Re: [PATCH 1/2] vdpa/mlx5: Support creating resources with uid == 0

Re: [PATCH 1/2] vdpa/mlx5: Support creating resources with uid == 0

[Jason Wang]

在 2021/5/30 下午3:54, Eli Cohen 写道:
> Currently all resources must be created with uid != 0 which is essential
> userspace processes allocating virtquueue resources. Since this is a
> kernel implementation, it is perfectly legal to open resources with
> uid == 0.
>
> In case frimware supports, avoid allocating user context.


Typo "frimware".

Otherwise.

Acked-by: Jason Wang <jasowang@redhat.com>

(I don't see any code to check the firmware capability, is this intended?)

Thanks


>
> Signed-off-by: Eli Cohen <elic@nvidia.com>
> ---
>   drivers/vdpa/mlx5/core/resources.c | 6 ++++++
>   include/linux/mlx5/mlx5_ifc.h      | 4 +++-
>   2 files changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/vdpa/mlx5/core/resources.c b/drivers/vdpa/mlx5/core/resources.c
> index 6521cbd0f5c2..836ab9ef0fa6 100644
> --- a/drivers/vdpa/mlx5/core/resources.c
> +++ b/drivers/vdpa/mlx5/core/resources.c
> @@ -54,6 +54,9 @@ static int create_uctx(struct mlx5_vdpa_dev *mvdev, u16 *uid)
>   	void *in;
>   	int err;
>   
> +	if (MLX5_CAP_GEN(mvdev->mdev, umem_uid_0))
> +		return 0;
> +
>   	/* 0 means not supported */
>   	if (!MLX5_CAP_GEN(mvdev->mdev, log_max_uctx))
>   		return -EOPNOTSUPP;
> @@ -79,6 +82,9 @@ static void destroy_uctx(struct mlx5_vdpa_dev *mvdev, u32 uid)
>   	u32 out[MLX5_ST_SZ_DW(destroy_uctx_out)] = {};
>   	u32 in[MLX5_ST_SZ_DW(destroy_uctx_in)] = {};
>   
> +	if (!uid)
> +		return;
> +
>   	MLX5_SET(destroy_uctx_in, in, opcode, MLX5_CMD_OP_DESTROY_UCTX);
>   	MLX5_SET(destroy_uctx_in, in, uid, uid);
>   
> diff --git a/include/linux/mlx5/mlx5_ifc.h b/include/linux/mlx5/mlx5_ifc.h
> index 9c68b2da14c6..606d2aeacad4 100644
> --- a/include/linux/mlx5/mlx5_ifc.h
> +++ b/include/linux/mlx5/mlx5_ifc.h
> @@ -1487,7 +1487,9 @@ struct mlx5_ifc_cmd_hca_cap_bits {
>   	u8         uar_4k[0x1];
>   	u8         reserved_at_241[0x9];
>   	u8         uar_sz[0x6];
> -	u8         reserved_at_250[0x8];
> +	u8         reserved_at_248[0x2];
> +	u8         umem_uid_0[0x1];
> +	u8         reserved_at_250[0x5];
>   	u8         log_pg_sz[0x8];
>   
>   	u8         bf[0x1];

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Re: [PATCH 1/2] vdpa/mlx5: Support creating resources with uid == 0

[Jason Wang]

在 2021/5/31 上午11:02, Jason Wang 写道:
>
> 在 2021/5/30 下午3:54, Eli Cohen 写道:
>> Currently all resources must be created with uid != 0 which is essential
>> userspace processes allocating virtquueue resources. Since this is a
>> kernel implementation, it is perfectly legal to open resources with
>> uid == 0.
>>
>> In case frimware supports, avoid allocating user context.
>
>
> Typo "frimware".
>
> Otherwise.
>
> Acked-by: Jason Wang <jasowang@redhat.com>
>
> (I don't see any code to check the firmware capability, is this 
> intended?)


Speak too fast. I see the MLX5_CAP_GEN(), so it's fine.

