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

[ Upstream commit 1d1142ac51307145dbb256ac3535a1d43a1c9800 ]

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@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/cee5050db750b391c9f35f5334f8ff40e66c01b9.1693889988.git.jpoimboe@kernel.org
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index 6322a08edbba57a74a11d2cc03d1a7263454aa79..d1ba55ea46a7b7f98b7598ff7ba0a03cedb249f0 100644 (file)
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -2477,7 +2477,7 @@ 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;
 }