From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:37423) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fHG3B-0005n5-ML for qemu-devel@nongnu.org; Fri, 11 May 2018 17:58:06 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fHG37-0003Oe-P2 for qemu-devel@nongnu.org; Fri, 11 May 2018 17:58:05 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:54478 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 1fHG37-0003OU-JD for qemu-devel@nongnu.org; Fri, 11 May 2018 17:58:01 -0400 Date: Sat, 12 May 2018 00:57:59 +0300 From: "Michael S. Tsirkin" Message-ID: <20180512005735-mutt-send-email-mst@kernel.org> References: <1523953455-28053-1-git-send-email-wanpengli@tencent.com> <20180417201904-mutt-send-email-mst@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Content-Transfer-Encoding: quoted-printable Subject: Re: [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: Wanpeng Li Cc: Paolo Bonzini , Eduardo Habkost , "qemu-devel@nongnu.org Developers" , kvm , Radim =?utf-8?B?S3LEjW3DocWZ?= On Wed, Apr 18, 2018 at 09:09:19AM +0800, Wanpeng Li wrote: > 2018-04-18 2:08 GMT+08:00 Michael S. Tsirkin : > > On Tue, Apr 17, 2018 at 01:24:15AM -0700, Wanpeng Li wrote: > >> From: Wanpeng Li > >> > >> This patch adds support for KVM_CAP_X86_DISABLE_EXITS. Provides user= space 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 Kr=C4=8Dm=C3=A1=C5=99 > >> 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 Ac= cumulation Single Precision */ > >> #define CPUID_7_0_EDX_SPEC_CTRL (1U << 26) /* Speculation Contr= ol */ > >> > >> +#define KVM_PV_UNHALT (1U << 7) > >> + > > > > Why don't we use KVM_FEATURE_PV_UNHALT from kvm_para.h? > > > >> #define KVM_HINTS_DEDICATED (1U << 0) > >> > > > > BTW I wonder whether we should switch to a value from > > kvm_para.h? I'll send a version to do it, pls take a look. >=20 > Yeah, your patchset looks good. >=20 > Regards, > Wanpeng Li Do you plan to rebase your patch and upstream it or do you expect me to do it? > > > > > >> #define CPUID_8000_0008_EBX_IBPB (1U << 12) /* Indirect Branch P= rediction 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 =3D kvm_check_extension(cs->kvm_state, KV= M_CAP_X86_DISABLE_EXITS); > >> + > >> + if (disable_exits) { > >> + disable_exits &=3D (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 &=3D ~KVM_X86_DISABLE_EXITS_HLT; > >> + } > >> + } > >> + if (kvm_vm_enable_cap(cs->kvm_state, KVM_CAP_X86_DISABLE_EX= ITS, 0, disable_exits)) { > >> + error_report("kvm: DISABLE EXITS not supported"); > >> + } > >> + } > >> + > >> qemu_add_vm_change_state_handler(cpu_update_state, env); > >> > >> c =3D cpuid_find_entry(&cpuid_data.cpuid, 1, 0); > >> -- > >> 2.7.4