From patchwork Tue Jul 11 15:52:28 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hanna Czenczek X-Patchwork-Id: 13309009 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 1635AEB64DC for ; Tue, 11 Jul 2023 15:53:27 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qJFfm-0000kn-T4; Tue, 11 Jul 2023 11:53:07 -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 1qJFfl-0000ix-Hh for qemu-devel@nongnu.org; Tue, 11 Jul 2023 11:53:05 -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 1qJFfk-0001kF-4N for qemu-devel@nongnu.org; Tue, 11 Jul 2023 11:53:05 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1689090783; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=yFCSSgRaAIPZO+XMfGJU2kcNt0glc0z3zOUfu/gEpeI=; b=gnT5jkM0hRfM+SSgShCIdSQMoXTghEgqZM3YyPUPii2j4FdSCZPwxP+UGwhtXVp3mIyaB2 HwKdCFxsjJ/SznXbFn7CWUl1PXTWxM5l4SDiF+gIPm+O6HX6HCPrj2hGUZnravrvxuNGie dk+tb2m2WjCRuq3P+p3UCF1I0nb1+CU= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-562-YBBEmGLCO3-KZJxRMbuXcA-1; Tue, 11 Jul 2023 11:52:59 -0400 X-MC-Unique: YBBEmGLCO3-KZJxRMbuXcA-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id BF5658FBA20 for ; Tue, 11 Jul 2023 15:52:58 +0000 (UTC) Received: from localhost (unknown [10.39.192.229]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 8534640C6CD1; Tue, 11 Jul 2023 13:27:44 +0000 (UTC) From: Hanna Czenczek To: qemu-devel@nongnu.org Cc: Hanna Czenczek , "Michael S . Tsirkin" , Stefan Hajnoczi , =?utf-8?q?Eugenio_P=C3=A9rez?= , German Maglione Subject: [PATCH 6/6] vhost-user: Have reset_status fall back to reset Date: Tue, 11 Jul 2023 17:52:28 +0200 Message-ID: <20230711155230.64277-7-hreitz@redhat.com> In-Reply-To: <20230711155230.64277-1-hreitz@redhat.com> References: <20230711155230.64277-1-hreitz@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.2 Received-SPF: pass client-ip=170.10.133.124; envelope-from=hreitz@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_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 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 The only user of vhost_user_reset_status() is vhost_dev_stop(), which only uses it as a fall-back to stop the back-end if it does not support SUSPEND. However, vhost-user's implementation is a no-op unless the back-end supports SET_STATUS. vhost-vdpa's implementation instead just calls vhost_vdpa_reset_device(), implying that it's OK to fully reset the device if SET_STATUS is not supported. To be fair, vhost_vdpa_reset_device() does nothing but to set the status to zero. However, that may well be because vhost-vdpa has no method besides this to reset a device. In contrast, vhost-user has RESET_DEVICE and a RESET_OWNER, which can be used instead. While it is not entirely clear from documentation or git logs, from discussions and the order of vhost-user protocol features, it appears to me as if RESET_OWNER originally had no real meaning for vhost-user, and was thus used to signal a device reset to the back-end. Then, RESET_DEVICE was introduced, to have a well-defined dedicated reset command. Finally, vhost-user received full STATUS support, including SET_STATUS, so setting the device status to 0 is now the preferred way of resetting a device. Still, RESET_DEVICE and RESET_OWNER should remain valid as fall-backs. Therefore, have vhost_user_reset_status() fall back to vhost_user_reset_device() if the back-end has no STATUS support. Signed-off-by: Hanna Czenczek --- hw/virtio/vhost-user.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c index 4507de5a92..53a881ec2a 100644 --- a/hw/virtio/vhost-user.c +++ b/hw/virtio/vhost-user.c @@ -2833,6 +2833,8 @@ static void vhost_user_reset_status(struct vhost_dev *dev) if (virtio_has_feature(dev->protocol_features, VHOST_USER_PROTOCOL_F_STATUS)) { vhost_user_set_status(dev, 0); + } else { + vhost_user_reset_device(dev); } }