[PATCH 1/3] cpu/bugs: Fix selecting Automatic IBRS using spectre_v2=eibrs
From: Kim Phillips
Date: Tue Feb 24 2026 - 13:17:11 EST
The original commit that added support for Automatic IBRS neglected
to amend a condition to include AUTOIBRS in addition to the
X86_FEATURE_IBRS_ENHANCED check. Fix that, and another couple
of minor outliers.
Fixes: e7862eda309e ("x86/cpu: Support AMD Automatic IBRS")
Reported-by: Tom Lendacky <thomas.lendacky@xxxxxxx>
Cc: Borislav Petkov (AMD) <bp@xxxxxxxxx>
Cc: stable@xxxxxxxxxx
Signed-off-by: Kim Phillips <kim.phillips@xxxxxxx>
---
arch/x86/kernel/cpu/bugs.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index d0a2847a4bb0..4eefbff4b19a 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -2136,7 +2136,8 @@ static void __init spectre_v2_select_mitigation(void)
if ((spectre_v2_cmd == SPECTRE_V2_CMD_EIBRS ||
spectre_v2_cmd == SPECTRE_V2_CMD_EIBRS_LFENCE ||
spectre_v2_cmd == SPECTRE_V2_CMD_EIBRS_RETPOLINE) &&
- !boot_cpu_has(X86_FEATURE_IBRS_ENHANCED)) {
+ !(boot_cpu_has(X86_FEATURE_IBRS_ENHANCED) ||
+ boot_cpu_has(X86_FEATURE_AUTOIBRS))) {
pr_err("EIBRS selected but CPU doesn't have Enhanced or Automatic IBRS. Switching to AUTO select\n");
spectre_v2_cmd = SPECTRE_V2_CMD_AUTO;
}
@@ -2182,7 +2183,8 @@ static void __init spectre_v2_select_mitigation(void)
break;
fallthrough;
case SPECTRE_V2_CMD_FORCE:
- if (boot_cpu_has(X86_FEATURE_IBRS_ENHANCED)) {
+ if (boot_cpu_has(X86_FEATURE_IBRS_ENHANCED) ||
+ boot_cpu_has(X86_FEATURE_AUTOIBRS)) {
spectre_v2_enabled = SPECTRE_V2_EIBRS;
break;
}
@@ -2262,7 +2264,8 @@ static void __init spectre_v2_apply_mitigation(void)
case SPECTRE_V2_IBRS:
setup_force_cpu_cap(X86_FEATURE_KERNEL_IBRS);
- if (boot_cpu_has(X86_FEATURE_IBRS_ENHANCED))
+ if (boot_cpu_has(X86_FEATURE_IBRS_ENHANCED) ||
+ boot_cpu_has(X86_FEATURE_AUTOIBRS))
pr_warn(SPECTRE_V2_IBRS_PERF_MSG);
break;
--
2.43.0