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

From: Wu, Hao
Date: Wed Apr 21 2021 - 01:26:00 EST


> 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