From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:46112) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1er3Io-0002lA-26 for qemu-devel@nongnu.org; Wed, 28 Feb 2018 10:05:55 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1er3Ij-0004A1-V3 for qemu-devel@nongnu.org; Wed, 28 Feb 2018 10:05:54 -0500 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:38494 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1er3Ij-00049j-QZ for qemu-devel@nongnu.org; Wed, 28 Feb 2018 10:05:49 -0500 References: <1518185725-69559-1-git-send-email-wanpengli@tencent.com> From: Paolo Bonzini Message-ID: Date: Wed, 28 Feb 2018 16:05:46 +0100 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [PATCH v2] target-i386: add KVM_HINTS_DEDICATED performance hint List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Wanpeng Li , kvm , "qemu-devel@nongnu.org Developers" Cc: =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= , Eduardo Habkost On 28/02/2018 13:31, Wanpeng Li wrote: > Ping, > 2018-02-09 22:15 GMT+08:00 Wanpeng Li : >> From: Wanpeng Li >> >> Add KVM_HINTS_DEDICATED performance hint, guest checks this feature bi= t >> to determine if they run on dedicated vCPUs, allowing optimizations su= ch >> as usage of qspinlocks. Eduardo is still on vacation; the patch is okay but the KVM parts are still in kvm/queue, so I'm just waiting for him (Radim owns the KVM tree right now). Feel free to post any patch on top of it. You can add Based-on: <1518185725-69559-1-git-send-email-wanpengli@tencent.com> when you post anything needing KVM_HINTS_DEDICATED, that way patchew can apply your series and test it correctly. Thanks, Paolo >> Cc: Paolo Bonzini >> Cc: Radim Kr=C4=8Dm=C3=A1=C5=99 >> 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] =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 { >> + "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_= 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 Accu= mulation 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 Pre= diction 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 &=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; >> } >> >> /* 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]; >> } >> >> cpu_x86_cpuid(env, 0, 0, &limit, &unused, &unused, &unused); >> -- >> 2.7.4 >>