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 BAE5EC021A4 for ; Fri, 14 Feb 2025 14:26:19 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1tiwXX-0005Ef-8u; Fri, 14 Feb 2025 09:19:35 -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 1tiwXP-00054i-8G for qemu-devel@nongnu.org; Fri, 14 Feb 2025 09:19:29 -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 1tiwXM-000576-SQ for qemu-devel@nongnu.org; Fri, 14 Feb 2025 09:19:26 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1739542763; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=akTXZD9bp3KcmxxqCVDuMhT0zCgv/f6BVQpEIXtj/Xc=; b=RuX+Mfl5iUHtTr/BIa693nhBGMdOMNo4ct/4iqOPM4hk++lWulBNNyF/mLEeCo/6JjL57y hH5tN1gjUldZEtWn1YHOGXYWTE0lTrzcPKN9V7GI982RABlteEAwgC1TsVAUe8db5hLO+V GXFUXs7GWEd9NAPpbZM0GFh2/RWSdUQ= Received: from mx-prod-mc-05.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-614-7snTw_JTOTuBti83E2DdHQ-1; Fri, 14 Feb 2025 09:19:22 -0500 X-MC-Unique: 7snTw_JTOTuBti83E2DdHQ-1 X-Mimecast-MFC-AGG-ID: 7snTw_JTOTuBti83E2DdHQ_1739542761 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-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 5362A190FF83 for ; Fri, 14 Feb 2025 14:19:21 +0000 (UTC) Received: from redhat.com (unknown [10.42.28.144]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id EA2BF300018D; Fri, 14 Feb 2025 14:19:16 +0000 (UTC) Date: Fri, 14 Feb 2025 14:19:13 +0000 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Laurent Vivier , Markus Armbruster , qemu-devel@nongnu.org, =?utf-8?Q?Marc-Andr=C3=A9?= Lureau , Eric Blake , Jason Wang , Paolo Bonzini , Laine Stump , Stefano Brivio , "Michael S. Tsirkin" Subject: Re: [PATCH] net: vhost-user: add QAPI events to report connection state Message-ID: References: <20250214072629.1033314-1-lvivier@redhat.com> <871pw07sdy.fsf@pond.sub.org> <2c5358eb-1abe-4fce-8b28-7935c71f1cff@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: 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: -37 X-Spam_score: -3.8 X-Spam_bar: --- X-Spam_report: (-3.8 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1.732, 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, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_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 Fri, Feb 14, 2025 at 01:59:20PM +0000, Daniel P. Berrangé wrote: > On Fri, Feb 14, 2025 at 11:18:55AM +0100, Laurent Vivier wrote: > > On 14/02/2025 11:06, Markus Armbruster wrote: > > > Laurent Vivier writes: > > > > > > > The netdev reports NETDEV_VHOST_USER_CONNECTED event when > > > > the chardev is connected, and NETDEV_VHOST_USER_DISCONNECTED > > > > when it is disconnected. > > > > > > > > The NETDEV_VHOST_USER_CONNECTED event includes the ChardevInfo > > > > (label, filename and frontend_open). > > > > > > > > This allows a system manager like libvirt to detect when the server > > > > fails. > > > > > > > > For instance with passt: > > > > > > > > { 'execute': 'qmp_capabilities' } > > > > { "return": { } } > > > > > > > > [killing passt here] > > > > > > > > { "timestamp": { "seconds": 1739517243, "microseconds": 115081 }, > > > > "event": "NETDEV_VHOST_USER_DISCONNECTED", > > > > "data": { "netdev-id": "netdev0" } } > > > > > > > > [automatic reconnection with reconnect-ms] > > > > > > > > { "timestamp": { "seconds": 1739517290, "microseconds": 343777 }, > > > > "event": "NETDEV_VHOST_USER_CONNECTED", > > > > "data": { "netdev-id": "netdev0", > > > > "info": { "frontend-open": true, > > > > "filename": "unix:", > > > > "label": "chr0" } } } > > > > > > > > Signed-off-by: Laurent Vivier > > > > > > Standard question for events: if a management application misses an > > > event, say because it restarts and reconnects, is there a way to obtain > > > the missed information with a query command? > > > > > > > query-chardev could help but it doesn't provide the netdev id. > > It doesn't have to IMHO. The application that created the NIC should know > what ID it assigned to both the netdev and chardev, and thus should be > able to use query-chardev to identify the chardev it previously > associated with the netdev. That said I kind of wonder whether we should be adding events against the chardev directly, instead of against the netdev use of chardev. ie CHARDEV_OPENED / CHARDEV_CLOSED events. For OPENED it is trivially equivalent. For CLOSED it is a little trickier, since this patch does delayed event dispatch from a bottom-half. If the chardev code was able to emit this event from a bottom half itself, that could be OK though. 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 :|