2017-08-24 16:57 GMT+08:00 Paolo Bonzini <pbonzini@xxxxxxxxxx>:
> On 24/08/2017 08:52, Wanpeng Li wrote:
>>> @@ -6862,6 +6876,7 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
>>> kvm_x86_ops->enable_nmi_window(vcpu);
>>> if (kvm_cpu_has_injectable_intr(vcpu) || req_int_win)
>>> kvm_x86_ops->enable_irq_window(vcpu);
>>> + WARN_ON(vcpu->arch.exception.pending);
>>
>> This WARN_ON() is suggested during the review of last version,
>> however, there are many cases in inject_pending_event() can result in
>> return directly w/ vcpu->arch.exception.pending is true. Actually I
>> have already catched the warning several times during the testing. I
>> think we should remove it when committing.
>
> No, it's a good thing that it's failing, because it's finding a bug.
> There's no such thing as an "exception window", so at the very least it
Good point, the code looks good, I will fold it in next version.
However, I still can observe the warning.
Regards,
Wanpeng Li
> should set req_immediate_exit to true.
>
> Does this help?
>
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index b698b2f135a2..76d5a192be6c 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -6365,14 +6365,20 @@ static int inject_pending_event(struct kvm_vcpu *vcpu, bool req_int_win)
> return 0;
> }
>
> - if (vcpu->arch.nmi_injected) {
> - kvm_x86_ops->set_nmi(vcpu);
> - return 0;
> - }
> + /*
> + * Exceptions must be injected immediately, or the exception
> + * frame will have the address of the NMI or interrupt handler.
> + */
> + if (!vcpu->arch.exception.pending) {
> + if (vcpu->arch.nmi_injected) {
> + kvm_x86_ops->set_nmi(vcpu);
> + return 0;
> + }
>
> - if (vcpu->arch.interrupt.pending) {
> - kvm_x86_ops->set_irq(vcpu);
> - return 0;
> + if (vcpu->arch.interrupt.pending) {
> + kvm_x86_ops->set_irq(vcpu);
> + return 0;
> + }
> }
>
> if (is_guest_mode(vcpu) && kvm_x86_ops->check_nested_events) {
>
> Paolo
