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=-15.1 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,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 D056FC48BD1 for ; Fri, 11 Jun 2021 17:24:03 +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 77E1F613FA for ; Fri, 11 Jun 2021 17:24:03 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 77E1F613FA 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]:40606 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lrkt0-0006Zi-KW for qemu-devel@archiver.kernel.org; Fri, 11 Jun 2021 13:24:02 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:38966) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lrkrH-00055w-JC for qemu-devel@nongnu.org; Fri, 11 Jun 2021 13:22:16 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:44418) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lrkrF-00050S-31 for qemu-devel@nongnu.org; Fri, 11 Jun 2021 13:22:15 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1623432132; 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:in-reply-to:in-reply-to: references:references; bh=qrLrvuwvkI7WHkhudjxAxlmf2J3jp6cvtlHPFw2Mhmo=; b=cv8bGMX0jec38aLuLrhUJmfNpusCfEz4v+BHzt6voJauuuRH9RZkx5kGbbu0zGXPKd34go AzpDxIHOpYGI8zeiucbPnJH+qzXBmAl9fIWkqGr1HoSrqwHo5lzCtVWH9tBAxQnxkiHLuo yYtYrF31yRX+wabxECssdZYABjFVRFo= 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-395-Wk7YDVxFNOy1bJSzFM7wcg-1; Fri, 11 Jun 2021 13:22:05 -0400 X-MC-Unique: Wk7YDVxFNOy1bJSzFM7wcg-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id D38D7100C660; Fri, 11 Jun 2021 17:22:03 +0000 (UTC) Received: from redhat.com (ovpn-115-90.ams2.redhat.com [10.36.115.90]) by smtp.corp.redhat.com (Postfix) with ESMTPS id A13C91007606; Fri, 11 Jun 2021 17:21:58 +0000 (UTC) Date: Fri, 11 Jun 2021 18:21:55 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Eric Blake Subject: Re: [RFC PATCH 4/5] qmp: Added qemu-ebpf-rss-path command. Message-ID: References: <20210609100457.142570-1-andrew@daynix.com> <20210609100457.142570-5-andrew@daynix.com> <20210611141552.ezkybuvewffln4dz@redhat.com> MIME-Version: 1.0 In-Reply-To: <20210611141552.ezkybuvewffln4dz@redhat.com> User-Agent: Mutt/2.0.7 (2021-05-04) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 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 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: -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, 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 Melnychenko , mst@redhat.com, jasowang@redhat.com, qemu-devel@nongnu.org, armbru@redhat.com, yuri.benditovich@daynix.com, yan@daynix.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Fri, Jun 11, 2021 at 09:15:52AM -0500, Eric Blake wrote: > On Wed, Jun 09, 2021 at 01:04:56PM +0300, Andrew Melnychenko wrote: > > New qmp command to query ebpf helper. > > It's crucial that qemu and helper are in sync and in touch. > > Technically helper should pass eBPF fds that qemu may accept. > > And different qemu's builds may have different eBPF programs and helpers. > > Qemu returns helper that should "fit" to virtio-net. > > > > Signed-off-by: Andrew Melnychenko > > --- > > monitor/qmp-cmds.c | 78 ++++++++++++++++++++++++++++++++++++++++++++++ > > qapi/misc.json | 29 +++++++++++++++++ > > 2 files changed, 107 insertions(+) > > > > diff --git a/monitor/qmp-cmds.c b/monitor/qmp-cmds.c > > index f7d64a6457..5dd2a58ea2 100644 > > --- a/monitor/qmp-cmds.c > > +++ b/monitor/qmp-cmds.c > > @@ -351,3 +351,81 @@ void qmp_display_reload(DisplayReloadOptions *arg, Error **errp) > > abort(); > > } > > } > > + > > +#ifdef CONFIG_LINUX > > + > > +static const char *get_dirname(char *path) > > +{ > > + char *sep; > > + > > + sep = strrchr(path, '/'); > > + if (sep == path) { > > + return "/"; > > + } else if (sep) { > > + *sep = 0; > > + return path; > > + } > > + return "."; > > +} > > Seems like this function is duplicating what glib should already be > able to do. > > > + > > +static char *find_helper(const char *name) > > +{ > > + char qemu_exec[PATH_MAX]; > > Stack-allocating a PATH_MAX array for readlink() is poor practice. > Better is to use g_file_read_link(). > > > + const char *qemu_dir = NULL; > > + char *helper = NULL; > > + > > + if (name == NULL) { > > + return NULL; > > + } > > + > > + if (readlink("/proc/self/exe", qemu_exec, PATH_MAX) > 0) { > > + qemu_dir = get_dirname(qemu_exec); > > + > > + helper = g_strdup_printf("%s/%s", qemu_dir, name); > > + if (access(helper, F_OK) == 0) { > > + return helper; > > + } > > + g_free(helper); > > + } > > + > > + helper = g_strdup_printf("%s/%s", CONFIG_QEMU_HELPERDIR, name); > > Could we use a compile-time determination of where we were (supposed) > to be installed, and therefore where our helper should be installed, > rather than the dynamic /proc/self/exe munging? Yeah I think avoiding /proc/self/exe is desirable, because I can imagine scenarios where this can lead to picking the wrong helper. Better to always use the compile time install directory. 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 :|