linux-kernel - [PATCH 18/23] x86/srso: Remove redundant X86_FEATURE_ENTRY

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Message-ID: <9b671422643939792afe05c625e93ef40d9b57b5.1692919072.git.jpoimboe@kernel.org>
Date:   Fri, 25 Aug 2023 00:01:49 -0700
From:   Josh Poimboeuf <jpoimboe@...nel.org>
To:     x86@...nel.org
Cc:     linux-kernel@...r.kernel.org, Borislav Petkov <bp@...en8.de>,
        Peter Zijlstra <peterz@...radead.org>,
        Babu Moger <babu.moger@....com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Sean Christopherson <seanjc@...gle.com>, David.Kaplan@....com,
        Andrew Cooper <andrew.cooper3@...rix.com>,
        Nikolay Borisov <nik.borisov@...e.com>,
        gregkh@...uxfoundation.org, Thomas Gleixner <tglx@...utronix.de>
Subject: [PATCH 18/23] x86/srso: Remove redundant X86_FEATURE_ENTRY_IBPB check

The X86_FEATURE_ENTRY_IBPB check is redundant here due to the above
RETBLEED_MITIGATION_IBPB check.  RETBLEED_MITIGATION_IBPB already
implies X86_FEATURE_ENTRY_IBPB.  So if we got here and 'has_microcode'
is true, it means X86_FEATURE_ENTRY_IBPB is not set.

Signed-off-by: Josh Poimboeuf <jpoimboe@...nel.org>
---
 arch/x86/kernel/cpu/bugs.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index b086fd46fa1b..563f09ba6446 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -2494,7 +2494,7 @@ static void __init srso_select_mitigation(void)
 
 	case SRSO_CMD_IBPB_ON_VMEXIT:
 		if (IS_ENABLED(CONFIG_CPU_SRSO)) {
-			if (!boot_cpu_has(X86_FEATURE_ENTRY_IBPB) && has_microcode) {
+			if (has_microcode) {
 				setup_force_cpu_cap(X86_FEATURE_IBPB_ON_VMEXIT);
 				srso_mitigation = SRSO_MITIGATION_IBPB_ON_VMEXIT;
 			}
-- 
2.41.0