On 03/06/20 12:34, Dan Carpenter wrote:
> Hello Paolo Bonzini,
>
> The patch c9d40913ac5a: "KVM: x86: enable event window in
> inject_pending_event" from May 22, 2020, leads to the following
> static checker warning:
>
> arch/x86/kvm/x86.c:10530 kvm_can_do_async_pf()
> warn: signedness bug returning '(-16)'
>
> arch/x86/kvm/x86.c
> 10516 bool kvm_can_do_async_pf(struct kvm_vcpu *vcpu)
> 10517 {
> 10518 if (unlikely(!lapic_in_kernel(vcpu) ||
> 10519 kvm_event_needs_reinjection(vcpu) ||
> 10520 vcpu->arch.exception.pending))
> 10521 return false;
> 10522
> 10523 if (kvm_hlt_in_guest(vcpu->kvm) && !kvm_can_deliver_async_pf(vcpu))
> 10524 return false;
> 10525
> 10526 /*
> 10527 * If interrupts are off we cannot even use an artificial
> 10528 * halt state.
> 10529 */
> 10530 return kvm_arch_interrupt_allowed(vcpu);
> 10531 }
>
> The svm_nmi_allowed() used to return false because interrupts aren't
> allowed but now it returns -EBUSY so it returns true/allowed.
This is intentional (i.e. not a bug) but it should have an explicit "!= 0".
Paolo
