RE: [PATCH] fpga: dfl: pci: gracefully handle misconfigured port entries

[Wu, Hao]

> Subject: [PATCH] fpga: dfl: pci: gracefully handle misconfigured port entries
> 
> From: Matthew Gerlach <matthew.gerlach@xxxxxxxxxxxxxxx>
> 
> Gracefully ignore misconfigured port entries encountered in
> incorrect FPGA images.
> 
> Signed-off-by: Matthew Gerlach <matthew.gerlach@xxxxxxxxxxxxxxx>
> ---
>  drivers/fpga/dfl-pci.c | 16 +++++++++++++++-
>  1 file changed, 15 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/fpga/dfl-pci.c b/drivers/fpga/dfl-pci.c
> index b44523e..660d3b6 100644
> --- a/drivers/fpga/dfl-pci.c
> +++ b/drivers/fpga/dfl-pci.c
> @@ -212,6 +212,7 @@ static int find_dfls_by_default(struct pci_dev *pcidev,
>  	int port_num, bar, i, ret = 0;
>  	resource_size_t start, len;
>  	void __iomem *base;
> +	int bars = 0;
>  	u32 offset;
>  	u64 v;
> 
> @@ -228,6 +229,7 @@ static int find_dfls_by_default(struct pci_dev *pcidev,
>  	if (dfl_feature_is_fme(base)) {
>  		start = pci_resource_start(pcidev, 0);
>  		len = pci_resource_len(pcidev, 0);
> +		bars |= BIT(0);
> 
>  		dfl_fpga_enum_info_add_dfl(info, start, len);
> 
> @@ -253,9 +255,21 @@ static int find_dfls_by_default(struct pci_dev *pcidev,
>  			 */
>  			bar = FIELD_GET(FME_PORT_OFST_BAR_ID, v);
>  			offset = FIELD_GET(FME_PORT_OFST_DFH_OFST, v);
> +			if (bars & BIT(bar)) {
> +				dev_warn(&pcidev->dev, "skipping bad port
> BAR %d\n", bar);
> +				continue;
> +			}

Will it be a real problem that multiple ports are inside one BAR but different offsets?

Hao

> +
>  			start = pci_resource_start(pcidev, bar) + offset;
> -			len = pci_resource_len(pcidev, bar) - offset;
> +			len = pci_resource_len(pcidev, bar);
> +			if (offset >= len) {
> +				dev_warn(&pcidev->dev, "bad port
> offset %u >= %pa\n",
> +					 offset, &len);
> +				continue;
> +			}
> 
> +			len -= offset;
> +			bars |= BIT(bar);
>  			dfl_fpga_enum_info_add_dfl(info, start, len);
>  		}
>  	} else if (dfl_feature_is_port(base)) {
> --
> 1.8.3.1