Re: [PATCH v18 01/13] cxl/ras: Fix cxl_rch_get_aer_severity() wrong severity register

On Fri, Jul 17, 2026 at 05:26:54PM +0800, Terry Bowman wrote:
> cxl_rch_get_aer_severity() classifies RCH Downstream Port uncorrectable
> errors as fatal or non-fatal by ANDing uncorrectable status with
> PCI_ERR_ROOT_FATAL_RCV. This is wrong because PCI_ERR_ROOT_FATAL_RCV is a
> Root Error Status register bit (bit 6), not a severity bit. ANDing it
> against uncorrectable status tests a reserved bit and produces incorrect
> severity classification.
> 
> Fix by ANDing the unmasked uncor_status against uncor_severity. Per
> PCIe Base Spec r6.0 Section 7.8.4.4, each bit in the Uncorrectable
> Error Severity register indicates whether the corresponding error is
> fatal (1) or non-fatal (0).
> 
> Fixes: 6ac07883dbb5 ("cxl/pci: Add RCH downstream port error logging")
> Cc: [email protected]
> Signed-off-by: Terry Bowman <[email protected]>
> 
> ---
> 
> Changes in v17 -> v18:
> - New patch.
> ---
>  drivers/cxl/core/ras_rch.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/cxl/core/ras_rch.c b/drivers/cxl/core/ras_rch.c
> index 0a8b3b9b63884..44b335d560708 100644
> --- a/drivers/cxl/core/ras_rch.c
> +++ b/drivers/cxl/core/ras_rch.c
> @@ -80,7 +80,8 @@ static bool cxl_rch_get_aer_severity(struct aer_capability_regs *aer_regs,
>  				     int *severity)
>  {
>  	if (aer_regs->uncor_status & ~aer_regs->uncor_mask) {
> -		if (aer_regs->uncor_status & PCI_ERR_ROOT_FATAL_RCV)
> +		if ((aer_regs->uncor_status & ~aer_regs->uncor_mask) &
> +		    aer_regs->uncor_severity)
>  			*severity = AER_FATAL;
>  		else
>  			*severity = AER_NONFATAL;

The logic looks correct to me, maybe the small tweak would be cleaner ?

"""
u32 status = aer_regs->uncor_status & ~aer_regs->uncor_mask;
if (status) {
    *severity = (status & aer_regs->uncor_severity) ? AER_FATAL : AER_NONFATAL;
}
"""

Reviewed-by: Richard Cheng <[email protected]>

> -- 
> 2.34.1
> 
>