On 2020/7/12 下午10:49, Zhu Lingshan wrote:
This patch introduce a set of functions for setup/unsetup
and update irq offloading respectively by register/unregister
and re-register the irq_bypass_producer.

Signed-off-by: Zhu Lingshan <[email protected]>
---
  drivers/vhost/vdpa.c | 69 ++++++++++++++++++++++++++++++++++++++++++++++++++++
  1 file changed, 69 insertions(+)

diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
index 2fcc422..92683e4 100644
--- a/drivers/vhost/vdpa.c
+++ b/drivers/vhost/vdpa.c
@@ -115,6 +115,63 @@ static irqreturn_t vhost_vdpa_config_cb(void *private)
        return IRQ_HANDLED;
  }
+static void vhost_vdpa_setup_vq_irq(struct vdpa_device *dev, int qid, int irq)
+{
+       struct vhost_vdpa *v = vdpa_get_drvdata(dev);
+       struct vhost_virtqueue *vq = &v->vqs[qid];
+       int ret;
+
+       vq_err(vq, "setup irq bypass for vq %d with irq = %d\n", qid, irq);
+       spin_lock(&vq->call_ctx.ctx_lock);
+       if (!vq->call_ctx.ctx)
+               return;
+
+       vq->call_ctx.producer.token = vq->call_ctx.ctx;
+       vq->call_ctx.producer.irq = irq;
+       ret = irq_bypass_register_producer(&vq->call_ctx.producer);
+       spin_unlock(&vq->call_ctx.ctx_lock);
+
+       if (unlikely(ret))
+               vq_err(vq,
+               "irq bypass producer (token %p registration fails: %d\n",
+               vq->call_ctx.producer.token, ret);


Not sure this deserves a vq_err(), irq will be relayed through eventfd if irq bypass manager can't work.


+}
+
+static void vhost_vdpa_unsetup_vq_irq(struct vdpa_device *dev, int qid)
+{
+       struct vhost_vdpa *v = vdpa_get_drvdata(dev);
+       struct vhost_virtqueue *vq = &v->vqs[qid];
+
+       spin_lock(&vq->call_ctx.ctx_lock);
+       irq_bypass_unregister_producer(&vq->call_ctx.producer);
+       spin_unlock(&vq->call_ctx.ctx_lock);
+
+       vq_err(vq, "unsetup irq bypass for vq %d\n", qid);


Why call vq_err() here?


+}
+
+static void vhost_vdpa_update_vq_irq(struct vhost_virtqueue *vq)
+{
+       struct eventfd_ctx *ctx;
+       void *token;
+
+       spin_lock(&vq->call_ctx.ctx_lock);
+       ctx = vq->call_ctx.ctx;
+       token = vq->call_ctx.producer.token;
+       if (ctx == token)
+               return;


Need do unlock here.


+
+       if (!ctx && token)
+               irq_bypass_unregister_producer(&vq->call_ctx.producer);
+
+       if (ctx && ctx != token) {
+               irq_bypass_unregister_producer(&vq->call_ctx.producer);
+               vq->call_ctx.producer.token = ctx;
+               irq_bypass_register_producer(&vq->call_ctx.producer);
+       }
+
+       spin_unlock(&vq->call_ctx.ctx_lock);


This should be rare so I'd use simple codes just do unregister and register.


+}
+
  static void vhost_vdpa_reset(struct vhost_vdpa *v)
  {
        struct vdpa_device *vdpa = v->vdpa;
@@ -332,6 +389,7 @@ static long vhost_vdpa_set_config_call(struct vhost_vdpa 
*v, u32 __user *argp)
return 0;
  }
+


Unnecessary change.


  static long vhost_vdpa_vring_ioctl(struct vhost_vdpa *v, unsigned int cmd,
                                   void __user *argp)
  {
@@ -390,6 +448,16 @@ static long vhost_vdpa_vring_ioctl(struct vhost_vdpa *v, 
unsigned int cmd,
                        cb.private = NULL;
                }
                ops->set_vq_cb(vdpa, idx, &cb);
+#ifdef CONFIG_HAVE_KVM_IRQ_BYPASS
+               /*
+                * if it has a non-zero irq, means there is a
+                * previsouly registered irq_bypass_producer,
+                * we should update it when ctx (its token)
+                * changes.
+                */
+               if (vq->call_ctx.producer.irq)
+                       vhost_vdpa_update_vq_irq(vq);
+#endif
                break;
case VHOST_SET_VRING_NUM:
@@ -741,6 +809,7 @@ static int vhost_vdpa_open(struct inode *inode, struct file 
*filep)
                vqs[i] = &v->vqs[i];
                vqs[i]->handle_kick = handle_vq_kick;
        }
+


Unnecessary change.

Thanks


        vhost_dev_init(dev, vqs, nvqs, 0, 0, 0, false,
                       vhost_vdpa_process_iotlb_msg);

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