Re: [PATCH vhost 22/23] vdpa/mlx5: Don't reset VQs more than necessary
From: Eugenio Perez Martin <eperezma@redhat.com>
Date: 2024-06-19 16:15:24
Also in:
linux-rdma, lkml, virtualization
On Mon, Jun 17, 2024 at 5:09 PM Dragos Tatulea [off-list ref] wrote:
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. Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com> Reviewed-by: Cosmin Ratiu <redacted>
Acked-by: Eugenio Pérez <eperezma@redhat.com>
quoted hunk ↗ jump to hunk
--- drivers/vdpa/mlx5/net/mlx5_vnet.c | 30 +++++++++++++++++++++++++++--- 1 file changed, 27 insertions(+), 3 deletions(-)diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c index d80d6b47da61..1a5ee0d2b47f 100644 --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c@@ -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); - teardown_vq_resources(ndev); - init_mvqs(ndev); + vq_reset = needs_vqs_reset(mvdev); + if (vq_reset) { + teardown_vq_resources(ndev); + init_mvqs(ndev); + } if (flags & VDPA_RESET_F_CLEAN_MAP) mlx5_vdpa_destroy_mr_resources(&ndev->mvdev);@@ -3165,7 +3188,8 @@ 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"); } - setup_vq_resources(ndev, false); + if (vq_reset) + setup_vq_resources(ndev, false); up_write(&ndev->reslock); return 0; --2.45.1