Messages in this thread Patch in this message | | | From | Josh Poimboeuf <> | Subject | [PATCH 05/22] x86/srso: Fix SBPB enablement for mitigations=off | Date | Sun, 20 Aug 2023 18:19:02 -0700 |
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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@kernel.org> --- 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
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