linux-kernel - [PATCH 5.13 137/151] powerpc/pseries: Fix update of LPAR security flavor after LPM

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Message-Id: <20210816125448.570107497@linuxfoundation.org>
Date:   Mon, 16 Aug 2021 15:02:47 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Laurent Dufour <ldufour@...ux.ibm.com>,
        Michael Ellerman <mpe@...erman.id.au>
Subject: [PATCH 5.13 137/151] powerpc/pseries: Fix update of LPAR security flavor after LPM

From: Laurent Dufour <ldufour@...ux.ibm.com>

commit c18956e6e0b95f78dad2773ecc8c61a9e41f6405 upstream.

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 # v5.13+
Signed-off-by: Laurent Dufour <ldufour@...ux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@...erman.id.au>
Link: https://lore.kernel.org/r/20210805152308.33988-1-ldufour@linux.ibm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 arch/powerpc/platforms/pseries/setup.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

--- 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(
 	 * 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;