Re: [dpdk-dev] [PATCH v2 11/29] net/ena/base: use 48-bit memory addresses in ena_com

[Ferruh Yigit <ferruh.yigit@intel.com>]

On 4/1/2020 3:21 PM, Michal Krawczyk wrote:
> ENA device is using 48-bit memory for IO. because of that, the upper
> limit had to be updated.

What is the impact of this change, and what is the reason of the change? Can you
please explain in the commit log?

> 
> Signed-off-by: Michal Krawczyk <mk@semihalf.com>
> Reviewed-by: Igor Chauskin <igorch@amazon.com>
> Reviewed-by: Guy Tzalik <gtzalik@amazon.com>
> ---
>  drivers/net/ena/base/ena_com.c                  | 2 +-
>  drivers/net/ena/base/ena_defs/ena_common_defs.h | 6 +++++-
>  2 files changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/ena/base/ena_com.c b/drivers/net/ena/base/ena_com.c
> index 7c1d0aef20..b7749209b3 100644
> --- a/drivers/net/ena/base/ena_com.c
> +++ b/drivers/net/ena/base/ena_com.c
> @@ -73,7 +73,7 @@ static int ena_com_mem_addr_set(struct ena_com_dev *ena_dev,
>  	}
>  
>  	ena_addr->mem_addr_low = lower_32_bits(addr);
> -	ena_addr->mem_addr_high = upper_32_bits(addr);
> +	ena_addr->mem_addr_high = (u16)upper_32_bits(addr);
>  
>  	return 0;
>  }
> diff --git a/drivers/net/ena/base/ena_defs/ena_common_defs.h b/drivers/net/ena/base/ena_defs/ena_common_defs.h
> index 1818c29a87..349474d265 100644
> --- a/drivers/net/ena/base/ena_defs/ena_common_defs.h
> +++ b/drivers/net/ena/base/ena_defs/ena_common_defs.h
> @@ -9,10 +9,14 @@
>  #define ENA_COMMON_SPEC_VERSION_MAJOR        2
>  #define ENA_COMMON_SPEC_VERSION_MINOR        0
>  
> +/* ENA operates with 48-bit memory addresses. ena_mem_addr_t */
>  struct ena_common_mem_addr {
>  	uint32_t mem_addr_low;
>  
> -	uint32_t mem_addr_high;
> +	uint16_t mem_addr_high;
> +
> +	/* MBZ */
> +	uint16_t reserved16;
>  };
>  
>  #endif /* _ENA_COMMON_H_ */
>