linux-kernel - [PATCH] powerpc/pseries: Fix update of LPAR security flavor after LPM

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Message-Id: <20210805152308.33988-1-ldufour@linux.ibm.com>
Date:   Thu,  5 Aug 2021 17:23:08 +0200
From:   Laurent Dufour <ldufour@...ux.ibm.com>
To:     mpe@...erman.id.au, benh@...nel.crashing.org, paulus@...ba.org
Cc:     linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org,
        stable@...r.kernel.org
Subject: [PATCH] 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: stable@...r.kernel.org # 5.13.x
Signed-off-by: Laurent Dufour <ldufour@...ux.ibm.com>
---
 arch/powerpc/platforms/pseries/setup.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c
index 6b0886668465..0dfaa6ab44cc 100644
--- a/arch/powerpc/platforms/pseries/setup.c
+++ b/arch/powerpc/platforms/pseries/setup.c
@@ -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;
-- 
2.32.0