Re: [dpdk-dev] [PATCH v5] bus/pci: netuio interface for windows

[Ranjit Menon <ranjit.menon@intel.com>]

Hi Tal,

On 9/29/2020 1:28 AM, Tal Shnaiderman wrote:
[snip]
> In general:
>
> Regarding the issue Ranjit mentioned in the last community call on duplicated detection of netuio devices both as GUID_DEVCLASS_NETUIO and GUID_DEVCLASS_NET, in pci_scan_one there is actually code that take cares of duplicated detection by leaving only one in the device list, up until nor I saw it in action only in virtualization where BDF of several devices was equal.
>
> Assuming this is resolved with the addition of segment id as domain id the change we need is to give precedence to GUID_DEVCLASS_NETUIO, something like:
>
> @@ -372,11 +372,15 @@ pci_scan_one(HDEVINFO dev_info, PSP_DEVINFO_DATA device_info_data)
>   	} else if (ret < 0) {
>   		rte_pci_insert_device(dev2, dev);
>   	} else { /* already registered */
> +		if (IsEqualGUID(&(device_info_data.ClassGuid),
> +			&GUID_DEVCLASS_NETUIO) {
>   		dev2->kdrv = dev->kdrv;
>   		dev2->max_vfs = dev->max_vfs;
> 		memmove(dev2->mem_resource, dev->mem_resource,
>   			sizeof(dev->mem_resource));
> +		}
>   		free(dev);
> 	}
>   	return 0;
>   }

The issue I raised is slightly different: How do we distinguish between 
different GUID_DEVCLASS_NET class devices - those that can support DPDK 
and those that can't?

For instance, say we have 3 NICs in the system - MLX5 NIC, Intel i40e 
NIC and Intel ice NIC - all loaded with standard ethernet (NDIS) drivers.

Now if I load and bind the netuio driver to the Intel ice NIC, I have 
one GUID_DEVCLASS_NETUIO class device and two GUID_DEVCLASS_NET class 
devices.

If I run the pci scan now, it will detect all 3 devices and add them to 
the list. However, the Intel i40e NIC which is correctly detected as a 
GUID_DEVCLASS_NET class and is bound to the standard NDIS driver cannot 
support DPDK and should be excluded from the list.

I think the suggestion at the community meeting was to define a DEV 
interface which can be queried for confirming DPDK support. In such a 
case, the MLX5 driver should support this interface, where as our 
standard i40e (NDIS) driver will not. This check can be used to exclude 
this device from the list.

ranjit m.