vdpa/mlx5: Initialize CVQ vringh only once

Currently, CVQ vringh is initialized inside setup_virtqueues() which is
called every time a memory update is done. This is undesirable since it
resets all the context of the vring, including the available and used
indices.

Move the initialization to mlx5_vdpa_set_status() when
VIRTIO_CONFIG_S_DRIVER_OK is set.

Signed-off-by: Eli Cohen <elic@nvidia.com>
Message-Id: <20220613075958.511064-2-elic@nvidia.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Acked-by: Eugenio Pérez <eperezma@redhat.com>

Author: elic307i

drivers/vdpa/mlx5/net/mlx5_vnet.c

@@ -2176,7 +2176,6 @@ static int verify_driver_features(struct mlx5_vdpa_dev *mvdev, u64 features)
 static int setup_virtqueues(struct mlx5_vdpa_dev *mvdev)
 {
 	struct mlx5_vdpa_net *ndev = to_mlx5_vdpa_ndev(mvdev);
-	struct mlx5_control_vq *cvq = &mvdev->cvq;
 	int err;
 	int i;
 
@@ -2186,16 +2185,6 @@ static int setup_virtqueues(struct mlx5_vdpa_dev *mvdev)
 			goto err_vq;
 	}
 
-	if (mvdev->actual_features & BIT_ULL(VIRTIO_NET_F_CTRL_VQ)) {
-		err = vringh_init_iotlb(&cvq->vring, mvdev->actual_features,
-					MLX5_CVQ_MAX_ENT, false,
-					(struct vring_desc *)(uintptr_t)cvq->desc_addr,
-					(struct vring_avail *)(uintptr_t)cvq->driver_addr,
-					(struct vring_used *)(uintptr_t)cvq->device_addr);
-		if (err)
-			goto err_vq;
-	}
-
 	return 0;
 
 err_vq:
@@ -2468,6 +2457,21 @@ static void clear_vqs_ready(struct mlx5_vdpa_net *ndev)
 	ndev->mvdev.cvq.ready = false;
 }
 
+static int setup_cvq_vring(struct mlx5_vdpa_dev *mvdev)
+{
+	struct mlx5_control_vq *cvq = &mvdev->cvq;
+	int err = 0;
+
+	if (mvdev->actual_features & BIT_ULL(VIRTIO_NET_F_CTRL_VQ))
+		err = vringh_init_iotlb(&cvq->vring, mvdev->actual_features,
+					MLX5_CVQ_MAX_ENT, false,
+					(struct vring_desc *)(uintptr_t)cvq->desc_addr,
+					(struct vring_avail *)(uintptr_t)cvq->driver_addr,
+					(struct vring_used *)(uintptr_t)cvq->device_addr);
+
+	return err;
+}
+
 static void mlx5_vdpa_set_status(struct vdpa_device *vdev, u8 status)
 {
 	struct mlx5_vdpa_dev *mvdev = to_mvdev(vdev);
@@ -2480,6 +2484,11 @@ static void mlx5_vdpa_set_status(struct vdpa_device *vdev, u8 status)
 
 	if ((status ^ ndev->mvdev.status) & VIRTIO_CONFIG_S_DRIVER_OK) {
 		if (status & VIRTIO_CONFIG_S_DRIVER_OK) {
+			err = setup_cvq_vring(mvdev);
+			if (err) {
+				mlx5_vdpa_warn(mvdev, "failed to setup control VQ vring\n");
+				goto err_setup;
+			}
 			err = setup_driver(mvdev);
 			if (err) {
 				mlx5_vdpa_warn(mvdev, "failed to setup driver\n");