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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B981DC433F5 for ; Thu, 18 Nov 2021 05:07:58 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 3389461AA9 for ; Thu, 18 Nov 2021 05:07:58 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 3389461AA9 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=nongnu.org Received: from localhost ([::1]:52630 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mnZeO-0000rK-Pv for qemu-devel@archiver.kernel.org; Thu, 18 Nov 2021 00:07:56 -0500 Received: from eggs.gnu.org ([209.51.188.92]:39938) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mnZdD-00005X-56 for qemu-devel@nongnu.org; Thu, 18 Nov 2021 00:06:43 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:48845) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mnZdA-0000n1-EA for qemu-devel@nongnu.org; Thu, 18 Nov 2021 00:06:42 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1637211999; 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=qFPT+jUFkIMM29qE+RfkFvvBhlibEHHmcxfUlXjTt8s=; b=HjoJcaJBJZMOG9DCBaj/iI0BtkgaAFxlktYcPVT42ghFgV1Ct/YWZEiER+I6msF+6/z5vB IeflaFI95j1erFlED6GHaGgCoNea4r+4nDXxBt07B5ulfpiqtuFATouC7A8mDt0heoqu4j R565+wUeAkjJ+S6Y5Jit8slP0yazUcU= Received: from mail-lf1-f72.google.com (mail-lf1-f72.google.com [209.85.167.72]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-536-__2YPtl1N5ex-6cdp7th9Q-1; Thu, 18 Nov 2021 00:06:38 -0500 X-MC-Unique: __2YPtl1N5ex-6cdp7th9Q-1 Received: by mail-lf1-f72.google.com with SMTP id c14-20020a056512104e00b004036d17f91bso3136800lfb.17 for ; Wed, 17 Nov 2021 21:06:38 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=qFPT+jUFkIMM29qE+RfkFvvBhlibEHHmcxfUlXjTt8s=; b=CcDBu/00PS7rfiOERTuxXBGHgBHf4wHlwqjRMkAUegVXHCfb//jsAMW0FU7tSKgoIf q8+lT6RUx9+hEJhk7W6ypE12CCizEXJw3Muc53Zr5Y7u1rj7lBPjHohdZ4P2E8kb3Guz VihviOgKd6/XZgwzovXdYPeRDt76dUq+nDAV/cl8cZJj89/BLAMTaRqX0FQWTaAbGK/r UblnvBBUFmJr9xw5jnckQ2smauQW1DadctmhqqH0y4sOfh2J2qmGEhtoBVDkOH0m6BdY kXy5mROfT5JhXmDjNPfrrp1chFGqRieFBOtBbQp5KqJum+8ahvwEK4ghjLQVb1Bo6u0r Dsmg== X-Gm-Message-State: AOAM533s4ewQ4hfb1uzatoUk2NgGXC+PrELYI9JkFoqtV3s+icVpZk2O 8XT6B9WEELySdKah/PS6FhK4pdomDN/ekOBEEu5UB2oD/S6yzhgkm4gFdwl4vFBoAhf/usO7Pgj RbahP/+VHJAn8Kp/NHjk4z4LzXT/96NA= X-Received: by 2002:a05:6512:3990:: with SMTP id j16mr20646118lfu.199.1637211996695; Wed, 17 Nov 2021 21:06:36 -0800 (PST) X-Google-Smtp-Source: ABdhPJyPqTpqshUUg7XHA5tOxI5yi9P/RIXNk25sZXm4xXgNwQS+sqlvo+DK6jOhGTIwr1zu/nzXreX07nn9DcKfns4= X-Received: by 2002:a05:6512:3990:: with SMTP id j16mr20646091lfu.199.1637211996445; Wed, 17 Nov 2021 21:06:36 -0800 (PST) MIME-Version: 1.0 References: <20211117192851.65529-1-eperezma@redhat.com> <20211117192851.65529-3-eperezma@redhat.com> In-Reply-To: <20211117192851.65529-3-eperezma@redhat.com> From: Jason Wang Date: Thu, 18 Nov 2021 13:06:25 +0800 Message-ID: Subject: Re: [PATCH 2/3] virtio-net: Only enable userland vq if using tap backend To: =?UTF-8?Q?Eugenio_P=C3=A9rez?= Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=jasowang@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Received-SPF: pass client-ip=170.10.133.124; envelope-from=jasowang@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -34 X-Spam_score: -3.5 X-Spam_bar: --- X-Spam_report: (-3.5 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.701, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H2=-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: , Cc: Laurent Vivier , qemu-devel , Cindy Lu , "Michael S . Tsirkin" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Thu, Nov 18, 2021 at 3:29 AM Eugenio P=C3=A9rez wr= ote: > > Qemu falls back on userland handlers even if vhost-user and vhost-vdpa > cases. These assumes a tap device can handle the packets. > > If a vdpa device fail to start, it can trigger a sigsegv because of > that. Do not resort on them unless actually possible. It would be better to show the calltrace here then we can see the root caus= e. > > Signed-off-by: Eugenio P=C3=A9rez > --- > include/hw/virtio/virtio.h | 2 ++ > hw/net/virtio-net.c | 4 ++++ > hw/virtio/virtio.c | 21 +++++++++++++-------- > 3 files changed, 19 insertions(+), 8 deletions(-) > > diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h > index 8bab9cfb75..1712ba0b4c 100644 > --- a/include/hw/virtio/virtio.h > +++ b/include/hw/virtio/virtio.h > @@ -105,6 +105,8 @@ struct VirtIODevice > VMChangeStateEntry *vmstate; > char *bus_name; > uint8_t device_endian; > + /* backend does not support userspace handler */ > + bool disable_ioeventfd_handler; > bool use_guest_notifier_mask; > AddressSpace *dma_as; > QLIST_HEAD(, VirtQueue) *vector_queues; > diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c > index 004acf858f..8c5c4e5a9d 100644 > --- a/hw/net/virtio-net.c > +++ b/hw/net/virtio-net.c > @@ -3501,6 +3501,10 @@ static void virtio_net_device_realize(DeviceState = *dev, Error **errp) > nc =3D qemu_get_queue(n->nic); > nc->rxfilter_notify_enabled =3D 1; > > + if (!nc->peer || nc->peer->info->type !=3D NET_CLIENT_DRIVER_TAP) { > + /* Only tap can use userspace networking */ > + vdev->disable_ioeventfd_handler =3D true; > + } > if (nc->peer && nc->peer->info->type =3D=3D NET_CLIENT_DRIVER_VHOST_= VDPA) { > struct virtio_net_config netcfg =3D {}; > memcpy(&netcfg.mac, &n->nic_conf.macaddr, ETH_ALEN); > diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c > index ea7c079fb0..1e04db6650 100644 > --- a/hw/virtio/virtio.c > +++ b/hw/virtio/virtio.c > @@ -3734,17 +3734,22 @@ static int virtio_device_start_ioeventfd_impl(Vir= tIODevice *vdev) > err =3D r; > goto assign_error; > } > - event_notifier_set_handler(&vq->host_notifier, > - virtio_queue_host_notifier_read); > + > + if (!vdev->disable_ioeventfd_handler) { > + event_notifier_set_handler(&vq->host_notifier, > + virtio_queue_host_notifier_read); This is just about not responding to ioeventfd. Does this happen only when ioeventfd is enabled? If yes, we probably need a consistent way to deal with that. Will having a dummy receiver be more simpler? Thanks > + } > } > > - for (n =3D 0; n < VIRTIO_QUEUE_MAX; n++) { > - /* Kick right away to begin processing requests already in vring= */ > - VirtQueue *vq =3D &vdev->vq[n]; > - if (!vq->vring.num) { > - continue; > + if (!vdev->disable_ioeventfd_handler) { > + for (n =3D 0; n < VIRTIO_QUEUE_MAX; n++) { > + /* Kick right away to begin processing requests already in v= ring */ > + VirtQueue *vq =3D &vdev->vq[n]; > + if (!vq->vring.num) { > + continue; > + } > + event_notifier_set(&vq->host_notifier); > } > - event_notifier_set(&vq->host_notifier); > } > memory_region_transaction_commit(); > return 0; > -- > 2.27.0 >