--- arch/x86/kernel/cpu/intel.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c index e5f34a90963e..4f8b02cbe8c5 100644 --- a/arch/x86/kernel/cpu/intel.c +++ b/arch/x86/kernel/cpu/intel.c @@ -297,6 +297,14 @@ static void early_init_intel(struct cpuinfo_x86 *c) c->x86_vfm <= INTEL_CORE_YONAH) clear_cpu_cap(c, X86_FEATURE_PAT); + /* + * Modern CPUs are generally expected to have a sane fast string + * implementation. However, the BIOS may disable it on certain CPUs + * via the architectural FAST_STRING bit. + */ + if (IS_ENABLED(CONFIG_X86_64) && (c->x86 == 6 || c->x86 > 15)) + set_cpu_cap(c, X86_FEATURE_REP_GOOD); + /* * If fast string is not enabled in IA32_MISC_ENABLE for any reason, * clear the fast string and enhanced fast string CPU capabilities. @@ -556,8 +564,6 @@ static void init_intel(struct cpuinfo_x86 *c) #ifdef CONFIG_X86_64 if (c->x86 == 15) c->x86_cache_alignment = c->x86_clflush_size * 2; - if (c->x86 == 6) - set_cpu_cap(c, X86_FEATURE_REP_GOOD); #else /* * Names for the Pentium II/Celeron processors -- 2.43.0
