linux-kernel - Re: [PATCH net-next v11 00/10] tun: Introduce virtio-net hashing feature

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

Message-ID: <CACGkMEu=pPTd-QHKRDw7noRCTu-18c7JLJNKZCEu5=BHAE0aJQ@mail.gmail.com>
Date: Tue, 18 Mar 2025 08:29:09 +0800
From: Jason Wang <jasowang@...hat.com>
To: Akihiko Odaki <akihiko.odaki@...nix.com>
Cc: Jonathan Corbet <corbet@....net>, Willem de Bruijn <willemdebruijn.kernel@...il.com>, 
	"David S. Miller" <davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>, 
	Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>, 
	"Michael S. Tsirkin" <mst@...hat.com>, Xuan Zhuo <xuanzhuo@...ux.alibaba.com>, 
	Shuah Khan <shuah@...nel.org>, linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org, 
	netdev@...r.kernel.org, kvm@...r.kernel.org, 
	virtualization@...ts.linux-foundation.org, linux-kselftest@...r.kernel.org, 
	Yuri Benditovich <yuri.benditovich@...nix.com>, Andrew Melnychenko <andrew@...nix.com>, 
	Stephen Hemminger <stephen@...workplumber.org>, gur.stavi@...wei.com, 
	Lei Yang <leiyang@...hat.com>, Simon Horman <horms@...nel.org>
Subject: Re: [PATCH net-next v11 00/10] tun: Introduce virtio-net hashing feature

On Mon, Mar 17, 2025 at 6:58 PM Akihiko Odaki <akihiko.odaki@...nix.com> wrote:
>
> virtio-net have two usage of hashes: one is RSS and another is hash
> reporting. Conventionally the hash calculation was done by the VMM.
> However, computing the hash after the queue was chosen defeats the
> purpose of RSS.
>
> Another approach is to use eBPF steering program. This approach has
> another downside: it cannot report the calculated hash due to the
> restrictive nature of eBPF.
>
> Introduce the code to compute hashes to the kernel in order to overcome
> thse challenges.
>
> An alternative solution is to extend the eBPF steering program so that it
> will be able to report to the userspace, but it is based on context
> rewrites, which is in feature freeze. We can adopt kfuncs, but they will
> not be UAPIs. We opt to ioctl to align with other relevant UAPIs (KVM
> and vhost_net).
>
> The patches for QEMU to use this new feature was submitted as RFC and
> is available at:
> https://patchew.org/QEMU/20250313-hash-v4-0-c75c494b495e@daynix.com/
>
> This work was presented at LPC 2024:
> https://lpc.events/event/18/contributions/1963/
>
> V1 -> V2:
>   Changed to introduce a new BPF program type.
>
> Signed-off-by: Akihiko Odaki <akihiko.odaki@...nix.com>
> ---
> Changes in v11:
> - Added the missing code to free vnet_hash in patch
>   "tap: Introduce virtio-net hash feature".
> - Link to v10: https://lore.kernel.org/r/20250313-rss-v10-0-3185d73a9af0@daynix.com
>

We only have 2 or 3 points that need to be sorted out. Let's hold on
to the iteration until we had an agreement.

Thanks