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 326B3C02181 for ; Wed, 22 Jan 2025 17:31:24 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1taeYw-0001qX-JJ; Wed, 22 Jan 2025 12:30:46 -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 1taeYu-0001p1-EW for qemu-devel@nongnu.org; Wed, 22 Jan 2025 12:30:44 -0500 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 1taeYr-0004G8-VQ for qemu-devel@nongnu.org; Wed, 22 Jan 2025 12:30:43 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1737567039; 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=NX+HOJh1PRf+A69qAh06HIHe68iq6l+1RcyLVLKYfXk=; b=IJlm/dp6ItWgjQrCfCCz4im4DmSznpUPCzl1ULSlzLZ8QSE4MA85kZ0+mm6yWpdJinYPCn Ya/kEkLRI+8JBZT1aREN8wSx244eZFqokNLMAdTXQqzvYV5WsiHcOdnezmNKlVYCjjKXua M2yk+nBnR8OrQR0kzXtMiH9MbJFUcjY= Received: from mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-562-GrtO3XiUNZGpEclz_wZ69Q-1; Wed, 22 Jan 2025 12:30:34 -0500 X-MC-Unique: GrtO3XiUNZGpEclz_wZ69Q-1 X-Mimecast-MFC-AGG-ID: GrtO3XiUNZGpEclz_wZ69Q Received: from mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.4]) (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 mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id D12A619560BD for ; Wed, 22 Jan 2025 17:30:33 +0000 (UTC) Received: from redhat.com (unknown [10.42.28.43]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id EEBA03003E7F; Wed, 22 Jan 2025 17:30:31 +0000 (UTC) Date: Wed, 22 Jan 2025 17:30:28 +0000 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Laurent Vivier Cc: Stefano Garzarella , "Michael S. Tsirkin" , qemu-devel@nongnu.org, Jason Wang Subject: Re: [PATCH] vhost-user: Silence unsupported VHOST_USER_PROTOCOL_F_RARP error Message-ID: References: <20250121100029.1106973-1-lvivier@redhat.com> <3mcx7u456pawkgz4dgf6tvk7izczuy55guipqacqkl66jhtltq@fofd5u3el4nj> <20250122085828-mutt-send-email-mst@kernel.org> <044af96f-791b-471f-ae90-c17597445fd3@redhat.com> <28e3e395-0eaa-4eeb-bd61-1cb031d8da7f@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <28e3e395-0eaa-4eeb-bd61-1cb031d8da7f@redhat.com> User-Agent: Mutt/2.2.13 (2024-03-09) X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 Received-SPF: pass client-ip=170.10.133.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -50 X-Spam_score: -5.1 X-Spam_bar: ----- X-Spam_report: (-5.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-2.996, 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=-0.043, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=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: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Wed, Jan 22, 2025 at 06:22:06PM +0100, Laurent Vivier wrote: > On 22/01/2025 17:51, Stefano Garzarella wrote: > > On Wed, Jan 22, 2025 at 05:41:15PM +0100, Laurent Vivier wrote: > > > On 22/01/2025 17:20, Stefano Garzarella wrote: > > > > On Wed, Jan 22, 2025 at 08:59:22AM -0500, Michael S. Tsirkin wrote: > > > > > On Wed, Jan 22, 2025 at 02:42:14PM +0100, Stefano Garzarella wrote: > > > > > > On Tue, Jan 21, 2025 at 11:00:29AM +0100, Laurent Vivier wrote: > > > > > > > In vhost_user_receive() if vhost_net_notify_migration_done() reports > > > > > > > an error we display on the console: > > > > > > > > > > > > > >   Vhost user backend fails to broadcast fake RARP > > > > > > > > > > > > > > This message can be useful if there is a problem to execute > > > > > > > VHOST_USER_SEND_RARP but it is useless if the backend doesn't > > > > > > > support VHOST_USER_PROTOCOL_F_RARP. > > > > > > > > > > > > > > Don't report the error if vhost_net_notify_migration_done() > > > > > > > returns -ENOTSUP (from vhost_user_migration_done()) > > > > > > > > > > > > > > Update vhost_net-stub.c to return -ENOTSUP too. > > > > > > > > > > > > > > Signed-off-by: Laurent Vivier > > > > > > > --- > > > > > > > hw/net/vhost_net-stub.c | 2 +- > > > > > > > net/vhost-user.c        | 2 +- > > > > > > > 2 files changed, 2 insertions(+), 2 deletions(-) > > > > > > > > > > > > > > diff --git a/hw/net/vhost_net-stub.c b/hw/net/vhost_net-stub.c > > > > > > > index 72df6d757e4d..875cd6c2b9c8 100644 > > > > > > > --- a/hw/net/vhost_net-stub.c > > > > > > > +++ b/hw/net/vhost_net-stub.c > > > > > > > @@ -93,7 +93,7 @@ void > > > > > > > vhost_net_config_mask(VHostNetState > > > > > > *net, VirtIODevice *dev, bool mask) > > > > > > > > > > > > > > int vhost_net_notify_migration_done(struct vhost_net *net, char* mac_addr) > > > > > > > { > > > > > > > -    return -1; > > > > > > > +    return -ENOTSUP; > > > > > > > } > > > > > > > > > > > > > > VHostNetState *get_vhost_net(NetClientState *nc) > > > > > > > diff --git a/net/vhost-user.c b/net/vhost-user.c > > > > > > > index 12555518e838..636fff8a84a2 100644 > > > > > > > --- a/net/vhost-user.c > > > > > > > +++ b/net/vhost-user.c > > > > > > > @@ -146,7 +146,7 @@ static ssize_t > > > > > > vhost_user_receive(NetClientState *nc, const uint8_t *buf, > > > > > > > > > > > > > >          r = vhost_net_notify_migration_done(s->vhost_net, mac_addr); > > > > > > > > > > > > > > -        if ((r != 0) && (display_rarp_failure)) { > > > > > > > +        if ((r != 0) && (r != -ENOTSUP) && (display_rarp_failure)) { > > > > > > >              fprintf(stderr, > > > > > > >                      "Vhost user backend fails to broadcast fake RARP\n"); > > > > > > >              fflush(stderr); > > > > > > > -- > > > > > > > 2.47.1 > > > > > > > > > > > > > > > > > > > IIUC the message was there since the introduction about 10 years ago > > > > > > from commit 3e866365e1 ("vhost user: add rarp sending after live > > > > > > migration for legacy guest"). IIUC -ENOTSUP is returned when both F_RARP > > > > > > and F_GUEST_ANNOUNCE are not negotiated. > > > > > > > > > > > > That said, I honestly don't know what F_RARP or F_GUEST_ANNOUNCE is for, > > > > > > > > > > rarp is to have destination host broadcast a message with VM address > > > > > to update the network. Guest announce is when it will instead > > > > > ask the guest to do this. > > > > > > > > Okay, thanks for explaining to me. > > > > So if both features are not negotiated, no one is going to broadcast > > > > the message, right? > > > > > > > > Could that be a valid reason to print an error message in QEMU? > > > > > > > > To me it might be reasonable because the user might experience some > > > > network problems, but I'm not a network guy :-) > > > > > > I'm working on adding vhost-user to passt[1], and in this case we > > > don't need to broadcast any message. > > > > Okay, so please can you add that to the commit description and also > > explaining why you don't need that? > > > > > > > > So I don't implement VHOST_USER_SEND_RARP and I don't want the error > > > message to spoil my console. > > > > Fair enough, but at that point, if it's valid to have both feature not > > negotiated, IMHO is better to return 0 in vhost_user_migration_done(). > > Maybe adding also a comment to explain that in your scenario you don't > > need to do nothing (like if guest supports GUEST_ANNOUNCE). > > I agree. > > > > > > > > > -ENOTSUP is an error message for developer not for user. > > > > I was referring to the "Vhost user backend fails to broadcast fake RARP" > > error message we are skipping here. > > So in the end my real question at this point is: > > is it better to suppress the error message in QEMU (1) or implement an empty > VHOST_USER_SEND_RARP in Passt (2)? If it is valid to interpret "VHOST_USER_SEND_RARP" to mean the service is "capable of sending a RARP where appropriate" rather than "will always unconditionally send an RARP", then it would be reasonable for Passt to have an empty VHOST_USER_SEND_RARP impl. With 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 :|