diff options
Diffstat (limited to 'arch/x86/kernel/cpu/bugs.c')
| -rw-r--r-- | arch/x86/kernel/cpu/bugs.c | 25 |
1 files changed, 18 insertions, 7 deletions
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index 47a01d4028f6..a5d0998d7604 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -1115,6 +1115,8 @@ do_cmd_auto: case RETBLEED_MITIGATION_IBPB: setup_force_cpu_cap(X86_FEATURE_ENTRY_IBPB); + setup_force_cpu_cap(X86_FEATURE_IBPB_ON_VMEXIT); + mitigate_smt = true; /* * IBPB on entry already obviates the need for @@ -1124,9 +1126,6 @@ do_cmd_auto: setup_clear_cpu_cap(X86_FEATURE_UNRET); setup_clear_cpu_cap(X86_FEATURE_RETHUNK); - setup_force_cpu_cap(X86_FEATURE_IBPB_ON_VMEXIT); - mitigate_smt = true; - /* * There is no need for RSB filling: entry_ibpb() ensures * all predictions, including the RSB, are invalidated, @@ -2615,6 +2614,9 @@ static void __init srso_select_mitigation(void) break; case SRSO_CMD_SAFE_RET: + if (boot_cpu_has(X86_FEATURE_SRSO_USER_KERNEL_NO)) + goto ibpb_on_vmexit; + if (IS_ENABLED(CONFIG_MITIGATION_SRSO)) { /* * Enable the return thunk for generated code @@ -2643,6 +2645,7 @@ static void __init srso_select_mitigation(void) if (IS_ENABLED(CONFIG_MITIGATION_IBPB_ENTRY)) { if (has_microcode) { setup_force_cpu_cap(X86_FEATURE_ENTRY_IBPB); + setup_force_cpu_cap(X86_FEATURE_IBPB_ON_VMEXIT); srso_mitigation = SRSO_MITIGATION_IBPB; /* @@ -2652,15 +2655,23 @@ static void __init srso_select_mitigation(void) */ setup_clear_cpu_cap(X86_FEATURE_UNRET); setup_clear_cpu_cap(X86_FEATURE_RETHUNK); + + /* + * There is no need for RSB filling: entry_ibpb() ensures + * all predictions, including the RSB, are invalidated, + * regardless of IBPB implementation. + */ + setup_clear_cpu_cap(X86_FEATURE_RSB_VMEXIT); } } else { pr_err("WARNING: kernel not compiled with MITIGATION_IBPB_ENTRY.\n"); } break; +ibpb_on_vmexit: case SRSO_CMD_IBPB_ON_VMEXIT: - if (IS_ENABLED(CONFIG_MITIGATION_SRSO)) { - if (!boot_cpu_has(X86_FEATURE_ENTRY_IBPB) && has_microcode) { + if (IS_ENABLED(CONFIG_MITIGATION_IBPB_ENTRY)) { + if (has_microcode) { setup_force_cpu_cap(X86_FEATURE_IBPB_ON_VMEXIT); srso_mitigation = SRSO_MITIGATION_IBPB_ON_VMEXIT; @@ -2672,8 +2683,8 @@ static void __init srso_select_mitigation(void) setup_clear_cpu_cap(X86_FEATURE_RSB_VMEXIT); } } else { - pr_err("WARNING: kernel not compiled with MITIGATION_SRSO.\n"); - } + pr_err("WARNING: kernel not compiled with MITIGATION_IBPB_ENTRY.\n"); + } break; default: break; |