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

[Claudio Imbrenda <imbrenda@linux.ibm.com>]

On Wed, 11 May 2022 10:56:52 +0200
Nico Boehr <nrb@linux.ibm.com> wrote:

> 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>

do we actually need this include?

if not, remove it, then you can add:
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>

> +#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