[kvm-unit-tests PATCH v6 1/1] s390x: add migration test for storage keys

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

Upon migration, we expect storage keys set by the guest to be preserved, so add
a test for it.

We keep 128 pages and set predictable storage keys. Then, we migrate and check
that they can be read back and match the value originally set.

Signed-off-by: Nico Boehr <nrb@linux.ibm.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
---
 s390x/Makefile         |  1 +
 s390x/migration-skey.c | 83 ++++++++++++++++++++++++++++++++++++++++++
 s390x/unittests.cfg    |  4 ++
 3 files changed, 88 insertions(+)
 create mode 100644 s390x/migration-skey.c

diff --git a/s390x/Makefile b/s390x/Makefile
index 1877c8a6e86e..efd5e0c13102 100644
--- a/s390x/Makefile
+++ b/s390x/Makefile
@@ -33,6 +33,7 @@ tests += $(TEST_DIR)/adtl-status.elf
 tests += $(TEST_DIR)/migration.elf
 tests += $(TEST_DIR)/pv-attest.elf
 tests += $(TEST_DIR)/migration-cmm.elf
+tests += $(TEST_DIR)/migration-skey.elf
 
 pv-tests += $(TEST_DIR)/pv-diags.elf
 
diff --git a/s390x/migration-skey.c b/s390x/migration-skey.c
new file mode 100644
index 000000000000..b7bd82581abe
--- /dev/null
+++ b/s390x/migration-skey.c
@@ -0,0 +1,83 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Storage Key migration tests
+ *
+ * Copyright IBM Corp. 2022
+ *
+ * Authors:
+ *  Nico Boehr <nrb@linux.ibm.com>
+ */
+
+#include <libcflat.h>
+#include <asm/facility.h>
+#include <asm/page.h>
+#include <asm/mem.h>
+#include <asm/interrupt.h>
+#include <hardware.h>
+
+#define NUM_PAGES 128
+static uint8_t pagebuf[NUM_PAGES][PAGE_SIZE] __attribute__((aligned(PAGE_SIZE)));
+
+static void test_migration(void)
+{
+	union skey expected_key, actual_key;
+	int i, key_to_set, key_mismatches = 0;
+
+	for (i = 0; i < NUM_PAGES; i++) {
+		/*
+		 * Storage keys are 7 bit, lowest bit is always returned as zero
+		 * by iske.
+		 * This loop will set all 7 bits which means we set fetch
+		 * protection as well as reference and change indication for
+		 * some keys.
+		 */
+		key_to_set = i * 2;
+		set_storage_key(pagebuf[i], key_to_set, 1);
+	}
+
+	puts("Please migrate me, then press return\n");
+	(void)getchar();
+
+	for (i = 0; i < NUM_PAGES; i++) {
+		actual_key.val = get_storage_key(pagebuf[i]);
+		expected_key.val = i * 2;
+
+		/*
+		 * The PoP neither gives a guarantee that the reference bit is
+		 * accurate nor that it won't be cleared by hardware. Hence we
+		 * don't rely on it and just clear the bits to avoid compare
+		 * errors.
+		 */
+		actual_key.str.rf = 0;
+		expected_key.str.rf = 0;
+
+		/* don't log anything when key matches to avoid spamming the log */
+		if (actual_key.val != expected_key.val) {
+			key_mismatches++;
+			report_fail("page %d expected_key=0x%x actual_key=0x%x", i, expected_key.val, actual_key.val);
+		}
+	}
+
+	report(!key_mismatches, "skeys after migration match");
+}
+
+int main(void)
+{
+	report_prefix_push("migration-skey");
+	if (test_facility(169)) {
+		report_skip("storage key removal facility is active");
+
+		/*
+		 * If we just exit and don't ask migrate_cmd to migrate us, it
+		 * will just hang forever. Hence, also ask for migration when we
+		 * skip this test altogether.
+		 */
+		puts("Please migrate me, then press return\n");
+		(void)getchar();
+	} else {
+		test_migration();
+	}
+
+	report_prefix_pop();
+	return report_summary();
+}
diff --git a/s390x/unittests.cfg b/s390x/unittests.cfg
index 9b97d0471bcf..8e52f560bb1e 100644
--- a/s390x/unittests.cfg
+++ b/s390x/unittests.cfg
@@ -180,3 +180,7 @@ smp = 2
 [migration-cmm]
 file = migration-cmm.elf
 groups = migration
+
+[migration-skey]
+file = migration-skey.elf
+groups = migration
-- 
2.36.1