Re: [PATCH 4/5] synchronize irqs in the reset routine

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在 2023/4/1 04:48, Zhu Lingshan 写道:
This commit synchronize irqs of the virtqueues
and config space in the reset routine.
Thus ifcvf_stop_hw() and reset() are refactored as well.

Signed-off-by: Zhu Lingshan <lingshan.zhu@xxxxxxxxx>
---
  drivers/vdpa/ifcvf/ifcvf_base.c | 61 ++++++++++++++++++++++++++-------
  drivers/vdpa/ifcvf/ifcvf_main.c | 45 +++---------------------
  2 files changed, 54 insertions(+), 52 deletions(-)

diff --git a/drivers/vdpa/ifcvf/ifcvf_base.c b/drivers/vdpa/ifcvf/ifcvf_base.c
index 79e313c5e10e..49949aec20ef 100644
--- a/drivers/vdpa/ifcvf/ifcvf_base.c
+++ b/drivers/vdpa/ifcvf/ifcvf_base.c
@@ -170,12 +170,7 @@ void ifcvf_set_status(struct ifcvf_hw *hw, u8 status)
void ifcvf_reset(struct ifcvf_hw *hw)
  {
-	hw->config_cb.callback = NULL;
-	hw->config_cb.private = NULL;
-
  	ifcvf_set_status(hw, 0);
-	/* flush set_status, make sure VF is stopped, reset */
-	ifcvf_get_status(hw);


If we don't flush or poll how can we know the reset is done?

E.g modern virtio-pci did:

        /* 0 status means a reset. */
        vp_modern_set_status(mdev, 0);
        /* After writing 0 to device_status, the driver MUST wait for a read of
         * device_status to return 0 before reinitializing the device.
         * This will flush out the status write, and flush in device writes,
         * including MSI-X interrupts, if any.
         */
        while (vp_modern_get_status(mdev))
                msleep(1);
        /* Flush pending VQ/configuration callbacks. */
       vp_synchronize_vectors(vdev);

  }
u64 ifcvf_get_hw_features(struct ifcvf_hw *hw)
@@ -368,20 +363,62 @@ void ifcvf_set_vq_ready(struct ifcvf_hw *hw, u16 qid, bool ready)
  	vp_iowrite16(ready, &cfg->queue_enable);
  }
-static void ifcvf_hw_disable(struct ifcvf_hw *hw)
+static void synchronize_per_vq_irq(struct ifcvf_hw *hw)
  {
-	u32 i;
+	u16 qid;
- ifcvf_set_config_vector(hw, VIRTIO_MSI_NO_VECTOR);
-	for (i = 0; i < hw->nr_vring; i++) {
-		ifcvf_set_vq_vector(hw, i, VIRTIO_MSI_NO_VECTOR);
+	for (qid = 0; qid < hw->nr_vring; qid++) {
+		if (hw->vring[qid].irq != -EINVAL)
+			synchronize_irq(hw->vring[qid].irq);
  	}
  }
+static void synchronize_vqs_reused_irq(struct ifcvf_hw *hw)
+{
+	if (hw->vqs_reused_irq != -EINVAL)
+		synchronize_irq(hw->vqs_reused_irq);
+}
+
+static void synchronize_vq_irq(struct ifcvf_hw *hw)
+{
+	u8 status = hw->msix_vector_status;
+
+	if (status == MSIX_VECTOR_PER_VQ_AND_CONFIG)
+		synchronize_per_vq_irq(hw);
+	else
+		synchronize_vqs_reused_irq(hw);
+}


I wonder if we need to go with such complicated ways,can we synchronize through the vectors like virtio-pci did?

        for (i = 0; i < vp_dev->msix_vectors; ++i)
                synchronize_irq(pci_irq_vector(vp_dev->pci_dev, i));
?


