From mboxrd@z Thu Jan  1 00:00:00 1970
From: Paolo Bonzini <pbonzini@redhat.com>
Subject: Re: [PATCH] arch: x86: kvm: x86.c:  Cleaning up uninitialized variables
Date: Tue, 03 Jun 2014 14:04:04 +0200
Message-ID: <538DB9B4.2070607@redhat.com>
References: <1401577506-4112-1-git-send-email-rickard_strandqvist@spectrumdigital.se>
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Cc: Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>,
	"H. Peter Anvin" <hpa@zytor.com>, x86@kernel.org,
	kvm@vger.kernel.org, linux-kernel@vger.kernel.org
To: Rickard Strandqvist <rickard_strandqvist@spectrumdigital.se>,
	Gleb Natapov <gleb@kernel.org>
Return-path: <linux-kernel-owner@vger.kernel.org>
In-Reply-To: <1401577506-4112-1-git-send-email-rickard_strandqvist@spectrumdigital.se>
Sender: linux-kernel-owner@vger.kernel.org
List-Id: kvm.vger.kernel.org

Il 01/06/2014 01:05, Rickard Strandqvist ha scritto:
> There is a risk that the variable will be used without being initialized.
> 
> This was largely found by using a static code analysis program called cppcheck.
> 
> Signed-off-by: Rickard Strandqvist <rickard_strandqvist@spectrumdigital.se>

No, there isn't.  The full context looks like this:

        longmode = is_long_mode(vcpu) && cs_l == 1;
        if (!longmode) {
                param = ((u64)kvm_register_read(vcpu, VCPU_REGS_RDX) << 32) |
                        (kvm_register_read(vcpu, VCPU_REGS_RAX) & 0xffffffff);
                ingpa = ((u64)kvm_register_read(vcpu, VCPU_REGS_RBX) << 32) |
                        (kvm_register_read(vcpu, VCPU_REGS_RCX) & 0xffffffff);
                outgpa = ((u64)kvm_register_read(vcpu, VCPU_REGS_RDI) << 32) |
                        (kvm_register_read(vcpu, VCPU_REGS_RSI) & 0xffffffff);
        }
#ifdef CONFIG_X86_64
        else {
                param = kvm_register_read(vcpu, VCPU_REGS_RCX);
                ingpa = kvm_register_read(vcpu, VCPU_REGS_RDX);
                outgpa = kvm_register_read(vcpu, VCPU_REGS_R8);
        }
#endif

and longmode must be zero if !CONFIG_X86_64:

static inline int is_long_mode(struct kvm_vcpu *vcpu)
{
#ifdef CONFIG_X86_64
        return vcpu->arch.efer & EFER_LMA;
#else
        return 0;
#endif
}

So it's the static checker that cannot understand #ifdef well
enough and ought to be fixed.

Paolo