Re: [kvm-unit-tests PATCH 7/7] common: add memory dirtying vs migration test

Thomas Huth
2024-03-04T06:22:28Z

On 26/02/2024 10.38, Nicholas Piggin wrote:
> This test stores to a bunch of pages and verifies previous stores,
> while being continually migrated. This can fail due to a QEMU TCG
> physical memory dirty bitmap bug.

Good idea, but could we then please drop "continuous" test from
selftest-migration.c again? ... having two common tests to exercise the
continuous migration that take quite a bunch of seconds to finish sounds
like a waste of time in the long run to me.

> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
> ---
> common/memory-verify.c | 48 +++++++++++++++++++++++++++++++++++++++++
> powerpc/Makefile.common | 1 +
> powerpc/memory-verify.c | 1 +
> powerpc/unittests.cfg | 7 ++++++
> s390x/Makefile | 1 +
> s390x/memory-verify.c | 1 +
> s390x/unittests.cfg | 6 ++++++
> 7 files changed, 65 insertions(+)
> create mode 100644 common/memory-verify.c
> create mode 120000 powerpc/memory-verify.c
> create mode 120000 s390x/memory-verify.c
>
> diff --git a/common/memory-verify.c b/common/memory-verify.c
> new file mode 100644
> index 000000000..7c4ec087b
> --- /dev/null
> +++ b/common/memory-verify.c
> @@ -0,0 +1,48 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Simple memory verification test, used to exercise dirty memory migration.
> + *
> + */
> +#include <libcflat.h>
> +#include <migrate.h>
> +#include <alloc.h>
> +#include <asm/page.h>
> +#include <asm/time.h>
> +
> +#define NR_PAGES 32
> +
> +int main(int argc, char **argv)
> +{
> + void *mem = malloc(NR_PAGES*PAGE_SIZE);
> + bool success = true;
> + uint64_t ms;
> + long i;
> +
> + report_prefix_push("memory");
> +
> + memset(mem, 0, NR_PAGES*PAGE_SIZE);
> +
> + migrate_begin_continuous();
> + ms = get_clock_ms();
> + i = 0;
> + do {
> + int j;
> +
> + for (j = 0; j < NR_PAGES*PAGE_SIZE; j += PAGE_SIZE) {
> + if (*(volatile long *)(mem + j) != i) {
> + success = false;
> + goto out;
> + }
> + *(volatile long *)(mem + j) = i + 1;
> + }
> + i++;
> + } while (get_clock_ms() - ms < 5000);

Maybe add a parameter so that the user can use different values for the
runtime than always doing 5 seconds?

Thomas

> +out:
> + migrate_end_continuous();
> +
> + report(success, "memory verification stress test");
> +
> + report_prefix_pop();
> +
> + return report_summary();
> +}