async PF event can fail to wakeup vcpu from halt

If vcpu executes hlt instruction while async PF is waiting to be delivered vcpu can block and deliver async PF only after another even wakes it up. This happens because kvm_check_async_pf_completion() will remove completion event from vcpu->async_pf.done before entering kvm_vcpu_block() and this will make kvm_arch_vcpu_runnable() return false. The solution is to make vcpu runnable when processing completion.

index 4de705c..6d44308 100644
@@ -6611,6 +6611,7 @@ void kvm_arch_async_page_present(struct kvm_vcpu *vcpu,
 		kvm_inject_page_fault(vcpu, &fault);
 	}
 	vcpu->arch.apf.halted = false;
+	vcpu->arch.mp_state = KVM_MP_STATE_RUNNABLE;
 }
 
 bool kvm_arch_can_inject_async_page_present(struct kvm_vcpu *vcpu)

--
Gleb.

Thanks, applied to master for 3.4.

error compiling committee.c: too many arguments to function