s390x: add migration TOD clock test
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. This is the minimal check for architectural
compliance; implementations may decide to do something more
sophisticated.
Signed-off-by: Nico Boehr <nrb@linux.ibm.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Message-Id: <20221011170024.972135-3-nrb@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
diff --git a/s390x/migration-sck.c b/s390x/migration-sck.c
new file mode 100644
index 0000000..2d9a195
--- /dev/null
+++ b/s390x/migration-sck.c
@@ -0,0 +1,54 @@
+/* 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>
+
+static void test_sck_migration(void)
+{
+ uint64_t now_before_set = 0, now_after_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 (600s) */
+ time_to_advance = (600ULL * 1000000) << STCK_SHIFT_US;
+ time_to_set = now_before_set + time_to_advance;
+
+ cc = sck(&time_to_set);
+ report(!cc, "setting clock succeeded");
+
+ /* Check the clock is running after being set */
+ cc = stckf(&now_after_set);
+ report(!cc, "clock running after set");
+ report(now_after_set >= time_to_set, "TOD clock value is larger than what has been set");
+
+ puts("Please migrate me, then press return\n");
+ (void)getchar();
+
+ cc = stckf(&now_after_migration);
+ report(!cc, "clock still set");
+
+ /*
+ * The architectural requirement for the TOD clock is that it doesn't move backwards after
+ * migration. Implementations can just migrate the guest TOD value or do something more
+ * sophisticated (e.g. slowly adjust to the host TOD).
+ */
+ report(now_after_migration >= time_to_set, "TOD clock value did not jump backwards");
+}
+
+int main(void)
+{
+ report_prefix_push("migration-sck");
+
+ test_sck_migration();
+ report_prefix_pop();
+ return report_summary();
+}
