linux-kernel - [PATCH v2 2/7] x86/retbleed: Simplify the =stuff checks

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

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

Simplify the nested checks, remove redundant print and comment.

Signed-off-by: Pawan Gupta <pawan.kumar.gupta@...ux.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