diff options
Diffstat (limited to 'arch/x86/kernel/cpu/bugs.c')
| -rw-r--r-- | arch/x86/kernel/cpu/bugs.c | 55 |
1 files changed, 32 insertions, 23 deletions
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index f84d59cd180b..c10d93d2773b 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -1092,6 +1092,8 @@ 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 @@ -1101,8 +1103,6 @@ do_cmd_auto: setup_clear_cpu_cap(X86_FEATURE_UNRET); setup_clear_cpu_cap(X86_FEATURE_RETHUNK); - mitigate_smt = true; - /* * There is no need for RSB filling: entry_ibpb() ensures * all predictions, including the RSB, are invalidated, @@ -1553,7 +1553,7 @@ static void __init spec_ctrl_disable_kernel_rrsba(void) rrsba_disabled = true; } -static void __init spectre_v2_determine_rsb_fill_type_at_vmexit(enum spectre_v2_mitigation mode) +static void __init spectre_v2_select_rsb_mitigation(enum spectre_v2_mitigation mode) { /* * Similar to context switches, there are two types of RSB attacks @@ -1577,27 +1577,30 @@ static void __init spectre_v2_determine_rsb_fill_type_at_vmexit(enum spectre_v2_ */ switch (mode) { case SPECTRE_V2_NONE: - return; + break; - case SPECTRE_V2_EIBRS_LFENCE: case SPECTRE_V2_EIBRS: + case SPECTRE_V2_EIBRS_LFENCE: + case SPECTRE_V2_EIBRS_RETPOLINE: if (boot_cpu_has_bug(X86_BUG_EIBRS_PBRSB)) { - setup_force_cpu_cap(X86_FEATURE_RSB_VMEXIT_LITE); pr_info("Spectre v2 / PBRSB-eIBRS: Retire a single CALL on VMEXIT\n"); + setup_force_cpu_cap(X86_FEATURE_RSB_VMEXIT_LITE); } - return; + break; - case SPECTRE_V2_EIBRS_RETPOLINE: case SPECTRE_V2_RETPOLINE: case SPECTRE_V2_LFENCE: case SPECTRE_V2_IBRS: + pr_info("Spectre v2 / SpectreRSB: Filling RSB on context switch and VMEXIT\n"); + setup_force_cpu_cap(X86_FEATURE_RSB_CTXSW); setup_force_cpu_cap(X86_FEATURE_RSB_VMEXIT); - pr_info("Spectre v2 / SpectreRSB : Filling RSB on VMEXIT\n"); - return; - } + break; - pr_warn_once("Unknown Spectre v2 mode, disabling RSB mitigation at VM exit"); - dump_stack(); + default: + pr_warn_once("Unknown Spectre v2 mode, disabling RSB mitigation\n"); + dump_stack(); + break; + } } /* @@ -1653,10 +1656,11 @@ static void __init bhi_select_mitigation(void) return; } - if (spec_ctrl_bhi_dis()) + if (!IS_ENABLED(CONFIG_X86_64)) return; - if (!IS_ENABLED(CONFIG_X86_64)) + /* Mitigate in hardware if supported */ + if (spec_ctrl_bhi_dis()) return; /* Mitigate KVM by default */ @@ -1822,10 +1826,7 @@ static void __init spectre_v2_select_mitigation(void) * * FIXME: Is this pointless for retbleed-affected AMD? */ - setup_force_cpu_cap(X86_FEATURE_RSB_CTXSW); - pr_info("Spectre v2 / SpectreRSB mitigation: Filling RSB on context switch\n"); - - spectre_v2_determine_rsb_fill_type_at_vmexit(mode); + spectre_v2_select_rsb_mitigation(mode); /* * Retpoline protects the kernel, but doesn't protect firmware. IBRS @@ -2607,6 +2608,7 @@ static void __init srso_select_mitigation(void) if (IS_ENABLED(CONFIG_CPU_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; /* @@ -2616,6 +2618,13 @@ 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 CPU_IBPB_ENTRY.\n"); @@ -2624,8 +2633,8 @@ static void __init srso_select_mitigation(void) break; case SRSO_CMD_IBPB_ON_VMEXIT: - if (IS_ENABLED(CONFIG_CPU_SRSO)) { - if (!boot_cpu_has(X86_FEATURE_ENTRY_IBPB) && has_microcode) { + if (IS_ENABLED(CONFIG_CPU_IBPB_ENTRY)) { + if (has_microcode) { setup_force_cpu_cap(X86_FEATURE_IBPB_ON_VMEXIT); srso_mitigation = SRSO_MITIGATION_IBPB_ON_VMEXIT; @@ -2637,9 +2646,9 @@ static void __init srso_select_mitigation(void) setup_clear_cpu_cap(X86_FEATURE_RSB_VMEXIT); } } else { - pr_err("WARNING: kernel not compiled with CPU_SRSO.\n"); + pr_err("WARNING: kernel not compiled with CPU_IBPB_ENTRY.\n"); goto pred_cmd; - } + } break; default: |