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=-10.1 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 0593AC433DF for ; Thu, 30 Jul 2020 00:57:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D56D1207F5 for ; Thu, 30 Jul 2020 00:57:01 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="PScGXoEr" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728311AbgG3A45 (ORCPT ); Wed, 29 Jul 2020 20:56:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43486 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726709AbgG3A4y (ORCPT ); Wed, 29 Jul 2020 20:56:54 -0400 Received: from mail-ot1-x341.google.com (mail-ot1-x341.google.com [IPv6:2607:f8b0:4864:20::341]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A1AFEC061794; Wed, 29 Jul 2020 17:56:54 -0700 (PDT) Received: by mail-ot1-x341.google.com with SMTP id q9so3234449oth.5; Wed, 29 Jul 2020 17:56:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=7VwGC5we8NqM1/WqIBKe+R0LI4Ddr3r8VHSb3CITwzE=; b=PScGXoErZ4EY/dcMyDRi4iDpWGOSewRjuyIKMrlTalG7wtmT091Lt9/sAWUYDwAizb BCOVQ8mNemL3Xyeq/DL0Oha973Qxmg1xvXizNdO1Q2bw1pMM0sMP0VfrNCIIyG3fFjlj y5jC8WjPtdtMl8LMTatvMHsxq1HzCqbs5rowcQkmCCrxSlZOIsF/82ZWjTjYQhzzcj2R VndzvkAxX6kQgpBWfryaNugjJ0Uy0ywd8oXn/hMzLCPY2BrEF4AOJnk74hETT94AEifl LGOwFVLh18IEZmN2S6EG08P5b9qvD77e+941IBd7wqM5eWR6N1Gt2/7/QpOCEEGvirGG +0FA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=7VwGC5we8NqM1/WqIBKe+R0LI4Ddr3r8VHSb3CITwzE=; b=nmgwpyN1lZYD+bHpj8uA6IfaeDdnusgvLZKoVTRuUuzxgDqqrcMMFELl1UEpfmSjhi lZTecH7bC1PMVXys5+sfqx5N7oe9us8uv/fkr8Tqqv3jVOkPIMNlIuQIgipBtD17Adfm d4pYM8VW5nuejskmcfL+qRHuPbXBuLFiPAzRn9o+FQaZsUukvwHftsY5vUqT2XRZna0y v7JAGBvfi0a7Xb03DrP5jNPpXmkykqW25qMjN4jGn5PGApMGFGg3pIRfyjnmukXJZ2F2 c5S93q8S25NQjrimosZbDJB/Px0cm1PYB0zi3rgtyRkwaWBPmm26XlcAZ2F4vSZltHzO +mDA== X-Gm-Message-State: AOAM531n6XJ15ZkgBoq2yFbuKlsHUirrhCCOYVEU3mY77XlFR5j8YDvZ hjxKvMySL7C9uELB/JpLZmSBCoZJyv/x9u+WDlU= X-Google-Smtp-Source: ABdhPJwkeeToi1bvgT2kK6So+NXMvcn8/ncDmL7dxNfHdEFMqAvWNpDMhVRqWyDmzoB1x0j8YMM+kmd3gX/NsczQwVg= X-Received: by 2002:a9d:37f5:: with SMTP id x108mr414581otb.254.1596070614099; Wed, 29 Jul 2020 17:56:54 -0700 (PDT) MIME-Version: 1.0 References: <1595929506-9203-1-git-send-email-wanpengli@tencent.com> <1595929506-9203-3-git-send-email-wanpengli@tencent.com> <87k0ymldg9.fsf@vitty.brq.redhat.com> In-Reply-To: <87k0ymldg9.fsf@vitty.brq.redhat.com> From: Wanpeng Li Date: Thu, 30 Jul 2020 08:56:42 +0800 Message-ID: Subject: Re: [PATCH v2 3/3] KVM: SVM: Fix disable pause loop exit/pause filtering capability on SVM To: Vitaly Kuznetsov Cc: LKML , kvm , Paolo Bonzini , Sean Christopherson , Wanpeng Li , Jim Mattson , Joerg Roedel Content-Type: text/plain; charset="UTF-8" Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Wed, 29 Jul 2020 at 20:21, Vitaly Kuznetsov wrote: > > Wanpeng Li writes: > > > From: Wanpeng Li > > > > Commit 8566ac8b (KVM: SVM: Implement pause loop exit logic in SVM) drops > > disable pause loop exit/pause filtering capability completely, I guess it > > is a merge fault by Radim since disable vmexits capabilities and pause > > loop exit for SVM patchsets are merged at the same time. This patch > > reintroduces the disable pause loop exit/pause filtering capability > > support. > > > > We can observe 2.9% hackbench improvement for a 92 vCPUs guest on AMD > > Rome Server. > > > > Reported-by: Haiwei Li > > Tested-by: Haiwei Li > > Fixes: 8566ac8b (KVM: SVM: Implement pause loop exit logic in SVM) > > Signed-off-by: Wanpeng Li > > --- > > arch/x86/kvm/svm/svm.c | 9 ++++++--- > > 1 file changed, 6 insertions(+), 3 deletions(-) > > > > diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c > > index c0da4dd..c20f127 100644 > > --- a/arch/x86/kvm/svm/svm.c > > +++ b/arch/x86/kvm/svm/svm.c > > @@ -1090,7 +1090,7 @@ static void init_vmcb(struct vcpu_svm *svm) > > svm->nested.vmcb = 0; > > svm->vcpu.arch.hflags = 0; > > > > - if (pause_filter_count) { > > + if (pause_filter_count && !kvm_pause_in_guest(svm->vcpu.kvm)) { > > control->pause_filter_count = pause_filter_count; > > if (pause_filter_thresh) > > control->pause_filter_thresh = pause_filter_thresh; > > @@ -2693,7 +2693,7 @@ static int pause_interception(struct vcpu_svm *svm) > > struct kvm_vcpu *vcpu = &svm->vcpu; > > bool in_kernel = (svm_get_cpl(vcpu) == 0); > > > > - if (pause_filter_thresh) > > + if (!kvm_pause_in_guest(vcpu->kvm)) > > grow_ple_window(vcpu); > > > > kvm_vcpu_on_spin(vcpu, in_kernel); > > @@ -3780,7 +3780,7 @@ static void svm_handle_exit_irqoff(struct kvm_vcpu *vcpu) > > > > static void svm_sched_in(struct kvm_vcpu *vcpu, int cpu) > > { > > - if (pause_filter_thresh) > > + if (!kvm_pause_in_guest(vcpu->kvm)) > > shrink_ple_window(vcpu); > > } > > > > @@ -3958,6 +3958,9 @@ static void svm_vm_destroy(struct kvm *kvm) > > > > static int svm_vm_init(struct kvm *kvm) > > { > > + if (!pause_filter_thresh) > > + kvm->arch.pause_in_guest = true; > > Would it make sense to do > > if (!pause_filter_count || !pause_filter_thresh) > kvm->arch.pause_in_guest = true; > > here and simplify the condition in init_vmcb()? kvm->arch.pause_in_guest can also be true when userspace sets the KVM_CAP_X86_DISABLE_EXITS capability, so we can't simplify the condition in init_vmcb(). Wanpeng