Re: [PATCH net] nfp: use full 40 bits of the NSP buffer address

[Jakub Kicinski <jakub.kicinski@netronome.com>]

On Fri, 23 Mar 2018 19:42:22 -0700, Jakub Kicinski wrote:
> From: Dirk van der Merwe <dirk.vandermerwe@netronome.com>
> 
> The NSP default buffer is a piece of NFP memory where additional
> command data can be placed.  Its format has been copied from
> host buffer, but the PCIe selection bits do not make sense in
> this case.  If those get masked out from a NFP address - writes
> to random place in the chip memory may be issued and crash the
> device.
> 
> This has never been an issue because the buffer used to be
> allocated in memory with less-than-38-bit-long address but that
> is about to change.
> 
> Signed-off-by: Dirk van der Merwe <dirk.vandermerwe@netronome.com>
> Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
> ---
>  drivers/net/ethernet/netronome/nfp/nfpcore/nfp_nsp.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_nsp.c b/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_nsp.c
> index 39abac678b71..b54ab02f5b33 100644
> --- a/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_nsp.c
> +++ b/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_nsp.c
> @@ -71,8 +71,7 @@
>  /* CPP address to retrieve the data from */
>  #define NSP_BUFFER		0x10
>  #define   NSP_BUFFER_CPP	GENMASK_ULL(63, 40)
> -#define   NSP_BUFFER_PCIE	GENMASK_ULL(39, 38)
> -#define   NSP_BUFFER_ADDRESS	GENMASK_ULL(37, 0)
> +#define   NSP_BUFFER_ADDRESS	GENMASK_ULL(39, 0)

self-nack, this is changing a shared define for all bufs, adding a new
define of NFP buf will be cleaner.