KVM: Send async PF when guest is not in userspace too.

If guest indicates that it can handle async pf in kernel mode too send
it, but only if interrupts are enabled.
Acked-by: NRik van Riel <riel@redhat.com>
Signed-off-by: NGleb Natapov <gleb@redhat.com>
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>

arch/x86/kvm/x86.c

@@ -6263,7 +6263,8 @@ void kvm_arch_async_page_not_present(struct kvm_vcpu *vcpu,
 	kvm_add_async_pf_gfn(vcpu, work->arch.gfn);
 
 	if (!(vcpu->arch.apf.msr_val & KVM_ASYNC_PF_ENABLED) ||
-	    kvm_x86_ops->get_cpl(vcpu) == 0)
+	    (vcpu->arch.apf.send_user_only &&
+	     kvm_x86_ops->get_cpl(vcpu) == 0))
 		kvm_make_request(KVM_REQ_APF_HALT, vcpu);
 	else if (!apf_put_user(vcpu, KVM_PV_REASON_PAGE_NOT_PRESENT)) {
 		vcpu->arch.fault.error_code = 0;