Re: [PATCH v2 2/2] cxl/region: Test CXL_DECODER_F_NORMALIZED_ADDRESSING as a bitmask

[Dave Jiang <dave.jiang@intel.com>]

On 2/23/26 12:13 PM, Alison Schofield wrote:
> The CXL decoder flags are defined as bitmasks, not bit indices.
> Using test_bit() to check them interprets the mask value as a bit
> index, which is the wrong test.
> 
> For CXL_DECODER_F_NORMALIZED_ADDRESSING the test reads beyond the
> flags word, making the flag sometimes appear set and blocking creation
> of CXL region debugfs attributes that support poison operations.
> 
> Replace test_bit() with a bitmask check.
> 
> Found with cxl-test.
> 
> Fixes: 208f432406b7 ("cxl: Disable HPA/SPA translation handlers for Normalized Addressing")
> Signed-off-by: Alison Schofield <alison.schofield@intel.com>

Applied to cxl/fixes
ebd11be59f7421e4b1ea19eaa8102d17ade3d6c6

> ---
> 
> Changes in v2:
> Split patches to align w Fixes Tags for backport ease
> Rebased on 7.0-rc1
> 
>  drivers/cxl/core/region.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
> index 780ec947ecf2..42874948b589 100644
> --- a/drivers/cxl/core/region.c
> +++ b/drivers/cxl/core/region.c
> @@ -1105,7 +1105,7 @@ static void cxl_region_setup_flags(struct cxl_region *cxlr,
>  		clear_bit(CXL_REGION_F_NEEDS_RESET, &cxlr->flags);
>  	}
>  
> -	if (test_bit(CXL_DECODER_F_NORMALIZED_ADDRESSING, &cxld->flags))
> +	if (cxld->flags & CXL_DECODER_F_NORMALIZED_ADDRESSING)
>  		set_bit(CXL_REGION_F_NORMALIZED_ADDRESSING, &cxlr->flags);
>  }
>