Re: [dpdk-dev] [PATCH 0/3] remove RTE_EAL_UNBIND_PORTS related code

["Burakov, Anatoly" <anatoly.burakov@intel.com>]

Hi David,

> This functionality is at least used by virtio-net-pmd.
> So we cannot remove this without a fix for virtio-net-pmd.

It appears that virtio-net-pmd hasn't been merged in yet? At least I can't see it in the git tree for 1.6 release.

> Yet, even if we remove this from the eal, I think we should provide a proper
> api to bind/unbind devices to kernel drivers.
> This way PMDs can use this api and forget about OS dependencies
> (linux/bsd).

Please forgive me for repeating myself, but I'm still not convinced that binding/unbinding the kernel drivers has to be the responsibility of the application in the first place. As far as I know, the reasons why the binding/unbinding code was there are purely historical and have no rationale behind them other than "this is how it was first implemented". Plus, correct me if I'm wrong, but FreeBSD has some issues with port binding/unbinding - i.e. it can't do that at all, at least during runtime, so on BSD it's even less of an issue.

Anyway, the reason I'm bringing this subject up in the first place is I'm preparing a patch to support VFIO driver alongside igb_uio. Among the changes I'm preparing to make is getting rid of the device ID list in igb_uio, so that any driver could be bound to it (via writing to new_id) - i.e. making it similar to how pci_stub, vfio-pci  et al work. A consequence of that will be that igb_uio won't try to bind any devices unless the user explicitly asks for it, meaning that the virtio device will not be bound to igb_uio by default. I think this will remedy the issues with virtio-net-pmd without the need for force-unbind logic in the EAL.

Best regards,
Anatoly Burakov
DPDK SW Engineer

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