From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,T_DKIMWL_WL_HIGH,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 64997C28CC0 for ; Wed, 29 May 2019 12:29:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3CB5B2081C for ; Wed, 29 May 2019 12:29:22 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="1vaQKuyI" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727086AbfE2M3U (ORCPT ); Wed, 29 May 2019 08:29:20 -0400 Received: from userp2130.oracle.com ([156.151.31.86]:60332 "EHLO userp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726960AbfE2M3T (ORCPT ); Wed, 29 May 2019 08:29:19 -0400 Received: from pps.filterd (userp2130.oracle.com [127.0.0.1]) by userp2130.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x4TCJCj6092062; Wed, 29 May 2019 12:28:41 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=content-type : mime-version : subject : from : in-reply-to : date : cc : content-transfer-encoding : message-id : references : to; s=corp-2018-07-02; bh=jzu0gfRpeQr3lgZAMVrA/Jz6k5UK87AqDwjxA5c2LmQ=; b=1vaQKuyIXrl4Lavh2BCp1tqrAF5BiatSmm4JFgYdlAeaRhTGPPUaf3Al+g+zR7NbxlqK Ea4ZZTz3z2ZRpQL6BAb2F6J30EgBEYuj5W2Z/5xCrGRBvgLaMPRUG++Ahdp1Tujrmm0c bXxxEF8qIis/FR0ag9z3oxi5udUbhXMTwHi9C5w9fgDUpjf+f04UDTynvD+H+CWMJj6D UyLW9a4MrJ/L37GccUfCmwfKy6UUCFG6g6L+mJZe3r1vsgd+kBX6okbilh4tyIBMIvE6 rIKcMi4n+6PFkSBnKb4m8wmvr2auITqsV6z888wn1Q7OiOrcTmTHOBWhrloUAZqHaBUA yQ== Received: from aserp3030.oracle.com (aserp3030.oracle.com [141.146.126.71]) by userp2130.oracle.com with ESMTP id 2spw4thb42-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 29 May 2019 12:28:41 +0000 Received: from pps.filterd (aserp3030.oracle.com [127.0.0.1]) by aserp3030.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x4TCRqcG188755; Wed, 29 May 2019 12:28:40 GMT Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by aserp3030.oracle.com with ESMTP id 2srbdxc11q-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 29 May 2019 12:28:40 +0000 Received: from abhmp0003.oracle.com (abhmp0003.oracle.com [141.146.116.9]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id x4TCSdpR030656; Wed, 29 May 2019 12:28:39 GMT Received: from [192.168.14.112] (/79.183.226.58) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Wed, 29 May 2019 05:28:39 -0700 Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (Mac OS X Mail 11.1 \(3445.4.7\)) Subject: Re: [PATCH v2 2/3] KVM: X86: Implement PV sched yield hypercall From: Liran Alon In-Reply-To: <1559004795-19927-3-git-send-email-wanpengli@tencent.com> Date: Wed, 29 May 2019 15:28:35 +0300 Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Paolo Bonzini , =?utf-8?B?UmFkaW0gS3LEjW3DocWZ?= Content-Transfer-Encoding: quoted-printable Message-Id: References: <1559004795-19927-1-git-send-email-wanpengli@tencent.com> <1559004795-19927-3-git-send-email-wanpengli@tencent.com> To: Wanpeng Li X-Mailer: Apple Mail (2.3445.4.7) X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9271 signatures=668687 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1905290083 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9271 signatures=668687 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1011 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1905290082 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > On 28 May 2019, at 3:53, Wanpeng Li wrote: >=20 > From: Wanpeng Li >=20 > The target vCPUs are in runnable state after vcpu_kick and suitable=20 > as a yield target. This patch implements the sched yield hypercall. >=20 > 17% performace increase of ebizzy benchmark can be observed in an=20 > over-subscribe environment. (w/ kvm-pv-tlb disabled, testing TLB flush=20= > call-function IPI-many since call-function is not easy to be trigged=20= > by userspace workload). >=20 > Cc: Paolo Bonzini > Cc: Radim Kr=C4=8Dm=C3=A1=C5=99 > Signed-off-by: Wanpeng Li > --- > arch/x86/kvm/x86.c | 24 ++++++++++++++++++++++++ > 1 file changed, 24 insertions(+) >=20 > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index e7e57de..2ceef51 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -7172,6 +7172,26 @@ void kvm_vcpu_deactivate_apicv(struct kvm_vcpu = *vcpu) > kvm_x86_ops->refresh_apicv_exec_ctrl(vcpu); > } >=20 > +void kvm_sched_yield(struct kvm *kvm, u64 dest_id) > +{ > + struct kvm_vcpu *target; > + struct kvm_apic_map *map; > + > + rcu_read_lock(); > + map =3D rcu_dereference(kvm->arch.apic_map); > + > + if (unlikely(!map)) > + goto out; > + We should have a bounds-check here on =E2=80=9Cdest_id=E2=80=9D. -Liran > + if (map->phys_map[dest_id]->vcpu) { > + target =3D map->phys_map[dest_id]->vcpu; > + kvm_vcpu_yield_to(target); > + } > + > +out: > + rcu_read_unlock(); > +} > + > int kvm_emulate_hypercall(struct kvm_vcpu *vcpu) > { > unsigned long nr, a0, a1, a2, a3, ret; > @@ -7218,6 +7238,10 @@ int kvm_emulate_hypercall(struct kvm_vcpu = *vcpu) > case KVM_HC_SEND_IPI: > ret =3D kvm_pv_send_ipi(vcpu->kvm, a0, a1, a2, a3, = op_64_bit); > break; > + case KVM_HC_SCHED_YIELD: > + kvm_sched_yield(vcpu->kvm, a0); > + ret =3D 0; > + break; > default: > ret =3D -KVM_ENOSYS; > break; > --=20 > 2.7.4 >=20