From patchwork Tue Oct 8 06:54:20 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Akihiko Odaki X-Patchwork-Id: 13825743 Received: from mail-pl1-f170.google.com (mail-pl1-f170.google.com [209.85.214.170]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B65141C6F66 for ; Tue, 8 Oct 2024 06:54:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.170 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728370478; cv=none; b=c9/43kwTpDUxMeyE1eXGwkuHnMV/2tnUZJOVSaqglcbYVIhBLZvQnudVqqMSJ+Brdfim9905Dah/Cohe7HKJhiRN2r+lAYDee6fN6KbNoOpQaC06fgId78hdSz+xEU8CB7i5+H+ihaB69Yw1nD+NETfcPKjfIvfIi3Mh/jijCTs= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728370478; c=relaxed/simple; bh=6j/9R+ZY3hri2Pq0LzMiZP+7u1JzeaSfqhBdxGp4lDo=; h=From:Subject:Date:Message-Id:MIME-Version:Content-Type:To; b=f8+betHWjo6w4b7sdoWfJVwEqO5fWxyrEE7Hg/ruPcXK29YSM8TzgP+78nCsTxHp5tHnl7ZLcl5NCF0ExTEC9y8iulsyc5aEWrRwsmSJxG2aEFJPkRP3HqmSq9lekOVYHmYlZLAUXm/P47ywKY5nij10sjqiSASOK3tCqGLWS+c= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=daynix.com; spf=none smtp.mailfrom=daynix.com; dkim=pass (2048-bit key) header.d=daynix-com.20230601.gappssmtp.com header.i=@daynix-com.20230601.gappssmtp.com header.b=qp+4PYjj; arc=none smtp.client-ip=209.85.214.170 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=daynix.com Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=daynix.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=daynix-com.20230601.gappssmtp.com header.i=@daynix-com.20230601.gappssmtp.com header.b="qp+4PYjj" Received: by mail-pl1-f170.google.com with SMTP id d9443c01a7336-20b7a4336easo38767625ad.3 for ; Mon, 07 Oct 2024 23:54:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=daynix-com.20230601.gappssmtp.com; s=20230601; t=1728370476; x=1728975276; darn=vger.kernel.org; h=to:content-transfer-encoding:mime-version:message-id:date:subject :from:from:to:cc:subject:date:message-id:reply-to; bh=8gty0dEnircfdREPGfEnkI3a1znlqYE3ZJr68g8y4pY=; b=qp+4PYjjKIP7yWhCdM47DkiyBzhDd1QwrCwW1dYjZ1x79FjhqkUyhTQMszvnAV7fx2 vTdu91qzoyZIVzsIE/HcMPwRNWwlyA357gK47EJWmyJXTNU/2zIrzlVxC+8x6hS6cFBo j4SUfUKP663X+phL1dxePLzjRj9xxFGn9+PqK+Ppawv45f+cKfs1WbMhyGfMku1MTk1I bFUmRH2kOX5/oojo3huyAKA5hmyWk/UB2n4/WigRu4Wx2mzQ3rNDCEkX4+NbJFruap0+ ZvxBPBqbHIj4F0rQ5EAkC64hEAynoyD6HBW1ImMeaM0Ji/NWhy+44QAdP9kQXJfNYcHG sDzQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1728370476; x=1728975276; h=to:content-transfer-encoding:mime-version:message-id:date:subject :from:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=8gty0dEnircfdREPGfEnkI3a1znlqYE3ZJr68g8y4pY=; b=YMjhD4Gsx70YKY7MNsYmhAJGWvJzEzYRr9F5OyDTA8h3zT0KP6STdx62dgLfwrXyC7 ksBLqM/rabMVQJAOfqpFqr9QSw55JgZ8QCR3kPsr0KdHFjifz4zS/TQXYibRyWl4CBGm MzQwbC+TZIS2uX5S9bf2SeUmGew+15B2vVotWEn3VO5FPXHNe9hAD7io4hYy092PS6mr 2Hl328rK3WQiWbFJO6qNUo+enXaV8zSt+KrGshMkysFwkVzTQqeYLQduY51EMswY/9cp XNsy37OmN77XD7n3aDe2hWd6Q6frgdkhundDjig91U/xEreAuGq2HcylV7dZ77F7Z+aZ WHoA== X-Forwarded-Encrypted: i=1; AJvYcCUVy7omYO4hYiySnsEENRDWNN7aPmgkROJPW3tFxHXKGN+p3Vugl0T8JgBydW05qRBxjQk=@vger.kernel.org X-Gm-Message-State: AOJu0YzMbpxPUKkN5VMVHQ0h87ZmuCdZpCkifxIxSGF0hTXXos/QRx+V hGGzM5jXxi2BvOkVevhGZkzubuZYQxycp2Ka8ReCdlRsQwJpbIWhKtsliZS4uuc= X-Google-Smtp-Source: AGHT+IHPQgocRRuVmNwy/y+36pGmysZiERFRRt/OUdpP+pXSUlRa9FCdE9Lo2jrORE0Se01AVBe7kQ== X-Received: by 2002:a17:902:e882:b0:20b:9078:707b with SMTP id d9443c01a7336-20bfe02199emr225978335ad.30.1728370475858; Mon, 07 Oct 2024 23:54:35 -0700 (PDT) Received: from localhost ([157.82.207.107]) by smtp.gmail.com with UTF8SMTPSA id d9443c01a7336-20c13987571sm49681435ad.250.2024.10.07.23.54.31 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 07 Oct 2024 23:54:35 -0700 (PDT) From: Akihiko Odaki Subject: [PATCH RFC v5 00/10] tun: Introduce virtio-net hashing feature Date: Tue, 08 Oct 2024 15:54:20 +0900 Message-Id: <20241008-rss-v5-0-f3cf68df005d@daynix.