vdpa/mlx5: Introduce per vq and device resume

Implement vdpa vq and device resume if capability detected. Add support
for suspend -> ready state change.

Reviewed-by: Gal Pressman <gal@nvidia.com>
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
Message-Id: <20231225151203.152687-4-dtatulea@nvidia.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

Author: dtatulea

drivers/vdpa/mlx5/net/mlx5_vnet.c

@@ -1170,14 +1170,20 @@ static int query_virtqueue(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtqueu
 	return err;
 }
 
-static bool is_valid_state_change(int oldstate, int newstate)
+static bool is_resumable(struct mlx5_vdpa_net *ndev)
+{
+	return ndev->mvdev.vdev.config->resume;
+}
+
+static bool is_valid_state_change(int oldstate, int newstate, bool resumable)
 {
 	switch (oldstate) {
 	case MLX5_VIRTIO_NET_Q_OBJECT_STATE_INIT:
 		return newstate == MLX5_VIRTIO_NET_Q_OBJECT_STATE_RDY;
 	case MLX5_VIRTIO_NET_Q_OBJECT_STATE_RDY:
 		return newstate == MLX5_VIRTIO_NET_Q_OBJECT_STATE_SUSPEND;
 	case MLX5_VIRTIO_NET_Q_OBJECT_STATE_SUSPEND:
+		return resumable ? newstate == MLX5_VIRTIO_NET_Q_OBJECT_STATE_RDY : false;
 	case MLX5_VIRTIO_NET_Q_OBJECT_STATE_ERR:
 	default:
 		return false;
@@ -1200,6 +1206,7 @@ static int modify_virtqueue(struct mlx5_vdpa_net *ndev,
 {
 	int inlen = MLX5_ST_SZ_BYTES(modify_virtio_net_q_in);
 	u32 out[MLX5_ST_SZ_DW(modify_virtio_net_q_out)] = {};
+	bool state_change = false;
 	void *obj_context;
 	void *cmd_hdr;
 	void *in;
@@ -1211,9 +1218,6 @@ static int modify_virtqueue(struct mlx5_vdpa_net *ndev,
 	if (!modifiable_virtqueue_fields(mvq))
 		return -EINVAL;
 
-	if (!is_valid_state_change(mvq->fw_state, state))
-		return -EINVAL;
-
 	in = kzalloc(inlen, GFP_KERNEL);
 	if (!in)
 		return -ENOMEM;
@@ -1226,17 +1230,29 @@ static int modify_virtqueue(struct mlx5_vdpa_net *ndev,
 	MLX5_SET(general_obj_in_cmd_hdr, cmd_hdr, uid, ndev->mvdev.res.uid);
 
 	obj_context = MLX5_ADDR_OF(modify_virtio_net_q_in, in, obj_context);
-	if (mvq->modified_fields & MLX5_VIRTQ_MODIFY_MASK_STATE)
+
+	if (mvq->modified_fields & MLX5_VIRTQ_MODIFY_MASK_STATE) {
+		if (!is_valid_state_change(mvq->fw_state, state, is_resumable(ndev))) {
+			err = -EINVAL;
+			goto done;
+		}
+
 		MLX5_SET(virtio_net_q_object, obj_context, state, state);
+		state_change = true;
+	}
 
 	MLX5_SET64(virtio_net_q_object, obj_context, modify_field_select, mvq->modified_fields);
 	err = mlx5_cmd_exec(ndev->mvdev.mdev, in, inlen, out, sizeof(out));
-	kfree(in);
-	if (!err)
+	if (err)
+		goto done;
+
+	if (state_change)
 		mvq->fw_state = state;
 
 	mvq->modified_fields = 0;
 
+done:
+	kfree(in);
 	return err;
 }
 
@@ -1430,6 +1446,24 @@ static void suspend_vqs(struct mlx5_vdpa_net *ndev)
 		suspend_vq(ndev, &ndev->vqs[i]);
 }
 
+static void resume_vq(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtqueue *mvq)
+{
+	if (!mvq->initialized || !is_resumable(ndev))
+		return;
+
+	if (mvq->fw_state != MLX5_VIRTIO_NET_Q_OBJECT_STATE_SUSPEND)
+		return;
+
+	if (modify_virtqueue_state(ndev, mvq, MLX5_VIRTIO_NET_Q_OBJECT_STATE_RDY))
+		mlx5_vdpa_warn(&ndev->mvdev, "modify to resume failed for vq %u\n", mvq->index);
+}
+
+static void resume_vqs(struct mlx5_vdpa_net *ndev)
+{
+	for (int i = 0; i < ndev->mvdev.max_vqs; i++)
+		resume_vq(ndev, &ndev->vqs[i]);
+}
+
 static void teardown_vq(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtqueue *mvq)
 {
 	if (!mvq->initialized)
@@ -3261,6 +3295,23 @@ static int mlx5_vdpa_suspend(struct vdpa_device *vdev)
 	return 0;
 }
 
+static int mlx5_vdpa_resume(struct vdpa_device *vdev)
+{
+	struct mlx5_vdpa_dev *mvdev = to_mvdev(vdev);
+	struct mlx5_vdpa_net *ndev;
+
+	ndev = to_mlx5_vdpa_ndev(mvdev);
+
+	mlx5_vdpa_info(mvdev, "resuming device\n");
+
+	down_write(&ndev->reslock);
+	mvdev->suspended = false;
+	resume_vqs(ndev);
+	register_link_notifier(ndev);
+	up_write(&ndev->reslock);
+	return 0;
+}
+
 static int mlx5_set_group_asid(struct vdpa_device *vdev, u32 group,
 			       unsigned int asid)
 {
@@ -3317,6 +3368,7 @@ static const struct vdpa_config_ops mlx5_vdpa_ops = {
 	.get_vq_dma_dev = mlx5_get_vq_dma_dev,
 	.free = mlx5_vdpa_free,
 	.suspend = mlx5_vdpa_suspend,
+	.resume = mlx5_vdpa_resume, /* Op disabled if not supported. */
 };
 
 static int query_mtu(struct mlx5_core_dev *mdev, u16 *mtu)
@@ -3688,6 +3740,9 @@ static int mlx5v_probe(struct auxiliary_device *adev,
 	if (!MLX5_CAP_DEV_VDPA_EMULATION(mdev, desc_group_mkey_supported))
 		mgtdev->vdpa_ops.get_vq_desc_group = NULL;
 
+	if (!MLX5_CAP_DEV_VDPA_EMULATION(mdev, freeze_to_rdy_supported))
+		mgtdev->vdpa_ops.resume = NULL;
+
 	err = vdpa_mgmtdev_register(&mgtdev->mgtdev);
 	if (err)
 		goto reg_err;