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,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 B8AC4C48BE5 for ; Tue, 22 Jun 2021 08:28:23 +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 523B56128C for ; Tue, 22 Jun 2021 08:28:23 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 523B56128C 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]:36532 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lvble-0006bR-AR for qemu-devel@archiver.kernel.org; Tue, 22 Jun 2021 04:28:22 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:46448) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lvbks-0005ZY-27 for qemu-devel@nongnu.org; Tue, 22 Jun 2021 04:27:34 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:56973) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lvbkq-0000Vj-93 for qemu-devel@nongnu.org; Tue, 22 Jun 2021 04:27:33 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1624350451; h=from:from:reply-to: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=gUSDzQn2JDNyce6kfkRiMCWobRGZ7nLKbW0Kv1C1Nco=; b=NpZFAQ/lr/UnT/BwbfIUDi1cfDM1o1tMaiE95Ejtw3cKGuIfneGp7jYSRW5A8IPadEBAKz f+pJgrgWt8Ng4EREJgRbUM+5SfXp5j8jSTd+C0Z6CzLZ3xOVTuxSMkjnd79AXWLzUw4f40 ze1+0sIwWY3/3Lk8i6i0U7mEIrTR8cU= 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-367-KTq7XycLNDqWaBpi9xihnw-1; Tue, 22 Jun 2021 04:27:25 -0400 X-MC-Unique: KTq7XycLNDqWaBpi9xihnw-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 83D8A80431F; Tue, 22 Jun 2021 08:27:24 +0000 (UTC) Received: from redhat.com (ovpn-114-176.ams2.redhat.com [10.36.114.176]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 75E6E5C1D1; Tue, 22 Jun 2021 08:27:13 +0000 (UTC) Date: Tue, 22 Jun 2021 09:27:10 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Toke =?utf-8?Q?H=C3=B8iland-J=C3=B8rgensen?= Subject: Re: [RFC PATCH 0/5] ebpf: Added ebpf helper for libvirtd. Message-ID: References: <3da88930-439c-1892-29b4-4977ddbb0b0a@redhat.com> <07a81543-c262-f153-6414-3d967dde02b2@redhat.com> <9157bf00-299f-993d-dd16-62f13e017a3f@redhat.com> <87o8byqpao.fsf@toke.dk> MIME-Version: 1.0 In-Reply-To: <87o8byqpao.fsf@toke.dk> User-Agent: Mutt/2.0.7 (2021-05-04) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=berrange@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=216.205.24.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -31 X-Spam_score: -3.2 X-Spam_bar: --- X-Spam_report: (-3.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.373, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, 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: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Cc: Andrew Melnichenko , "Michael S . Tsirkin" , Jason Wang , Markus Armbruster , qemu-devel@nongnu.org, Yuri Benditovich , Yan Vugenfirer , Eric Blake Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Tue, Jun 22, 2021 at 10:25:19AM +0200, Toke Høiland-Jørgensen wrote: > Jason Wang writes: > > > 在 2021/6/22 上午11:29, Yuri Benditovich 写道: > >> On Mon, Jun 21, 2021 at 12:20 PM Jason Wang wrote: > >>> > >>> 在 2021/6/19 上午4:03, Andrew Melnichenko 写道: > >>>> Hi Jason, > >>>> I've checked "kernel.unprivileged_bpf_disabled=0" on Fedora, Ubuntu, > >>>> and Debian - no need permissions to update BPF maps. > >>> > >>> How about RHEL :) ? > >> If I'm not mistaken, the RHEL releases do not use modern kernels yet > >> (for BPF we need 5.8+). > >> So this will be (probably) relevant for RHEL 9. Please correct me if I'm wrong. > > > > Adding Toke for more ideas on this. > > Ignore the kernel version number; we backport all of BPF to RHEL, > basically. RHEL8.4 is up to upstream kernel 5.10, feature-wise. > > However, we completely disable unprivileged BPF on RHEL kernels. Also, > there's upstream commit: > 08389d888287 ("bpf: Add kconfig knob for disabling unpriv bpf by default") > > which adds a new value of '2' to the unprivileged_bpf_disable sysctl. I > believe this may end up being the default on Fedora as well. > > So any design relying on unprivileged BPF is likely to break; I'd > suggest you look into how you can get this to work with CAP_BPF :) QEMU will never have any capabilities. Any resources that required privileges have to be opened by a separate privileged helper, and the open FD then passed across to the QEMU process. This relies on the capabilities checks only being performed at time of initial opening, and *not* on operations performed on the already open FD. Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|