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 9243BCCD194 for ; Thu, 16 Oct 2025 10:39:58 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1v9LNv-00013u-P4; Thu, 16 Oct 2025 06:39:03 -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 1v9LNs-00012r-JR for qemu-devel@nongnu.org; Thu, 16 Oct 2025 06:39:00 -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 1v9LNn-0002aK-8x for qemu-devel@nongnu.org; Thu, 16 Oct 2025 06:38:58 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1760611131; 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=N874HbHUUU7TnJyKEhqUOv79wOFms/6Fki3m6zA07mY=; b=A7aKgCeuKrWUQR/KbTt8fSBYFvpmZA06xMvM1+DCXUj2EGmpmaszMCUjhFvSBKwjBSTakU sccrViSnM0ZZ24vdKuSPKPBvWoaXGl3X/7WclqHKrXzjm5vEjgZPsWfG1JmHrr9GkWMWwG /lXH5gx+yzT5gHqjn9TjI8Wb+9B8H14= Received: from mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-626-dxUhf6ZLNsC8qucGANvAog-1; Thu, 16 Oct 2025 06:38:48 -0400 X-MC-Unique: dxUhf6ZLNsC8qucGANvAog-1 X-Mimecast-MFC-AGG-ID: dxUhf6ZLNsC8qucGANvAog_1760611127 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-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 7EA851800637; Thu, 16 Oct 2025 10:38:46 +0000 (UTC) Received: from blackfin.pond.sub.org (unknown [10.45.242.19]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id B98A9300019F; Thu, 16 Oct 2025 10:38:45 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id 4E9E021E6A27; Thu, 16 Oct 2025 12:38:43 +0200 (CEST) From: Markus Armbruster To: Vladimir Sementsov-Ogievskiy Cc: jasowang@redhat.com, devel@lists.libvirt.org, eblake@redhat.com, farosas@suse.de, lvivier@redhat.com, pbonzini@redhat.com, qemu-devel@nongnu.org Subject: Re: [PATCH v4] qapi: net: deprecate vhostforce option In-Reply-To: <239dc7b4-de5a-4e47-912d-543347d1f90b@yandex-team.ru> (Vladimir Sementsov-Ogievskiy's message of "Thu, 16 Oct 2025 12:03:33 +0300") References: <20251015143941.1109499-1-vsementsov@yandex-team.ru> <87bjm7teou.fsf@pond.sub.org> <239dc7b4-de5a-4e47-912d-543347d1f90b@yandex-team.ru> Date: Thu, 16 Oct 2025 12:38:43 +0200 Message-ID: <87frbjrv0s.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 10.30.177.4 Received-SPF: pass client-ip=170.10.133.124; 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=-0.001, 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_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, SPF_HELO_PASS=-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 Vladimir Sementsov-Ogievskiy writes: > On 16.10.25 11:48, Markus Armbruster wrote: >> Vladimir Sementsov-Ogievskiy writes: >> >>> This option for tap and vhost-user netdevs doesn't make sense >>> since long ago (10 years!), starting from commits: >>> >>> 1e7398a140f7a6 ("vhost: enable vhost without without MSI-X") >>> 24f938a682d934 ("vhost user:support vhost user nic for non msi guests") >>> >>> Prior these commits, to enable kernel vhost-net, or vhost-user-net for >>> some specific kind of guests (that don't have MSI-X support), you should >>> have set vhostforce=on. >>> >>> Now guest type doesn't matter, all guests are equal for these >>> options logic. >>> >>> For tap the current logic is: >>> vhost=on / vhost=off : vhostforce ignored, doesn't make sense >>> vhost unset : vhostforce counts, enabling vhost >>> >>> So you may enable vhost for tap several ways: >>> - vhost=on >>> - vhostforce=on >>> - vhost=on + vhostforce=on >>> - and even vhost=on + vhostforce=off >>> >>> - they are all equal. >>> >>> For vhost-user we simply ignore the vhostforce option at all in the >>> code. >>> >>> Let's finally deprecate the extra options. >>> >>> Also, fix @vhostforce documentation everywhere to show the real picture, >>> and update vhost-user test to not use deprecated option. >>> >>> Signed-off-by: Vladimir Sementsov-Ogievskiy [...] >>> diff --git a/qemu-options.hx b/qemu-options.hx >>> index 0223ceffeb..35a70096e8 100644 >>> --- a/qemu-options.hx >>> +++ b/qemu-options.hx >>> @@ -2882,7 +2882,7 @@ DEF("netdev", HAS_ARG, QEMU_OPTION_netdev, >>> #else >>> "-netdev tap,id=str[,fd=h][,fds=x:y:...:z][,ifname=name][,script=file][,downscript=dfile]\n" >>> " [,br=bridge][,helper=helper][,sndbuf=nbytes][,vnet_hdr=on|off][,vhost=on|off]\n" >>> - " [,vhostfd=h][,vhostfds=x:y:...:z][,vhostforce=on|off][,queues=n]\n" >>> + " [,vhostfd=h][,vhostfds=x:y:...:z][,queues=n]\n" >>> " [,poll-us=n]\n" >>> " configure a host TAP network backend with ID 'str'\n" >>> " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" >>> @@ -2898,9 +2898,7 @@ DEF("netdev", HAS_ARG, QEMU_OPTION_netdev, >>> " default is disabled 'sndbuf=0' to enable flow control set 'sndbuf=1048576')\n" >>> " use vnet_hdr=off to avoid enabling the IFF_VNET_HDR tap flag\n" >>> " use vnet_hdr=on to make the lack of IFF_VNET_HDR support an error condition\n" >>> - " use vhost=on to enable experimental in kernel accelerator\n" >>> - " (only has effect for virtio guests which use MSIX)\n" >>> - " use vhostforce=on to force vhost on for non-MSIX virtio guests\n" >>> + " use vhost=on to enable in kernel accelerator\n" >> >> So the kernel's accelerator is no longer experimental? > > Reading this, I heard the first time that vhost-net is experimental. > It's about 15 years old, and used in production. I think "experimental" > is inappropriate word here) Just double-checking :) The text you adjust is from 2010 (commit 82b0d80ef6a). I guess the accelerator was experimental back then. Mention the correction in the commit message? [...]