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=-10.1 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham 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 6EE73C4743D for ; Fri, 11 Jun 2021 05:37:19 +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 C44DB6008E for ; Fri, 11 Jun 2021 05:37:18 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C44DB6008E 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]:49360 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lrZr3-0000Fu-JM for qemu-devel@archiver.kernel.org; Fri, 11 Jun 2021 01:37:17 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:35310) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lrZqJ-00082k-Lf for qemu-devel@nongnu.org; Fri, 11 Jun 2021 01:36:31 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:35810) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lrZqF-0006qU-Go for qemu-devel@nongnu.org; Fri, 11 Jun 2021 01:36:30 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1623389784; 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=pKI8kLdAVv2IiNpKnnLXm18h8NOAq5jVe9PXLtDWns8=; b=Xmw9EnvDJ9VhTBaMxoPbg+l0niIfIDXRXR/Xm7VSjcjQW51zZU1JxUNnk3DSzmqm1GBuFt 8QMykAUaKegyQVTi8AnMFxZmvH2F/mp4cl05wqIyymCPwIBd3YEno+qbe2H9Vo0g7VRX+o IjEqtOc2h0AjEFynVJczc4jOA00S0H8= Received: from mail-pg1-f198.google.com (mail-pg1-f198.google.com [209.85.215.198]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-460-OPF7nkjxPxm6zVeML3KJuw-1; Fri, 11 Jun 2021 01:36:21 -0400 X-MC-Unique: OPF7nkjxPxm6zVeML3KJuw-1 Received: by mail-pg1-f198.google.com with SMTP id a10-20020a65418a0000b029021b78388f57so1075417pgq.15 for ; Thu, 10 Jun 2021 22:36:21 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-transfer-encoding :content-language; bh=pKI8kLdAVv2IiNpKnnLXm18h8NOAq5jVe9PXLtDWns8=; b=UeXbcmtUav3tW50ZGsHFZu8YWLSHOI8VWgpbgwTf6uQ/TalkJNRA5GjJ950N9YCEC6 Bs/IHTxFEJLl8Nq2jvaqQ0RDmFsVfgC5fTT88XbDlXjeFcYwAyW6YrmCBVGrWRUWr0wD aXDrCIaph76KGKHpV/Xa59xRmhU3RKE0YkOZN+UqVb23h7bPmN1oY52NOX8SRqTv7m88 XihvuZHs6YniqQuuVgRZ5SGwUTS2B5XcKXUSUyktSZHsXLGx9WZPdhuljFvdQLc4TrmJ mryMXwSo6nux1/20Twhh3V1cDq3mVRAdrXf2dAgHzXvyMIjPMaQN1OUZt8SgdG5mWy9n ke8w== X-Gm-Message-State: AOAM532KhWdB6eCQgp3GtHWv8ehuuFEkWmLSmYsEDWOOiCHlPsGjQgP7 Q7vR/GCz3GjNd7sgiBYgm7Kp1id8kFBddDkjS04k/PZuYcot6v3QDXdTQoevGDiF/m9HbJQyAZ6 2Hh3UWz+Hz0UKZCc= X-Received: by 2002:a17:90b:1bc4:: with SMTP id oa4mr2814938pjb.18.1623389780873; Thu, 10 Jun 2021 22:36:20 -0700 (PDT) X-Google-Smtp-Source: ABdhPJyaAzSjtdkuBRiVSUPATGG7o4DW88xj/MEUhSUqxIS2oS/3jXkU8NZc2+oGi476lLGL0dNIqw== X-Received: by 2002:a17:90b:1bc4:: with SMTP id oa4mr2814923pjb.18.1623389780599; Thu, 10 Jun 2021 22:36:20 -0700 (PDT) Received: from wangxiaodeMacBook-Air.local ([209.132.188.80]) by smtp.gmail.com with ESMTPSA id r9sm3982366pfq.158.2021.06.10.22.36.17 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 10 Jun 2021 22:36:20 -0700 (PDT) Subject: Re: [RFC PATCH 0/5] ebpf: Added ebpf helper for libvirtd. To: Yuri Benditovich References: <20210609100457.142570-1-andrew@daynix.com> From: Jason Wang Message-ID: <3da88930-439c-1892-29b4-4977ddbb0b0a@redhat.com> Date: Fri, 11 Jun 2021 13:36:15 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: 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=170.10.133.124; envelope-from=jasowang@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -29 X-Spam_score: -3.0 X-Spam_bar: --- X-Spam_report: (-3.0 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.199, 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_LOW=-0.7, 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: Andrew Melnychenko , =?UTF-8?Q?Daniel_P=2e_Berrang=c3=a9?= , "Michael S . Tsirkin" , qemu-devel@nongnu.org, Markus Armbruster , Yan Vugenfirer , Eric Blake Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" 在 2021/6/10 下午2:55, Yuri Benditovich 写道: > On Thu, Jun 10, 2021 at 9:41 AM Jason Wang wrote: >> 在 2021/6/9 下午6:04, Andrew Melnychenko 写道: >>> Libvirt usually launches qemu with strict permissions. >>> To enable eBPF RSS steering, qemu-ebpf-rss-helper was added. >> A silly question: >> >> Kernel had the following permission checks in bpf syscall: >> >> if (sysctl_unprivileged_bpf_disabled && !bpf_capable()) >> return -EPERM; >> ... >> >> err = security_bpf(cmd, &attr, size); >> if (err < 0) >> return err; >> >> So if I understand the code correctly, bpf syscall can only be done if: >> >> 1) unprivileged_bpf is enabled or >> 2) has the capability and pass the LSM checks >> >> So I think the series is for unprivileged_bpf disabled. If I'm not >> wrong, I guess the policy is to grant CAP_BPF but do fine grain checks >> via LSM. >> >> If this is correct, need to describe it in the commit log. >> >> >>> Added property "ebpf_rss_fds" for "virtio-net" that allows to >>> initialize eBPF RSS context with passed program & maps fds. >>> >>> Added qemu-ebpf-rss-helper - simple helper that loads eBPF >>> context and passes fds through unix socket. >>> Libvirt should call the helper and pass fds to qemu through >>> "ebpf_rss_fds" property. >>> >>> Added explicit target OS check for libbpf dependency in meson. >>> eBPF RSS works only with Linux TAP, so there is no reason to >>> build eBPF loader/helper for non-Linux. >>> >>> Overall, libvirt process should not be aware of the "interface" >>> of eBPF RSS, it will not be aware of eBPF maps/program "type" and >>> their quantity. >> I'm not sure this is the best. We have several examples that let libvirt >> to involve. Examples: >> >> 1) create TAP device (and the TUN_SETIFF) >> >> 2) open vhost devices >> >> >>> That's why qemu and the helper should be from >>> the same build and be "synchronized". Technically each qemu may >>> have its own helper. That's why "query-helper-paths" qmp command >>> was added. Qemu should return the path to the helper that suits >>> and libvirt should use "that" helper for "that" emulator. >>> >>> qmp sample: >>> C: { "execute": "query-helper-paths" } >>> S: { "return": [ >>> { >>> "name": "qemu-ebpf-rss-helper", >>> "path": "/usr/local/libexec/qemu-ebpf-rss-helper" >>> } >>> ] >>> } >> I think we need an example on the detail steps for how libvirt is >> expected to use this. > The preliminary patches for libvirt are at > https://github.com/daynix/libvirt/tree/RSSv1 Will have a look but it would be better if the assumption of the management is detailed here to ease the reviewers. Thanks >