Re: [PATCH v3 2/8] KVM: nSVM: Sync interrupt shadow to cached vmcb12 after VMRUN of L2

[Yosry Ahmed]

> diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
> index de90b104a0dd5..9909ff237e5ca 100644
> --- a/arch/x86/kvm/svm/nested.c
> +++ b/arch/x86/kvm/svm/nested.c
> @@ -521,6 +521,7 @@ void nested_sync_control_from_vmcb02(struct vcpu_svm *svm)
>         u32 mask;
>         svm->nested.ctl.event_inj      = svm->vmcb->control.event_inj;
>         svm->nested.ctl.event_inj_err  = svm->vmcb->control.event_inj_err;
> +       svm->nested.ctl.int_state       = svm->vmcb->control.int_state;

FWIW, this is an incomplete fix. KVM might update the interrupt shadow
after this point through __svm_skip_emulated_instruction(), and that
won't be captured in svm->nested.ctl.int_state.

I think it's not worth fixing that case too, and any further effort
should go toward teaching KVM_GET_NESTED_STATE to pull state from the
correct place as discussed earlier.