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?
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
