From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.0 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 55A62C2D0A3 for ; Wed, 4 Nov 2020 02:08:46 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 97CDC206F9 for ; Wed, 4 Nov 2020 02:08:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="HG8eoIv7" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 97CDC206F9 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:44062 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ka8E8-0001Be-Ck for qemu-devel@archiver.kernel.org; Tue, 03 Nov 2020 21:08:44 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:49926) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ka8DZ-0000mY-JD for qemu-devel@nongnu.org; Tue, 03 Nov 2020 21:08:09 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:58327) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1ka8DW-00076I-9w for qemu-devel@nongnu.org; Tue, 03 Nov 2020 21:08:08 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1604455684; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=N5ZFD5yMsH2ZfQogTAtlr5nqksssj3/5TP1ePFcYupI=; b=HG8eoIv7baywq50yl1TlW/IfrbH0BX0+tvVzgq9SDH72T5VrI5wLJV609nDmVJDRITtWCe xv/Tco/z+3YY9fCIA8OO0FrFGLTFD766nuKsekUBDG0IHf5yxdj2bxNSGqqZvHZ0AOP8dN uk0zc2txwuMgkvsJaKQwHkN4u4v7tpw= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-453-xEmzMeWkPA2nhof1Kzd7mQ-1; Tue, 03 Nov 2020 21:08:00 -0500 X-MC-Unique: xEmzMeWkPA2nhof1Kzd7mQ-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 39B341007464; Wed, 4 Nov 2020 02:07:59 +0000 (UTC) Received: from [10.72.13.133] (ovpn-13-133.pek2.redhat.com [10.72.13.133]) by smtp.corp.redhat.com (Postfix) with ESMTP id 478C573661; Wed, 4 Nov 2020 02:07:54 +0000 (UTC) Subject: Re: [RFC PATCH 0/6] eBPF RSS support for virtio-net To: Yuri Benditovich References: <20201102185115.7425-1-andrew@daynix.com> <0164a42f-4542-6f3e-bd71-3319dfaae190@redhat.com> From: Jason Wang Message-ID: Date: Wed, 4 Nov 2020 10:07:52 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=jasowang@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US Received-SPF: pass client-ip=216.205.24.124; envelope-from=jasowang@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/11/03 00:03:41 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, NICE_REPLY_A=-0.001, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Yan Vugenfirer , Andrew Melnychenko , qemu-devel@nongnu.org, "Michael S . Tsirkin" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 2020/11/3 下午6:32, Yuri Benditovich wrote: > > > On Tue, Nov 3, 2020 at 11:02 AM Jason Wang > wrote: > > > On 2020/11/3 上午2:51, Andrew Melnychenko wrote: > > Basic idea is to use eBPF to calculate and steer packets in TAP. > > RSS(Receive Side Scaling) is used to distribute network packets > to guest virtqueues > > by calculating packet hash. > > eBPF RSS allows us to use RSS with vhost TAP. > > > > This set of patches introduces the usage of eBPF for packet steering > > and RSS hash calculation: > > * RSS(Receive Side Scaling) is used to distribute network packets to > > guest virtqueues by calculating packet hash > > * eBPF RSS suppose to be faster than already existing 'software' > > implementation in QEMU > > * Additionally adding support for the usage of RSS with vhost > > > > Supported kernels: 5.8+ > > > > Implementation notes: > > Linux TAP TUNSETSTEERINGEBPF ioctl was used to set the eBPF program. > > Added eBPF support to qemu directly through a system call, see the > > bpf(2) for details. > > The eBPF program is part of the qemu and presented as an array > of bpf > > instructions. > > The program can be recompiled by provided Makefile.ebpf(need to > adjust > > 'linuxhdrs'), > > although it's not required to build QEMU with eBPF support. > > Added changes to virtio-net and vhost, primary eBPF RSS is used. > > 'Software' RSS used in the case of hash population and as a > fallback option. > > For vhost, the hash population feature is not reported to the guest. > > > > Please also see the documentation in PATCH 6/6. > > > > I am sending those patches as RFC to initiate the discussions > and get > > feedback on the following points: > > * Fallback when eBPF is not supported by the kernel > > > Yes, and it could also a lacking of CAP_BPF. > > > > * Live migration to the kernel that doesn't have eBPF support > > > Is there anything that we needs special treatment here? > > Possible case: rss=on, vhost=on, source