Re: [kvm-unit-tests PATCH v3 1/1] s390x: add migration test for storage keys

Thomas Huth
2022-05-31T08:55:36Z

On 31/05/2022 10.37, Nico Boehr wrote:
> 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>
> ---
> s390x/Makefile | 1 +
> s390x/migration-skey.c | 76 ++++++++++++++++++++++++++++++++++++++++++
> s390x/unittests.cfg | 4 +++
> 3 files changed, 81 insertions(+)
> create mode 100644 s390x/migration-skey.c
>
> diff --git a/s390x/Makefile b/s390x/Makefile
> index 25802428fa13..94fc5c1a3527 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..f846ac435836
> --- /dev/null
> +++ b/s390x/migration-skey.c
> @@ -0,0 +1,76 @@
> +/* 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;
> +
> + for (i = 0; i < NUM_PAGES; i++) {
> + /*
> + * Storage keys are 7 bit, lowest bit is always returned as zero
> + * by iske
> + */
> + 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++) {
> + report_prefix_pushf("page %d", i);
> +
> + actual_key.val = get_storage_key(pagebuf[i]);
> + expected_key.val = i * 2;
> +
> + /* ignore reference bit */
> + actual_key.str.rf = 0;
> + expected_key.str.rf = 0;

If the reference bit gets always ignored, testing 64 pages should be enough?
OTOH this will complicate the for-loop / creation of the key value, so I
don't mind too much if we keep it this way.

> + report(actual_key.val == expected_key.val, "expected_key=0x%x actual_key=0x%x", expected_key.val, actual_key.val);
> +
> + report_prefix_pop();
> + }
> +}
> +
> +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();
> +
> + goto done;
> + }
> +
> + test_migration();
> +
> +done:

} else {
test_migration();
}

to get rid of the goto?

> + report_prefix_pop();
> + return report_summary();
> +}

Either way:
Reviewed-by: Thomas Huth <thuth@redhat.com>