diff options
author | Jason Wang <jasowang@redhat.com> | 2022-03-29 07:21:07 +0300 |
---|---|---|
committer | Michael S. Tsirkin <mst@redhat.com> | 2022-03-30 11:18:14 +0300 |
commit | 55ebf0d60e3cc6c9e8593399e185842c00e12f36 (patch) | |
tree | 247b49c2514822cdf5debac17e9d362b3dc4ff07 /drivers/vdpa/mlx5/net | |
parent | c18c86808b78c4c2dc69f27f37c57abab14ee387 (diff) | |
download | linux-55ebf0d60e3cc6c9e8593399e185842c00e12f36.tar.xz |
vdpa: mlx5: prevent cvq work from hogging CPU
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: 5262912ef3cfc ("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>
Diffstat (limited to 'drivers/vdpa/mlx5/net')
-rw-r--r-- | drivers/vdpa/mlx5/net/mlx5_vnet.c | 21 |
1 files changed, 9 insertions, 12 deletions
diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c index 2f4fb09f1e89..da21e5430434 100644 --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c @@ -163,6 +163,7 @@ struct mlx5_vdpa_net { u32 cur_num_vqs; struct notifier_block nb; struct vdpa_callback config_cb; + struct mlx5_vdpa_wq_ent cvq_ent; }; static void free_resources(struct mlx5_vdpa_net *ndev); @@ -1659,10 +1660,10 @@ static void mlx5_cvq_kick_handler(struct work_struct *work) ndev = to_mlx5_vdpa_ndev(mvdev); cvq = &mvdev->cvq; if (!(ndev->mvdev.actual_features & BIT_ULL(VIRTIO_NET_F_CTRL_VQ))) - goto out; + return; if (!cvq->ready) - goto out; + return; while (true) { err = vringh_getdesc_iotlb(&cvq->vring, &cvq->riov, &cvq->wiov, &cvq->head, @@ -1696,9 +1697,10 @@ static void mlx5_cvq_kick_handler(struct work_struct *work) if (vringh_need_notify_iotlb(&cvq->vring)) vringh_notify(&cvq->vring); + + queue_work(mvdev->wq, &wqent->work); + break; } -out: - kfree(wqent); } static void mlx5_vdpa_kick_vq(struct vdpa_device *vdev, u16 idx) @@ -1706,7 +1708,6 @@ static void mlx5_vdpa_kick_vq(struct vdpa_device *vdev, u16 idx) struct mlx5_vdpa_dev *mvdev = to_mvdev(vdev); struct mlx5_vdpa_net *ndev = to_mlx5_vdpa_ndev(mvdev); struct mlx5_vdpa_virtqueue *mvq; - struct mlx5_vdpa_wq_ent *wqent; if (!is_index_valid(mvdev, idx)) return; @@ -1715,13 +1716,7 @@ static void mlx5_vdpa_kick_vq(struct vdpa_device *vdev, u16 idx) if (!mvdev->wq || !mvdev->cvq.ready) return; - wqent = kzalloc(sizeof(*wqent), GFP_ATOMIC); - if (!wqent) - return; - - wqent->mvdev = mvdev; - INIT_WORK(&wqent->work, mlx5_cvq_kick_handler); - queue_work(mvdev->wq, &wqent->work); + queue_work(mvdev->wq, &ndev->cvq_ent.work); return; } @@ -2740,6 +2735,8 @@ static int mlx5_vdpa_dev_add(struct vdpa_mgmt_dev *v_mdev, const char *name, if (err) goto err_mr; + ndev->cvq_ent.mvdev = mvdev; + INIT_WORK(&ndev->cvq_ent.work, mlx5_cvq_kick_handler); mvdev->wq = create_singlethread_workqueue("mlx5_vdpa_wq"); if (!mvdev->wq) { err = -ENOMEM; |