Re: [PATCH] KVM: x86: async_pf: check earlier if can deliver async pf

[Sean Christopherson <seanjc@google.com>]

On Fri, Nov 22, 2024, Vitaly Kuznetsov wrote:
> diff --git a/arch/x86/include/uapi/asm/kvm_para.h b/arch/x86/include/uapi/asm/kvm_para.h
> index a1efa7907a0b..5558a1ec3dc9 100644
> --- a/arch/x86/include/uapi/asm/kvm_para.h
> +++ b/arch/x86/include/uapi/asm/kvm_para.h
> @@ -87,7 +87,7 @@ struct kvm_clock_pairing {
>  #define KVM_MAX_MMU_OP_BATCH           32
>  
>  #define KVM_ASYNC_PF_ENABLED                   (1 << 0)
> -#define KVM_ASYNC_PF_SEND_ALWAYS               (1 << 1)
> +#define KVM_ASYNC_PF_SEND_ALWAYS               (1 << 1) /* deprecated */
>  #define KVM_ASYNC_PF_DELIVERY_AS_PF_VMEXIT     (1 << 2)
>  #define KVM_ASYNC_PF_DELIVERY_AS_INT           (1 << 3)
>  
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 83fe0a78146f..cd15e738ca9b 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -3585,7 +3585,6 @@ static int kvm_pv_enable_async_pf(struct kvm_vcpu *vcpu, u64 data)
>                                         sizeof(u64)))
>                 return 1;
>  
> -       vcpu->arch.apf.send_user_only = !(data & KVM_ASYNC_PF_SEND_ALWAYS);
>         vcpu->arch.apf.delivery_as_pf_vmexit = data & KVM_ASYNC_PF_DELIVERY_AS_PF_VMEXIT;
>  
>         kvm_async_pf_wakeup_all(vcpu);
> @@ -13374,8 +13373,7 @@ static bool kvm_can_deliver_async_pf(struct kvm_vcpu *vcpu)
>         if (!kvm_pv_async_pf_enabled(vcpu))
>                 return false;
>  
> -       if (vcpu->arch.apf.send_user_only &&
> -           kvm_x86_call(get_cpl)(vcpu) == 0)
> +       if (kvm_x86_call(get_cpl)(vcpu) == 0)

By x86's general definition of "user", this should be "!= 3" :-)