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 F064FC48BC3 for ; Wed, 21 Feb 2024 15:26:01 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1rcoPy-0007UI-Et; Wed, 21 Feb 2024 10:21:55 -0500 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 1rcoL4-00010D-9i for qemu-devel@nongnu.org; Wed, 21 Feb 2024 10:16:51 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rclkZ-0006bw-Ii for qemu-devel@nongnu.org; Wed, 21 Feb 2024 07:31:06 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1708518656; 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: in-reply-to:in-reply-to:references:references; bh=0izBSbbHIueP8VABdK7wpWQFGQTEczRcEHj1BQZ0JHA=; b=gqbaiBHnVyTjNpw/u+P2FwPazKrCDdOA9DhgkDtL7m8ijmPL9KBasMCTsTHQ5eAKOd1b1u TFzsest/JiSgm9Wc6XGp56WMC5XrsgVWBoyf46AIrfxoCV2+jTSu6afhYXYkOoDWdjpaQq 07yRoYZtGLe6SKI/UINunc/fMFZw0R8= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-45-CNOKigFJPlyC99SVhMEgXw-1; Wed, 21 Feb 2024 07:30:52 -0500 X-MC-Unique: CNOKigFJPlyC99SVhMEgXw-1 Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.rdu2.redhat.com [10.11.54.9]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 3F992830DCF; Wed, 21 Feb 2024 12:30:51 +0000 (UTC) Received: from blackfin.pond.sub.org (unknown [10.39.192.55]) by smtp.corp.redhat.com (Postfix) with ESMTPS id F38CD492BC6; Wed, 21 Feb 2024 12:30:50 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id DF04621E66C8; Wed, 21 Feb 2024 13:30:49 +0100 (CET) From: Markus Armbruster To: Andrew Melnychenko Cc: jasowang@redhat.com, mst@redhat.com, armbru@redhat.com, eblake@redhat.com, qemu-devel@nongnu.org, berrange@redhat.com, yuri.benditovich@daynix.com, yan@daynix.com, akihiko.odaki@daynix.com Subject: Re: [PATCH v9 4/5] qmp: Added new command to retrieve eBPF blob. In-Reply-To: <20240205165437.1965981-5-andrew@daynix.com> (Andrew Melnychenko's message of "Mon, 5 Feb 2024 18:54:34 +0200") References: <20240205165437.1965981-1-andrew@daynix.com> <20240205165437.1965981-5-andrew@daynix.com> Date: Wed, 21 Feb 2024 13:30:49 +0100 Message-ID: <87ttm2gft2.fsf@pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.9 Received-SPF: pass client-ip=170.10.129.124; envelope-from=armbru@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=-0.05, 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, T_SCC_BODY_TEXT_LINE=-0.01, T_SPF_TEMPERROR=0.01 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 Commit message style nitpick: qmp: Add command to retrieve eBPF blob or qmp: New command to retrieve eBPF blob It's a title, not a sentence. Andrew Melnychenko writes: > Now, the binary objects may be retrieved by id. > It would require for future qmp commands that may require specific > eBPF blob. > > Added command "request-ebpf". This command returns > eBPF program encoded base64. The program taken from the > skeleton and essentially is an ELF object that can be > loaded in the future with libbpf. > > The reason to use the command to provide the eBPF object > instead of a separate artifact was to avoid issues related > to finding the eBPF itself. eBPF object is an ELF binary > that contains the eBPF program and eBPF map description(BTF). > Overall, eBPF object should contain the program and enough > metadata to create/load eBPF with libbpf. As the eBPF > maps/program should correspond to QEMU, the eBPF can't > be used from different QEMU build. > > The first solution was a helper that comes with QEMU > and loads appropriate eBPF objects. And the issue is > to find a proper helper if the system has several > different QEMUs installed and/or built from the source, > which helpers may not be compatible. > > Another issue is QEMU updating while there is a running > QEMU instance. With an updated helper, it may not be > possible to hotplug virtio-net device to the already > running