Messages in this thread | | | Date | Tue, 03 Jun 2014 15:11:20 +0200 | From | Paolo Bonzini <> | Subject | Re: [PATCH] arch: x86: kvm: x86.c: Cleaning up uninitialized variables |
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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 <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: > > 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
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