vdpa: mlx5: prevent cvq work from hogging CPU
[ Upstream commit55ebf0d60e
] A userspace triggerable infinite loop could happen in mlx5_cvq_kick_handler() if userspace keeps sending a huge amount of cvq requests. Fixing this by introducing a quota and re-queue the work if we're out of the budget (currently the implicit budget is one) . While at it, using a per device work struct to avoid on demand memory allocation for cvq. Fixes:5262912ef3
("vdpa/mlx5: Add support for control VQ and MAC setting") Signed-off-by: Jason Wang <jasowang@redhat.com> Link: https://lore.kernel.org/r/20220329042109.4029-1-jasowang@redhat.com Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Acked-by: Eli Cohen <elic@nvidia.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
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893c70f8b8
Коммит
69ec350a41
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@ -163,6 +163,7 @@ struct mlx5_vdpa_net {
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u32 cur_num_vqs;
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struct notifier_block nb;
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struct vdpa_callback config_cb;
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struct mlx5_vdpa_wq_ent cvq_ent;
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};
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static void free_resources(struct mlx5_vdpa_net *ndev);
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@ -1587,10 +1588,10 @@ static void mlx5_cvq_kick_handler(struct work_struct *work)
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ndev = to_mlx5_vdpa_ndev(mvdev);
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cvq = &mvdev->cvq;
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if (!(ndev->mvdev.actual_features & BIT_ULL(VIRTIO_NET_F_CTRL_VQ)))
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goto out;
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return;
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if (!cvq->ready)
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goto out;
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return;
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while (true) {
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err = vringh_getdesc_iotlb(&cvq->vring, &cvq->riov, &cvq->wiov, &cvq->head,
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@ -1624,9 +1625,10 @@ static void mlx5_cvq_kick_handler(struct work_struct *work)
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if (vringh_need_notify_iotlb(&cvq->vring))
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vringh_notify(&cvq->vring);
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queue_work(mvdev->wq, &wqent->work);
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break;
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}
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out:
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kfree(wqent);
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}
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static void mlx5_vdpa_kick_vq(struct vdpa_device *vdev, u16 idx)
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@ -1634,7 +1636,6 @@ static void mlx5_vdpa_kick_vq(struct vdpa_device *vdev, u16 idx)
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struct mlx5_vdpa_dev *mvdev = to_mvdev(vdev);
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struct mlx5_vdpa_net *ndev = to_mlx5_vdpa_ndev(mvdev);
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struct mlx5_vdpa_virtqueue *mvq;
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struct mlx5_vdpa_wq_ent *wqent;
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if (!is_index_valid(mvdev, idx))
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return;
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@ -1643,13 +1644,7 @@ static void mlx5_vdpa_kick_vq(struct vdpa_device *vdev, u16 idx)
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if (!mvdev->cvq.ready)
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return;
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wqent = kzalloc(sizeof(*wqent), GFP_ATOMIC);
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if (!wqent)
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return;
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wqent->mvdev = mvdev;
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INIT_WORK(&wqent->work, mlx5_cvq_kick_handler);
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queue_work(mvdev->wq, &wqent->work);
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queue_work(mvdev->wq, &ndev->cvq_ent.work);
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return;
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}
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@ -2588,6 +2583,8 @@ static int mlx5_vdpa_dev_add(struct vdpa_mgmt_dev *v_mdev, const char *name)
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if (err)
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goto err_mr;
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ndev->cvq_ent.mvdev = mvdev;
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INIT_WORK(&ndev->cvq_ent.work, mlx5_cvq_kick_handler);
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mvdev->wq = create_singlethread_workqueue("mlx5_vdpa_wq");
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if (!mvdev->wq) {
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err = -ENOMEM;
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