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=-12.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 39360C433E2 for ; Sat, 12 Sep 2020 06:46:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E7FF3214D8 for ; Sat, 12 Sep 2020 06:46:27 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Tjc/rZwr" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725844AbgILGq0 (ORCPT ); Sat, 12 Sep 2020 02:46:26 -0400 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:28886 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725813AbgILGqX (ORCPT ); Sat, 12 Sep 2020 02:46:23 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1599893181; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=TFfBOM91iLP1SjI0vZrul8BPW6RVcNXYqE3XcKBqSQA=; b=Tjc/rZwr/ezAPC0jdyBKJuUf+xTkNr2nxlYRlXNvleEHmbTBwkiOFY5HZXEhDn/l7QKLBa QC6pTT375ija8EKcPkFjyNx7j81qEKnDZlAl7JV3nhQDwjNM18tcVnFdlvtJL5bsclzoCs d8/8C5jBve8MCU9raYEulkVFJompxEA= Received: from mail-wm1-f72.google.com (mail-wm1-f72.google.com [209.85.128.72]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-120-TKZAky5VNUO6HNYIrfdpmQ-1; Sat, 12 Sep 2020 02:46:19 -0400 X-MC-Unique: TKZAky5VNUO6HNYIrfdpmQ-1 Received: by mail-wm1-f72.google.com with SMTP id l26so2311639wmg.7 for ; Fri, 11 Sep 2020 23:46:19 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=TFfBOM91iLP1SjI0vZrul8BPW6RVcNXYqE3XcKBqSQA=; b=IGi7I93n65zFviSdCdRmB7O9cmU1FEAN1F9rK6XlSiLQlxWVw62DICO7MEgLUWsejI ON6UXU6o9dgIYAp/mU3V6idXRMAoLB7dH4TDOTs1IeDlM5Se1FSOB/aS8GCwhnkc5gn1 YkYtgj4QUNzCjfkXMZSG2Tz5a4JE8bMKse6pgibHrgBpux2rRvSX7B1jZWXx7QCGIhqh A8hR5yHYEJR/qkVU9LeYTYPFYP91A0LnTrIVfHRNv325Q3cp2z8/qq7hlo/2hK8+9PE7 BGcyU07qATiHgx2J92WD1JyToMKuin+Qin8+GJVleg0pNBBZMFwotemnNxz4/ExAXFGl foVA== X-Gm-Message-State: AOAM531TzmiNIsme0GVWikMb/iHaIrf0SdGWxcPQJ7k6YrEBdtapAYNI 3d4uC0RuIUk7HNED0jw3kLZTpk7eb0H5s6Q8AKlSzSG5VWjk63NPSD2xVr4SFhvXZvkaQ5XK717 ahYhiCT3JXnJAkmkzrPv9IZll X-Received: by 2002:adf:84c3:: with SMTP id 61mr5375726wrg.131.1599893178160; Fri, 11 Sep 2020 23:46:18 -0700 (PDT) X-Google-Smtp-Source: ABdhPJytNHdaGj7CH2JrSIfFxD6Mr0PL45XbVa+e8uovi64GV/yFY9bz3q4vtw91Ojua76ATT2UcUw== X-Received: by 2002:adf:84c3:: with SMTP id 61mr5375704wrg.131.1599893177896; Fri, 11 Sep 2020 23:46:17 -0700 (PDT) Received: from [192.168.10.150] ([93.56.170.5]) by smtp.gmail.com with ESMTPSA id p16sm8681576wro.71.2020.09.11.23.46.16 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 11 Sep 2020 23:46:17 -0700 (PDT) Subject: Re: [PATCH v2 5/9] KVM: LAPIC: Narrow down the kick target vCPU To: Wanpeng Li , linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel References: <1599731444-3525-1-git-send-email-wanpengli@tencent.com> <1599731444-3525-6-git-send-email-wanpengli@tencent.com> From: Paolo Bonzini Message-ID: <9281f28a-e2bd-a79c-fc94-4999f4c6307a@redhat.com> Date: Sat, 12 Sep 2020 08:46:15 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.11.0 MIME-Version: 1.0 In-Reply-To: <1599731444-3525-6-git-send-email-wanpengli@tencent.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/09/20 11:50, Wanpeng Li wrote: > From: Wanpeng Li > > The kick after setting KVM_REQ_PENDING_TIMER is used to handle the timer > fires on a different pCPU which vCPU is running on, this kick is expensive > since memory barrier, rcu, preemption disable/enable operations. We don't > need this kick when injecting already-expired timer, we also should call > out the VMX preemption timer case, which also passes from_timer_fn=false > but doesn't need a kick because kvm_lapic_expired_hv_timer() is called > from the target vCPU. > > Reviewed-by: Sean Christopherson > Signed-off-by: Wanpeng Li > --- > arch/x86/kvm/lapic.c | 4 +++- > arch/x86/kvm/x86.c | 6 ------ > arch/x86/kvm/x86.h | 1 - > 3 files changed, 3 insertions(+), 8 deletions(-) > > diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c > index e446bdf..3b32d3b 100644 > --- a/arch/x86/kvm/lapic.c > +++ b/arch/x86/kvm/lapic.c > @@ -1642,7 +1642,9 @@ static void apic_timer_expired(struct kvm_lapic *apic, bool from_timer_fn) > } > > atomic_inc(&apic->lapic_timer.pending); > - kvm_set_pending_timer(vcpu); > + kvm_make_request(KVM_REQ_PENDING_TIMER, vcpu); > + if (from_timer_fn) > + kvm_vcpu_kick(vcpu); > } This only matters for !APICv, but it's nice anyway. Paolo > static void start_sw_tscdeadline(struct kvm_lapic *apic) > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index d39d6cf..dcf4494 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -1774,12 +1774,6 @@ static s64 get_kvmclock_base_ns(void) > } > #endif > > -void kvm_set_pending_timer(struct kvm_vcpu *vcpu) > -{ > - kvm_make_request(KVM_REQ_PENDING_TIMER, vcpu); > - kvm_vcpu_kick(vcpu); > -} > - > static void kvm_write_wall_clock(struct kvm *kvm, gpa_t wall_clock) > { > int version; > diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h > index 995ab69..ea20b8b 100644 > --- a/arch/x86/kvm/x86.h > +++ b/arch/x86/kvm/x86.h > @@ -246,7 +246,6 @@ static inline bool kvm_vcpu_latch_init(struct kvm_vcpu *vcpu) > return is_smm(vcpu) || kvm_x86_ops.apic_init_signal_blocked(vcpu); > } > > -void kvm_set_pending_timer(struct kvm_vcpu *vcpu); > void kvm_inject_realmode_interrupt(struct kvm_vcpu *vcpu, int irq, int inc_eip); > > void kvm_write_tsc(struct kvm_vcpu *vcpu, struct msr_data *msr); >