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powerpc/pseries: Fix update of LPAR security flavor after LPM

PATCH Applied Laurent Dufour 2 participants 2 messages Aug 5, 2021 – Aug 13, 2021

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Stable branch PowerPC
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Laurent Dufour

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PATCH 1/1 powerpc/pseries: Fix update of LPAR security flavor after LPM

After LPM, when migrating from a system with security mitigation enabled to a system with mitigation disabled, the security flavor exposed in /proc is not correctly set back to 0.

Do not assume the value of the security flavor is set to 0 when entering init_cpu_char_feature_flags(), so when called after a LPM, the value is set correctly even if the mitigation are not turned off.

Fixes 6ce56e1ac380 ("powerpc/pseries: export LPAR security flavor in

lparcfg")

Cc [email protected] # 5.13.x
Signed-off-by Laurent Dufour <[email protected]>
---
 arch/powerpc/platforms/pseries/setup.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)
arch/powerpc/platforms/pseries/setup.c +3 -2
index 6b0886668465..0dfaa6ab44cc 100644
@@ -539,9 +539,10 @@ static void init_cpu_char_feature_flags(struct h_cpu_char_result *result)
 	 * H_CPU_BEHAV_FAVOUR_SECURITY_H could be set only if
 	 * H_CPU_BEHAV_FAVOUR_SECURITY is.
 	 */
-	if (!(result->behaviour & H_CPU_BEHAV_FAVOUR_SECURITY))
+	if (!(result->behaviour & H_CPU_BEHAV_FAVOUR_SECURITY)) {
 		security_ftr_clear(SEC_FTR_FAVOUR_SECURITY);
-	else if (result->behaviour & H_CPU_BEHAV_FAVOUR_SECURITY_H)
+		pseries_security_flavor = 0;
+	} else if (result->behaviour & H_CPU_BEHAV_FAVOUR_SECURITY_H)
 		pseries_security_flavor = 1;
 	else
 		pseries_security_flavor = 2;
Signature · 1 line
2.32.0
Applied
#1 lore raw
Quoted 9 lines · Laurent Dufour

After LPM, when migrating from a system with security mitigation enabled to a system with mitigation disabled, the security flavor exposed in /proc is not correctly set back to 0.

Do not assume the value of the security flavor is set to 0 when entering init_cpu_char_feature_flags(), so when called after a LPM, the value is set correctly even if the mitigation are not turned off.

[...]

Applied to powerpc/fixes.

[1/1] powerpc/pseries: Fix update of LPAR security flavor after LPM

      https://git.kernel.org/powerpc/c/c18956e6e0b95f78dad2773ecc8c61a9e41f6405

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