From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp2.osuosl.org (smtp2.osuosl.org [140.211.166.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BDF58253342 for ; Wed, 5 Mar 2025 17:52:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=140.211.166.133 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741197135; cv=none; b=NAGvy5GtnwPdhVxIA163VS4KJDX1zx7Jp/A8n/EkgC+CXtiC9Ss0BHN1TbbE7tSfmzMJjFmOWD14m2UELBVQGQNffnR97kp07rlN6NpI4EMAm5doKqIAH1nn4+XpfSv01uBMH9HV1hnqbEnw4zNJ9IMl0GtsxRWc/x+cDlrkwWc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741197135; c=relaxed/simple; bh=+fO6QHFZK3v34T0UbQQG+Rs4wUa/4vaaUqJFHDD+cJA=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=LarKI+jOkipYcDAIoXzRh2KndIe2gJIv3Xoy1tF018jeSYyJvlBX5uPb6k1jgKvd7IHqgmf55SPNFNVvUwxcabkKEdMMyZJDxqzfiUEgOX2PuLpfKzUPyWvKoD32d9lqhljqn+SIwQoAuUqVLSLTokfZKJdsba2vChGrgyZmNyg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=tLjGYBKb; arc=none smtp.client-ip=140.211.166.133 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="tLjGYBKb" Received: from localhost (localhost [127.0.0.1]) by smtp2.osuosl.org (Postfix) with ESMTP id 42377401FB for ; Wed, 5 Mar 2025 17:52:13 +0000 (UTC) X-Virus-Scanned: amavis at osuosl.org X-Spam-Flag: NO X-Spam-Score: -8.092 X-Spam-Level: Received: from smtp2.osuosl.org ([127.0.0.1]) by localhost (smtp2.osuosl.org [127.0.0.1]) (amavis, port 10024) with ESMTP id 6NvWYPw7Apfz for ; Wed, 5 Mar 2025 17:52:12 +0000 (UTC) Received-SPF: Pass (mailfrom) identity=mailfrom; client-ip=147.75.193.91; helo=nyc.source.kernel.org; envelope-from=horms@kernel.org; receiver= DMARC-Filter: OpenDMARC Filter v1.4.2 smtp2.osuosl.org 38CA0400FE Authentication-Results: smtp2.osuosl.org; dmarc=pass (p=quarantine dis=none) header.from=kernel.org DKIM-Filter: OpenDKIM Filter v2.11.0 smtp2.osuosl.org 38CA0400FE Authentication-Results: smtp2.osuosl.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=tLjGYBKb Received: from nyc.source.kernel.org (nyc.source.kernel.org [147.75.193.91]) by smtp2.osuosl.org (Postfix) with ESMTPS id 38CA0400FE for ; Wed, 5 Mar 2025 17:52:12 +0000 (UTC) Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by nyc.source.kernel.org (Postfix) with ESMTP id E0AD5A45C95; Wed, 5 Mar 2025 17:46:39 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 60757C4CEEA; Wed, 5 Mar 2025 17:52:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1741197130; bh=+fO6QHFZK3v34T0UbQQG+Rs4wUa/4vaaUqJFHDD+cJA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=tLjGYBKb2Crad0G/NITWxBaBxqZgqDl+WHtPV/INm9ZGzYEuYRxMovqxsAw8g9F7n 6GKC/zA3gIBNEe3IQbEIX2voyimvey/XiDv9YyHcfniDhPi/FtDpb3ckaaSo42teoO gYN6zX8dZV+z9eCW50WR45oIzlMXO5CT+FQBwNCYKERCp694nN62/2glkpvvAMxuaj RGGx3yukJw17Ry7zuiXdoE721k8i4Uc812+jnw16YiKYjQ6U1haNvUewQLZMYfHrBd MCWnPFT80c+anlS38oocNHqYco2JryFGb/mlHMl+dQktVXF12U7BUndPiZiRE20Eii HUn/+p3uqdIEw== Date: Wed, 5 Mar 2025 17:52:04 +0000 From: Simon Horman To: Akihiko Odaki Cc: Jonathan Corbet , Willem de Bruijn , Jason Wang , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , "Michael S. Tsirkin" , Xuan Zhuo , Shuah Khan , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, linux-kselftest@vger.kernel.org, Yuri Benditovich , Andrew Melnychenko , Stephen Hemminger , gur.stavi@huawei.com, Lei Yang Subject: Re: [PATCH net-next v7 3/6] tun: Introduce virtio-net hash feature Message-ID: <20250305175204.GP3666230@kernel.org> References: <20250228-rss-v7-0-844205cbbdd6@daynix.com> <20250228-rss-v7-3-844205cbbdd6@daynix.com> Precedence: bulk X-Mailing-List: virtualization@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250228-rss-v7-3-844205cbbdd6@daynix.com> On Fri, Feb 28, 2025 at 04:58:49PM +0900, Akihiko Odaki wrote: > Hash reporting > -------------- > > Allow the guest to reuse the hash value to make receive steering > consistent between the host and guest, and to save hash computation. > > RSS > --- Odaki-san, Please reformat the patch description to avoid including "^---$". Git will truncate the commit message at that point, excluding the text below and your Signed-off-by line. > > RSS is a receive steering algorithm that can be negotiated to use with > virtio_net. 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 steering program. > > Introduce the code to perform RSS 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 I didn't > opt for it because extending the current mechanism of eBPF steering > program as is because it relies on legacy context rewriting, and > introducing kfunc-based eBPF will result in non-UAPI dependency while > the other relevant virtualization APIs such as KVM and vhost_net are > UAPIs. > > Signed-off-by: Akihiko Odaki > --- This one is ok, as the commit message should end here. > Documentation/networking/tuntap.rst | 7 ++ > drivers/net/Kconfig | 1 + > drivers/net/tap.c | 62 ++++++++++++- > drivers/net/tun.c | 89 ++++++++++++++---- > drivers/net/tun_vnet.h | 180 +++++++++++++++++++++++++++++++++--- > include/linux/if_tap.h | 2 + > include/linux/skbuff.h | 3 + > include/uapi/linux/if_tun.h | 75 +++++++++++++++ > net/core/skbuff.c | 4 + > 9 files changed, 390 insertions(+), 33 deletions(-) ...