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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>,
	Nikolay Borisov <nik.borisov@suse.com>
Subject: [PATCH v3 2/7] x86/retbleed: Simplify the =stuff checks
Date: Thu, 22 May 2025 18:20:47 -0700	[thread overview]
Message-ID: <20250522-eibrs-fix-v3-2-12704e291e1e@linux.intel.com> (raw)
In-Reply-To: <20250522-eibrs-fix-v3-0-12704e291e1e@linux.intel.com>

Simplify the nested checks, remove redundant print and comment.

Reviewed-by: Nikolay Borisov <nik.borisov@suse.com>
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 53649df2c4d66c6bd3aa34dec69af9df253bccfc..94d0de3e61aec32b3b67c8d21f89a8c67b93dff3 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -1263,24 +1263,16 @@ static void __init retbleed_update_mitigation(void)
 	if (!boot_cpu_has_bug(X86_BUG_RETBLEED) || cpu_mitigations_off())
 		return;
 
-	/*
-	 * 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_NONE;
-		} 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_NONE;
 	}
+
 	/*
 	 * 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:[~2025-05-23  1:20 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-05-23  1:20 [PATCH v3 0/7] eIBRS fixes Pawan Gupta
2025-05-23  1:20 ` [PATCH v3 1/7] x86/retbleed: Avoid AUTO after the select step Pawan Gupta
2025-05-24  9:29   ` Borislav Petkov
2025-05-23  1:20 ` Pawan Gupta [this message]
2025-05-24 11:16   ` [PATCH v3 2/7] x86/retbleed: Simplify the =stuff checks Borislav Petkov
2025-05-23  1:21 ` [PATCH v3 3/7] x86/bugs: Exit early if return thunk is already set Pawan Gupta
2025-05-23 10:28   ` Nikolay Borisov
2025-05-24 11:27   ` Borislav Petkov
2025-05-28 21:55     ` Pawan Gupta
2025-05-23  1:21 ` [PATCH v3 4/7] x86/its: Use switch/case to apply mitigation Pawan Gupta
2025-05-23  1:21 ` [PATCH v3 5/7] x86/retbleed: Introduce cdt_possible() Pawan Gupta
2025-05-23  1:21 ` [PATCH v3 6/7] x86/its: Remove =stuff dependency on retbleed Pawan Gupta
2025-05-23  1:22 ` [PATCH v3 7/7] x86/its: Allow stuffing in eIBRS+retpoline mode also Pawan Gupta

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