[kvm-unit-tests PATCH v1 2/2] s390x: add migration TOD clock test

[Nico Boehr <nrb@linux.ibm.com>]

On migration, we expect the guest clock value to be preserved. Add a
test to verify this:
- advance the guest TOD by much more than we need to migrate
- migrate the guest
- get the guest TOD

After migration, assert the guest TOD value is at least the value we set
before migration.

Signed-off-by: Nico Boehr <nrb@linux.ibm.com>
---
 s390x/Makefile        |  1 +
 s390x/migration-sck.c | 45 +++++++++++++++++++++++++++++++++++++++++++
 s390x/unittests.cfg   |  4 ++++
 3 files changed, 50 insertions(+)
 create mode 100644 s390x/migration-sck.c

diff --git a/s390x/Makefile b/s390x/Makefile
index efd5e0c13102..be8e647bb35f 100644
--- a/s390x/Makefile
+++ b/s390x/Makefile
@@ -34,6 +34,7 @@ tests += $(TEST_DIR)/migration.elf
 tests += $(TEST_DIR)/pv-attest.elf
 tests += $(TEST_DIR)/migration-cmm.elf
 tests += $(TEST_DIR)/migration-skey.elf
+tests += $(TEST_DIR)/migration-sck.elf
 
 pv-tests += $(TEST_DIR)/pv-diags.elf
 
diff --git a/s390x/migration-sck.c b/s390x/migration-sck.c
new file mode 100644
index 000000000000..701d33f9db5a
--- /dev/null
+++ b/s390x/migration-sck.c
@@ -0,0 +1,45 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * SET CLOCK migration tests
+ *
+ * Copyright IBM Corp. 2022
+ *
+ * Authors:
+ *  Nico Boehr <nrb@linux.ibm.com>
+ */
+
+#include <libcflat.h>
+#include <asm/time.h>
+#include <bitops.h>
+
+static void test_sck_migration(void)
+{
+	uint64_t now_before_set = 0, now_after_migration, time_to_set, time_to_advance;
+	int cc;
+
+	stckf(&now_before_set);
+
+	/* Advance the clock by a lot more than we might ever need to migrate (60s) */
+	time_to_advance = (60ULL * 1000ULL * 1000ULL << STCK_SHIFT_US);
+	time_to_set = now_before_set + time_to_advance;
+
+	cc = sck(&time_to_set);
+	report(!cc, "setting clock succeeded");
+
+	puts("Please migrate me, then press return\n");
+	(void)getchar();
+
+	cc = stckf(&now_after_migration);
+	report(!cc, "clock still set");
+
+	report(now_after_migration >= time_to_set, "TOD clock value preserved");
+}
+
+int main(void)
+{
+	report_prefix_push("migration-sck");
+
+	test_sck_migration();
+	report_prefix_pop();
+	return report_summary();
+}
diff --git a/s390x/unittests.cfg b/s390x/unittests.cfg
index f7b1fc3dbca1..808e8a28ba96 100644
--- a/s390x/unittests.cfg
+++ b/s390x/unittests.cfg
@@ -185,3 +185,7 @@ groups = migration
 [migration-skey]
 file = migration-skey.elf
 groups = migration
+
+[migration-sck]
+file = migration-sck.elf
+groups = migration
-- 
2.36.1