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SubjectRe: [PATCH] arch: x86: kvm: x86.c: Cleaning up uninitialized variables
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?

Thanks,

/mjt



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