* [PATCH] arch: x86: kvm: x86.c: Cleaning up uninitialized variables @ 2014-05-31 23:05 Rickard Strandqvist 2014-06-03 12:04 ` Paolo Bonzini 0 siblings, 1 reply; 4+ messages in thread From: Rickard Strandqvist @ 2014-05-31 23:05 UTC (permalink / raw) To: Gleb Natapov, Paolo Bonzini Cc: Rickard Strandqvist, Thomas Gleixner, Ingo Molnar, H. Peter Anvin, x86, kvm, linux-kernel 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(-) 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; -- 1.7.10.4 ^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] arch: x86: kvm: x86.c: Cleaning up uninitialized variables 2014-05-31 23:05 [PATCH] arch: x86: kvm: x86.c: Cleaning up uninitialized variables Rickard Strandqvist @ 2014-06-03 12:04 ` Paolo Bonzini 2014-06-03 13:06 ` Michael Tokarev 0 siblings, 1 reply; 4+ messages in thread From: Paolo Bonzini @ 2014-06-03 12:04 UTC (permalink / raw) To: Rickard Strandqvist, Gleb Natapov Cc: Thomas Gleixner, Ingo Molnar, H. Peter Anvin, x86, kvm, linux-kernel 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 ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] arch: x86: kvm: x86.c: Cleaning up uninitialized variables 2014-06-03 12:04 ` Paolo Bonzini @ 2014-06-03 13:06 ` Michael Tokarev 2014-06-03 13:11 ` Paolo Bonzini 0 siblings, 1 reply; 4+ messages in thread From: Michael Tokarev @ 2014-06-03 13:06 UTC (permalink / raw) To: Paolo Bonzini, Rickard Strandqvist, Gleb Natapov Cc: Thomas Gleixner, Ingo Molnar, H. Peter Anvin, x86, kvm, linux-kernel 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 ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] arch: x86: kvm: x86.c: Cleaning up uninitialized variables 2014-06-03 13:06 ` Michael Tokarev @ 2014-06-03 13:11 ` Paolo Bonzini 0 siblings, 0 replies; 4+ messages in thread From: Paolo Bonzini @ 2014-06-03 13:11 UTC (permalink / raw) To: Michael Tokarev, Rickard Strandqvist, Gleb Natapov Cc: Thomas Gleixner, Ingo Molnar, H. Peter Anvin, x86, kvm, linux-kernel 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 ^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2014-06-03 13:14 UTC | newest] Thread overview: 4+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2014-05-31 23:05 [PATCH] arch: x86: kvm: x86.c: Cleaning up uninitialized variables Rickard Strandqvist 2014-06-03 12:04 ` Paolo Bonzini 2014-06-03 13:06 ` Michael Tokarev 2014-06-03 13:11 ` Paolo Bonzini
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