From patchwork Thu Dec 22 06:04:27 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jason Wang X-Patchwork-Id: 13079438 X-Patchwork-Delegate: kuba@kernel.org 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 254B0C4332F for ; Thu, 22 Dec 2022 06:06:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235166AbiLVGGd (ORCPT ); Thu, 22 Dec 2022 01:06:33 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47916 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235084AbiLVGGM (ORCPT ); Thu, 22 Dec 2022 01:06:12 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E67F21CB1F for ; Wed, 21 Dec 2022 22:05:06 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1671689106; 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=iq4cHvbMQpVcmBqe5fyUmrngiKVykMmjcTZb1s9VM+M=; b=XisQSdIjVpfRAH0vj57/2guOh0iUndxVGfbCROpTSCm3ZGmGCql2UWF6NUsnEuPBFkb31f 1ktkaJgZRwEUyguCfmB4Y4zYFAiwz0dHK5+h/tklkkfOfZpaQUs1vG9veV7kY7LQa0ICdm WWWKt+B3uIszyhtd99gT5NH+nwbHVlI= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-456-A0Z1sWhoPamSGCtY6shq7w-1; Thu, 22 Dec 2022 01:05:02 -0500 X-MC-Unique: A0Z1sWhoPamSGCtY6shq7w-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 7C82F38149BC; Thu, 22 Dec 2022 06:05:02 +0000 (UTC) Received: from localhost.localdomain (ovpn-13-179.pek2.redhat.com [10.72.13.179]) by smtp.corp.redhat.com (Postfix) with ESMTP id CC707112132C; Thu, 22 Dec 2022 06:04:55 +0000 (UTC) From: Jason Wang To: mst@redhat.com, jasowang@redhat.com Cc: davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, maxime.coquelin@redhat.com, alvaro.karsz@solid-run.com, eperezma@redhat.com Subject: [RFC PATCH 4/4] virtio-net: sleep instead of busy waiting for cvq command Date: Thu, 22 Dec 2022 14:04:27 +0800 Message-Id: <20221222060427.21626-5-jasowang@redhat.com> In-Reply-To: <20221222060427.21626-1-jasowang@redhat.com> References: <20221222060427.21626-1-jasowang@redhat.com> MIME-Version: 1.0 Content-type: text/plain X-Scanned-By: MIMEDefang 3.1 on 10.11.54.3 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org X-Patchwork-State: RFC We used to busy waiting on the cvq command this tends to be problematic since: 1) CPU could wait for ever on a buggy/malicous device 2) There's no wait to terminate the process that triggers the cvq command So this patch switch to use sleep with a timeout (1s) instead of busy polling for the cvq command forever. This gives the scheduler a breath and can let the process can respond to a signal. Signed-off-by: Jason Wang --- drivers/net/virtio_net.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 8225496ccb1e..69173049371f 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -405,6 +405,7 @@ static void disable_rx_mode_work(struct virtnet_info *vi) vi->rx_mode_work_enabled = false; spin_unlock_bh(&vi->rx_mode_lock); + virtqueue_wake_up(vi->cvq); flush_work(&vi->rx_mode_work); } @@ -1497,6 +1498,11 @@ static bool try_fill_recv(struct virtnet_info *vi, struct receive_queue *rq, return !oom; } +static void virtnet_cvq_done(struct virtqueue *cvq) +{ + virtqueue_wake_up(cvq); +} + static void skb_recv_done(struct virtqueue *rvq) { struct virtnet_info *vi = rvq->vdev->priv; @@ -2024,12 +2030,7 @@ static bool virtnet_send_command(struct virtnet_info *vi, u8 class, u8 cmd, if (unlikely(!virtqueue_kick(vi->cvq))) return vi->ctrl->status == VIRTIO_NET_OK; - /* Spin for a response, the kick causes an ioport write, trapping - * into the hypervisor, so the request should be handled immediately. - */ - while (!virtqueue_get_buf(vi->cvq, &tmp) && - !virtqueue_is_broken(vi->cvq)) - cpu_relax(); + virtqueue_wait_for_used(vi->cvq, &tmp); return vi->ctrl->status == VIRTIO_NET_OK; } @@ -3524,7 +3525,7 @@ static int virtnet_find_vqs(struct virtnet_info *vi) /* Parameters for control virtqueue, if any */ if (vi->has_cvq) { - callbacks[total_vqs - 1] = NULL; + callbacks[total_vqs - 1] = virtnet_cvq_done; names[total_vqs - 1] = "control"; }