linux-kernel - [tip: x86/bugs] x86/srso: Fix SBPB enablement for (possible) future fixed HW

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Date:   Sat, 23 Sep 2023 12:20:12 -0000
From:   "tip-bot2 for Josh Poimboeuf" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     Josh Poimboeuf <jpoimboe@...nel.org>,
        Ingo Molnar <mingo@...nel.org>,
        "Borislav Petkov (AMD)" <bp@...en8.de>, x86@...nel.org,
        linux-kernel@...r.kernel.org
Subject: [tip: x86/bugs] x86/srso: Fix SBPB enablement for (possible) future fixed HW

The following commit has been merged into the x86/bugs branch of tip:

Commit-ID:     06c8c5f9db4e6103294dd528c09568131c2f520a
Gitweb:        https://git.kernel.org/tip/06c8c5f9db4e6103294dd528c09568131c2f520a
Author:        Josh Poimboeuf <jpoimboe@...nel.org>
AuthorDate:    Mon, 04 Sep 2023 22:04:49 -07:00
Committer:     Ingo Molnar <mingo@...nel.org>
CommitterDate: Sat, 23 Sep 2023 14:13:02 +02:00

x86/srso: Fix SBPB enablement for (possible) future fixed HW

Make the SBPB check more robust against the (possible) case where future
HW has SRSO fixed but doesn't have the SRSO_NO bit set.

Fixes: 1b5277c0ea0b ("x86/srso: Add SRSO_NO support")
Signed-off-by: Josh Poimboeuf <jpoimboe@...nel.org>
Signed-off-by: Ingo Molnar <mingo@...nel.org>
Acked-by: Borislav Petkov (AMD) <bp@...en8.de>
Link: https://lore.kernel.org/r/cee5050db750b391c9f35f5334f8ff40e66c01b9.1693889988.git.jpoimboe@kernel.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 10499bc..2859a54 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -2496,7 +2496,7 @@ static void __init srso_select_mitigation(void)
 	pr_info("%s%s\n", srso_strings[srso_mitigation], (has_microcode ? "" : ", no microcode"));
 
 pred_cmd:
-	if ((boot_cpu_has(X86_FEATURE_SRSO_NO) || srso_cmd == SRSO_CMD_OFF) &&
+	if ((!boot_cpu_has_bug(X86_BUG_SRSO) || srso_cmd == SRSO_CMD_OFF) &&
 	     boot_cpu_has(X86_FEATURE_SBPB))
 		x86_pred_cmd = PRED_CMD_SBPB;
 }