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From: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
To: linuxppc-dev@lists.ozlabs.org
Cc: linux-kselftest@vger.kernel.org, mpe@ellerman.id.au
Subject: [PATCH] selftests/powerpc/spectre_v2: Return skip code when miss_percent is high
Date: Tue,  7 Dec 2021 10:05:57 -0300	[thread overview]
Message-ID: <20211207130557.40566-1-cascardo@canonical.com> (raw)

A mis-match between reported and actual mitigation is not restricted to the
Vulnerable case. The guest might also report the mitigation as "Software
count cache flush" and the host will still mitigate with branch cache
disabled.

So, instead of skipping depending on the detected mitigation, simply skip
whenever the detected miss_percent is the expected one for a fully
mitigated system, that is, above 95%.

Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
---
 tools/testing/selftests/powerpc/security/spectre_v2.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/powerpc/security/spectre_v2.c b/tools/testing/selftests/powerpc/security/spectre_v2.c
index adc2b7294e5f..83647b8277e7 100644
--- a/tools/testing/selftests/powerpc/security/spectre_v2.c
+++ b/tools/testing/selftests/powerpc/security/spectre_v2.c
@@ -193,7 +193,7 @@ int spectre_v2_test(void)
 			 * We are not vulnerable and reporting otherwise, so
 			 * missing such a mismatch is safe.
 			 */
-			if (state == VULNERABLE)
+			if (miss_percent > 95)
 				return 4;
 
 			return 1;
-- 
2.32.0


WARNING: multiple messages have this Message-ID (diff)
From: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
To: linuxppc-dev@lists.ozlabs.org
Cc: linux-kselftest@vger.kernel.org
Subject: [PATCH] selftests/powerpc/spectre_v2: Return skip code when miss_percent is high
Date: Tue,  7 Dec 2021 10:05:57 -0300	[thread overview]
Message-ID: <20211207130557.40566-1-cascardo@canonical.com> (raw)

A mis-match between reported and actual mitigation is not restricted to the
Vulnerable case. The guest might also report the mitigation as "Software
count cache flush" and the host will still mitigate with branch cache
disabled.

So, instead of skipping depending on the detected mitigation, simply skip
whenever the detected miss_percent is the expected one for a fully
mitigated system, that is, above 95%.

Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
---
 tools/testing/selftests/powerpc/security/spectre_v2.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/powerpc/security/spectre_v2.c b/tools/testing/selftests/powerpc/security/spectre_v2.c
index adc2b7294e5f..83647b8277e7 100644
--- a/tools/testing/selftests/powerpc/security/spectre_v2.c
+++ b/tools/testing/selftests/powerpc/security/spectre_v2.c
@@ -193,7 +193,7 @@ int spectre_v2_test(void)
 			 * We are not vulnerable and reporting otherwise, so
 			 * missing such a mismatch is safe.
 			 */
-			if (state == VULNERABLE)
+			if (miss_percent > 95)
 				return 4;
 
 			return 1;
-- 
2.32.0


             reply	other threads:[~2021-12-07 13:06 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-12-07 13:05 Thadeu Lima de Souza Cascardo [this message]
2021-12-07 13:05 ` [PATCH] selftests/powerpc/spectre_v2: Return skip code when miss_percent is high Thadeu Lima de Souza Cascardo
2021-12-15  0:24 ` Michael Ellerman
2021-12-15  0:24   ` Michael Ellerman

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