Commit 2638134f authored by Dragos Tatulea's avatar Dragos Tatulea Committed by Michael S. Tsirkin
Browse files

vdpa/mlx5: Don't reset VQs more than necessary 



The vdpa device can be reset many times in sequence without any
significant state changes in between. Previously this was not a problem:
VQs were torn down only on first reset. But after VQ pre-creation was
introduced, each reset will delete and re-create the hardware VQs and
their associated resources.

To solve this problem, avoid resetting hardware VQs if the VQs are still
in a blank state.

Reviewed-by: default avatarCosmin Ratiu <cratiu@nvidia.com>
Acked-by: default avatarEugenio Pérez <eperezma@redhat.com>
Signed-off-by: default avatarDragos Tatulea <dtatulea@nvidia.com>
Message-Id: <20240626-stage-vdpa-vq-precreate-v2-23-560c491078df@nvidia.com>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
parent 0fe963d6

drivers/vdpa/mlx5/net/mlx5_vnet.c

+27 −3
Original line number Diff line number Diff line
@@ -3134,18 +3134,41 @@ static void init_group_to_asid_map(struct mlx5_vdpa_dev *mvdev) 
		mvdev->group2asid[i] = 0;

}



static bool needs_vqs_reset(const struct mlx5_vdpa_dev *mvdev)

{

	struct mlx5_vdpa_net *ndev = to_mlx5_vdpa_ndev(mvdev);

	struct mlx5_vdpa_virtqueue *mvq = &ndev->vqs[0];



	if (mvdev->status & VIRTIO_CONFIG_S_DRIVER_OK)

		return true;



	if (mvq->fw_state != MLX5_VIRTIO_NET_Q_OBJECT_STATE_INIT)

		return true;



	return mvq->modified_fields & (

		MLX5_VIRTQ_MODIFY_MASK_STATE |

		MLX5_VIRTQ_MODIFY_MASK_VIRTIO_Q_ADDRS |

		MLX5_VIRTQ_MODIFY_MASK_VIRTIO_Q_AVAIL_IDX |

		MLX5_VIRTQ_MODIFY_MASK_VIRTIO_Q_USED_IDX

	);

}



static int mlx5_vdpa_compat_reset(struct vdpa_device *vdev, u32 flags)

{

	struct mlx5_vdpa_dev *mvdev = to_mvdev(vdev);

	struct mlx5_vdpa_net *ndev = to_mlx5_vdpa_ndev(mvdev);

	bool vq_reset;



	print_status(mvdev, 0, true);

	mlx5_vdpa_info(mvdev, "performing device reset\n");



	down_write(&ndev->reslock);

	unregister_link_notifier(ndev);

	vq_reset = needs_vqs_reset(mvdev);

	if (vq_reset) {

		teardown_vq_resources(ndev);

		mvqs_set_defaults(ndev);

	}



	if (flags & VDPA_RESET_F_CLEAN_MAP)

		mlx5_vdpa_destroy_mr_resources(&ndev->mvdev);
@@ -3165,6 +3188,7 @@ static int mlx5_vdpa_compat_reset(struct vdpa_device *vdev, u32 flags) 
		if (mlx5_vdpa_create_dma_mr(mvdev))

			mlx5_vdpa_warn(mvdev, "create MR failed\n");

	}

	if (vq_reset)

		setup_vq_resources(ndev, false);

	up_write(&ndev->reslock);