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From: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
To: x86@kernel.org
Cc: David Kaplan <david.kaplan@amd.com>,
	linux-kernel@vger.kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
	Josh Poimboeuf <jpoimboe@kernel.org>
Subject: [PATCH v2 2/7] x86/retbleed: Simplify the =stuff checks
Date: Wed, 21 May 2025 19:44:37 -0700	[thread overview]
Message-ID: <20250521-eibrs-fix-v2-2-70e2598e932c@linux.intel.com> (raw)
In-Reply-To: <20250521-eibrs-fix-v2-0-70e2598e932c@linux.intel.com>

Simplify the nested checks, remove redundant print and comment.

Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
---
 arch/x86/kernel/cpu/bugs.c | 24 ++++++++----------------
 1 file changed, 8 insertions(+), 16 deletions(-)

diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index 19ff705b3128eacad5659990ed345d7a19bcb0f4..20d7d14b08298d4f610f2ebc7f13a490ee3d957a 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -1258,24 +1258,16 @@ static void __init retbleed_update_mitigation(void)
 	if (retbleed_mitigation == RETBLEED_MITIGATION_NONE)
 		goto out;
 
-	/*
-	 * retbleed=stuff is only allowed on Intel.  If stuffing can't be used
-	 * then a different mitigation will be selected below.
-	 *
-	 * its=stuff will also attempt to enable stuffing.
-	 */
-	if (retbleed_mitigation == RETBLEED_MITIGATION_STUFF ||
-	    its_mitigation == ITS_MITIGATION_RETPOLINE_STUFF) {
-		if (spectre_v2_enabled != SPECTRE_V2_RETPOLINE) {
-			pr_err("WARNING: retbleed=stuff depends on spectre_v2=retpoline\n");
-			retbleed_mitigation = RETBLEED_MITIGATION_AUTO;
-		} else {
-			if (retbleed_mitigation != RETBLEED_MITIGATION_STUFF)
-				pr_info("Retbleed mitigation updated to stuffing\n");
+	 /* ITS can also enable stuffing */
+	if (its_mitigation == ITS_MITIGATION_RETPOLINE_STUFF)
+		retbleed_mitigation = RETBLEED_MITIGATION_STUFF;
 
-			retbleed_mitigation = RETBLEED_MITIGATION_STUFF;
-		}
+	if (retbleed_mitigation == RETBLEED_MITIGATION_STUFF &&
+	    spectre_v2_enabled != SPECTRE_V2_RETPOLINE) {
+		pr_err("WARNING: retbleed=stuff depends on spectre_v2=retpoline\n");
+		retbleed_mitigation = RETBLEED_MITIGATION_AUTO;
 	}
+
 	/*
 	 * Let IBRS trump all on Intel without affecting the effects of the
 	 * retbleed= cmdline option except for call depth based stuffing

-- 
2.34.1



  parent reply	other threads:[~2025-05-22  2:44 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-05-22  2:44 [PATCH v2 0/7] eIBRS fixes Pawan Gupta
2025-05-22  2:44 ` [PATCH v2 1/7] x86/retbleed: Check for AUTO in all cases Pawan Gupta
2025-05-22  9:52   ` Nikolay Borisov
2025-05-22 11:27   ` Borislav Petkov
2025-05-22 17:42     ` Pawan Gupta
2025-05-22  2:44 ` Pawan Gupta [this message]
2025-05-22 10:18   ` [PATCH v2 2/7] x86/retbleed: Simplify the =stuff checks Nikolay Borisov
2025-05-22 11:42   ` Borislav Petkov
2025-05-22 18:02     ` Pawan Gupta
2025-05-22  2:44 ` [PATCH v2 3/7] x86/bugs: Exit early if return thunk is already set Pawan Gupta
2025-05-22 10:22   ` Nikolay Borisov
2025-05-22 10:26     ` Nikolay Borisov
2025-05-22 18:03       ` Pawan Gupta
2025-05-22  2:45 ` [PATCH v2 4/7] x86/its: Use switch/case to apply mitigation Pawan Gupta
2025-05-22 11:15   ` Nikolay Borisov
2025-05-22 18:04     ` Pawan Gupta
2025-05-22  2:45 ` [PATCH v2 5/7] x86/retbleed: Introduce cdt_possible() Pawan Gupta
2025-05-22  2:45 ` [PATCH v2 6/7] x86/its: Remove =stuff dependency on retbleed Pawan Gupta
2025-05-22  2:45 ` [PATCH v2 7/7] x86/its: Allow stuffing in eIBRS+retpoline mode also Pawan Gupta

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