diff options
Diffstat (limited to 'arch/x86/kernel/cpu/bugs.c')
| -rw-r--r-- | arch/x86/kernel/cpu/bugs.c | 16 |
1 files changed, 11 insertions, 5 deletions
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index b6f927f6c567..45675da354f3 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -1625,6 +1625,7 @@ static bool __init spec_ctrl_bhi_dis(void) enum bhi_mitigations { BHI_MITIGATION_OFF, BHI_MITIGATION_ON, + BHI_MITIGATION_VMEXIT_ONLY, }; static enum bhi_mitigations bhi_mitigation __ro_after_init = @@ -1639,6 +1640,8 @@ static int __init spectre_bhi_parse_cmdline(char *str) bhi_mitigation = BHI_MITIGATION_OFF; else if (!strcmp(str, "on")) bhi_mitigation = BHI_MITIGATION_ON; + else if (!strcmp(str, "vmexit")) + bhi_mitigation = BHI_MITIGATION_VMEXIT_ONLY; else pr_err("Ignoring unknown spectre_bhi option (%s)", str); @@ -1659,19 +1662,22 @@ static void __init bhi_select_mitigation(void) return; } + /* Mitigate in hardware if supported */ if (spec_ctrl_bhi_dis()) return; if (!IS_ENABLED(CONFIG_X86_64)) return; - /* Mitigate KVM by default */ - setup_force_cpu_cap(X86_FEATURE_CLEAR_BHB_LOOP_ON_VMEXIT); - pr_info("Spectre BHI mitigation: SW BHB clearing on vm exit\n"); + if (bhi_mitigation == BHI_MITIGATION_VMEXIT_ONLY) { + pr_info("Spectre BHI mitigation: SW BHB clearing on VM exit only\n"); + setup_force_cpu_cap(X86_FEATURE_CLEAR_BHB_LOOP_ON_VMEXIT); + return; + } - /* Mitigate syscalls when the mitigation is forced =on */ + pr_info("Spectre BHI mitigation: SW BHB clearing on syscall and VM exit\n"); setup_force_cpu_cap(X86_FEATURE_CLEAR_BHB_LOOP); - pr_info("Spectre BHI mitigation: SW BHB clearing on syscall\n"); + setup_force_cpu_cap(X86_FEATURE_CLEAR_BHB_LOOP_ON_VMEXIT); } static void __init spectre_v2_select_mitigation(void) |