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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id B2616C6FD18 for ; Fri, 31 Mar 2023 08:04:19 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pi9jq-00057V-LQ; Fri, 31 Mar 2023 04:03:58 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pi9jo-00057D-AR for qemu-devel@nongnu.org; Fri, 31 Mar 2023 04:03:56 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pi9jm-00039N-MX for qemu-devel@nongnu.org; Fri, 31 Mar 2023 04:03:56 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1680249833; 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=9NmPE5Jq62qE89ZzPMkSx44IPjv/qhP8BucpGu6mxGE=; b=Apuss+RtSXMjQnxMbTHYLwbQTZCXstIdvgvQMvul1eDE/2FfSC1wplr4t4gqTWkpvalZlc 83rv9JK3B2HxbBTMxKzqJn/2vnFbnVuKeg1k4A1vbWIa4aCQauZYwuz8iToWSgfqW80giY HMQYQtg8nKSuGLjcRGnwX9nAXPElVRE= Received: from mail-oa1-f71.google.com (mail-oa1-f71.google.com [209.85.160.71]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-512-FEcAjLqAOA6MsxAqDkfJrg-1; Fri, 31 Mar 2023 04:03:51 -0400 X-MC-Unique: FEcAjLqAOA6MsxAqDkfJrg-1 Received: by mail-oa1-f71.google.com with SMTP id 586e51a60fabf-17fd0d597dcso3715427fac.6 for ; Fri, 31 Mar 2023 01:03:51 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1680249830; x=1682841830; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=9NmPE5Jq62qE89ZzPMkSx44IPjv/qhP8BucpGu6mxGE=; b=5fJWZStxdxh8RmEDYFyowQb5e4BgeAMrBxKrj6ztkL++jYkKU5dfMMauyMnmJXOWZP I+U0EiQQU3asT9kGnEqPLIn4Zm4xVmSNJlZMKBIlXlnNX4VM+x1K+oj9tmkmlaja3fir klGRruIwwFPgeEwUZ5PabhXx121BEFIqLRNBzJPAZeGRNj3MMC+kOYVXyWEKaIaMk4oV TTGMClzMbw9XZC5cEwRDWjgKVY9d8Dy/6EsicmlKXSbC2g+Mj8C3pVzMHskTouToFxow a6+j2n9KX4P4ZGONfGz0liKav7p3lMTZuaV2koyZnS6Pcf8161ibre0kWwjbjKrDa4Mg FXYw== X-Gm-Message-State: AAQBX9ffRfzVVFuh5gk6RL86GWLDn+1XOgF6Vmbk+gm5aEXBF7Ogr8u+ G29oRnFHeONDQBXTEyfFOOFbbmNZfLEniPiuE1B1cR+0HOukCxiHJK9GanB1PaxAVjn1cou8ThX QYStTU1koY89wGxOHhgZay4kL4lvHupI= X-Received: by 2002:a05:6871:4d03:b0:17d:1287:1b5c with SMTP id ug3-20020a0568714d0300b0017d12871b5cmr9177862oab.9.1680249830638; Fri, 31 Mar 2023 01:03:50 -0700 (PDT) X-Google-Smtp-Source: AKy350Z1VkjjYynTL490nqfubRNQRgb1n6wUbdolVFnwAnHQ1ppR3BcZzSf3gmPaNISiV1+PEV1VmkGN8R8KikWvW5s= X-Received: by 2002:a05:6871:4d03:b0:17d:1287:1b5c with SMTP id ug3-20020a0568714d0300b0017d12871b5cmr9177842oab.9.1680249830407; Fri, 31 Mar 2023 01:03:50 -0700 (PDT) MIME-Version: 1.0 References: <20230330001522.120774-1-andrew@daynix.com> <20230330001522.120774-4-andrew@daynix.com> In-Reply-To: From: Jason Wang Date: Fri, 31 Mar 2023 16:03:39 +0800 Message-ID: Subject: Re: [RFC PATCH 3/5] ebpf: Added declaration/initialization routines. To: =?UTF-8?Q?Daniel_P=2E_Berrang=C3=A9?= Cc: Andrew Melnychenko , mst@redhat.com, pbonzini@redhat.com, marcandre.lureau@redhat.com, thuth@redhat.com, philmd@linaro.org, armbru@redhat.com, eblake@redhat.com, qemu-devel@nongnu.org, toke@redhat.com, mprivozn@redhat.com, yuri.benditovich@daynix.com, yan@daynix.com Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable 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: -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, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-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: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Fri, Mar 31, 2023 at 3:59=E2=80=AFPM Daniel P. Berrang=C3=A9 wrote: > > On Fri, Mar 31, 2023 at 03:48:18PM +0800, Jason Wang wrote: > > On Thu, Mar 30, 2023 at 4:34=E2=80=AFPM Daniel P. Berrang=C3=A9 wrote: > > > > > > On Thu, Mar 30, 2023 at 02:54:32PM +0800, Jason Wang wrote: > > > > On Thu, Mar 30, 2023 at 8:33=E2=80=AFAM Andrew Melnychenko wrote: > > > > > > > > Who or how the ABI compatibility is preserved between libvirt and Q= emu? > > > > > > There's no real problem with binary compatibility to solve any more. > > > > > > When libvirt first launches a QEMU VM, it will fetch the eBPF program= s > > > it needs from that running QEMU using QMP. WHen it later needs to > > > enable features that use eBPF, it already has the program data that > > > matches the running QEMU > > > > Ok, then who will validate the eBPF program? I don't think libvirt can > > trust what is received from Qemu otherwise arbitrary eBPF programs > > could be executed by Qemu in this way. One example is that when guests > > escape to Qemu it can modify the rss_bpf__elf_bytes. Though > > BPF_PROG_TYPE_SOCKET_FILTER gives some of the restrictions, we still > > need to evaluate side effects of this. Or we need to find other ways > > like using the binary in libvirt or use rx filter events. > > As I mentioned, when libvirt first launches QEMU it will fetch the > eBPF programs and keep them for later use. At that point the guest > CPUs haven't started running, and so QEMU it still sufficiently > trustworthy. Well, this means the QMP command is safe only before Qemu starts to run VCPU. I'm not sure this is a good design. Or at least we need to fail the QMP command if VCPU starts to run. Thanks > > With regards, > Daniel > -- > |: https://berrange.com -o- https://www.flickr.com/photos/dberran= ge :| > |: https://libvirt.org -o- https://fstop138.berrange.c= om :| > |: https://entangle-photo.org -o- https://www.instagram.com/dberran= ge :| >