From 303752a9068bfe84b9b05f1cd5ad5ff65b7f3ea6 Mon Sep 17 00:00:00 2001 From: Marcelo Tosatti Date: Wed, 30 Apr 2014 13:48:45 -0300 Subject: target-i386: Support "invariant tsc" flag MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Expose "Invariant TSC" flag, if KVM is enabled. From Intel documentation: 17.13.1 Invariant TSC The time stamp counter in newer processors may support an enhancement, referred to as invariant TSC. Processor’s support for invariant TSC is indicated by CPUID.80000007H:EDX[8]. The invariant TSC will run at a constant rate in all ACPI P-, C-. and T-states. This is the architectural behavior moving forward. On processors with invariant TSC support, the OS may use the TSC for wall clock timer services (instead of ACPI or HPET timers). TSC reads are much more efficient and do not incur the overhead associated with a ring transition or access to a platform resource. Signed-off-by: Marcelo Tosatti [ehabkost: redo feature filtering to use .tcg_features] [ehabkost: add CPUID_APM_INVTSC macro, add it to .unmigratable_flags] Signed-off-by: Eduardo Habkost Signed-off-by: Andreas Färber --- target-i386/cpu.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'target-i386/cpu.h') diff --git a/target-i386/cpu.h b/target-i386/cpu.h index b5e1b41..e634d83 100644 --- a/target-i386/cpu.h +++ b/target-i386/cpu.h @@ -402,6 +402,7 @@ typedef enum FeatureWord { FEAT_7_0_EBX, /* CPUID[EAX=7,ECX=0].EBX */ FEAT_8000_0001_EDX, /* CPUID[8000_0001].EDX */ FEAT_8000_0001_ECX, /* CPUID[8000_0001].ECX */ + FEAT_8000_0007_EDX, /* CPUID[8000_0007].EDX */ FEAT_C000_0001_EDX, /* CPUID[C000_0001].EDX */ FEAT_KVM, /* CPUID[4000_0001].EAX (KVM_CPUID_FEATURES) */ FEAT_SVM, /* CPUID[8000_000A].EDX */ @@ -561,6 +562,9 @@ typedef uint32_t FeatureWordArray[FEATURE_WORDS]; #define CPUID_7_0_EBX_ADX (1U << 19) #define CPUID_7_0_EBX_SMAP (1U << 20) +/* CPUID[0x80000007].EDX flags: */ +#define CPUID_APM_INVTSC (1U << 8) + #define CPUID_VENDOR_SZ 12 #define CPUID_VENDOR_INTEL_1 0x756e6547 /* "Genu" */ -- cgit v1.1