[GIT PULL] Kselftest fixes for Linux 6.10-rc7

[Shuah Khan <skhan@linuxfoundation.org>]

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Hi Linus,

Please pull this kselftest fixes update for Linux 6.10-rc7.

This kselftest fixes update for Linux 6.10-rc7 consists of one single
patch to fix the non-contiguous CBM resctrl:

- AMD supports non-contiguous CBM but does not report it via CPUID. This
   test should not use CPUID on AMD to detect non-contiguous CBM support.
   Fix the problem so the test uses CPUID to discover non-contiguous CBM
   support only on Intel.

diff is attached.

thanks,
-- Shuah

----------------------------------------------------------------

The following changes since commit ed3994ac847e0d6605f248e7f6776b1d4f445f4b:

   selftests/fchmodat2: fix clang build failure due to -static-libasan (2024-06-11 15:05:05 -0600)

are available in the Git repository at:

   git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest tags/linux_kselftest-fixes-6.10-rc7

for you to fetch changes up to 48236960c06d32370bfa6f2cc408e786873262c8:

   selftests/resctrl: Fix non-contiguous CBM for AMD (2024-06-26 13:22:34 -0600)

----------------------------------------------------------------
linux_kselftest-fixes-6.10-rc7

This kselftest fixes update for Linux 6.10-rc7 consists of one single
patch to fix the non-contiguous CBM resctrl:

- AMD supports non-contiguous CBM but does not report it via CPUID. This
   test should not use CPUID on AMD to detect non-contiguous CBM support.
   Fix the problem so the test uses CPUID to discover non-contiguous CBM
   support only on Intel.

----------------------------------------------------------------
Babu Moger (1):
       selftests/resctrl: Fix non-contiguous CBM for AMD

  tools/testing/selftests/resctrl/cat_test.c | 32 ++++++++++++++++++++----------
  1 file changed, 22 insertions(+), 10 deletions(-)

----------------------------------------------------------------

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diff --git a/tools/testing/selftests/resctrl/cat_test.c b/tools/testing/selftests/resctrl/cat_test.c
index c7686fb6641a..55315ed695f4 100644
--- a/tools/testing/selftests/resctrl/cat_test.c
+++ b/tools/testing/selftests/resctrl/cat_test.c
@@ -291,11 +291,30 @@ static int cat_run_test(const struct resctrl_test *test, const struct user_param
 	return ret;
 }
 
+static bool arch_supports_noncont_cat(const struct resctrl_test *test)
+{
+	unsigned int eax, ebx, ecx, edx;
+
+	/* AMD always supports non-contiguous CBM. */
+	if (get_vendor() == ARCH_AMD)
+		return true;
+
+	/* Intel support for non-contiguous CBM needs to be discovered. */
+	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 false;
+
+	return ((ecx >> 3) & 1);
+}
+
 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, sparse_masks;
+	unsigned int sparse_masks;
 	int bit_center, ret;
 	char schemata[64];
 
@@ -304,15 +323,8 @@ static int noncont_cat_run_test(const struct resctrl_test *test,
 	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");
+	if (arch_supports_noncont_cat(test) != sparse_masks) {
+		ksft_print_msg("Hardware and kernel differ on non-contiguous CBM support!\n");
 		return 1;
 	}