diff options
| author | David Kaplan <david.kaplan@amd.com> | 2025-07-07 13:33:07 -0500 |
|---|---|---|
| committer | Borislav Petkov (AMD) <bp@alien8.de> | 2025-07-11 17:56:41 +0200 |
| commit | 9687eb2399379ae4e5b5cc1bccdf893c753dcffb (patch) | |
| tree | 4ee8ff4274517d32ae23ef45afa5e58a2072f4de | |
| parent | 19a5f3ea4394bf813a03d1ff0efe59a7f74cc12c (diff) | |
x86/bugs: Add attack vector controls for retbleed
Use attack vector controls to determine if retbleed mitigation is
required.
Disable SMT if cross-thread protection is desired and STIBP is not
available.
Signed-off-by: David Kaplan <david.kaplan@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/20250707183316.1349127-13-david.kaplan@amd.com
| -rw-r--r-- | arch/x86/kernel/cpu/bugs.c | 11 |
1 files changed, 8 insertions, 3 deletions
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index 130db820d49d..de6eb59fd485 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -1313,7 +1313,7 @@ early_param("retbleed", retbleed_parse_cmdline); static void __init retbleed_select_mitigation(void) { - if (!boot_cpu_has_bug(X86_BUG_RETBLEED) || cpu_mitigations_off()) { + if (!boot_cpu_has_bug(X86_BUG_RETBLEED)) { retbleed_mitigation = RETBLEED_MITIGATION_NONE; return; } @@ -1350,6 +1350,11 @@ static void __init retbleed_select_mitigation(void) if (retbleed_mitigation != RETBLEED_MITIGATION_AUTO) return; + if (!should_mitigate_vuln(X86_BUG_RETBLEED)) { + retbleed_mitigation = RETBLEED_MITIGATION_NONE; + return; + } + /* Intel mitigation selected in retbleed_update_mitigation() */ if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD || boot_cpu_data.x86_vendor == X86_VENDOR_HYGON) { @@ -1373,7 +1378,7 @@ static void __init retbleed_select_mitigation(void) static void __init retbleed_update_mitigation(void) { - if (!boot_cpu_has_bug(X86_BUG_RETBLEED) || cpu_mitigations_off()) + if (!boot_cpu_has_bug(X86_BUG_RETBLEED)) return; /* ITS can also enable stuffing */ @@ -1468,7 +1473,7 @@ static void __init retbleed_apply_mitigation(void) } if (mitigate_smt && !boot_cpu_has(X86_FEATURE_STIBP) && - (retbleed_nosmt || cpu_mitigations_auto_nosmt())) + (retbleed_nosmt || smt_mitigations == SMT_MITIGATIONS_ON)) cpu_smt_disable(false); } |