From: Jason Wang jasowang@redhat.com
[ Upstream commit 55ebf0d60e3cc6c9e8593399e185842c00e12f36 ]
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 Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/vdpa/mlx5/net/mlx5_vnet.c | 21 +++++++++------------ 1 file changed, 9 insertions(+), 12 deletions(-)
diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c index 57bed3d74060..be50c15609b7 100644 --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c @@ -164,6 +164,7 @@ 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); @@ -1627,10 +1628,10 @@ 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, @@ -1664,9 +1665,10 @@ 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) @@ -1674,7 +1676,6 @@ 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; @@ -1683,13 +1684,7 @@ 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; }
@@ -2634,6 +2629,8 @@ 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;