Re: [dpdk-dev] [PATCH v2 1/2] raw/ioat: add pci address handling to python script

[Bruce Richardson <bruce.richardson@intel.com>]

On Fri, May 28, 2021 at 02:19:01PM +0100, Kevin Laatz wrote:
> Currently the user needs to find the DSA instance number for any DSA device
> they would like to configure using this script, which can be cumbersome and
> error-prone since the instance numbering changes when changing the binding
> of the devices between vfio-pci and idxd.
> 
s/changes/may change/
I've found a number of times that after unbinding and rebinding a device the
number did not change.

> This patch improved the usability of the script by adding the ability to
s/improved/improves/

> specify the DSA device to configure using the device's PCI address instead
> of the DSA instance number. For example, "$dpdk_idxd_cfg.py 0" and
> "$dpdk_idxd_cfg.py 6a:01.0" are both valid references to the same device
> (assuming the numbering).
> 
> Signed-off-by: Kevin Laatz <kevin.laatz@intel.com>
> 
With the above minor commit-log tweaks

Acked-by: Bruce Richardson <bruce.richardson@intel.com>

> ---
> v2:
>    - split the device reset change into its own patch
>    - changed sysfs dir search
>    - improved error case handling
> ---
>  drivers/raw/ioat/dpdk_idxd_cfg.py | 28 ++++++++++++++++++++++++++--
>  1 file changed, 26 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/raw/ioat/dpdk_idxd_cfg.py b/drivers/raw/ioat/dpdk_idxd_cfg.py
> index ff06d9e240..ad8393a645 100755
> --- a/drivers/raw/ioat/dpdk_idxd_cfg.py
> +++ b/drivers/raw/ioat/dpdk_idxd_cfg.py
> @@ -29,6 +29,26 @@ def write_values(self, values):
>                  f.write(str(contents))
>  
>  
> +def get_pci_dir(pci):
> +    "Search for the sysfs directory of the PCI device"
> +    base_dir = '/sys/bus/pci/devices/'
> +    for path, dirs, files in os.walk(base_dir):
> +        for dir in dirs:
> +            if pci in dir:
> +                return os.path.join(base_dir, dir)
> +    sys.exit(f"Could not find sysfs directory for device {pci}")
> +
> +
> +def get_dsa_id(pci):
> +    "Get the DSA instance ID using the PCI address of the device"
> +    pci_dir = get_pci_dir(pci)
> +    for path, dirs, files in os.walk(pci_dir):
> +        for dir in dirs:
> +            if dir.startswith('dsa') and 'wq' not in dir:
> +                return int(dir[3:])
> +    sys.exit(f"Could not get device ID for device {pci}")
> +
> +
>  def configure_dsa(dsa_id, queues, prefix):
>      "Configure the DSA instance with appropriate number of queues"
>      dsa_dir = SysfsDir(f"/sys/bus/dsa/devices/dsa{dsa_id}")
> @@ -68,14 +88,18 @@ def main(args):
>      "Main function, does arg parsing and calls config function"
>      arg_p = argparse.ArgumentParser(
>          description="Configure whole DSA device instance for DPDK use")
> -    arg_p.add_argument('dsa_id', type=int, help="DSA instance number")
> +    arg_p.add_argument('dsa_id',
> +                       help="Specify DSA instance either via DSA instance number or PCI address")
>      arg_p.add_argument('-q', metavar='queues', type=int, default=255,
>                         help="Number of queues to set up")
>      arg_p.add_argument('--name-prefix', metavar='prefix', dest='prefix',
>                         default="dpdk",
>                         help="Prefix for workqueue name to mark for DPDK use [default: 'dpdk']")
>      parsed_args = arg_p.parse_args(args[1:])
> -    configure_dsa(parsed_args.dsa_id, parsed_args.q, parsed_args.prefix)
> +
> +    dsa_id = parsed_args.dsa_id
> +    dsa_id = get_dsa_id(dsa_id) if ':' in dsa_id else dsa_id
> +    configure_dsa(dsa_id, parsed_args.q, parsed_args.prefix)
>  
>  
>  if __name__ == "__main__":
> -- 
> 2.30.2
>