From nobody Sun Feb 8 12:38:57 2026 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1520885054023613.9714953069165; Mon, 12 Mar 2018 13:04:14 -0700 (PDT) Received: from localhost ([::1]:34354 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1evTg5-0001t8-C4 for importer@patchew.org; Mon, 12 Mar 2018 16:04:13 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:37136) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1evTcT-0008Ft-U6 for qemu-devel@nongnu.org; Mon, 12 Mar 2018 16:00:31 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1evTcS-0000zM-12 for qemu-devel@nongnu.org; Mon, 12 Mar 2018 16:00:30 -0400 Received: from mx1.redhat.com ([209.132.183.28]:44344) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1evTcR-0000yy-PF for qemu-devel@nongnu.org; Mon, 12 Mar 2018 16:00:27 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id F33B4C0587C9; Mon, 12 Mar 2018 20:00:26 +0000 (UTC) Received: from localhost (ovpn-116-64.gru2.redhat.com [10.97.116.64]) by smtp.corp.redhat.com (Postfix) with ESMTP id EBBC217D6F; Mon, 12 Mar 2018 20:00:24 +0000 (UTC) From: Eduardo Habkost To: Peter Maydell Date: Mon, 12 Mar 2018 17:00:20 -0300 Message-Id: <20180312200022.9760-2-ehabkost@redhat.com> In-Reply-To: <20180312200022.9760-1-ehabkost@redhat.com> References: <20180312200022.9760-1-ehabkost@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.32]); Mon, 12 Mar 2018 20:00:27 +0000 (UTC) Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PULL 1/3] target-i386: add KVM_HINTS_DEDICATED performance hint X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Paolo Bonzini , =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= , Wanpeng Li , qemu-devel@nongnu.org, Richard Henderson Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Type: text/plain; charset="utf-8" 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 Kr=C4=8Dm=C3=A1=C5=99 Cc: Eduardo Habkost Signed-off-by: Wanpeng Li Message-Id: <1518185725-69559-1-git-send-email-wanpengli@tencent.com> [ehabkost: Renamed property to kvm-hint-dedicated] Signed-off-by: Eduardo Habkost --- target/i386/cpu.h | 3 +++ target/i386/cpu.c | 14 ++++++++++++++ target/i386/kvm.c | 4 ++++ 3 files changed, 21 insertions(+) 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 Accumulat= ion Single Precision */ #define CPUID_7_0_EDX_SPEC_CTRL (1U << 26) /* Speculation Control */ =20 +#define KVM_HINTS_DEDICATED (1U << 0) + #define CPUID_8000_0008_EBX_IBPB (1U << 12) /* Indirect Branch Predicti= on Barrier */ =20 #define CPUID_XSAVE_XSAVEOPT (1U << 0) 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= ] =3D { .cpuid_eax =3D KVM_CPUID_FEATURES, .cpuid_reg =3D R_EAX, .tcg_features =3D TCG_KVM_FEATURES, }, + [FEAT_KVM_HINTS] =3D { + .feat_names =3D { + "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 =3D KVM_CPUID_FEATURES, .cpuid_reg =3D R_EDX, + .tcg_features =3D TCG_KVM_FEATURES, + }, [FEAT_HYPERV_EAX] =3D { .feat_names =3D { NULL /* hv_msr_vp_runtime_access */, NULL /* hv_msr_time_refco= unt_access */, 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, uint= 32_t function, if (!kvm_irqchip_in_kernel()) { ret &=3D ~(1U << KVM_FEATURE_PV_UNHALT); } + } else if (function =3D=3D KVM_CPUID_FEATURES && reg =3D=3D R_EDX) { + ret |=3D KVM_HINTS_DEDICATED; + found =3D 1; } =20 /* fallback for older kernels */ @@ -801,6 +804,7 @@ int kvm_arch_init_vcpu(CPUState *cs) c =3D &cpuid_data.entries[cpuid_i++]; c->function =3D KVM_CPUID_FEATURES | kvm_base; c->eax =3D env->features[FEAT_KVM]; + c->edx =3D env->features[FEAT_KVM_HINTS]; } =20 cpu_x86_cpuid(env, 0, 0, &limit, &unused, &unused, &unused); --=20 2.14.3