vdpa/mlx5: Update cvq iotlb mapping on ASID change

For the following sequence:
- cvq group is in ASID 0
- .set_map(1, cvq_iotlb)
- .set_group_asid(cvq_group, 1)

... the cvq mapping from ASID 0 will be used. This is not always correct
behaviour.

This patch adds support for the above mentioned flow by saving the iotlb
on each .set_map and updating the cvq iotlb with it on a cvq group change.

Acked-by: Jason Wang <jasowang@redhat.com>
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
Message-Id: <20231018171456.1624030-18-dtatulea@nvidia.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

Author: dtatulea

drivers/vdpa/mlx5/core/mlx5_vdpa.h

@@ -32,6 +32,8 @@ struct mlx5_vdpa_mr {
 	unsigned long num_directs;
 	unsigned long num_klms;
 
+	struct vhost_iotlb *iotlb;
+
 	bool user_mr;
 };
 

drivers/vdpa/mlx5/core/mr.c

@@ -502,6 +502,8 @@ static void _mlx5_vdpa_destroy_mr(struct mlx5_vdpa_dev *mvdev, struct mlx5_vdpa_
 		destroy_user_mr(mvdev, mr);
 	else
 		destroy_dma_mr(mvdev, mr);
+
+	vhost_iotlb_free(mr->iotlb);
 }
 
 void mlx5_vdpa_destroy_mr(struct mlx5_vdpa_dev *mvdev,
@@ -561,6 +563,30 @@ static int _mlx5_vdpa_create_mr(struct mlx5_vdpa_dev *mvdev,
 	else
 		err = create_dma_mr(mvdev, mr);
 
+	if (err)
+		return err;
+
+	mr->iotlb = vhost_iotlb_alloc(0, 0);
+	if (!mr->iotlb) {
+		err = -ENOMEM;
+		goto err_mr;
+	}
+
+	err = dup_iotlb(mr->iotlb, iotlb);
+	if (err)
+		goto err_iotlb;
+
+	return 0;
+
+err_iotlb:
+	vhost_iotlb_free(mr->iotlb);
+
+err_mr:
+	if (iotlb)
+		destroy_user_mr(mvdev, mr);
+	else
+		destroy_dma_mr(mvdev, mr);
+
 	return err;
 }
 

drivers/vdpa/mlx5/net/mlx5_vnet.c

@@ -3209,12 +3209,19 @@ static int mlx5_set_group_asid(struct vdpa_device *vdev, u32 group,
 			       unsigned int asid)
 {
 	struct mlx5_vdpa_dev *mvdev = to_mvdev(vdev);
+	int err = 0;
 
 	if (group >= MLX5_VDPA_NUMVQ_GROUPS)
 		return -EINVAL;
 
 	mvdev->group2asid[group] = asid;
-	return 0;
+
+	mutex_lock(&mvdev->mr_mtx);
+	if (group == MLX5_VDPA_CVQ_GROUP && mvdev->mr[asid])
+		err = mlx5_vdpa_update_cvq_iotlb(mvdev, mvdev->mr[asid]->iotlb, asid);
+	mutex_unlock(&mvdev->mr_mtx);
+
+	return err;
 }
 
 static const struct vdpa_config_ops mlx5_vdpa_ops = {