[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-changelog] [xen stable-4.4] x86/Intel: work around Xeon 7400 series erratum AAI65
commit 46e32001165a2d85cc6cda41240e6fbe9103bf07 Author: Jan Beulich <jbeulich@xxxxxxxx> AuthorDate: Fri Apr 4 10:42:18 2014 +0200 Commit: Jan Beulich <jbeulich@xxxxxxxx> CommitDate: Fri Apr 4 10:42:18 2014 +0200 x86/Intel: work around Xeon 7400 series erratum AAI65 Linux commit 40e2d7f9b5dae048789c64672bf3027fbb663ffa ("x86 idle: Repair large-server 50-watt idle-power regression") tells us that this applies not just to the named Xeon 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> Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> Acked-by: Kevin Tian <kevin.tian@xxxxxxxxx> master commit: 96d1b237ae9b2f2718bb1c59820701f17d3d86e0 master date: 2014-03-17 16:47:22 +0100 --- xen/arch/x86/acpi/cpu_idle.c | 3 +++ xen/arch/x86/cpu/intel.c | 7 +++++++ xen/include/asm-x86/cpufeature.h | 1 + 3 files changed, 11 insertions(+), 0 deletions(-) diff --git a/xen/arch/x86/acpi/cpu_idle.c b/xen/arch/x86/acpi/cpu_idle.c index 597befa..ab86c75 100644 --- a/xen/arch/x86/acpi/cpu_idle.c +++ b/xen/arch/x86/acpi/cpu_idle.c @@ -296,6 +296,9 @@ void mwait_idle_with_hints(unsigned int eax, unsigned int ecx) 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(); diff --git a/xen/arch/x86/cpu/intel.c b/xen/arch/x86/cpu/intel.c index 27fe762..992650f 100644 --- a/xen/arch/x86/cpu/intel.c +++ b/xen/arch/x86/cpu/intel.c @@ -147,6 +147,9 @@ void __devinit early_intel_workaround(struct cpuinfo_x86 *c) /* * 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_workarounds(struct cpuinfo_x86 *c) 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); } diff --git a/xen/include/asm-x86/cpufeature.h b/xen/include/asm-x86/cpufeature.h index 1cfaf94..526821f 100644 --- 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 */ -- generated by git-patchbot for /home/xen/git/xen.git#stable-4.4 _______________________________________________ Xen-changelog mailing list Xen-changelog@xxxxxxxxxxxxx http://lists.xensource.com/xen-changelog
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