system with kernel 5.8 > (everything works) -> dest. system 5.6 (bpf does not work), the > adapter functions, but all the steering does not use proper queues. Right, I think we need to disable vhost on dest. > > > > > * Integration with current QEMU build > > > Yes, a question here: > > 1) Any reason for not using libbpf, e.g it has been shipped with some > distros > > > We intentionally do not use libbpf, as it present only on some distros. > We can switch to libbpf, but this will disable bpf if libbpf is not > installed That's better I think. > 2) It would be better if we can avoid shipping bytecodes > > > > This creates new dependencies: llvm + clang + ... > We would prefer byte code and ability to generate it if prerequisites > are installed. It's probably ok if we treat the bytecode as a kind of firmware. But in the long run, it's still worthwhile consider the qemu source is used for development and llvm/clang should be a common requirement for generating eBPF bytecode for host. > > > > * Additional usage for eBPF for packet filtering > > > Another interesting topics in to implement mac/vlan filters. And > in the > future, I plan to add mac based steering. All of these could be > done via > eBPF. > > > No problem, we can cooperate if needed > > > > > > Know issues: > > * hash population not supported by eBPF RSS: 'software' RSS used > > > Is this because there's not way to write to vnet header in > STERRING BPF? > > Yes. We plan to submit changes for kernel to cooperate with BPF and > populate the hash, this work is in progress That would require a new type of eBPF program and may need some work on verifier. Btw, macvtap is still lacking even steering ebpf program. Would you want to post a patch to support that? > > > as a fallback, also, hash population feature is not reported to > guests > > with vhost. > > * big-endian BPF support: for now, eBPF is disabled for > big-endian systems. > > > Are there any blocker for this? > > > No, can be added in v2 Cool. Thanks > > Just some quick questions after a glance of the codes. Will go > through > them tomorrow. > > Thanks > > > > > > Andrew (6): > >    Added SetSteeringEBPF method for NetClientState. > >    ebpf: Added basic eBPF API. > >    ebpf: Added eBPF RSS program. > >    ebpf: Added eBPF RSS loader. > >    virtio-net: Added eBPF RSS to virtio-net. > >    docs: Added eBPF documentation. > > > >   MAINTAINERS                    |   6 + > >   configure                      |  36 +++ > >   docs/ebpf.rst                  |  29 ++ > >   docs/ebpf_rss.rst              | 129 ++++++++ > >   ebpf/EbpfElf_to_C.py           |  67 ++++ > >   ebpf/Makefile.ebpf             |  38 +++ > >   ebpf/ebpf-stub.c               |  28 ++ > >   ebpf/ebpf.c                    | 107 +++++++ > >   ebpf/ebpf.h                    |  35 +++ > >   ebpf/ebpf_rss.c                | 178 +++++++++++ > >   ebpf/ebpf_rss.h                |  30 ++ > >   ebpf/meson.build               |   1 + > >   ebpf/rss.bpf.c                 | 470 ++++++++++++++++++++++++++++ > >   ebpf/trace-events              |   4 + > >   ebpf/trace.h                   |   2 + > >   ebpf/tun_rss_steering.h        | 556 > +++++++++++++++++++++++++++++++++ > >   hw/net/vhost_net.c             |   2 + > >   hw/net/virtio-net.c            | 120 ++++++- > >   include/hw/virtio/virtio-net.h |   4 + > >   include/net/net.h              |   2 + > >   meson.build                    |   3 + > >   net/tap-bsd.c                  |   5 + > >   net/tap-linux.c                |  19 ++ > >   net/tap-solaris.c              |   5 + > >   net/tap-stub.c                 |   5 + > >   net/tap.c                      |   9 + > >   net/tap_int.h                  |   1 + > >   net/vhost-vdpa.c               |   2 + > >   28 files changed, 1889 insertions(+), 4 deletions(-) > >   create mode 100644 docs/ebpf.rst > >   create mode 100644 docs/ebpf_rss.rst > >   create mode 100644 ebpf/EbpfElf_to_C.py > >   create mode 100755 ebpf/Makefile.ebpf > >   create mode 100644 ebpf/ebpf-stub.c > >   create mode 100644 ebpf/ebpf.c > >   create mode 100644 ebpf/ebpf.h > >   create mode 100644 ebpf/ebpf_rss.c > >   create mode 100644 ebpf/ebpf_rss.h > >   create mode 100644 ebpf/meson.build > >   create mode 100644 ebpf/rss.bpf.c > >   create mode 100644 ebpf/trace-events > >   create mode 100644 ebpf/trace.h > >   create mode 100644 ebpf/tun_rss_steering.h > > >