[kvm-unit-tests PATCH v2 2/2] s390x: add cmm migration test

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

When a VM is migrated, we expect the page states to be preserved. Add a test
which checks for that.

Signed-off-by: Nico Boehr <nrb@linux.ibm.com>
---
 s390x/Makefile        |  1 +
 s390x/migration-cmm.c | 78 +++++++++++++++++++++++++++++++++++++++++++
 s390x/unittests.cfg   |  4 +++
 3 files changed, 83 insertions(+)
 create mode 100644 s390x/migration-cmm.c

diff --git a/s390x/Makefile b/s390x/Makefile
index a8e04aa6fe4d..1877c8a6e86e 100644
--- a/s390x/Makefile
+++ b/s390x/Makefile
@@ -32,6 +32,7 @@ tests += $(TEST_DIR)/epsw.elf
 tests += $(TEST_DIR)/adtl-status.elf
 tests += $(TEST_DIR)/migration.elf
 tests += $(TEST_DIR)/pv-attest.elf
+tests += $(TEST_DIR)/migration-cmm.elf
 
 pv-tests += $(TEST_DIR)/pv-diags.elf
 
diff --git a/s390x/migration-cmm.c b/s390x/migration-cmm.c
new file mode 100644
index 000000000000..97bba138bcf9
--- /dev/null
+++ b/s390x/migration-cmm.c
@@ -0,0 +1,78 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * CMM migration tests (ESSA)
+ *
+ * Copyright IBM Corp. 2022
+ *
+ * Authors:
+ *  Nico Boehr <nrb@linux.ibm.com>
+ */
+
+#include <libcflat.h>
+#include <asm/asm-offsets.h>
+#include <asm/interrupt.h>
+#include <asm/page.h>
+#include <asm/cmm.h>
+#include <bitops.h>
+
+#define NUM_PAGES 128
+static uint8_t pagebuf[NUM_PAGES][PAGE_SIZE] __attribute__((aligned(PAGE_SIZE)));
+
+static void test_migration(void)
+{
+	int i, state_mask, actual_state;
+	/*
+	 * Maps ESSA actions to states the page is allowed to be in after the
+	 * respective action was executed.
+	 */
+	int allowed_essa_state_masks[4] = {
+		BIT(ESSA_USAGE_STABLE),					/* ESSA_SET_STABLE */
+		BIT(ESSA_USAGE_UNUSED),					/* ESSA_SET_UNUSED */
+		BIT(ESSA_USAGE_VOLATILE),				/* ESSA_SET_VOLATILE */
+		BIT(ESSA_USAGE_VOLATILE) | BIT(ESSA_USAGE_POT_VOLATILE) /* ESSA_SET_POT_VOLATILE */
+	};
+
+	assert(NUM_PAGES % 4 == 0);
+	for (i = 0; i < NUM_PAGES; i += 4) {
+		essa(ESSA_SET_STABLE, (unsigned long)pagebuf[i]);
+		essa(ESSA_SET_UNUSED, (unsigned long)pagebuf[i + 1]);
+		essa(ESSA_SET_VOLATILE, (unsigned long)pagebuf[i + 2]);
+		essa(ESSA_SET_POT_VOLATILE, (unsigned long)pagebuf[i + 3]);
+	}
+
+	puts("Please migrate me, then press return\n");
+	(void)getchar();
+
+	for (i = 0; i < NUM_PAGES; i++) {
+		actual_state = essa(ESSA_GET_STATE, (unsigned long)pagebuf[i]);
+		/* extract the usage state in bits 60 and 61 */
+		actual_state = (actual_state >> 2) & 0x3;
+		state_mask = allowed_essa_state_masks[i % ARRAY_SIZE(allowed_essa_state_masks)];
+		report(BIT(actual_state) & state_mask, "page %d state: expected_mask=0x%x actual_mask=0x%lx", i, state_mask, BIT(actual_state));
+	}
+}
+
+int main(void)
+{
+	bool has_essa = check_essa_available();
+
+	report_prefix_push("cmm-migration");
+	if (!has_essa) {
+		report_skip("ESSA is not available");
+
+		/*
+		 * 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 alltogether.
+		 */
+		puts("Please migrate me, then press return\n");
+		(void)getchar();
+
+		goto done;
+	}
+
+	test_migration();
+done:
+	report_prefix_pop();
+	return report_summary();
+}
diff --git a/s390x/unittests.cfg b/s390x/unittests.cfg
index b456b2881448..9b97d0471bcf 100644
--- a/s390x/unittests.cfg
+++ b/s390x/unittests.cfg
@@ -176,3 +176,7 @@ extra_params = -cpu qemu,gs=off,vx=off
 file = migration.elf
 groups = migration
 smp = 2
+
+[migration-cmm]
+file = migration-cmm.elf
+groups = migration
-- 
2.31.1