGICAL, t.size, 9);
+	default_read(t.vcpu, t.vm, ABSOLUTE, t.size, 9);
 
 	kvm_vm_free(t.kvm_vm);
 }