QEMU. Overall, requesting the eBPF object from > QEMU itself solves possible failures with acceptable effort. > > Links: > [PATCH 3/5] qmp: Added the helper stamp check. > https://lore.kernel.org/all/20230219162100.174318-4-andrew@daynix.com/ > > Signed-off-by: Andrew Melnychenko > --- > ebpf/ebpf.c | 69 +++++++++++++++++++++++++++++++++++++++++++ > ebpf/ebpf.h | 29 ++++++++++++++++++ > ebpf/ebpf_rss.c | 6 ++++ > ebpf/meson.build | 2 +- > qapi/ebpf.json | 66 +++++++++++++++++++++++++++++++++++++++++ > qapi/meson.build | 1 + > qapi/qapi-schema.json | 1 + > 7 files changed, 173 insertions(+), 1 deletion(-) > create mode 100644 ebpf/ebpf.c > create mode 100644 ebpf/ebpf.h > create mode 100644 qapi/ebpf.json > > diff --git a/ebpf/ebpf.c b/ebpf/ebpf.c > new file mode 100644 > index 0000000000..2d73beb479 > --- /dev/null > +++ b/ebpf/ebpf.c > @@ -0,0 +1,69 @@ > +/* > + * QEMU eBPF binary declaration routine. > + * > + * Developed by Daynix Computing LTD (http://www.daynix.com) > + * > + * Authors: > + * Andrew Melnychenko > + * > + * SPDX-License-Identifier: GPL-2.0-or-later > + */ > + > +#include "qemu/osdep.h" > +#include "qemu/queue.h" > +#include "qapi/error.h" > +#include "qapi/qapi-commands-ebpf.h" > +#include "ebpf/ebpf.h" > + > +typedef struct ElfBinaryDataEntry { > + int id; > + const void *data; > + size_t datalen; > + > + QSLIST_ENTRY(ElfBinaryDataEntry) node; > +} ElfBinaryDataEntry; > + > +static QSLIST_HEAD(, ElfBinaryDataEntry) ebpf_elf_obj_list = > + QSLIST_HEAD_INITIALIZER(); > + > +void ebpf_register_binary_data(int id, const void *data, size_t datalen) > +{ > + struct ElfBinaryDataEntry *dataentry = NULL; > + > + dataentry = g_new0(struct ElfBinaryDataEntry, 1); > + dataentry->data = data; > + dataentry->datalen = datalen; > + dataentry->id = id; > + > + QSLIST_INSERT_HEAD(&ebpf_elf_obj_list, dataentry, node); > +} > + > +const void *ebpf_find_binary_by_id(int id, size_t *sz, Error **errp) > +{ > + struct ElfBinaryDataEntry *it = NULL; > + QSLIST_FOREACH(it, &ebpf_elf_obj_list, node) { > + if (id == it->id) { > + *sz = it->datalen; > + return it->data; > + } > + } > + > + error_setg(errp, "can't find eBPF object with id: %d", id); > + > + return NULL; > +} > + > +EbpfObject *qmp_request_ebpf(EbpfProgramID id, Error **errp) > +{ > + EbpfObject *ret = NULL; > + size_t size = 0; > + const void *data = ebpf_find_binary_by_id(id, &size, errp); > + if (!data) { > + return NULL; > + } > + > + ret = g_new0(EbpfObject, 1); > + ret->object = g_base64_encode(data, size); > + > + return ret; > +} > diff --git a/ebpf/ebpf.h b/ebpf/ebpf.h > new file mode 100644 > index 0000000000..378d4e9c70 > --- /dev/null > +++ b/ebpf/ebpf.h > @@ -0,0 +1,29 @@ > +/* > + * QEMU eBPF binary declaration routine. > + * > + * Developed by Daynix Computing LTD (http://www.daynix.com) > + * > + * Authors: > + * Andrew Melnychenko > + * > + * SPDX-License-Identifier: GPL-2.0-or-later > + */ > + > +#ifndef EBPF_H > +#define EBPF_H > + > + > +void ebpf_register_binary_data(int id, const void *data, > + size_t datalen); > +const void *ebpf_find_binary_by_id(int id, size_t *sz, > + struct Error **errp); > + > +#define ebpf_binary_init(id, fn) \ > +static void __attribute__((constructor)) ebpf_binary_init_ ## fn(void) \ > +{ \ > + size_t datalen = 0; \ > + const void *data = fn(&datalen); \ > + ebpf_register_binary_data(id, data, datalen); \ > +} > + > +#endif /* EBPF_H */ > diff --git a/ebpf/ebpf_rss.c b/ebpf/ebpf_rss.c > index 150aa40813..c8a68da2c5 100644 > --- a/ebpf/ebpf_rss.c > +++ b/ebpf/ebpf_rss.c > @@ -13,6 +13,8 @@ > > #include "qemu/osdep.h" > #include "qemu/error-report.h" > +#include "qapi/qapi-types-misc.h" > +#include "qapi/qapi-commands-ebpf.h" > > #include > #include > @@ -21,6 +23,8 @@ > > #include "ebpf/ebpf_rss.h" > #include "ebpf/rss.bpf.skeleton.h" > +#include "ebpf/ebpf.h" > + > #include "trace.h" > > void ebpf_rss_init(struct EBPFRSSContext *ctx) > @@ -261,3 +265,5 @@ void ebpf_rss_unload(struct EBPFRSSContext *ctx) > ctx->map_toeplitz_key = -1; > ctx->map_indirections_table = -1; > } > + > +ebpf_binary_init(EBPF_PROGRAMID_RSS, rss_bpf__elf_bytes) > diff --git a/ebpf/meson.build b/ebpf/meson.build > index 2f627d6c7d..c5bf9295a2 100644 > --- a/ebpf/meson.build > +++ b/ebpf/meson.build > @@ -1 +1 @@ > -system_ss.add(when: libbpf, if_true: files('ebpf_rss.c'), if_false: files('ebpf_rss-stub.c')) > +common_ss.add(when: libbpf, if_true: files('ebpf.c', 'ebpf_rss.c'), if_false: files('ebpf_rss-stub.c')) > diff --git a/qapi/ebpf.json b/qapi/ebpf.json > new file mode 100644 > index 0000000000..f413d00154 > --- /dev/null > +++ b/qapi/ebpf.json > @@ -0,0 +1,66 @@ > +# -*- Mode: Python -*- > +# vim: filetype=python > +# > +# This work is licensed under the terms of the GNU GPL, version 2 or later. > +# See the COPYING file in the top-level directory. > + > +## > +# = eBPF Objects > +# > +# eBPF object is an ELF binary that contains the eBPF > +# program and eBPF map description(BTF). Overall, eBPF > +# object should contain the program and enough metadata > +# to create/load eBPF with libbpf. As the eBPF maps/program > +# should correspond to QEMU, the eBPF can't be used from > +# different QEMU build. An introduction, nice! Two spaces between sentences for consistency, please. Wrap comment lines at column 70, like this: # eBPF object is an ELF binary that contains the eBPF program and eBPF # map description(BTF). Overall, eBPF object should contain the # program and enough metadata to create/load eBPF with libbpf. As the # eBPF maps/program should correspond to QEMU, the eBPF can't be used # from different QEMU build. > +# > +# Currently, there is a possible eBPF for receive-side scaling (RSS). > +# > +## > + > +## > +# @EbpfObject: > +# > +# An eBPF ELF object. > +# > +# @object: the eBPF object encoded in base64 > +# > +# Since: 9.0 > +## > +{ 'struct': 'EbpfObject', > + 'data': {'object': 'str'}, > + 'if': 'CONFIG_EBPF' } > + > +## > +# @EbpfProgramID: > +# > +# The eBPF programs that can be gotten with request-ebpf. > +# > +# @rss: Receive side scaling, technology that allows steering traffic > +# between queues by calculation hash. Users may set up > +# indirection table and hash/packet types configurations. Used > +# with virtio-net. > +# > +# Since: 9.0 > +## > +{ 'enum': 'EbpfProgramID', > + 'if': 'CONFIG_EBPF', > + 'data': [ { 'name': 'rss' } ] } > + > +## > +# @request-ebpf: > +# > +# Retrieve an eBPF object that can be loaded with libbpf. Management > +# applications (g.e. libvirt) may load it and pass file descriptors to > +# QEMU, so they can run running QEMU without BPF capabilities. > +# > +# @id: The ID of the program to return. > +# > +# Returns: eBPF object encoded in base64. > +# > +# Since: 9.0 > +## > +{ 'command': 'request-ebpf', > + 'data': { 'id': 'EbpfProgramID' }, > + 'returns': 'EbpfObject', > + 'if': 'CONFIG_EBPF' } > diff --git a/qapi/meson.build b/qapi/meson.build > index f81a37565c..375d564277 100644 > --- a/qapi/meson.build > +++ b/qapi/meson.build > @@ -33,6 +33,7 @@ qapi_all_modules = [ > 'crypto', > 'cxl', > 'dump', > + 'ebpf', > 'error', > 'introspect', > 'job', > diff --git a/qapi/qapi-schema.json b/qapi/qapi-schema.json > index c01ec335e6..8304d45625 100644 > --- a/qapi/qapi-schema.json > +++ b/qapi/qapi-schema.json > @@ -53,6 +53,7 @@ > { 'include': 'char.json' } > { 'include': 'dump.json' } > { 'include': 'net.json' } > +{ 'include': 'ebpf.json' } > { 'include': 'rdma.json' } > { 'include': 'rocker.json' } > { 'include': 'tpm.json' } With the (minor) doc comment fixes: Acked-by: Markus Armbruster