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 lists1p.gnu.org (lists1p.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 1006EF94CA7 for ; Tue, 21 Apr 2026 21:13:43 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists1p.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1wFIOu-000845-2Y; Tue, 21 Apr 2026 17:12:56 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists1p.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1wFIOp-00083h-Jp for qemu-devel@nongnu.org; Tue, 21 Apr 2026 17:12:51 -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 1wFIOo-0007bq-97 for qemu-devel@nongnu.org; Tue, 21 Apr 2026 17:12:51 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1776805968; 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=M4iY6tDg2VjYozxVRxZlX/JEU//pNZ4zTJzziDPcsEU=; b=PPwGMJmtkRvs/zgbgFke1RNEKIQfiIQ3udbC2ZYGCu67YG5NlDxYckdBvu0Hqth/Ojs6VV pDTRNLMIVcYsR6NSNMBue2MiWwXpO1XkcTGUs48oSNsRGc9sZM8ZOpj8OMUMDYAi8vmxzZ uTNDyOuFRB+gnnOIGPn58OYsR6FzMbo= 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-550-1Y58pOq7O6GItg9LnQN0dA-1; Tue, 21 Apr 2026 17:12:44 -0400 X-MC-Unique: 1Y58pOq7O6GItg9LnQN0dA-1 X-Mimecast-MFC-AGG-ID: 1Y58pOq7O6GItg9LnQN0dA_1776805963 Received: from mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.93]) (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 D5583195609E; Tue, 21 Apr 2026 21:12:42 +0000 (UTC) Received: from localhost (unknown [10.44.32.90]) by mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 883561800357; Tue, 21 Apr 2026 21:12:40 +0000 (UTC) Date: Tue, 21 Apr 2026 17:12:37 -0400 From: Stefan Hajnoczi To: Jorge Moreira Cc: Stefano Garzarella , hreitz@redhat.com, gmaglione@redhat.com, "Michael S . Tsirkin" , Hanna Czenczek , Pierrick Bouvier , qemu-devel@nongnu.org Subject: Re: [PATCH] vhost-user.rst: Explicitly allow front-end to write to kick FDs Message-ID: <20260421211237.GC466778@fedora> References: <20260411021205.3592118-1-jemoreira@google.com> <20260420181818.GC405461@fedora> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="+ty7g7TBfkBFfUng" Content-Disposition: inline In-Reply-To: X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.93 Received-SPF: pass client-ip=170.10.133.124; envelope-from=stefanha@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, 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: qemu development 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 --+ty7g7TBfkBFfUng Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Mon, Apr 20, 2026 at 05:48:13PM -0700, Jorge Moreira wrote: > While starting the vrings on SET_VRING_KICK could solve the state > machine issue, it still won't notify the back-end that buffers are > ready (the driver won't do this). Non-polling back-ends depend on this > kick, especially for queues where data flows only from the driver to > the back-end. Most implementations likely attempt to read from the > queue only after receiving the kick. This is an interesting question to clarify in the spec. Stefan --+ty7g7TBfkBFfUng Content-Type: application/pgp-signature; name=signature.asc -----BEGIN PGP SIGNATURE----- iQEzBAEBCgAdFiEEhpWov9P5fNqsNXdanKSrs4Grc8gFAmnn6EUACgkQnKSrs4Gr c8hrCwgAvIY6BkFu3IzSsD+Ui67HoqflSS2rca7UWRo4KuI2slrRgypklDNiCBuk IhK3STGWUaaE3gKQViGaArjDRXf9rZbzA6NBJcsA0JKGIk3TsYICYJTZ6i4o6NQu BMIC1RNh0R/AcdfTJY8iKgyg7KgwLtuzKI+ztkk4grZgLhcFkHue4FJT+Mh/VTPy xRQSSdZOp/+A9j/7skMjV9yWHmCHyU6HIOdYS71WUdv0smufJBYEcd6TuxLHofZJ caeJbmBzrJJWjzoMNKzWf5IBlAsNCSv48oDRpAvR7FsFwrDz6xkssjTiH+SHUdAe Q/b1HWtrm6ULJBOyb6QOveQInJOy2Q== =kgsf -----END PGP SIGNATURE----- --+ty7g7TBfkBFfUng--