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-B4-Tracking: v=1; b=H4sIABzXBGcC/4XOwWrDMAyA4VcpPtdBkhUn6akw6APsOnbIbLUxp fGwS2gpefcZj0HHDrtZlr8fP1SWFCSr3eahkiwhhziXod1ulJvG+SQ6+DIrAmJgMDrlrKUzne8 HOY5dp8rLzyTHcKuVN/V6eFHv5XIK+RrTvZYXrKsSMQjQQ0sI2CAzE2nU4zlM4Ryb6Mtp78f7H G6Ni5faWejJYouMlrkhC5btv9b8WIYB2/r5xWjQzhooMf8BPf1B/ISIvxEX1LMMhsSBWPcLrev 6BaOSk/1JAQAA To: 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, Akihiko Odaki X-Mailer: b4 0.14-dev-fd6e3 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/20240915-hash-v3-0-79cb08d28647@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 --- Changes in v5: - Fixed a compilation error with CONFIG_TUN_VNET_CROSS_LE. - Optimized the calculation of the hash value according to: https://git.dpdk.org/dpdk/commit/?id=3fb1ea032bd6ff8317af5dac9af901f1f324cab4 - Added patch "tun: Unify vnet implementation". - Dropped patch "tap: Pad virtio header with zero". - Added patch "selftest: tun: Test vnet ioctls without device". - Reworked selftests to skip for older kernels. - Documented the case when the underlying device is deleted and packets have queue_mapping set by TC. - Reordered test harness arguments. - Added code to handle fragmented packets. - Link to v4: https://lore.kernel.org/r/20240924-rss-v4-0-84e932ec0e6c@daynix.com Changes in v4: - Moved tun_vnet_hash_ext to if_tun.h. - Renamed virtio_net_toeplitz() to virtio_net_toeplitz_calc(). - Replaced htons() with cpu_to_be16(). - Changed virtio_net_hash_rss() to return void. - Reordered variable declarations in virtio_net_hash_rss(). - Removed virtio_net_hdr_v1_hash_from_skb(). - Updated messages of "tap: Pad virtio header with zero" and "tun: Pad virtio header with zero". - Fixed vnet_hash allocation size. - Ensured to free vnet_hash when destructing tun_struct. - Link to v3: https://lore.kernel.org/r/20240915-rss-v3-0-c630015db082@daynix.com Changes in v3: - Reverted back to add ioctl. - Split patch "tun: Introduce virtio-net hashing feature" into "tun: Introduce virtio-net hash reporting feature" and "tun: Introduce virtio-net RSS". - Changed to reuse hash values computed for automq instead of performing RSS hashing when hash reporting is requested but RSS is not. - Extracted relevant data from struct tun_struct to keep it minimal. - Added kernel-doc. - Changed to allow calling TUNGETVNETHASHCAP before TUNSETIFF. - Initialized num_buffers with 1. - Added a test case for unclassified packets. - Fixed error handling in tests. - Changed tests to verify that the queue index will not overflow. - Rebased. - Link to v2: https://lore.kernel.org/r/20231015141644.260646-1-akihiko.odaki@daynix.com --- Akihiko Odaki (10): virtio_net: Add functions for hashing skbuff: Introduce SKB_EXT_TUN_VNET_HASH net: flow_dissector: Export flow_keys_dissector_symmetric tun: Unify vnet implementation tun: Pad virtio header with zero tun: Introduce virtio-net hash reporting feature tun: Introduce virtio-net RSS selftest: tun: Test vnet ioctls without device selftest: tun: Add tests for virtio-net hashing vhost/net: Support VIRTIO_NET_F_HASH_REPORT Documentation/networking/tuntap.rst | 7 + MAINTAINERS | 1 + drivers/net/Kconfig | 1 + drivers/net/tap.c | 218 ++++-------- drivers/net/tun.c | 293 ++++++---------- drivers/net/tun_vnet.h | 342 +++++++++++++++++++ drivers/vhost/net.c | 16 +- include/linux/if_tap.h | 2 + include/linux/skbuff.h | 3 + include/linux/virtio_net.h | 188 +++++++++++ include/net/flow_dissector.h | 1 + include/uapi/linux/if_tun.h | 75 +++++ net/core/flow_dissector.c | 3 +- net/core/skbuff.c | 4 + tools/testing/selftests/net/Makefile | 2 +- tools/testing/selftests/net/tun.c | 630 ++++++++++++++++++++++++++++++++++- 16 files changed, 1430 insertions(+), 356 deletions(-) --- base-commit: 752ebcbe87aceeb6334e846a466116197711a982 change-id: 20240403-rss-e737d89efa77 Best regards,