[PATCH 05/22] x86/srso: Fix SBPB enablement for mitigations=off

[Josh Poimboeuf]

If the user has requested no mitigations with mitigations=off, use the
lighter-weight SBPB instead of IBPB for other mitigations.

Note that even with mitigations=off, IBPB/SBPB may still be used for
Spectre v2 user <-> user protection.  Whether that makes sense is a
question for another day.

Fixes: fb3bd914b3ec ("x86/srso: Add a Speculative RAS Overflow mitigation")
Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
---
 arch/x86/kernel/cpu/bugs.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index 10499bcd4e39..ff5bfe8f0ee9 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -2496,8 +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) &&
-	     boot_cpu_has(X86_FEATURE_SBPB))
+	if (boot_cpu_has(X86_FEATURE_SBPB) && srso_mitigation == SRSO_MITIGATION_NONE)
 		x86_pred_cmd = PRED_CMD_SBPB;
 }
 
-- 
2.41.0