Re: [PATCH v2 net-next] ixgbe: Fix endian handling for ACI descriptor registers

[Przemek Kitszel <przemyslaw.kitszel@intel.com>]

On 1/16/25 17:21, Simon Horman wrote:
> On Wed, Jan 15, 2025 at 09:11:17AM +0530, Dheeraj Reddy Jonnalagadda wrote:
>> The ixgbe driver was missing proper endian conversion for ACI descriptor
>> register operations. Add the necessary conversions when reading and
>> writing to the registers.
>>
>> Fixes: 46761fd52a88 ("ixgbe: Add support for E610 FW Admin Command Interface")
>> Closes: https://scan7.scan.coverity.com/#/project-view/52337/11354?selectedIssue=1602757
>> Signed-off-by: Dheeraj Reddy Jonnalagadda <dheeraj.linuxdev@gmail.com>
> 
> Hi Dheeraj,
> 
> It seems that Sparse is not very happy about __le32 values appearing
> where u32 ones are expected. I wonder if something like what is below
> (compile tested only!) would both address the problem at hand and
> keep Sparse happy (even if negting much of it's usefulness by using casts).
> 
> diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_common.h b/drivers/net/ethernet/intel/ixgbe/ixgbe_common.h
> index 6639069ad528..8b3787837128 100644
> --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_common.h
> +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_common.h
> @@ -150,6 +150,9 @@ static inline void ixgbe_write_reg(struct ixgbe_hw *hw, u32 reg, u32 value)
>   }
>   #define IXGBE_WRITE_REG(a, reg, value) ixgbe_write_reg((a), (reg), (value))

Simon,

As all ixgbe registers are LE, it would be beneficial to change
ixgbe_write_reg(), as @value should be __le32, (perhaps @reg too).
Similar for 64b.

This clearly would not be a "fix" material, as all call sites should be
examined to check if they conform.

>   
> +#define IXGBE_WRITE_REG_LE32(a, reg, value) \
> +	ixgbe_write_reg((a), (reg), (u32 __force)cpu_to_le32(value))
> +