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=-0.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 87409C43215 for ; Tue, 19 Nov 2019 12:26:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5A40920730 for ; Tue, 19 Nov 2019 12:26:57 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="bN2FxnB1" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727890AbfKSM04 (ORCPT ); Tue, 19 Nov 2019 07:26:56 -0500 Received: from us-smtp-1.mimecast.com ([205.139.110.61]:30296 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726555AbfKSM0z (ORCPT ); Tue, 19 Nov 2019 07:26:55 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1574166414; 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=bN2FxnB10vB131p8Xkt55M12mxH5qcXTH0IBtZhpxw1sLXHlCIAXen2J7TnxKcQLEa286n zSffA3OJer/8O5aZBM5UkHWIlro3B1pXGhrurB5sGED8HlANh79mE9jkwk+bYcdBvk7sUb RExAEKNi3GljIWJTxUTQ+r1icB8tJm8= 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-84--MEvi0MTNgyR8BABDs7p2A-1; Tue, 19 Nov 2019 07:26:53 -0500 Received: by mail-wm1-f72.google.com with SMTP id f14so2177400wmc.0 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=nUwhTu16El0K+pzbCwXu4rx43EyemDw1RCz3KRWkQOSNSWx+e7kiGliKnEDT7/AEcq DjaCdeXJU7qYoHgOadeHss0zy1Z7lR7lfcn41c4ej9rdIilK0bN576X6ExF8oHXcJli8 JKBkXCcMsWFJ4EQX9and0SeNSqn2zfPMl23XJn4ZtBuQlOhL1Np66dij/dbG5YyF1Px5 t1Naly32ITbRlr58bFhD5h7kj7qzcjYa89PJw0dIUMBRi/gOM53gK8HWE7hsgbidNSut E5eUXQrRwcwuWEmq+/GX0W5KTDy10QSY1leJp226ddv/GIq3udC8MY7dJsDP2P0aQG87 B2cA== X-Gm-Message-State: APjAAAUPFYGo0Fl8i/yrkYsXNm7AHlatCh8VoEUY2PRBBhO6UpjI8KGb ykO8KYJH/WAgox52tzgrIYu81bsIyFZ9a0bTsOhd34kyxVhTyiXsFhUWCApvDU1FV3Rx2x9ht6j 8VszUbmGWpX3e X-Received: by 2002:a5d:4ecd:: with SMTP id s13mr24376671wrv.216.1574166412578; 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: -MEvi0MTNgyR8BABDs7p2A-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=WINDOWS-1252 Content-Transfer-Encoding: quoted-printable Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@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