On Mon, 5 Feb 2024, Maciej Wieczor-Retman wrote:
> Add tests for both L2 and L3 CAT to verify the return values
> generated by writing non-contiguous CBMs don't contradict the
> reported non-contiguous support information.
>
> Use a logical XOR to confirm return value of write_schemata() and
> non-contiguous CBMs support information match.
>
> Signed-off-by: Maciej Wieczor-Retman <maciej.wieczor-retman@xxxxxxxxx>
> ---
> Changelog v4:
> - Return failure instead of error on check of cpuid against sparse_masks
> and on contiguous write_schemata fail. (Reinette)
>
> Changelog v3:
> - Roll back __cpuid_count part. (Reinette)
> - Update function name to read sparse_masks file.
> - Roll back get_cache_level() changes.
> - Add ksft_print_msg() to contiguous schemata write error handling
> (Reinette).
>
> Changelog v2:
> - Redo the patch message. (Ilpo)
> - Tidy up __cpuid_count calls. (Ilpo)
> - Remove redundant AND in noncont_mask calculations (Ilpo)
> - Fix bit_center offset.
> - Add newline before function return. (Ilpo)
> - Group non-contiguous tests with CAT tests. (Ilpo)
> - Use a helper for reading sparse_masks file. (Ilpo)
> - Make get_cache_level() available in other source files. (Ilpo)
>
> tools/testing/selftests/resctrl/cat_test.c | 81 +++++++++++++++++++
> tools/testing/selftests/resctrl/resctrl.h | 2 +
> .../testing/selftests/resctrl/resctrl_tests.c | 2 +
> 3 files changed, 85 insertions(+)
>
> diff --git a/tools/testing/selftests/resctrl/cat_test.c b/tools/testing/selftests/resctrl/cat_test.c
> index 39fc9303b8e8..20eb978e624b 100644
> --- a/tools/testing/selftests/resctrl/cat_test.c
> +++ b/tools/testing/selftests/resctrl/cat_test.c
> @@ -294,6 +294,71 @@ static int cat_run_test(const struct resctrl_test *test, const struct user_param
> return ret;
> }
>
> +static int noncont_cat_run_test(const struct resctrl_test *test,
> + const struct user_params *uparams)
> +{
> + unsigned long full_cache_mask, cont_mask, noncont_mask;
> + unsigned int eax, ebx, ecx, edx, ret, sparse_masks;
> + char schemata[64];
> + int bit_center;
> +
> + /* Check to compare sparse_masks content to CPUID output. */
> + ret = resource_info_unsigned_get(test->resource, "sparse_masks", &sparse_masks);
> + if (ret)
> + return ret;
> +
> + if (!strcmp(test->resource, "L3"))
> + __cpuid_count(0x10, 1, eax, ebx, ecx, edx);
> + else if (!strcmp(test->resource, "L2"))
> + __cpuid_count(0x10, 2, eax, ebx, ecx, edx);
> + else
> + return -EINVAL;
> +
> + if (sparse_masks != ((ecx >> 3) & 1)) {
> + ksft_print_msg("CPUID output doesn't match 'sparse_masks' file content!\n");
> + return 1;
> + }
> +
> + /* Write checks initialization. */
> + ret = get_full_cbm(test->resource, &full_cache_mask);
> + if (ret < 0)
> + return ret;
> + bit_center = count_bits(full_cache_mask) / 2;
> + cont_mask = full_cache_mask >> bit_center;
> +
> + /* Contiguous mask write check. */
> + snprintf(schemata, sizeof(schemata), "%lx", cont_mask);
> + ret = write_schemata("", schemata, uparams->cpu, test->resource);
> + if (ret) {
> + ksft_print_msg("Write of contiguous CBM failed\n");
> + return 1;
> + }
> +
> + /*
> + * Non-contiguous mask write check. CBM has a 0xf hole approximately in the middle.
> + * Output is compared with support information to catch any edge case errors.
> + */
> + noncont_mask = ~(0xf << (bit_center - 2)) & full_cache_mask;
To be on the safe side, I think the types could be made to match here
with 0xfUL to avoid sizeof(int) vs sizeof(unsigned long) related bit
drops in the & (although it feel somewhat theoretical given the bitmask
sizes we are currently seeing).
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx>
--
i.