+
+static void synchronize_config_irq(struct ifcvf_hw *hw)
+{
+	if (hw->config_irq != -EINVAL)
+		synchronize_irq(hw->config_irq);
+}
+
+static void ifcvf_reset_vring(struct ifcvf_hw *hw)
+{
+	u16 qid;
+
+	for (qid = 0; qid < hw->nr_vring; qid++) {
+		synchronize_vq_irq(hw);

Since IRQ could be shared, this will result extra complexity, like a irq could be flushed multiple times?

Thanks


+		hw->vring[qid].cb.callback = NULL;
+		hw->vring[qid].cb.private = NULL;
+		ifcvf_set_vq_vector(hw, qid, VIRTIO_MSI_NO_VECTOR);
+	}
+}
+
+static void ifcvf_reset_config_handler(struct ifcvf_hw *hw)
+{
+	synchronize_config_irq(hw);
+	hw->config_cb.callback = NULL;
+	hw->config_cb.private = NULL;
+	ifcvf_set_config_vector(hw, VIRTIO_MSI_NO_VECTOR);
+}
+
  void ifcvf_stop_hw(struct ifcvf_hw *hw)
  {
-	ifcvf_hw_disable(hw);
-	ifcvf_reset(hw);
+	ifcvf_reset_vring(hw);
+	ifcvf_reset_config_handler(hw);
  }
void ifcvf_notify_queue(struct ifcvf_hw *hw, u16 qid)
diff --git a/drivers/vdpa/ifcvf/ifcvf_main.c b/drivers/vdpa/ifcvf/ifcvf_main.c
index 968687159e44..15c6157ee841 100644
--- a/drivers/vdpa/ifcvf/ifcvf_main.c
+++ b/drivers/vdpa/ifcvf/ifcvf_main.c
@@ -346,33 +346,6 @@ static int ifcvf_request_irq(struct ifcvf_hw *vf)
  	return 0;
  }
-static int ifcvf_stop_datapath(struct ifcvf_adapter *adapter)
-{
-	struct ifcvf_hw *vf = adapter->vf;
-	int i;
-
-	for (i = 0; i < vf->nr_vring; i++)
-		vf->vring[i].cb.callback = NULL;
-
-	ifcvf_stop_hw(vf);
-
-	return 0;
-}
-
-static void ifcvf_reset_vring(struct ifcvf_adapter *adapter)
-{
-	struct ifcvf_hw *vf = adapter->vf;
-	int i;
-
-	for (i = 0; i < vf->nr_vring; i++) {
-		vf->vring[i].last_avail_idx = 0;
-		vf->vring[i].cb.callback = NULL;
-		vf->vring[i].cb.private = NULL;
-	}
-
-	ifcvf_reset(vf);
-}
-
  static struct ifcvf_adapter *vdpa_to_adapter(struct vdpa_device *vdpa_dev)
  {
  	return container_of(vdpa_dev, struct ifcvf_adapter, vdpa);
@@ -462,23 +435,15 @@ static void ifcvf_vdpa_set_status(struct vdpa_device *vdpa_dev, u8 status)
static int ifcvf_vdpa_reset(struct vdpa_device *vdpa_dev)
  {
-	struct ifcvf_adapter *adapter;
-	struct ifcvf_hw *vf;
-	u8 status_old;
-
-	vf  = vdpa_to_vf(vdpa_dev);
-	adapter = vdpa_to_adapter(vdpa_dev);
-	status_old = ifcvf_get_status(vf);
+	struct ifcvf_hw *vf = vdpa_to_vf(vdpa_dev);
+	u8 status = ifcvf_get_status(vf);
- if (status_old == 0)
-		return 0;
+	ifcvf_stop_hw(vf);
- if (status_old & VIRTIO_CONFIG_S_DRIVER_OK) {
-		ifcvf_stop_datapath(adapter);
+	if (status & VIRTIO_CONFIG_S_DRIVER_OK)
  		ifcvf_free_irq(vf);
-	}
- ifcvf_reset_vring(adapter);
+	ifcvf_reset(vf);
return 0;
  }

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