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=-2.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 65693C3A5A9 for ; Mon, 4 May 2020 17:07:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 41662206C0 for ; Mon, 4 May 2020 17:07:00 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="GPY1Wbuq" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729928AbgEDRG7 (ORCPT ); Mon, 4 May 2020 13:06:59 -0400 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:24842 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728158AbgEDRG7 (ORCPT ); Mon, 4 May 2020 13:06:59 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1588612017; 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=qM6cBcDrv7XvtKNZfJ9tygW5NlSD4IQZrqyuCyi/QkE=; b=GPY1Wbuqc/jJIfG5fxx4WVf8y7LltsTHhtbGdNk36F1oLrPHYAcy57rpXETwxbycFy77gZ lHberMU4uas//dTEMBoHnvw6Ce2paPoc4+rAWU7+/P7OLDT5maW/nc/5tmlY6wb2eCjtFQ munquh0Eyf1Txj0XUZgeAGWJZpd1g9w= Received: from mail-wr1-f71.google.com (mail-wr1-f71.google.com [209.85.221.71]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-267-yV9g12gtOcifytI6bikVfg-1; Mon, 04 May 2020 13:06:55 -0400 X-MC-Unique: yV9g12gtOcifytI6bikVfg-1 Received: by mail-wr1-f71.google.com with SMTP id j16so13970wrw.20 for ; Mon, 04 May 2020 10:06:55 -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=qM6cBcDrv7XvtKNZfJ9tygW5NlSD4IQZrqyuCyi/QkE=; b=nsT4+Is1KwRbmKpoNUNpwvx9kGPEDW0/FOte0uycG1oEc6KNaGnhehDoqqE7CEAJay rqsJPd/dlJB5eSCs8ziHx3u0PSrYrBhUmmghQxdkdtnL3LsNNIjxSxAlL/WWwyWMeDDA NtM7/E5SIiWnsbVqBn9ze96iQr371iE1lO1NdYZ92J5CjrknV307cnTfjZltXCo40tvs h9wCq53StJMgLcUmImC5gjo1A+nC+6MLjTdmRhrcf1Ae72ANwPcQrLbg+rRVRw0juLlr YxeFI5i4EGRUTF2/B6XkilovbgDlG3cHKow1cLSUocFZEqpaxT6ZTPaU+13tYIBC7Cdx 88kg== X-Gm-Message-State: AGi0PuYStU6qf8DHrPB6nu0NNP17XmyhP/5//Rv8hDt+UCDP7d1yV3qK 6P3Pnes7CYC+R3uBk77Yl9LzavzpGUArJ0rK2kgD+Qbz1byT6txJCXaEtvGeWjEyjpN4/bP3gxR gT9JtgLV7KESsvUlnqPf8/Zza X-Received: by 2002:a1c:c302:: with SMTP id t2mr16273729wmf.85.1588612014739; Mon, 04 May 2020 10:06:54 -0700 (PDT) X-Google-Smtp-Source: APiQypLCobPwEfAYjjdMh4VD49vcI+LbaenE5QaeltpkG+Q9TXPlbUuum+mLzyOuaiLQN9CRB9k2yA== X-Received: by 2002:a1c:c302:: with SMTP id t2mr16273705wmf.85.1588612014488; Mon, 04 May 2020 10:06:54 -0700 (PDT) Received: from [192.168.178.58] ([151.20.132.175]) by smtp.gmail.com with ESMTPSA id r2sm94839wmg.2.2020.05.04.10.06.53 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 04 May 2020 10:06:53 -0700 (PDT) Subject: Re: [PATCH v4 2/7] KVM: X86: Enable fastpath when APICv is enabled To: Vitaly Kuznetsov , Wanpeng Li , linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: Sean Christopherson , Wanpeng Li , Jim Mattson , Joerg Roedel , Haiwei Li References: <1588055009-12677-1-git-send-email-wanpengli@tencent.com> <1588055009-12677-3-git-send-email-wanpengli@tencent.com> <87a72tf67l.fsf@vitty.brq.redhat.com> From: Paolo Bonzini Message-ID: <906b09e3-edcf-9d0e-e43b-ae77741c55e9@redhat.com> Date: Mon, 4 May 2020 19:06:53 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.6.0 MIME-Version: 1.0 In-Reply-To: <87a72tf67l.fsf@vitty.brq.redhat.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 30/04/20 15:34, Vitaly Kuznetsov wrote: >> static enum exit_fastpath_completion vmx_exit_handlers_fastpath(struct kvm_vcpu *vcpu) >> { >> - if (!is_guest_mode(vcpu)) { >> + if (!is_guest_mode(vcpu) && vcpu->arch.apicv_active) { >> switch (to_vmx(vcpu)->exit_reason) { >> case EXIT_REASON_MSR_WRITE: >> return handle_fastpath_set_msr_irqoff(vcpu); > I think that apicv_active checks are specific to APIC MSRs but > handle_fastpath_set_msr_irqoff() can handle any other MSR as well. I'd > suggest to move the check inside handle_fastpath_set_msr_irqoff(). > > Also, enabling Hyper-V SynIC leads to disabling apicv. It it still > pointless to keep fastpath enabled? Indeed, only fast paths that only apply to apicv should be disabled (and ideally there should be a WARN_ON in the code that doesn't support !apicv). Paolo