vdpa/mlx5: Take cvq iotlb lock during refresh

The reslock is taken while refresh is called but iommu_lock is more
specific to this resource. So take the iommu_lock during cvq iotlb
refresh.

Based on Eugenio's patch [0].

[0] https://lore.kernel.org/lkml/20230112142218.725622-4-eperezma@redhat.com/Acked-by: Jason Wang <jasowang@redhat.com>
Suggested-by: Eugenio Pérez <eperezma@redhat.com>
Reviewed-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
Message-Id: <20231018171456.1624030-9-dtatulea@nvidia.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Si-Wei Liu <si-wei.liu@oracle.com>
Tested-by: Si-Wei Liu <si-wei.liu@oracle.com>
Tested-by: Lei Yang <leiyang@redhat.com>

drivers/vdpa/mlx5/core/mr.c

@@ -590,11 +590,19 @@ int mlx5_vdpa_update_cvq_iotlb(struct mlx5_vdpa_dev *mvdev,
 				struct vhost_iotlb *iotlb,
 				unsigned int asid)
 {
+	int err;
+
 	if (mvdev->group2asid[MLX5_VDPA_CVQ_GROUP] != asid)
 		return 0;
 
+	spin_lock(&mvdev->cvq.iommu_lock);
+
 	prune_iotlb(mvdev);
-	return dup_iotlb(mvdev, iotlb);
+	err = dup_iotlb(mvdev, iotlb);
+
+	spin_unlock(&mvdev->cvq.iommu_lock);
+
+	return err;
 }
 
 int mlx5_vdpa_create_dma_mr(struct mlx5_vdpa_dev *mvdev)