Re: [PATCH v3 11/17] rdma_rxe: Address an issue with hardened user copy

[Zhu Yanjun <zyjzyj2000@xxxxxxxxx>]

On 8/21/2020 6:46 AM, Bob Pearson wrote:
> Added a new feature to pools to let driver white list a region of
> a pool object. This removes a kernel oops caused when create qp
> returns the qp number so the next patch will work without errors.
>
> Signed-off-by: Bob Pearson <rpearson@xxxxxxx>
> ---
>   drivers/infiniband/sw/rxe/rxe_pool.c | 20 +++++++++++++++++---
>   drivers/infiniband/sw/rxe/rxe_pool.h |  4 ++++
>   2 files changed, 21 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/infiniband/sw/rxe/rxe_pool.c b/drivers/infiniband/sw/rxe/rxe_pool.c
> index 5679714827ec..374e56689d30 100644
> --- a/drivers/infiniband/sw/rxe/rxe_pool.c
> +++ b/drivers/infiniband/sw/rxe/rxe_pool.c
> @@ -40,9 +40,12 @@ struct rxe_type_info rxe_type_info[RXE_NUM_TYPES] = {
>   		.name		= "rxe-qp",
>   		.size		= sizeof(struct rxe_qp),
>   		.cleanup	= rxe_qp_cleanup,
> -		.flags		= RXE_POOL_INDEX,
> +		.flags		= RXE_POOL_INDEX
> +				| RXE_POOL_WHITELIST,
>   		.min_index	= RXE_MIN_QP_INDEX,
>   		.max_index	= RXE_MAX_QP_INDEX,
> +		.user_offset	= offsetof(struct rxe_qp, ibqp.qp_num),
> +		.user_size	= sizeof(u32),
>   	},
>   	[RXE_TYPE_CQ] = {
>   		.name		= "rxe-cq",
> @@ -116,10 +119,21 @@ int rxe_cache_init(void)
>   		type = &rxe_type_info[i];
>   		size = ALIGN(type->size, RXE_POOL_ALIGN);
>   		if (!(type->flags & RXE_POOL_NO_ALLOC)) {
> -			type->cache =
> -				kmem_cache_create(type->name, size,
> +			if (type->flags & RXE_POOL_WHITELIST) {
> +				type->cache =
> +					kmem_cache_create_usercopy(
> +						type->name, size,
> +						RXE_POOL_ALIGN,
> +						RXE_POOL_CACHE_FLAGS,
> +						type->user_offset,
> +						type->user_size, NULL);
> +			} else {
> +				type->cache =
> +					kmem_cache_create(type->name, size,
>   						  RXE_POOL_ALIGN,
>   						  RXE_POOL_CACHE_FLAGS, NULL);
> +			}
> +
>   			if (!type->cache) {
>   				pr_err("Unable to init kmem cache for %s\n",
>   				       type->name);
> diff --git a/drivers/infiniband/sw/rxe/rxe_pool.h b/drivers/infiniband/sw/rxe/rxe_pool.h
> index 664153bf9392..fc5b584a8137 100644
> --- a/drivers/infiniband/sw/rxe/rxe_pool.h
> +++ b/drivers/infiniband/sw/rxe/rxe_pool.h
> @@ -17,6 +17,7 @@ enum rxe_pool_flags {
>   	RXE_POOL_INDEX		= BIT(1),
>   	RXE_POOL_KEY		= BIT(2),
>   	RXE_POOL_NO_ALLOC	= BIT(4),
> +	RXE_POOL_WHITELIST	= BIT(5),
>   };
>   
>   enum rxe_elem_type {
> @@ -44,6 +45,9 @@ struct rxe_type_info {
>   	u32			min_index;
>   	size_t			key_offset;
>   	size_t			key_size;
> +	/* for white listing where necessary */

s/where/when


> +	unsigned int		user_offset;
> +	unsigned int		user_size;
>   	struct kmem_cache	*cache;
>   };
>