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Message-ID: <117f8549-85c5-6603-c941-77c63b596bdd@redhat.com>
Date: Tue, 1 Jun 2021 10:09:45 +0800
From: Jason Wang <jasowang@...hat.com>
To: Eli Cohen <elic@...dia.com>, mst@...hat.com,
virtualization@...ts.linux-foundation.org,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1] vdpa/mlx5: Add support for running with virtio_vdpa
在 2021/6/1 上午12:04, Eli Cohen 写道:
> In order to support running vdpa using vritio_vdpa driver, we need to
> create a different kind of MR, one that has 1:1 mapping, since the
> addresses referring to virtqueues are dma addresses.
>
> We create the 1:1 MR in mlx5_vdpa_dev_add() only in case firmware
> supports the general capability umem_uid_0. The reason for that is that
> 1:1 MRs must be created with uid == 0 while virtqueue objects can be
> created with uid == 0 only when the firmware capability is on.
>
> If the set_map() callback is called with new translations provided
> through iotlb, the driver will destroy the 1:1 MR and create a regular
> one.
>
> Signed-off-by: Eli Cohen <elic@...dia.com>
> ---
> v0 --> v1:
> 1. Clear user_mr after successful creation of DMA MR
> 2. Check return code of mlx5_vdpa_create_mr() and emit warning if
> failed.
>
> drivers/vdpa/mlx5/core/mlx5_vdpa.h | 1 +
> drivers/vdpa/mlx5/core/mr.c | 84 +++++++++++++++++++++++++-----
> drivers/vdpa/mlx5/net/mlx5_vnet.c | 15 +++++-
> 3 files changed, 85 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/vdpa/mlx5/core/mlx5_vdpa.h b/drivers/vdpa/mlx5/core/mlx5_vdpa.h
> index b6cc53ba980c..09a16a3d1b2a 100644
> --- a/drivers/vdpa/mlx5/core/mlx5_vdpa.h
> +++ b/drivers/vdpa/mlx5/core/mlx5_vdpa.h
> @@ -35,6 +35,7 @@ struct mlx5_vdpa_mr {
>
> /* serialize mkey creation and destruction */
> struct mutex mkey_mtx;
> + bool user_mr;
> };
>
> struct mlx5_vdpa_resources {
> diff --git a/drivers/vdpa/mlx5/core/mr.c b/drivers/vdpa/mlx5/core/mr.c
> index 800cfd1967ad..3c6c1d846f5e 100644
> --- a/drivers/vdpa/mlx5/core/mr.c
> +++ b/drivers/vdpa/mlx5/core/mr.c
> @@ -360,7 +360,7 @@ static int add_direct_chain(struct mlx5_vdpa_dev *mvdev, u64 start, u64 size, u8
> * indirect memory key that provides access to the enitre address space given
> * by iotlb.
> */
> -static int _mlx5_vdpa_create_mr(struct mlx5_vdpa_dev *mvdev, struct vhost_iotlb *iotlb)
> +static int create_user_mr(struct mlx5_vdpa_dev *mvdev, struct vhost_iotlb *iotlb)
> {
> struct mlx5_vdpa_mr *mr = &mvdev->mr;
> struct mlx5_vdpa_direct_mr *dmr;
> @@ -374,9 +374,6 @@ static int _mlx5_vdpa_create_mr(struct mlx5_vdpa_dev *mvdev, struct vhost_iotlb
> int err = 0;
> int nnuls;
>
> - if (mr->initialized)
> - return 0;
> -
> INIT_LIST_HEAD(&mr->head);
> for (map = vhost_iotlb_itree_first(iotlb, start, last); map;
> map = vhost_iotlb_itree_next(map, start, last)) {
> @@ -414,7 +411,7 @@ static int _mlx5_vdpa_create_mr(struct mlx5_vdpa_dev *mvdev, struct vhost_iotlb
> if (err)
> goto err_chain;
>
> - mr->initialized = true;
> + mr->user_mr = true;
> return 0;
>
> err_chain:
> @@ -426,33 +423,92 @@ static int _mlx5_vdpa_create_mr(struct mlx5_vdpa_dev *mvdev, struct vhost_iotlb
> return err;
> }
>
> -int mlx5_vdpa_create_mr(struct mlx5_vdpa_dev *mvdev, struct vhost_iotlb *iotlb)
> +static int create_dma_mr(struct mlx5_vdpa_dev *mvdev, struct mlx5_vdpa_mr *mr)
> +{
> + int inlen = MLX5_ST_SZ_BYTES(create_mkey_in);
> + void *mkc;
> + u32 *in;
> + int err;
> +
> + in = kzalloc(inlen, GFP_KERNEL);
> + if (!in)
> + return -ENOMEM;
> +
> + mkc = MLX5_ADDR_OF(create_mkey_in, in, memory_key_mkey_entry);
> +
> + MLX5_SET(mkc, mkc, access_mode_1_0, MLX5_MKC_ACCESS_MODE_PA);
> + MLX5_SET(mkc, mkc, length64, 1);
> + MLX5_SET(mkc, mkc, lw, 1);
> + MLX5_SET(mkc, mkc, lr, 1);
> + MLX5_SET(mkc, mkc, pd, mvdev->res.pdn);
> + MLX5_SET(mkc, mkc, qpn, 0xffffff);
> +
> + err = mlx5_vdpa_create_mkey(mvdev, &mr->mkey, in, inlen);
> + if (!err)
> + mr->user_mr = false;
Rethink about this. I wonder this is correct when we fail to create
memory key.
