From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752795AbeBIOQl (ORCPT ); Fri, 9 Feb 2018 09:16:41 -0500 Received: from mail-it0-f67.google.com ([209.85.214.67]:38655 "EHLO mail-it0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752696AbeBIOQ2 (ORCPT ); Fri, 9 Feb 2018 09:16:28 -0500 X-Google-Smtp-Source: AH8x224+gJzTyVEJ12hc+DKuayJn6KR8btPidGO0QrZuIrgm2BSih3Rl2efjEIOyi8Sm44G/wWdoDA== From: Wanpeng Li X-Google-Original-From: Wanpeng Li To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: Paolo Bonzini , =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= , Peter Zijlstra , Eduardo Habkost Subject: [PATCH v2] target-i386: add KVM_HINTS_DEDICATED performance hint Date: Fri, 9 Feb 2018 06:15:25 -0800 Message-Id: <1518185725-69559-1-git-send-email-wanpengli@tencent.com> X-Mailer: git-send-email 2.7.4 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Wanpeng Li 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 Cc: Radim Krčmář Cc: Eduardo Habkost Signed-off-by: Wanpeng Li --- v1 -> v2: * add a new feature word target/i386/cpu.c | 14 ++++++++++++++ target/i386/cpu.h | 3 +++ target/i386/kvm.c | 4 ++++ 3 files changed, 21 insertions(+) diff --git a/target/i386/cpu.c b/target/i386/cpu.c index d70954b..e2974ad 100644 --- a/target/i386/cpu.c +++ b/target/i386/cpu.c @@ -358,6 +358,20 @@ 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 = { + "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 f91e37d..9f73692 100644 --- a/target/i386/cpu.h +++ b/target/i386/cpu.h @@ -475,6 +475,7 @@ 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 */ @@ -670,6 +671,8 @@ 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 ad4b159..44ee524 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); -- 2.7.4