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 <[email protected]>
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
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 <[email protected]>
>>
>> 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
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 <[email protected]>
>
> 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