[virtio-dev] Re: [PATCH v9] virtio-net: support inner header hash

From: "Michael S. Tsirkin" <mst@redhat.com>
To: Jason Wang <jasowang@redhat.com>
Cc: Heng Qi <hengqi@linux.alibaba.com>,
	virtio-comment@lists.oasis-open.org,
	virtio-dev@lists.oasis-open.org, Parav Pandit <parav@nvidia.com>,
	Yuri Benditovich <yuri.benditovich@daynix.com>,
	Cornelia Huck <cohuck@redhat.com>,
	Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Subject: [virtio-dev] Re: [PATCH v9] virtio-net: support inner header hash
Date: Mon, 27 Feb 2023 02:39:02 -0500	[thread overview]
Message-ID: <20230227023657-mutt-send-email-mst@kernel.org> (raw)
Message-ID: <20230227073902.yRjyPEJeEFciVk91gTgJqwWSo4nHsDVEJZ4Mnkvt1Gw@z> (raw)
In-Reply-To: <CACGkMEuOu=6qKQO2TJ0B6ZLRH_-rGtZMYVtw7gn+BFbnJgWkrw@mail.gmail.com>

On Mon, Feb 27, 2023 at 12:07:17PM +0800, Jason Wang wrote:
> Btw, this kind of 1:1 hash features seems not scalable and flexible.
> It requires an endless extension on bits/fields. Modern NICs allow the
> user to customize the hash calculation, for virtio-net we can allow to
> use eBPF program to classify the packets. It seems to be more flexible
> and scalable and there's almost no maintain burden in the spec (only
> bytecode is required, no need any fancy features/interactions like
> maps), easy to be migrated etc.
> 
> Prototype is also easy, tun/tap had an eBPF classifier for years.
> 
> Thanks

Yea BPF offload would be great to have. We have been discussing it for
years though - security issues keep blocking it. *Maybe* it's finally
going to be there but I'm not going to block this work waiting for BPF
offload.  And easily migrated is what BPF is not.

-- 
MST

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