Thanks


>
> Thanks
>
>
>>
>> Signed-off-by: Eli Cohen <elic@nvidia.com>
>> ---
>>   drivers/vdpa/mlx5/core/resources.c | 6 ++++++
>>   include/linux/mlx5/mlx5_ifc.h      | 4 +++-
>>   2 files changed, 9 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/vdpa/mlx5/core/resources.c 
>> b/drivers/vdpa/mlx5/core/resources.c
>> index 6521cbd0f5c2..836ab9ef0fa6 100644
>> --- a/drivers/vdpa/mlx5/core/resources.c
>> +++ b/drivers/vdpa/mlx5/core/resources.c
>> @@ -54,6 +54,9 @@ static int create_uctx(struct mlx5_vdpa_dev *mvdev, 
>> u16 *uid)
>>       void *in;
>>       int err;
>>   +    if (MLX5_CAP_GEN(mvdev->mdev, umem_uid_0))
>> +        return 0;
>> +
>>       /* 0 means not supported */
>>       if (!MLX5_CAP_GEN(mvdev->mdev, log_max_uctx))
>>           return -EOPNOTSUPP;
>> @@ -79,6 +82,9 @@ static void destroy_uctx(struct mlx5_vdpa_dev 
>> *mvdev, u32 uid)
>>       u32 out[MLX5_ST_SZ_DW(destroy_uctx_out)] = {};
>>       u32 in[MLX5_ST_SZ_DW(destroy_uctx_in)] = {};
>>   +    if (!uid)
>> +        return;
>> +
>>       MLX5_SET(destroy_uctx_in, in, opcode, MLX5_CMD_OP_DESTROY_UCTX);
>>       MLX5_SET(destroy_uctx_in, in, uid, uid);
>>   diff --git a/include/linux/mlx5/mlx5_ifc.h 
>> b/include/linux/mlx5/mlx5_ifc.h
>> index 9c68b2da14c6..606d2aeacad4 100644
>> --- a/include/linux/mlx5/mlx5_ifc.h
>> +++ b/include/linux/mlx5/mlx5_ifc.h
>> @@ -1487,7 +1487,9 @@ struct mlx5_ifc_cmd_hca_cap_bits {
>>       u8         uar_4k[0x1];
>>       u8         reserved_at_241[0x9];
>>       u8         uar_sz[0x6];
>> -    u8         reserved_at_250[0x8];
>> +    u8         reserved_at_248[0x2];
>> +    u8         umem_uid_0[0x1];
>> +    u8         reserved_at_250[0x5];
>>       u8         log_pg_sz[0x8];
>>         u8         bf[0x1];

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Re: [PATCH 2/2] vdpa/mlx5: Add support for running with virtio_vdpa

[Jason Wang]

在 2021/5/30 下午3:54, 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@nvidia.com>
> ---
>   drivers/vdpa/mlx5/core/mlx5_vdpa.h |  1 +
>   drivers/vdpa/mlx5/core/mr.c        | 81 ++++++++++++++++++++++++------
>   drivers/vdpa/mlx5/net/mlx5_vnet.c  | 13 ++++-
>   3 files changed, 80 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..020c0ce4d203 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 +423,89 @@ 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);
> +	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);


Do we need to set user_mr to false here?


> +
> +	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..f16756661c19 100644
> --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
> +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> @@ -1780,6 +1780,8 @@ 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))
> +			mlx5_vdpa_create_mr(mvdev, NULL);


I wonder if it's possible/worth to avoid the destroy and re-create of 
dma MR here. (In the case of it has been used by us).

Thanks


>   		return;
>   	}
>   
> @@ -1859,6 +1861,7 @@ 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 +2026,15 @@ 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 +2046,8 @@ 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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Re: [PATCH 1/2] vdpa/mlx5: Support creating resources with uid == 0

[Jason Wang]

在 2021/5/31 下午12:59, Eli Cohen 写道:
> On Mon, May 31, 2021 at 11:06:59AM +0800, Jason Wang wrote:
>> 在 2021/5/31 上午11:02, Jason Wang 写道:
>>> 在 2021/5/30 下午3:54, Eli Cohen 写道:
>>>> Currently all resources must be created with uid != 0 which is essential
>>>> userspace processes allocating virtquueue resources. Since this is a
>>>> kernel implementation, it is perfectly legal to open resources with
>>>> uid == 0.
>>>>
>>>> In case frimware supports, avoid allocating user context.
>>>
>>> Typo "frimware".
>>>
>>> Otherwise.
>>>
>>> Acked-by: Jason Wang <jasowang@redhat.com>
>>>
>>> (I don't see any code to check the firmware capability, is this
>>> intended?)
>>
>> Speak too fast. I see the MLX5_CAP_GEN(), so it's fine.
> And I responded too fast :-)


Right and thanks for the quick response :)


