Re: [PATCH net,1/6] octeontx2-af: replace cpt slot with lf id on reg write

[Michal Kubiak <michal.kubiak@intel.com>]

On Mon, Jul 01, 2024 at 02:37:41PM +0530, Srujana Challa wrote:
> From: Nithin Dabilpuram <ndabilpuram@marvell.com>
> 
> Replace cpt slot id with lf id on reg read/write as
> CPTPF/VF driver would send slot number instead of lf id
> in the reg offset.
> 
> Fixes: ae454086e3c2 ("octeontx2-af: add mailbox interface for CPT")
> Signed-off-by: Nithin Dabilpuram <ndabilpuram@marvell.com>
> ---
>  drivers/net/ethernet/marvell/octeontx2/af/rvu_cpt.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/ethernet/marvell/octeontx2/af/rvu_cpt.c b/drivers/net/ethernet/marvell/octeontx2/af/rvu_cpt.c
> index f047185f38e0..98440a0241a2 100644
> --- a/drivers/net/ethernet/marvell/octeontx2/af/rvu_cpt.c
> +++ b/drivers/net/ethernet/marvell/octeontx2/af/rvu_cpt.c
> @@ -663,6 +663,8 @@ static bool is_valid_offset(struct rvu *rvu, struct cpt_rd_wr_reg_msg *req)
>  		if (lf < 0)
>  			return false;
>  
> +		req->reg_offset &= 0xFF000;
> +		req->reg_offset += lf << 3;

I think it's not great to modify an input parameter from the function
named like "is_valid_offset()". From the function like that I would
rather expect doing just a simple check if the parameter is correct.
It seems calling that function from a different context can be risky
now.

>  		return true;
>  	} else if (!(req->hdr.pcifunc & RVU_PFVF_FUNC_MASK)) {
>  		/* Registers that can be accessed from PF */
> @@ -707,12 +709,13 @@ int rvu_mbox_handler_cpt_rd_wr_register(struct rvu *rvu,
>  	    !is_cpt_vf(rvu, req->hdr.pcifunc))
>  		return CPT_AF_ERR_ACCESS_DENIED;
>  
> +	if (!is_valid_offset(rvu, req))
> +		return CPT_AF_ERR_ACCESS_DENIED;
> +
>  	rsp->reg_offset = req->reg_offset;
>  	rsp->ret_val = req->ret_val;
>  	rsp->is_write = req->is_write;
>  
> -	if (!is_valid_offset(rvu, req))
> -		return CPT_AF_ERR_ACCESS_DENIED;

Is moving that call also a necessary part of the fix? Or is it just an extra
improvement?
Maybe it's worth mentioning in the commit message?

>  
>  	if (req->is_write)
>  		rvu_write64(rvu, blkaddr, req->reg_offset, req->val);
> -- 
> 2.25.1
> 
> 


Thanks,
Michal