Re: [PATCH 04/10] KVM: SVM: add warning for mistmatch between AVIC state and AVIC access page state

[Paolo Bonzini]

On 23/06/21 13:29, Maxim Levitsky wrote:
> It is never a good idea to enter a guest when the AVIC state doesn't match
> the state of the AVIC MMIO memory slot.
>
> Signed-off-by: Maxim Levitsky <mlevitsk@xxxxxxxxxx>
> ---
>   arch/x86/kvm/svm/svm.c | 3 +++
>   1 file changed, 3 insertions(+)
>
> diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
> index 12c06ea28f5c..50405c561394 100644
> --- a/arch/x86/kvm/svm/svm.c
> +++ b/arch/x86/kvm/svm/svm.c
> @@ -3780,6 +3780,9 @@ static __no_kcsan fastpath_t svm_vcpu_run(struct kvm_vcpu *vcpu)
>   
>   	pre_svm_run(vcpu);
>   
> +	WARN_ON_ONCE(vcpu->kvm->arch.apic_access_memslot_enabled !=
> +		     kvm_vcpu_apicv_active(vcpu));
> +
>   	sync_lapic_to_cr8(vcpu);
>   
>   	if (unlikely(svm->asid != svm->vmcb->control.asid)) {

For patches 4-6, can the warnings actually fire without the fix in patch 2?

Paolo