From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:34119) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1f8LvM-0008WH-Bd for qemu-devel@nongnu.org; Tue, 17 Apr 2018 04:25:13 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1f8LvH-0007XF-E0 for qemu-devel@nongnu.org; Tue, 17 Apr 2018 04:25:12 -0400 Received: from mail-pf0-x241.google.com ([2607:f8b0:400e:c00::241]:43231) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1f8LvH-0007Wv-6L for qemu-devel@nongnu.org; Tue, 17 Apr 2018 04:25:07 -0400 Received: by mail-pf0-x241.google.com with SMTP id j11so5269330pff.10 for ; Tue, 17 Apr 2018 01:25:07 -0700 (PDT) From: Wanpeng Li Date: Tue, 17 Apr 2018 01:24:15 -0700 Message-Id: <1523953455-28053-1-git-send-email-wanpengli@tencent.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Subject: [Qemu-devel] [PATCH RESEND v2] i386/kvm: add support for KVM_CAP_X86_DISABLE_EXITS List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org, kvm@vger.kernel.org Cc: Paolo Bonzini , =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= , Eduardo Habkost From: Wanpeng Li This patch adds support for KVM_CAP_X86_DISABLE_EXITS. Provides userspace with per-VM capability(KVM_CAP_X86_DISABLE_EXITS) to not intercept MWAIT/HLT/PAUSE in order that to improve latency in some workloads. Cc: Paolo Bonzini Cc: Radim Krčmář Cc: Eduardo Habkost Signed-off-by: Wanpeng Li --- linux-headers/linux/kvm.h | 6 +++++- target/i386/cpu.h | 2 ++ target/i386/kvm.c | 16 ++++++++++++++++ 3 files changed, 23 insertions(+), 1 deletion(-) diff --git a/linux-headers/linux/kvm.h b/linux-headers/linux/kvm.h index a167be8..857df15 100644 --- a/linux-headers/linux/kvm.h +++ b/linux-headers/linux/kvm.h @@ -925,7 +925,7 @@ struct kvm_ppc_resize_hpt { #define KVM_CAP_S390_GS 140 #define KVM_CAP_S390_AIS 141 #define KVM_CAP_SPAPR_TCE_VFIO 142 -#define KVM_CAP_X86_GUEST_MWAIT 143 +#define KVM_CAP_X86_DISABLE_EXITS 143 #define KVM_CAP_ARM_USER_IRQ 144 #define KVM_CAP_S390_CMMA_MIGRATION 145 #define KVM_CAP_PPC_FWNMI 146 @@ -1508,6 +1508,10 @@ struct kvm_assigned_msix_entry { #define KVM_X2APIC_API_USE_32BIT_IDS (1ULL << 0) #define KVM_X2APIC_API_DISABLE_BROADCAST_QUIRK (1ULL << 1) +#define KVM_X86_DISABLE_EXITS_MWAIT (1 << 0) +#define KVM_X86_DISABLE_EXITS_HLT (1 << 1) +#define KVM_X86_DISABLE_EXITS_PAUSE (1 << 2) + /* Available with KVM_CAP_ARM_USER_IRQ */ /* Bits for run->s.regs.device_irq_level */ diff --git a/target/i386/cpu.h b/target/i386/cpu.h index 1b219fa..965de1b 100644 --- a/target/i386/cpu.h +++ b/target/i386/cpu.h @@ -685,6 +685,8 @@ 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_PV_UNHALT (1U << 7) + #define KVM_HINTS_DEDICATED (1U << 0) #define CPUID_8000_0008_EBX_IBPB (1U << 12) /* Indirect Branch Prediction Barrier */ diff --git a/target/i386/kvm.c b/target/i386/kvm.c index 6c49954..3e99830 100644 --- a/target/i386/kvm.c +++ b/target/i386/kvm.c @@ -1029,6 +1029,22 @@ int kvm_arch_init_vcpu(CPUState *cs) } } + if (env->features[FEAT_KVM_HINTS] & KVM_HINTS_DEDICATED) { + int disable_exits = kvm_check_extension(cs->kvm_state, KVM_CAP_X86_DISABLE_EXITS); + + if (disable_exits) { + disable_exits &= (KVM_X86_DISABLE_EXITS_MWAIT | + KVM_X86_DISABLE_EXITS_HLT | + KVM_X86_DISABLE_EXITS_PAUSE); + if (env->user_features[FEAT_KVM] & KVM_PV_UNHALT) { + disable_exits &= ~KVM_X86_DISABLE_EXITS_HLT; + } + } + if (kvm_vm_enable_cap(cs->kvm_state, KVM_CAP_X86_DISABLE_EXITS, 0, disable_exits)) { + error_report("kvm: DISABLE EXITS not supported"); + } + } + qemu_add_vm_change_state_handler(cpu_update_state, env); c = cpuid_find_entry(&cpuid_data.cpuid, 1, 0); -- 2.7.4