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authorWanpeng Li <wanpengli@tencent.com>2018-02-09 06:15:25 -0800
committerEduardo Habkost <ehabkost@redhat.com>2018-03-12 15:57:39 -0300
commitbe7773268d98176489483a315d3e2323cb0615b9 (patch)
tree04b4bf0a8a714996bac98ac8ec5af7f52edce048 /target/i386
parentb16a54da0696efc5d91b6c3597a37a317abb5de7 (diff)
target-i386: add KVM_HINTS_DEDICATED performance hint
Add KVM_HINTS_DEDICATED performance hint, guest checks this feature bit to determine if they run on dedicated vCPUs, allowing optimizations such as usage of qspinlocks. Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Radim Krčmář <rkrcmar@redhat.com> Cc: Eduardo Habkost <ehabkost@redhat.com> Signed-off-by: Wanpeng Li <wanpengli@tencent.com> Message-Id: <1518185725-69559-1-git-send-email-wanpengli@tencent.com> [ehabkost: Renamed property to kvm-hint-dedicated] Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Diffstat (limited to 'target/i386')
-rw-r--r--target/i386/cpu.c14
-rw-r--r--target/i386/cpu.h3
-rw-r--r--target/i386/kvm.c4
3 files changed, 21 insertions, 0 deletions
diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index 2c04645cea..5ea1931b7e 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -359,6 +359,20 @@ static FeatureWordInfo feature_word_info[FEATURE_WORDS] = {
.cpuid_eax = KVM_CPUID_FEATURES, .cpuid_reg = R_EAX,
.tcg_features = TCG_KVM_FEATURES,
},
+ [FEAT_KVM_HINTS] = {
+ .feat_names = {
+ "kvm-hint-dedicated", NULL, NULL, NULL,
+ NULL, NULL, NULL, NULL,
+ NULL, NULL, NULL, NULL,
+ NULL, NULL, NULL, NULL,
+ NULL, NULL, NULL, NULL,
+ NULL, NULL, NULL, NULL,
+ NULL, NULL, NULL, NULL,
+ NULL, NULL, NULL, NULL,
+ },
+ .cpuid_eax = KVM_CPUID_FEATURES, .cpuid_reg = R_EDX,
+ .tcg_features = TCG_KVM_FEATURES,
+ },
[FEAT_HYPERV_EAX] = {
.feat_names = {
NULL /* hv_msr_vp_runtime_access */, NULL /* hv_msr_time_refcount_access */,
diff --git a/target/i386/cpu.h b/target/i386/cpu.h
index faf39ec1ce..8d977ec567 100644
--- a/target/i386/cpu.h
+++ b/target/i386/cpu.h
@@ -471,6 +471,7 @@ typedef enum FeatureWord {
FEAT_8000_0008_EBX, /* CPUID[8000_0008].EBX */
FEAT_C000_0001_EDX, /* CPUID[C000_0001].EDX */
FEAT_KVM, /* CPUID[4000_0001].EAX (KVM_CPUID_FEATURES) */
+ FEAT_KVM_HINTS, /* CPUID[4000_0001].EDX */
FEAT_HYPERV_EAX, /* CPUID[4000_0003].EAX */
FEAT_HYPERV_EBX, /* CPUID[4000_0003].EBX */
FEAT_HYPERV_EDX, /* CPUID[4000_0003].EDX */
@@ -666,6 +667,8 @@ typedef uint32_t FeatureWordArray[FEATURE_WORDS];
#define CPUID_7_0_EDX_AVX512_4FMAPS (1U << 3) /* AVX512 Multiply Accumulation Single Precision */
#define CPUID_7_0_EDX_SPEC_CTRL (1U << 26) /* Speculation Control */
+#define KVM_HINTS_DEDICATED (1U << 0)
+
#define CPUID_8000_0008_EBX_IBPB (1U << 12) /* Indirect Branch Prediction Barrier */
#define CPUID_XSAVE_XSAVEOPT (1U << 0)
diff --git a/target/i386/kvm.c b/target/i386/kvm.c
index ad4b159b28..44ee524188 100644
--- a/target/i386/kvm.c
+++ b/target/i386/kvm.c
@@ -383,6 +383,9 @@ uint32_t kvm_arch_get_supported_cpuid(KVMState *s, uint32_t function,
if (!kvm_irqchip_in_kernel()) {
ret &= ~(1U << KVM_FEATURE_PV_UNHALT);
}
+ } else if (function == KVM_CPUID_FEATURES && reg == R_EDX) {
+ ret |= KVM_HINTS_DEDICATED;
+ found = 1;
}
/* fallback for older kernels */
@@ -801,6 +804,7 @@ int kvm_arch_init_vcpu(CPUState *cs)
c = &cpuid_data.entries[cpuid_i++];
c->function = KVM_CPUID_FEATURES | kvm_base;
c->eax = env->features[FEAT_KVM];
+ c->edx = env->features[FEAT_KVM_HINTS];
}
cpu_x86_cpuid(env, 0, 0, &limit, &unused, &unused, &unused);