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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, 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 E8A2DC04AAC for ; Mon, 20 May 2019 12:56:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BED1D20645 for ; Mon, 20 May 2019 12:56:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733197AbfETM4F (ORCPT ); Mon, 20 May 2019 08:56:05 -0400 Received: from mail-wm1-f66.google.com ([209.85.128.66]:34836 "EHLO mail-wm1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732625AbfETM4E (ORCPT ); Mon, 20 May 2019 08:56:04 -0400 Received: by mail-wm1-f66.google.com with SMTP id q15so12934447wmj.0 for ; Mon, 20 May 2019 05:56:03 -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=POdzCkn+BD1xo1P2qkRXdnWiMHzE1h+gIx0vGRX+ho8=; b=WjxLLvzhcm86lah3jHAQ5NfVUiRYqo2VNMR4YMXmcKYnCJjML3+nCqe2Nz2z3rFvsv ONS4vjSHklbVBT0OhR6tWM2woZZEQqIhTk358V0/7MaxmLD1gbRLTz3vEHA2U71wVfj8 IJt3RDtN+6TjRMB7kNUpBwq5KSHKlpgvsWmH7m71B3TRqxmgmxaqq3yuEmeaInUcnTJM 1ogrcN3D5SUY60zXGGA+7W6mOViam4LEGTmnoFBcxuc1edYm7R88N0uPddTfKmf03HhZ 1yJ7zkVjdnwnvlWALxgpe6XYUihag7kYcwSeoXQs7lcfk0QByVydEHlVSedx+OsnPoyb txGg== X-Gm-Message-State: APjAAAV/TOY1RTXlsdlYOHVmhx8yJRd7HELtWogNdP2VZJxS8MGU2Wej FcmKIS4j+7MW4ZCyqXoUpmsqNA== X-Google-Smtp-Source: APXvYqx5pXXCwxwx4x3VvqGSmM62foFIjaxcXPie2D4bBE9OAyupnN+bbaEloCiMX9qJ4TNU8ne+BQ== X-Received: by 2002:a7b:c5cd:: with SMTP id n13mr7138843wmk.67.1558356962715; Mon, 20 May 2019 05:56:02 -0700 (PDT) Received: from ?IPv6:2001:b07:6468:f312:ac04:eef9:b257:b844? ([2001:b07:6468:f312:ac04:eef9:b257:b844]) by smtp.gmail.com with ESMTPSA id a10sm20115664wrm.94.2019.05.20.05.56.01 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 20 May 2019 05:56:02 -0700 (PDT) Subject: Re: [PATCH] svm/avic: Do not send AVIC doorbell to self To: "Suthikulpanit, Suravee" , "linux-kernel@vger.kernel.org" , "kvm@vger.kernel.org" Cc: "rkrcmar@redhat.com" , "joro@8bytes.org" References: <1556890721-9613-1-git-send-email-suravee.suthikulpanit@amd.com> From: Paolo Bonzini Message-ID: <4275b74a-a228-d2a3-cb7d-5abce0a86f59@redhat.com> Date: Mon, 20 May 2019 14:56:01 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <1556890721-9613-1-git-send-email-suravee.suthikulpanit@amd.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 03/05/19 15:38, Suthikulpanit, Suravee wrote: > AVIC doorbell is used to notify a running vCPU that interrupts > has been injected into the vCPU AVIC backing page. Current logic > checks only if a VCPU is running before sending a doorbell. > However, the doorbell is not necessary if the destination > CPU is itself. > > Add logic to check currently running CPU before sending doorbell. > > Signed-off-by: Suravee Suthikulpanit > --- > arch/x86/kvm/svm.c | 11 +++++++---- > 1 file changed, 7 insertions(+), 4 deletions(-) > > diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c > index 122788f..4bbf6fc 100644 > --- a/arch/x86/kvm/svm.c > +++ b/arch/x86/kvm/svm.c > @@ -5283,10 +5283,13 @@ static void svm_deliver_avic_intr(struct kvm_vcpu *vcpu, int vec) > kvm_lapic_set_irr(vec, vcpu->arch.apic); > smp_mb__after_atomic(); > > - if (avic_vcpu_is_running(vcpu)) > - wrmsrl(SVM_AVIC_DOORBELL, > - kvm_cpu_get_apicid(vcpu->cpu)); > - else > + if (avic_vcpu_is_running(vcpu)) { > + int cpuid = vcpu->cpu; > + > + if (cpuid != get_cpu()) > + wrmsrl(SVM_AVIC_DOORBELL, kvm_cpu_get_apicid(cpuid)); > + put_cpu(); > + } else > kvm_vcpu_wake_up(vcpu); > } > > Queued, thanks. Paolo