Re: [PATCH V5 4/6] vhost_vdpa: implement IRQ offloading in vhost_vdpa

[Jason Wang]

On 2020/7/31 下午2:55, Zhu Lingshan wrote:
+static void vhost_vdpa_setup_vq_irq(struct vhost_vdpa *v, u16 qid)
+{
+       struct vhost_virtqueue *vq = &v->vqs[qid];
+       const struct vdpa_config_ops *ops = v->vdpa->config;
+       struct vdpa_device *vdpa = v->vdpa;
+       int ret, irq;
+
+       spin_lock(&vq->call_ctx.ctx_lock);
+       irq = ops->get_vq_irq(vdpa, qid);


Btw, this assumes that get_vq_irq is mandatory. This looks wrong since 
there's no guarantee that the vDPA device driver can see irq. And this 
break vdpa simulator.

Let's add a check and make it optional by document this assumption in 
the vdpa.h.

Thanks


+       if (!vq->call_ctx.ctx || irq < 0) {
+               spin_unlock(&vq->call_ctx.ctx_lock);
+               return;
+       }
+