Add L3_CBM_VALIDATE to verify that resctrl enforces the L3 CBM rules advertised by cbm_mask and min_cbm_bits.
Confirm that the full mask is accepted. Check the empty mask according to min_cbm_bits, and confirm that out-of-range and undersized masks are rejected. This catches inconsistencies between the advertised capabilities and schemata validation. Signed-off-by: Richard Cheng <[email protected]> --- Changelog: v1 -> v2: - Rename L3_CAT_VALIDATE to L3_CBM_VALIDATE - Handle empty CBMs according to min_cbm_bits - Check count_contiguous_bits() before using its result - Use KSFT_FAIL and reverse-fir-tree ordering - Use a 64-bit out-of-range mask Best regards, Richard Cheng. --- tools/testing/selftests/resctrl/cat_test.c | 91 +++++++++++++++++++ tools/testing/selftests/resctrl/resctrl.h | 1 + .../testing/selftests/resctrl/resctrl_tests.c | 1 + 3 files changed, 93 insertions(+) diff --git a/tools/testing/selftests/resctrl/cat_test.c b/tools/testing/selftests/resctrl/cat_test.c index 371a2f26dc47..a06c57954740 100644 --- a/tools/testing/selftests/resctrl/cat_test.c +++ b/tools/testing/selftests/resctrl/cat_test.c @@ -357,6 +357,89 @@ static bool noncont_cat_feature_check(const struct resctrl_test *test) return resource_info_file_exists(test->resource, "sparse_masks"); } +/* + * L3_CBM_VALIDATE - Verify L3 CBM write validation. + * + * A full CBM must be accepted. An empty CBM is valid only when min_cbm_bits + * is zero. Masks with bits outside cbm_mask or fewer than min_cbm_bits must + * be rejected. + */ +static int cbm_validate_run_test(const struct resctrl_test *test, + const struct user_params *uparams) +{ + unsigned int min_cbm_bits, contiguous_bits; + unsigned long long invalid_mask; + unsigned int count_of_bits; + unsigned long full_mask; + unsigned int start; + char schemata[64]; + int ret; + + ret = get_full_cbm(test->resource, &full_mask); + if (ret) + return ret; + + ret = resource_info_unsigned_get(test->resource, "min_cbm_bits", + &min_cbm_bits); + if (ret) + return ret; + + count_of_bits = count_bits(full_mask); + + /* A valid full CBM must be accepted. */ + snprintf(schemata, sizeof(schemata), "%lx", full_mask); + if (write_schemata("", schemata, uparams->cpu, test->resource)) { + ksft_print_msg("Valid CBM 0x%lx was rejected\n", full_mask); + return KSFT_FAIL; + } + + ret = write_schemata("", "0", uparams->cpu, test->resource); + if (min_cbm_bits && !ret) { + ksft_print_msg("Empty CBM was accepted, must be rejected\n"); + return KSFT_FAIL; + } + if (!min_cbm_bits && ret) { + ksft_print_msg("Empty CBM was rejected, must be accepted\n"); + return KSFT_FAIL; + } + + /* A mask with a bit outside cbm_mask must be rejected. */ + invalid_mask = (unsigned long long)full_mask | (1ULL << count_of_bits); + snprintf(schemata, sizeof(schemata), "%llx", invalid_mask); + if (!write_schemata("", schemata, uparams->cpu, test->resource)) { + ksft_print_msg("Out-of-range CBM 0x%llx was accepted, must be rejected\n", + invalid_mask); + return KSFT_FAIL; + } + + /* + * When min_cbm_bits is greater than one, a non-empty mask with fewer + * bits must be rejected. + */ + if (min_cbm_bits > 1) { + contiguous_bits = count_contiguous_bits(full_mask, &start); + if (contiguous_bits < min_cbm_bits) { + ksft_print_msg("Full CBM has %u contiguous bits, fewer than " + "min_cbm_bits=%u\n", + contiguous_bits, min_cbm_bits); + return KSFT_FAIL; + } + + invalid_mask = create_bit_mask(start, min_cbm_bits - 1); + snprintf(schemata, sizeof(schemata), "%llx", invalid_mask); + if (!write_schemata("", schemata, uparams->cpu, + test->resource)) { + ksft_print_msg("CBM 0x%llx with too few bits was accepted\n", + invalid_mask); + return KSFT_FAIL; + } + } + + ksft_print_msg("Pass: L3 CBM writes were validated correctly\n"); + + return 0; +} + struct resctrl_test l3_cat_test = { .name = "L3_CAT", .group = "CAT", @@ -366,6 +449,14 @@ struct resctrl_test l3_cat_test = { .cleanup = cat_test_cleanup, }; +struct resctrl_test l3_cbm_validate_test = { + .name = "L3_CBM_VALIDATE", + .group = "CAT", + .resource = "L3", + .feature_check = test_resource_feature_check, + .run_test = cbm_validate_run_test, +}; + struct resctrl_test l3_noncont_cat_test = { .name = "L3_NONCONT_CAT", .group = "CAT", diff --git a/tools/testing/selftests/resctrl/resctrl.h b/tools/testing/selftests/resctrl/resctrl.h index 175101022bf3..a6fc688ed997 100644 --- a/tools/testing/selftests/resctrl/resctrl.h +++ b/tools/testing/selftests/resctrl/resctrl.h @@ -240,6 +240,7 @@ extern struct resctrl_test mbm_test; extern struct resctrl_test mba_test; extern struct resctrl_test cmt_test; extern struct resctrl_test l3_cat_test; +extern struct resctrl_test l3_cbm_validate_test; extern struct resctrl_test l3_noncont_cat_test; extern struct resctrl_test l2_noncont_cat_test; diff --git a/tools/testing/selftests/resctrl/resctrl_tests.c b/tools/testing/selftests/resctrl/resctrl_tests.c index dbcd5eea9fbc..57a4d0815b67 100644 --- a/tools/testing/selftests/resctrl/resctrl_tests.c +++ b/tools/testing/selftests/resctrl/resctrl_tests.c @@ -19,6 +19,7 @@ static struct resctrl_test *resctrl_tests[] = { &mba_test, &cmt_test, &l3_cat_test, + &l3_cbm_validate_test, &l3_noncont_cat_test, &l2_noncont_cat_test, }; -- 2.53.0
