linux-kernel - Re: [PATCH v2 1/1] fpga: altera-cvp: Use pci_find_vsec

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <aG4rZNGgROrXXy+F@yilunxu-OptiPlex-7050>
Date: Wed, 9 Jul 2025 16:42:12 +0800
From: Xu Yilun <yilun.xu@...ux.intel.com>
To: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc: Xu Yilun <yilun.xu@...el.com>, linux-fpga@...r.kernel.org,
	linux-kernel@...r.kernel.org, Moritz Fischer <mdf@...nel.org>,
	Wu Hao <hao.wu@...el.com>, Tom Rix <trix@...hat.com>
Subject: Re: [PATCH v2 1/1] fpga: altera-cvp: Use pci_find_vsec_capability()
 when probing FPGA device

On Fri, Jun 27, 2025 at 02:26:22PM +0300, Andy Shevchenko wrote:
> Currently altera_cvp_probe() open-codes pci_find_vsec_capability().
> Refactor the former to use the latter. No functional change intended.
> 
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
> ---
> 
> v2: removed unused variable (LKP)
> 
>  drivers/fpga/altera-cvp.c | 20 +++++---------------
>  1 file changed, 5 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/fpga/altera-cvp.c b/drivers/fpga/altera-cvp.c
> index 5af0bd33890c..514d2ac18e5f 100644
> --- a/drivers/fpga/altera-cvp.c
> +++ b/drivers/fpga/altera-cvp.c
> @@ -22,9 +22,6 @@
>  #define TIMEOUT_US	2000	/* CVP STATUS timeout for USERMODE polling */
>  
>  /* Vendor Specific Extended Capability Registers */
> -#define VSE_PCIE_EXT_CAP_ID		0x0
> -#define VSE_PCIE_EXT_CAP_ID_VAL		0x000b	/* 16bit */
> -
>  #define VSE_CVP_STATUS			0x1c	/* 32bit */
>  #define VSE_CVP_STATUS_CFG_RDY		BIT(18)	/* CVP_CONFIG_READY */
>  #define VSE_CVP_STATUS_CFG_ERR		BIT(19)	/* CVP_CONFIG_ERROR */
> @@ -577,25 +574,18 @@ static int altera_cvp_probe(struct pci_dev *pdev,
>  {
>  	struct altera_cvp_conf *conf;
>  	struct fpga_manager *mgr;
> -	int ret, offset;
> -	u16 cmd, val;
> +	u16 cmd, offset;
>  	u32 regval;
> -
> -	/* Discover the Vendor Specific Offset for this device */
> -	offset = pci_find_next_ext_capability(pdev, 0, PCI_EXT_CAP_ID_VNDR);
> -	if (!offset) {
> -		dev_err(&pdev->dev, "No Vendor Specific Offset.\n");
> -		return -ENODEV;
> -	}
> +	int ret;
>  
>  	/*
>  	 * First check if this is the expected FPGA device. PCI config
>  	 * space access works without enabling the PCI device, memory
>  	 * space access is enabled further down.
>  	 */
> -	pci_read_config_word(pdev, offset + VSE_PCIE_EXT_CAP_ID, &val);
> -	if (val != VSE_PCIE_EXT_CAP_ID_VAL) {
> -		dev_err(&pdev->dev, "Wrong EXT_CAP_ID value 0x%x\n", val);
> +	offset = pci_find_vsec_capability(pdev, PCI_VENDOR_ID_ALTERA, 0);

Mm.. the original code seems broken. It doesn't check the VSEC ID. And
you filled '0'. Is '0' specified in any SPEC? I didn't see it as a
wildcard.

Anyway, we should describe the change and remove "No functional change
intended".

> +	if (!offset) {
> +		dev_err(&pdev->dev, "Wrong EXT_CAP_ID value\n");

Should be "VSEC ID not found"

Thanks,
Yilun

>  		return -ENODEV;
>  	}
>  
> -- 
> 2.47.2
> 
>