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=-0.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED 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 83F53C432C3 for ; Tue, 19 Nov 2019 12:27:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5574221850 for ; Tue, 19 Nov 2019 12:27:00 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="NLkWeI8u" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728002AbfKSM07 (ORCPT ); Tue, 19 Nov 2019 07:26:59 -0500 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:36480 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726555AbfKSM05 (ORCPT ); Tue, 19 Nov 2019 07:26:57 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1574166416; 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=J3mOxYKpBUtrD3Eqhq7wj1DaBWOdzGNG7B02AqP8/hk=; b=NLkWeI8ucX14T04b25xPQAKDIVsvWm9r1sJU41iuRVI49PqH1o5Ad4zOpTPB4kSmeM9SAX IBhDlH60NDojRgnI0GooYVT/1Dspzp9W36KkyyY1yj6iDGhsLvB3VeQjhmjtPXyRo20jUg NR8RdD0j920ad7nYgX41fxKb6tQKcbg= Received: from mail-wr1-f72.google.com (mail-wr1-f72.google.com [209.85.221.72]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-186--gp4uBufNUSA0e-H8apqKw-1; Tue, 19 Nov 2019 07:26:53 -0500 Received: by mail-wr1-f72.google.com with SMTP id p4so18100002wrw.15 for ; Tue, 19 Nov 2019 04:26:53 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:in-reply-to:references:date :message-id:mime-version; bh=awmu6I9Y99dmJSWRPIQLmc8tQlVRK2cI0mOpA3pzvDw=; b=Zy+SYI1hkaWUcjnIOr2TN+QGkGx1tsC/91RKEgbpGkN502aX1wtLm3BNuoovfT1FYZ AeHnrmqWV7W7cvB6g30M/itRO6su6+1jMoGEPozcDbqFcZ5i64//blJYWlufG0Z21mAz obGZxOnQwRLKFJ6sMh4HcocS2piR2ArtHK9y+DqTdTIAY2PtiplVehE6FStVxcEgBNbY uvB/d7+ciWudLyoccw6PJY4bKckBJ4bRT3EHl2wgC2dA6x2eaSvEd3zzEBQTqIlGrCc1 1NEs86/WVM/8g6DsbXk63Sb3ZzbQO+nbw7ijvSNUMCT2A/OLTrQfXksllgRM4pWunkIg jBow== X-Gm-Message-State: APjAAAW1c6jAYuTUrtDu1i9Re8mCzuCFj7XjuFyWyISGIDDUxDUNNgAD M4RJStinFpA9Jpf3mENNG9CK0FtpTnfPTPKCEOXTyuAXUN78gF0HV2WFTouIHCnFPl5pH6hUJUR hvXQ8DSkY3evnqNgROcJtNhpw X-Received: by 2002:a5d:4ecd:: with SMTP id s13mr24376672wrv.216.1574166412579; Tue, 19 Nov 2019 04:26:52 -0800 (PST) X-Google-Smtp-Source: APXvYqzB7t6Kre2ZE9oFyNHnTMEuPPAI1X0nkDnc5BMRHHjljrglZNrSttKN8ypZKLm/cv+A52kMjQ== X-Received: by 2002:a5d:4ecd:: with SMTP id s13mr24376651wrv.216.1574166412383; Tue, 19 Nov 2019 04:26:52 -0800 (PST) Received: from vitty.brq.redhat.com (nat-pool-brq-t.redhat.com. [213.175.37.10]) by smtp.gmail.com with ESMTPSA id n13sm2816854wmi.25.2019.11.19.04.26.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 19 Nov 2019 04:26:51 -0800 (PST) From: Vitaly Kuznetsov To: Wanpeng Li Cc: LKML , kvm , Paolo Bonzini , Radim =?utf-8?B?S3LEjW3DocWZ?= , Sean Christopherson , Wanpeng Li , Jim Mattson , Joerg Roedel Subject: Re: [PATCH v2 1/2] KVM: VMX: FIXED+PHYSICAL mode single target IPI fastpath In-Reply-To: References: <1574145389-12149-1-git-send-email-wanpengli@tencent.com> <87r224gjyt.fsf@vitty.brq.redhat.com> Date: Tue, 19 Nov 2019 13:26:51 +0100 Message-ID: <87lfscgigk.fsf@vitty.brq.redhat.com> MIME-Version: 1.0 X-MC-Unique: -gp4uBufNUSA0e-H8apqKw-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=WINDOWS-1252 Content-Transfer-Encoding: quoted-printable Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Wanpeng Li writes: > On Tue, 19 Nov 2019 at 19:54, Vitaly Kuznetsov wrot= e: >> >> Wanpeng Li writes: >> >> > From: Wanpeng Li >> > >> > + if (lapic_in_kernel(vcpu) && apic_x2apic_mode(vcpu->arch.apic)) = { >> > + /* >> > + * fastpath to IPI target, FIXED+PHYSICAL which is popul= ar >> > + */ >> > + index =3D kvm_rcx_read(vcpu); >> > + data =3D kvm_read_edx_eax(vcpu); >> > + >> > + if (((index - APIC_BASE_MSR) << 4 =3D=3D APIC_ICR) && >> >> What if index (RCX) is < APIC_BASE_MSR? > > How about if (index =3D=3D (APIC_BASE_MSR + 0x300) && > What about ' << 4', don't we still need it? :-) And better APIC_ICR instead of 0x300... Personally, I'd write something like if (index > APIC_BASE_MSR && (index - APIC_BASE_MSR) =3D=3D APIC_ICR >> 4) and let compiler optimize this, I bet it's going to be equally good. --=20 Vitaly