linux-kernel - Re: [PATCH] fpga: dfl: pci: gracefully handle misconfigured port entries

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Date:   Tue, 20 Apr 2021 11:49:21 -0700
From:   Tom Rix <trix@...hat.com>
To:     matthew.gerlach@...ux.intel.com, hao.wu@...el.com,
        linux-fpga@...r.kernel.org, linux-kernel@...r.kernel.org,
        yilun.xu@...el.com, russell.h.weight@...el.com, mdf@...nel.org
Subject: Re: [PATCH] fpga: dfl: pci: gracefully handle misconfigured port
 entries


On 4/20/21 10:27 AM, matthew.gerlach@...ux.intel.com wrote:
> From: Matthew Gerlach <matthew.gerlach@...ux.intel.com>
>
> Gracefully ignore misconfigured port entries encountered in
> incorrect FPGA images.
>
> Signed-off-by: Matthew Gerlach <matthew.gerlach@...ux.intel.com>
> ---
>   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,
Does something similar need to be added to find_dfls_by_vsec ?
>   	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;
> +			}
> +
>   			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);

why %pa,&len for instead of %u,len ?

Tom

> +				continue;
> +			}
>   
> +			len -= offset;
> +			bars |= BIT(bar);
>   			dfl_fpga_enum_info_add_dfl(info, start, len);
>   		}
>   	} else if (dfl_feature_is_port(base)) {