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From: Sean Christopherson <seanjc@google.com>
To: Like Xu <like.xu.linux@gmail.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
	kvm@vger.kernel.org, Wanpeng Li <wanpengli@tencent.com>,
	Jim Mattson <jmattson@google.com>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	Joerg Roedel <joro@8bytes.org>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] KVM: x86/i8259: Remove a dead store of irq in a conditional block
Date: Tue, 1 Mar 2022 16:01:12 +0000	[thread overview]
Message-ID: <Yh5DSMiqDrMPb/YH@google.com> (raw)
In-Reply-To: <20220301120217.38092-1-likexu@tencent.com>

On Tue, Mar 01, 2022, Like Xu wrote:
> From: Like Xu <likexu@tencent.com>
> 
> The [clang-analyzer-deadcode.DeadStores] helper reports
> that the value stored to 'irq' is never read.
> 
> Signed-off-by: Like Xu <likexu@tencent.com>

Reviewed-by: Sean Christopherson <seanjc@google.com>

> ---
> 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?

  reply	other threads:[~2022-03-01 16:01 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-03-01 12:02 [PATCH] KVM: x86/i8259: Remove a dead store of irq in a conditional block Like Xu
2022-03-01 16:01 ` Sean Christopherson [this message]
2022-03-15 21:38 ` Paolo Bonzini

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