In this case, user_mr is true but user_mr is already destroyed. Can this
lead double free for user mr?
Thanks
> +
> + kfree(in);
> + return err;
> +}
> +
> +static void destroy_dma_mr(struct mlx5_vdpa_dev *mvdev, struct mlx5_vdpa_mr *mr)
> +{
> + mlx5_vdpa_destroy_mkey(mvdev, &mr->mkey);
> +}
> +
> +static int _mlx5_vdpa_create_mr(struct mlx5_vdpa_dev *mvdev, struct vhost_iotlb *iotlb)
> {
> struct mlx5_vdpa_mr *mr = &mvdev->mr;
> int err;
>
> - mutex_lock(&mr->mkey_mtx);
> + if (mr->initialized)
> + return 0;
> +
> + if (iotlb)
> + err = create_user_mr(mvdev, iotlb);
> + else
> + err = create_dma_mr(mvdev, mr);
> +
> + mr->initialized = true;
> + return err;
> +}
> +
> +int mlx5_vdpa_create_mr(struct mlx5_vdpa_dev *mvdev, struct vhost_iotlb *iotlb)
> +{
> + int err;
> +
> + mutex_lock(&mvdev->mr.mkey_mtx);
> err = _mlx5_vdpa_create_mr(mvdev, iotlb);
> - mutex_unlock(&mr->mkey_mtx);
> + mutex_unlock(&mvdev->mr.mkey_mtx);
> return err;
> }
>
> -void mlx5_vdpa_destroy_mr(struct mlx5_vdpa_dev *mvdev)
> +static void destroy_user_mr(struct mlx5_vdpa_dev *mvdev, struct mlx5_vdpa_mr *mr)
> {
> - struct mlx5_vdpa_mr *mr = &mvdev->mr;
> struct mlx5_vdpa_direct_mr *dmr;
> struct mlx5_vdpa_direct_mr *n;
>
> - mutex_lock(&mr->mkey_mtx);
> - if (!mr->initialized)
> - goto out;
> -
> destroy_indirect_key(mvdev, mr);
> list_for_each_entry_safe_reverse(dmr, n, &mr->head, list) {
> list_del_init(&dmr->list);
> unmap_direct_mr(mvdev, dmr);
> kfree(dmr);
> }
> +}
> +
> +void mlx5_vdpa_destroy_mr(struct mlx5_vdpa_dev *mvdev)
> +{
> + struct mlx5_vdpa_mr *mr = &mvdev->mr;
> +
> + mutex_lock(&mr->mkey_mtx);
> + if (!mr->initialized)
> + goto out;
> +
> + if (mr->user_mr)
> + destroy_user_mr(mvdev, mr);
> + else
> + destroy_dma_mr(mvdev, mr);
> +
> memset(mr, 0, sizeof(*mr));
> mr->initialized = false;
> out:
> diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> index fdf3e74bffbd..02a05492204c 100644
> --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
> +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> @@ -1780,6 +1780,10 @@ static void mlx5_vdpa_set_status(struct vdpa_device *vdev, u8 status)
> ndev->mvdev.status = 0;
> ndev->mvdev.mlx_features = 0;
> ++mvdev->generation;
> + if (MLX5_CAP_GEN(mvdev->mdev, umem_uid_0)) {
> + if (mlx5_vdpa_create_mr(mvdev, NULL))
> + mlx5_vdpa_warn(mvdev, "create MR failed\n");
> + }
> return;
> }
>
> @@ -1859,6 +1863,7 @@ static void mlx5_vdpa_free(struct vdpa_device *vdev)
> ndev = to_mlx5_vdpa_ndev(mvdev);
>
> free_resources(ndev);
> + mlx5_vdpa_destroy_mr(mvdev);
> mlx5_vdpa_free_resources(&ndev->mvdev);
> mutex_destroy(&ndev->reslock);
> }
> @@ -2023,9 +2028,15 @@ static int mlx5_vdpa_dev_add(struct vdpa_mgmt_dev *v_mdev, const char *name)
> if (err)
> goto err_mtu;
>
> + if (MLX5_CAP_GEN(mvdev->mdev, umem_uid_0)) {
> + err = mlx5_vdpa_create_mr(mvdev, NULL);
> + if (err)
> + goto err_res;
> + }
> +
> err = alloc_resources(ndev);
> if (err)
> - goto err_res;
> + goto err_mr;
>
> mvdev->vdev.mdev = &mgtdev->mgtdev;
> err = _vdpa_register_device(&mvdev->vdev, 2 * mlx5_vdpa_max_qps(max_vqs));
> @@ -2037,6 +2048,8 @@ static int mlx5_vdpa_dev_add(struct vdpa_mgmt_dev *v_mdev, const char *name)
>
> err_reg:
> free_resources(ndev);
> +err_mr:
> + mlx5_vdpa_destroy_mr(mvdev);
> err_res:
> mlx5_vdpa_free_resources(&ndev->mvdev);
> err_mtu:
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