diff options
Diffstat (limited to 'arch/x86/kernel/cpu/amd.c')
| -rw-r--r-- | arch/x86/kernel/cpu/amd.c | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c index 380753b14cab..571abf808ea3 100644 --- a/arch/x86/kernel/cpu/amd.c +++ b/arch/x86/kernel/cpu/amd.c @@ -880,6 +880,15 @@ void init_spectral_chicken(struct cpuinfo_x86 *c) } } #endif + /* + * Work around Erratum 1386. The XSAVES instruction malfunctions in + * certain circumstances on Zen1/2 uarch, and not all parts have had + * updated microcode at the time of writing (March 2023). + * + * Affected parts all have no supervisor XSAVE states, meaning that + * the XSAVEC instruction (which works fine) is equivalent. + */ + clear_cpu_cap(c, X86_FEATURE_XSAVES); } static void init_amd_zn(struct cpuinfo_x86 *c) @@ -920,6 +929,10 @@ static void init_amd(struct cpuinfo_x86 *c) if (c->x86 >= 0x10) set_cpu_cap(c, X86_FEATURE_REP_GOOD); + /* AMD FSRM also implies FSRS */ + if (cpu_has(c, X86_FEATURE_FSRM)) + set_cpu_cap(c, X86_FEATURE_FSRS); + /* get apicid instead of initial apic id from cpuid */ c->apicid = hard_smp_processor_id(); @@ -996,6 +1009,17 @@ static void init_amd(struct cpuinfo_x86 *c) msr_set_bit(MSR_K7_HWCR, MSR_K7_HWCR_IRPERF_EN_BIT); check_null_seg_clears_base(c); + + /* + * Make sure EFER[AIBRSE - Automatic IBRS Enable] is set. The APs are brought up + * using the trampoline code and as part of it, MSR_EFER gets prepared there in + * order to be replicated onto them. Regardless, set it here again, if not set, + * to protect against any future refactoring/code reorganization which might + * miss setting this important bit. + */ + if (spectre_v2_in_eibrs_mode(spectre_v2_enabled) && + cpu_has(c, X86_FEATURE_AUTOIBRS)) + WARN_ON_ONCE(msr_set_bit(MSR_EFER, _EFER_AUTOIBRS)); } #ifdef CONFIG_X86_32 |