Re: [PATCH] accel/qaic: Fix possible data corruption in BOs > 2G

[Lizhi Hou <lizhi.hou@amd.com>]

On 3/6/25 09:19, Jeff Hugo wrote:
> From: Jeffrey Hugo <quic_jhugo@quicinc.com>
>
> When slicing a BO, we need to iterate through the BO's sgt to find the
> right pieces to construct the slice. Some of the data types chosen for
> this process are incorrectly too small, and can overflow. This can
> result in the incorrect slice construction, which can lead to data
> corruption in workload execution.
>
> The device can only handle 32-bit sized transfers, and the scatterlist
> struct only supports 32-bit buffer sizes, so our upper limit for an
> individual transfer is an unsigned int. Using an int is incorrect due to
> the reservation of the sign bit. Upgrade the length of a scatterlist
> entry and the offsets into a scatterlist entry to unsigned int for a
> correct representation.
>
> While each transfer may be limited to 32-bits, the overall BO may exceed
> that size. For counting the total length of the BO, we need a type that
> can represent the largest allocation possible on the system. That is the
> definition of size_t, so use it.
>
> Fixes: ff13be830333 ("accel/qaic: Add datapath")
> Signed-off-by: Jeffrey Hugo <quic_jhugo@quicinc.com>
> Signed-off-by: Jeff Hugo <jeff.hugo@oss.qualcomm.com>
> ---
>   drivers/accel/qaic/qaic_data.c | 5 ++++-
>   1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/accel/qaic/qaic_data.c b/drivers/accel/qaic/qaic_data.c
> index c20eb63750f5..ffcdf5738d09 100644
> --- a/drivers/accel/qaic/qaic_data.c
> +++ b/drivers/accel/qaic/qaic_data.c
> @@ -172,9 +172,10 @@ static void free_slice(struct kref *kref)
>   static int clone_range_of_sgt_for_slice(struct qaic_device *qdev, struct sg_table **sgt_out,
>   					struct sg_table *sgt_in, u64 size, u64 offset)
>   {
> -	int total_len, len, nents, offf = 0, offl = 0;
>   	struct scatterlist *sg, *sgn, *sgf, *sgl;
> +	unsigned int len, nents, offf, offl;
>   	struct sg_table *sgt;
> +	size_t total_len;
>   	int ret, j;
>   
>   	/* find out number of relevant nents needed for this mem */
> @@ -182,6 +183,8 @@ static int clone_range_of_sgt_for_slice(struct qaic_device *qdev, struct sg_tabl
>   	sgf = NULL;
>   	sgl = NULL;
>   	nents = 0;
> +	offf = 0;
> +	offl = 0;
Reviewed-by: Lizhi Hou <lizhi.hou@amd.com>
>   
>   	size = size ? size : PAGE_SIZE;
>   	for_each_sgtable_dma_sg(sgt_in, sg, j) {