[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] Ping: [PATCH] x86/Intel: work around Xeon 7400 series erratum AAI65
>>> On 05.03.14 at 17:52, "Jan Beulich" <JBeulich@xxxxxxxx> wrote: > Linux commit 40e2d7f9b5dae048789c64672bf3027fbb663ffa ("x86 idle: > Repair large-server 50-watt idle-power regression") tells us that this > applie snot just to the named Xen 7400 series, but also NHM-EX and > WSM-EX; sadly Intel's documentation is so badly searchable that I > wasn't able to locate the respective errata (and hence can't quote > their numbers here). > > Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx> > > --- a/xen/arch/x86/acpi/cpu_idle.c > +++ b/xen/arch/x86/acpi/cpu_idle.c > @@ -335,6 +335,9 @@ void mwait_idle_with_hints(unsigned int > unsigned int cpu = smp_processor_id(); > s_time_t expires = per_cpu(timer_deadline, cpu); > > + if ( boot_cpu_has(X86_FEATURE_CLFLUSH_MONITOR) ) > + clflush((void *)&mwait_wakeup(cpu)); > + > __monitor((void *)&mwait_wakeup(cpu), 0, 0); > smp_mb(); > > --- a/xen/arch/x86/cpu/intel.c > +++ b/xen/arch/x86/cpu/intel.c > @@ -147,6 +147,9 @@ void __devinit early_intel_workaround(st > /* > * P4 Xeon errata 037 workaround. > * Hardware prefetcher may cause stale data to be loaded into the cache. > + * > + * Xeon 7400 erratum AAI65 (and further newer Xeons) > + * MONITOR/MWAIT may have excessive false wakeups > */ > static void __devinit Intel_errata_workarounds(struct cpuinfo_x86 *c) > { > @@ -161,6 +164,10 @@ static void __devinit Intel_errata_worka > wrmsr (MSR_IA32_MISC_ENABLE, lo, hi); > } > } > + > + if (c->x86 == 6 && cpu_has_clflush && > + (c->x86_model == 29 || c->x86_model == 46 || c->x86_model == 47)) > + set_bit(X86_FEATURE_CLFLUSH_MONITOR, c->x86_capability); > } > > > --- a/xen/include/asm-x86/cpufeature.h > +++ b/xen/include/asm-x86/cpufeature.h > @@ -71,6 +71,7 @@ > #define X86_FEATURE_TSC_RELIABLE (3*32+12) /* TSC is known to be reliable */ > #define X86_FEATURE_XTOPOLOGY (3*32+13) /* cpu topology enum extensions */ > #define X86_FEATURE_CPUID_FAULTING (3*32+14) /* cpuid faulting */ > +#define X86_FEATURE_CLFLUSH_MONITOR (3*32+15) /* clflush reqd with monitor */ > > /* Intel-defined CPU features, CPUID level 0x00000001 (ecx), word 4 */ > #define X86_FEATURE_XMM3 (4*32+ 0) /* Streaming SIMD Extensions-3 */ _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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