diff options
Diffstat (limited to 'arch/x86/kernel/cpu/amd.c')
| -rw-r--r-- | arch/x86/kernel/cpu/amd.c | 12 |
1 files changed, 6 insertions, 6 deletions
diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c index 169cb255c483..834f310b2f1a 100644 --- a/arch/x86/kernel/cpu/amd.c +++ b/arch/x86/kernel/cpu/amd.c @@ -1240,12 +1240,12 @@ bool cpu_has_ibpb_brtype_microcode(void) { u8 fam = boot_cpu_data.x86; - if (fam == 0x17) { - /* Zen1/2 IBPB flushes branch type predictions too. */ + /* Zen1/2 IBPB flushes branch type predictions too. */ + if (fam == 0x17) return boot_cpu_has(X86_FEATURE_AMD_IBPB); - } else if (fam == 0x19) { + /* Poke the MSR bit on Zen3/4 to check its presence. */ + else if (fam == 0x19) + return !wrmsrl_safe(MSR_IA32_PRED_CMD, PRED_CMD_SBPB); + else return false; - } - - return false; } |