From patchwork Fri May 14 16:02:07 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Balazs Nemeth X-Patchwork-Id: 93270 X-Patchwork-Delegate: maxime.coquelin@redhat.com Return-Path: X-Original-To: patchwork@inbox.dpdk.org Delivered-To: patchwork@inbox.dpdk.org Received: from mails.dpdk.org (mails.dpdk.org [217.70.189.124]) by inbox.dpdk.org (Postfix) with ESMTP id 3B828A0A0C; Fri, 14 May 2021 18:02:26 +0200 (CEST) Received: from [217.70.189.124] (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id AB61B40042; Fri, 14 May 2021 18:02:25 +0200 (CEST) Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [216.205.24.124]) by mails.dpdk.org (Postfix) with ESMTP id C556140041 for ; Fri, 14 May 2021 18:02:23 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1621008142; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=xYshReLnX/ccKaFeOX5hxvTgbbmr3ZnUdArdfSEwzA4=; b=XsEDBP8MyZHnPSLKB7xfvmnqw6fRHz+0DbAZ8C2H6zItiZAkXJQMMHmSISfO3Mq4l/qjyQ eGahJJRvi5yrTIuPyUZE7bVlHRSkh9tzXuweOEwpgXYtGWgY6bm2wYTxoPIxGmxOgbmCAT jXBS+NVeXJa7+iZhZ7ldLyiKijd9Oqc= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-63-AuZ21RSAMsy5X8-5RuU5sg-1; Fri, 14 May 2021 12:02:20 -0400 X-MC-Unique: AuZ21RSAMsy5X8-5RuU5sg-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 754AE80B70A; Fri, 14 May 2021 16:02:19 +0000 (UTC) Received: from bnemeth.users.ipa.redhat.com (ovpn-113-158.ams2.redhat.com [10.36.113.158]) by smtp.corp.redhat.com (Postfix) with ESMTP id 538D55D9D7; Fri, 14 May 2021 16:02:18 +0000 (UTC) From: Balazs Nemeth To: bnemeth@redhat.com, dev@dpdk.org, weix.ling@intel.com Date: Fri, 14 May 2021 18:02:07 +0200 Message-Id: <83fa6253725a7bc69bccb7897f380422354a2898.1621008025.git.bnemeth@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=bnemeth@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Subject: [dpdk-dev] [PATCH] vhost: fix invalid use of stored last used index X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" The optimization introduced by commit d18db8049c7c ("vhost: read last used index once") didn't account for the fact that vhost_flush_enqueue_shadow_packed increments the last_used_idx. For this reason, store last_used_idx after the potential call to vhost_flush_enqueue_shadow_packed. Fixes: d18db8049c7c ("vhost: read last used index once") Signed-off-by: Balazs Nemeth Reviewed-by: David Marchand Reviewed-by: Maxime Coquelin Tested-by: Wei Ling --- lib/vhost/virtio_net.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/lib/vhost/virtio_net.c b/lib/vhost/virtio_net.c index abfd67d38c..8da8a86a10 100644 --- a/lib/vhost/virtio_net.c +++ b/lib/vhost/virtio_net.c @@ -218,14 +218,17 @@ vhost_flush_enqueue_batch_packed(struct virtio_net *dev, { uint16_t i; uint16_t flags; - uint16_t last_used_idx = vq->last_used_idx; - struct vring_packed_desc *desc_base = &vq->desc_packed[last_used_idx]; + uint16_t last_used_idx; + struct vring_packed_desc *desc_base; if (vq->shadow_used_idx) { do_data_copy_enqueue(dev, vq); vhost_flush_enqueue_shadow_packed(dev, vq); } + last_used_idx = vq->last_used_idx; + desc_base = &vq->desc_packed[last_used_idx]; + flags = PACKED_DESC_ENQUEUE_USED_FLAG(vq->used_wrap_counter); vhost_for_each_try_unroll(i, 0, PACKED_BATCH_SIZE) {