On Sat, 2020-05-02 at 18:42 +0200, Paolo Bonzini wrote:
> On 02/05/20 15:58, Maxim Levitsky wrote:
> > The AVIC is disabled by svm_toggle_avic_for_irq_window, which calls
> > kvm_request_apicv_update, which broadcasts the KVM_REQ_APICV_UPDATE vcpu request,
> > however it doesn't broadcast it to CPU on which now we are running, which seems OK,
> > because the code that handles that broadcast runs on each VCPU entry, thus
> > when this CPU will enter guest mode it will notice and disable the AVIC.
> >
> > However later in svm_enable_vintr, there is test 'WARN_ON(kvm_vcpu_apicv_active(&svm->vcpu));'
> > which is still true on current CPU because of the above.
>
> Good point! We can just remove the WARN_ON I think. Can you send a patch?
>
> svm_set_vintr also has a rather silly
>
> static void svm_set_vintr(struct vcpu_svm *svm)
> {
> set_intercept(svm, INTERCEPT_VINTR);
> if (is_intercept(svm, INTERCEPT_VINTR))
> svm_enable_vintr(svm);
> }
>
> so I'm thinking of just inlining svm_enable_vintr and renaming
> svm_{set,clear}_vintr to svm_{enable,disable}_vintr_window. Would you
> like to send two patches for this, the first to remove the WARN_ON and
> the second to do the cleanup?
Absolutely! I will send a patch very soon.
Best regards,
Maxim Levitsky
>
> Thanks,
>
> Paolo
>
> > The code containing this warning was added in commit
> >
> > 64b5bd27042639dfcc1534f01771b7b871a02ffe
> > KVM: nSVM: ignore L1 interrupt window while running L2 with V_INTR_MASKING=1
