Non-contiguous CBM support for Intel CAT has been merged into the kernel
with Commit 0e3cd31f6e90 ("x86/resctrl: Enable non-contiguous CBMs in
Intel CAT") but there is no selftest that would validate if this feature
works correctly.The selftest needs to verify if writing non-contiguous CBMs to the schemata file behaves as expected in comparison to the information about non-contiguous CBMs support. Add tests for both L2 and L3 CAT to verify if the return values generated by writing non-contiguous CBMs don't contradict the reported non-contiguous support information. Comparing the return value of write_schemata() with non-contiguous CBMs support information can be simplified as a logical XOR operation. In other words if non-contiguous CBMs are supported and if non-contiguous write succeeds the test should succeed and if the write fails the test should also fail. The opposite should happen if non-contiguous CBMs are not supported. Signed-off-by: Maciej Wieczor-Retman <[email protected]> --- This patch is based on a rework of resctrl selftests that's currently in review [1]. The patch also implements a similiar functionality presented in the bash script included in the cover letter to the original non-contiguous CBMs in Intel CAT series [2]. [1] https://lore.kernel.org/all/[email protected]/ [2] https://lore.kernel.org/all/[email protected]/ tools/testing/selftests/resctrl/cat_test.c | 97 +++++++++++++++++++ tools/testing/selftests/resctrl/resctrl.h | 2 + .../testing/selftests/resctrl/resctrl_tests.c | 2 + 3 files changed, 101 insertions(+) diff --git a/tools/testing/selftests/resctrl/cat_test.c b/tools/testing/selftests/resctrl/cat_test.c index bc88eb891f35..6a01a5da30b4 100644 --- a/tools/testing/selftests/resctrl/cat_test.c +++ b/tools/testing/selftests/resctrl/cat_test.c @@ -342,6 +342,87 @@ 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 res_path[PATH_MAX]; + char schemata[64]; + int bit_center; + FILE *fp; + + /* Check to compare sparse_masks content to cpuid output. */ + snprintf(res_path, sizeof(res_path), "%s/%s/%s", INFO_PATH, + test->resource, "sparse_masks"); + + fp = fopen(res_path, "r"); + if (!fp) { + perror("# Error in opening file\n"); + return errno; + } + + if (fscanf(fp, "%u", &sparse_masks) <= 0) { + perror("Could not get sparse_masks contents\n"); + fclose(fp); + return -1; + } + + fclose(fp); + + 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)) + return -1; + + /* Write checks initialization. */ + ret = get_cbm_mask(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) + return ret; + + /* + * 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 = ~(full_cache_mask & (0xf << bit_center)) & full_cache_mask; + snprintf(schemata, sizeof(schemata), "%lx", noncont_mask); + ret = write_schemata("", schemata, uparams->cpu, test->resource); + if (ret && sparse_masks) + ksft_print_msg("Non-contiguous CBMs supported but write failed\n"); + else if (ret && !sparse_masks) + ksft_print_msg("Non-contiguous CBMs not supported and write failed as expected\n"); + else if (!ret && !sparse_masks) + ksft_print_msg("Non-contiguous CBMs not supported but write succeeded\n"); + return !ret == !sparse_masks; +} + +static bool noncont_cat_feature_check(const struct resctrl_test *test) +{ + char res_path[PATH_MAX]; + struct stat statbuf; + + snprintf(res_path, sizeof(res_path), "%s/%s/%s", INFO_PATH, + test->resource, "sparse_masks"); + + if (stat(res_path, &statbuf)) + return false; + + return test_resource_feature_check(test); +} + struct resctrl_test l3_cat_test = { .name = "L3_CAT", .group = "CAT", @@ -357,3 +438,19 @@ struct resctrl_test l2_cat_test = { .feature_check = test_resource_feature_check, .run_test = cat_run_test, }; + +struct resctrl_test l3_noncont_cat_test = { + .name = "L3_NONCONT_CAT", + .group = "NONCONT_CAT", + .resource = "L3", + .feature_check = noncont_cat_feature_check, + .run_test = noncont_cat_run_test, +}; + +struct resctrl_test l2_noncont_cat_test = { + .name = "L2_NONCONT_CAT", + .group = "NONCONT_CAT", + .resource = "L2", + .feature_check = noncont_cat_feature_check, + .run_test = noncont_cat_run_test, +}; diff --git a/tools/testing/selftests/resctrl/resctrl.h b/tools/testing/selftests/resctrl/resctrl.h index fffeb442c173..51b8a6ff3a0d 100644 --- a/tools/testing/selftests/resctrl/resctrl.h +++ b/tools/testing/selftests/resctrl/resctrl.h @@ -184,5 +184,7 @@ extern struct resctrl_test mba_test; extern struct resctrl_test cmt_test; extern struct resctrl_test l3_cat_test; extern struct resctrl_test l2_cat_test; +extern struct resctrl_test l3_noncont_cat_test; +extern struct resctrl_test l2_noncont_cat_test; #endif /* RESCTRL_H */ diff --git a/tools/testing/selftests/resctrl/resctrl_tests.c b/tools/testing/selftests/resctrl/resctrl_tests.c index 9e254bca6c25..fdeef82feb4e 100644 --- a/tools/testing/selftests/resctrl/resctrl_tests.c +++ b/tools/testing/selftests/resctrl/resctrl_tests.c @@ -16,6 +16,8 @@ static struct resctrl_test *resctrl_tests[] = { &cmt_test, &l3_cat_test, &l2_cat_test, + &l3_noncont_cat_test, + &l2_noncont_cat_test, }; static int detect_vendor(void) -- 2.42.1
