| Message ID | 1401577506-4112-1-git-send-email-rickard_strandqvist@spectrumdigital.se (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
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 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 20316c6..88bf642 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -5691,13 +5691,17 @@ int kvm_hv_hypercall(struct kvm_vcpu *vcpu) outgpa = ((u64)kvm_register_read(vcpu, VCPU_REGS_RDI) << 32) | (kvm_register_read(vcpu, VCPU_REGS_RSI) & 0xffffffff); } -#ifdef CONFIG_X86_64 else { +#ifdef CONFIG_X86_64 param = kvm_register_read(vcpu, VCPU_REGS_RCX); ingpa = kvm_register_read(vcpu, VCPU_REGS_RDX); outgpa = kvm_register_read(vcpu, VCPU_REGS_R8); - } +#else + param = 0; + ingpa = 0; + outgpa = 0; #endif + } code = param & 0xffff; fast = (param >> 16) & 0x1;
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> --- arch/x86/kvm/x86.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)