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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7B310C433EF for ; Tue, 1 Mar 2022 16:01:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235937AbiCAQCF (ORCPT ); Tue, 1 Mar 2022 11:02:05 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60400 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235936AbiCAQB6 (ORCPT ); Tue, 1 Mar 2022 11:01:58 -0500 Received: from mail-pj1-x102b.google.com (mail-pj1-x102b.google.com [IPv6:2607:f8b0:4864:20::102b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 71B5CAA2E9 for ; Tue, 1 Mar 2022 08:01:17 -0800 (PST) Received: by mail-pj1-x102b.google.com with SMTP id b8so14425796pjb.4 for ; Tue, 01 Mar 2022 08:01:17 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=FOTnEnGACgB5Bk0D14/AB+9Z+trEttYfi5rz0BAbtxY=; b=I/HkopzXNorheEyhcZ/g76CVw+5ll/sQ/+aXHyYy0GCtNyb39Gco5O+XdpP2j2CTGR UCp1DFd6yS2gs1jCniIkJmuUYLBEArSEXPKdwIks79kh6iuoZQOzE/i/h+cpXLRzsJS+ ct42/TAF7A7jxr+lgGt90tdPIAl4isDw0cdKWNs3NmNdzwigV9aU/pZqWak28uEdOecw +NJ9JZljECf7fCgAfyMlRwYCcuHFdVXY9Jg4cXotUH9CXkvq5sSFUgo4tOJb69gcq/ED jbNtO3YqLJ5n/WhpP79q4bJVmlegR/q6saVmeX9KwVrbRd6jXhPjpHnNo7UimSUm3Ha3 wpyA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=FOTnEnGACgB5Bk0D14/AB+9Z+trEttYfi5rz0BAbtxY=; b=C+4k7Ay6uubqXJHXc6npDHJ0UKqttzezlTXj51eKTrEjYez4ENN/zCok5gBiHGqwyb umNWWyTQ6/3tJ7JC42jXtVKj6Qi973rP1Y31z+CHDO4X1GL1IpTUwDRXZEyEluwfq+UI A3p7+10lV60tV33QjRF1yOcixKF4cYGSIZoHcwOAQokPxe6TrKm/1/iipe62W446KQWb ENBzundHu4/LivuDZO8jIhsHfKGtuamscNXDWDmeN4sNk2flko7z/BEAlA8qEUrTCald t51boaHyLzPBcnz/RnicSA+enKOTFQa3pcZfgXZTCKxbTODj7deF6789FZ4nT141eQzn iriw== X-Gm-Message-State: AOAM531wYJRuzx9JyMcHgwH2akaFyFH1obacAA/g9K6pEM7FgLVxChzE bLGNUsl3JJqVC3rjuRumPFTZaQ== X-Google-Smtp-Source: ABdhPJwu+wbd17ov15qZLV0fRQZUccsU1xthamy45d06vJwkcDblxej43LRcZVyrB+uveMXngfSLQw== X-Received: by 2002:a17:902:f68b:b0:14f:c84c:ad6d with SMTP id l11-20020a170902f68b00b0014fc84cad6dmr26210741plg.155.1646150476695; Tue, 01 Mar 2022 08:01:16 -0800 (PST) Received: from google.com (157.214.185.35.bc.googleusercontent.com. [35.185.214.157]) by smtp.gmail.com with ESMTPSA id 124-20020a620582000000b004dee0e77128sm16390756pff.166.2022.03.01.08.01.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 01 Mar 2022 08:01:16 -0800 (PST) Date: Tue, 1 Mar 2022 16:01:12 +0000 From: Sean Christopherson To: Like Xu Cc: Paolo Bonzini , kvm@vger.kernel.org, Wanpeng Li , Jim Mattson , Vitaly Kuznetsov , Joerg Roedel , linux-kernel@vger.kernel.org Subject: Re: [PATCH] KVM: x86/i8259: Remove a dead store of irq in a conditional block Message-ID: References: <20220301120217.38092-1-likexu@tencent.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220301120217.38092-1-likexu@tencent.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Mar 01, 2022, Like Xu wrote: > From: Like Xu > > The [clang-analyzer-deadcode.DeadStores] helper reports > that the value stored to 'irq' is never read. > > Signed-off-by: Like Xu Reviewed-by: Sean Christopherson > --- > Note: not sure if "irq2 + 8" should be needed for "s->pics[0].irq_base + irq" Nope, IRQ 2 is used to cascade PIC controllers, and the two controllers have separate vector offsets/bases. The code was there in the original commit, 85f455f7ddbe ("KVM: Add support for in-kernel PIC emulation"), best guess is that it was leftover from development, e.g. maybe a flawed assumption the the second PIC's vector was simply +8?