Re: [PATCH v3 2/3] KVM: x86: Drop superfluous caching of KVM_ASYNC_PF_DELIVERY_AS_PF_VMEXIT

[Xiaoyao Li]

On 4/7/2026 6:53 AM, Sean Christopherson wrote:
> Drop kvm_vcpu_arch.delivery_as_pf_vmexit and instead use msr_en_val as the
> source of truth to reduce the probability of operating on stale data.  This
> fixes flaws where KVM fails to update delivery_as_pf_vmexit when APF is
> explicitly disabled by the guest or implicitly disabled by KVM on INIT.
> Absent other bugs, the flaws are benign as KVM *shouldn't* consume
> delivery_as_pf_vmexit when PV APF support is disabled.
>
> Simply delete the field, as there's zero benefit to maintaining a separate
> "cache" of the state.
>
> Fixes: 52a5c155cf79 ("KVM: async_pf: Let guest support delivery of async_pf from guest mode")
> Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>

Reviewed-by: Xiaoyao Li <xiaoyao.li@xxxxxxxxx>