Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754479AbaFCNLm (ORCPT ); Tue, 3 Jun 2014 09:11:42 -0400 Received: from mx1.redhat.com ([209.132.183.28]:27977 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754433AbaFCNLk (ORCPT ); Tue, 3 Jun 2014 09:11:40 -0400 Message-ID: <538DC978.5040300@redhat.com> Date: Tue, 03 Jun 2014 15:11:20 +0200 From: Paolo Bonzini User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.5.0 MIME-Version: 1.0 To: Michael Tokarev , Rickard Strandqvist , Gleb Natapov CC: Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , x86@kernel.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] arch: x86: kvm: x86.c: Cleaning up uninitialized variables References: <1401577506-4112-1-git-send-email-rickard_strandqvist@spectrumdigital.se> <538DB9B4.2070607@redhat.com> <538DC844.2040808@msgid.tls.msk.ru> In-Reply-To: <538DC844.2040808@msgid.tls.msk.ru> X-Enigmail-Version: 1.6 Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Il 03/06/2014 15:06, Michael Tokarev ha scritto: > 03.06.2014 16:04, Paolo Bonzini wrote: >> 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 >> >> 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: > > This is not the first time this code is attempted to be changed. > > Maybe adding an additional #ifdef..endif around the longmode > assignment and the "if" above will solve this for good? > > Or maybe something like this: > > #ifdef CONFIG_X86_64 > if (!(is_long_mode(vcpu) && cs_l == 1)) { > #else > if (1) { > #endif > 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); > } > 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); > } > > , to make it all explicit and obvious? ... and ugly too. If the first person who got the answer had reported a bug against cppcheck, this perhaps would have been avoided. Paolo -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/