>> Thanks
>>
>>
>>> Thanks
>>>
>>>
>>>> Signed-off-by: Eli Cohen <elic@nvidia.com>
>>>> ---
>>>>    drivers/vdpa/mlx5/core/resources.c | 6 ++++++
>>>>    include/linux/mlx5/mlx5_ifc.h      | 4 +++-
>>>>    2 files changed, 9 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/drivers/vdpa/mlx5/core/resources.c
>>>> b/drivers/vdpa/mlx5/core/resources.c
>>>> index 6521cbd0f5c2..836ab9ef0fa6 100644
>>>> --- a/drivers/vdpa/mlx5/core/resources.c
>>>> +++ b/drivers/vdpa/mlx5/core/resources.c
>>>> @@ -54,6 +54,9 @@ static int create_uctx(struct mlx5_vdpa_dev
>>>> *mvdev, u16 *uid)
>>>>        void *in;
>>>>        int err;
>>>>    +    if (MLX5_CAP_GEN(mvdev->mdev, umem_uid_0))
>>>> +        return 0;
>>>> +
>>>>        /* 0 means not supported */
>>>>        if (!MLX5_CAP_GEN(mvdev->mdev, log_max_uctx))
>>>>            return -EOPNOTSUPP;
>>>> @@ -79,6 +82,9 @@ static void destroy_uctx(struct mlx5_vdpa_dev
>>>> *mvdev, u32 uid)
>>>>        u32 out[MLX5_ST_SZ_DW(destroy_uctx_out)] = {};
>>>>        u32 in[MLX5_ST_SZ_DW(destroy_uctx_in)] = {};
>>>>    +    if (!uid)
>>>> +        return;
>>>> +
>>>>        MLX5_SET(destroy_uctx_in, in, opcode, MLX5_CMD_OP_DESTROY_UCTX);
>>>>        MLX5_SET(destroy_uctx_in, in, uid, uid);
>>>>    diff --git a/include/linux/mlx5/mlx5_ifc.h
>>>> b/include/linux/mlx5/mlx5_ifc.h
>>>> index 9c68b2da14c6..606d2aeacad4 100644
>>>> --- a/include/linux/mlx5/mlx5_ifc.h
>>>> +++ b/include/linux/mlx5/mlx5_ifc.h
>>>> @@ -1487,7 +1487,9 @@ struct mlx5_ifc_cmd_hca_cap_bits {
>>>>        u8         uar_4k[0x1];
>>>>        u8         reserved_at_241[0x9];
>>>>        u8         uar_sz[0x6];
>>>> -    u8         reserved_at_250[0x8];
>>>> +    u8         reserved_at_248[0x2];
>>>> +    u8         umem_uid_0[0x1];
>>>> +    u8         reserved_at_250[0x5];
>>>>        u8         log_pg_sz[0x8];
>>>>          u8         bf[0x1];

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Re: [PATCH 2/2] vdpa/mlx5: Add support for running with virtio_vdpa

[Jason Wang]

在 2021/5/31 下午1:13, Eli Cohen 写道:
> On Mon, May 31, 2021 at 11:16:11AM +0800, Jason Wang wrote:
>> 在 2021/5/30 下午3:54, 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@nvidia.com>
>>> ---
>>>    drivers/vdpa/mlx5/core/mlx5_vdpa.h |  1 +
>>>    drivers/vdpa/mlx5/core/mr.c        | 81 ++++++++++++++++++++++++------
>>>    drivers/vdpa/mlx5/net/mlx5_vnet.c  | 13 ++++-
>>>    3 files changed, 80 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..020c0ce4d203 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 +423,89 @@ 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);
>>> +	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);
>>
>> Do we need to set user_mr to false here?
> I think the right place to do this should be inside create_dma_mr(), the
> same as we set it true in ().


Fine.


>>
>>> +
>>> +	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..f16756661c19 100644
>>> --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
>>> +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
>>> @@ -1780,6 +1780,8 @@ 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))
>>> +			mlx5_vdpa_create_mr(mvdev, NULL);
>>
>> I wonder if it's possible/worth to avoid the destroy and re-create of dma MR
>> here. (In the case of it has been used by us).
> If it is a user MR, you must destroy it since it is useless. If it's
> DMA MR, you might be able to do it but since the DMA MR's are
> lightweight, I don't think it's worth it.


Yes, I agree.

Thanks


>
>> Thanks
>>
>>
>>>    		return;
>>>    	}
>>> @@ -1859,6 +1861,7 @@ 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 +2026,15 @@ 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 +2046,8 @@ 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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