On Fri, Dec 13, 2024 at 05:46:17PM +0800, zhangdongdong@xxxxxxxxxxxxxxxxxx wrote:
> From: Dongdong Zhang <zhangdongdong@xxxxxxxxxxxxxxxxxx>
>
> Removed the duplicate macro definition PCI_VSEC_HDR from
> pci_regs.h to avoid redundancy. Updated the VFIO PCI code
> to use the existing `PCI_VNDR_HEADER` macro for consistency,
> ensuring minimal changes to the codebase.
>
> Signed-off-by: Dongdong Zhang <zhangdongdong@xxxxxxxxxxxxxxxxxx>
> ---
> drivers/vfio/pci/vfio_pci_config.c | 3 ++-
> include/uapi/linux/pci_regs.h | 1 -
> 2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/vfio/pci/vfio_pci_config.c b/drivers/vfio/pci/vfio_pci_config.c
> index ea2745c1ac5e..c30748912ff1 100644
> --- a/drivers/vfio/pci/vfio_pci_config.c
> +++ b/drivers/vfio/pci/vfio_pci_config.c
> @@ -1389,7 +1389,8 @@ static int vfio_ext_cap_len(struct vfio_pci_core_device *vdev, u16 ecap, u16 epo
>
> switch (ecap) {
> case PCI_EXT_CAP_ID_VNDR:
> - ret = pci_read_config_dword(pdev, epos + PCI_VSEC_HDR, &dword);
> + ret = pci_read_config_dword(pdev, epos + PCI_VNDR_HEADER,
> + &dword);
> if (ret)
> return pcibios_err_to_errno(ret);
>
> diff --git a/include/uapi/linux/pci_regs.h b/include/uapi/linux/pci_regs.h
> index 1601c7ed5fab..7b6cad788de3 100644
> --- a/include/uapi/linux/pci_regs.h
> +++ b/include/uapi/linux/pci_regs.h
> @@ -1001,7 +1001,6 @@
> #define PCI_ACS_CTRL 0x06 /* ACS Control Register */
> #define PCI_ACS_EGRESS_CTL_V 0x08 /* ACS Egress Control Vector */
>
> -#define PCI_VSEC_HDR 4 /* extended cap - vendor-specific */
> #define PCI_VSEC_HDR_LEN_SHIFT 20 /* shift for length field */
We should resolve the duplication of PCI_VSEC_HDR and PCI_VNDR_HEADER,
but I don't like the fact that we're left with this dangling
PCI_VSEC_HDR_LEN_SHIFT.
That leaves vfio using PCI_VNDR_HEADER and PCI_VSEC_HDR_LEN_SHIFT,
which don't match at all.
I think you should remove PCI_VSEC_HDR_LEN_SHIFT as well and change
vfio to use PCI_VNDR_HEADER_LEN() instead.
It's somewhat dicey removing things from pci_regs.h since it's in
include/uapi/, but this is such a niche thing we might be able to get
away with it.
Bjorn
